Pacific Flyway Shorebird Migration Program: Spring Western … · Spring Western Sandpiper migration, Northern Baja California, Mexico to Alaska Final Report 2004 NILS WARNOCK1, MARY

Pacific Flyway Shorebird Migration Program: Spring Western Sandpiper migration,

Northern Baja California, Mexico to Alaska Final Report 2004

NILS WARNOCK1, MARY ANNE BISHOP2, JOHN Y. TAKEKAWA3, and TONY D. WILLIAMS4

1 PRBO Conservation Science, 4990 Shoreline Highway, Stinson Beach, CA 94970 2 Prince William Sound Science Center, PO Box 705, Cordova, AK 99574 3 U. S. Geological Survey, Western Ecological Research Center, San Francisco Bay Estuary Field Station, 505 Azuar Drive, Vallejo, CA 94592 4 Center for Wildlife Ecology, Department of Biological Sciences, Simon Fraser University, Burnaby, BC V5A 1S6, Canada Suggested citation: Warnock, N., M. A. Bishop, J. Y. Takekawa, and T. D. Williams. 2004. Pacific Flyway Shorebird Migration Program: Spring Western Sandpiper migration, Northern Baja California, Mexico to Alaska - Final Report 2004. Unpubl. Prog. Rep., PRBO Conservation Science, Stinson Beach, CA; Prince William Sound Science Center, Cordova, AK; U.S. Geological Survey, Vallejo, CA; and Simon Fraser University, Burnaby, BC.

Data reported herein are not for citation or publication without permission from the authors

EXECUTIVE SUMMARY

In Spring 2004, the Pacific Flyway Shorebird Migration Program organized and coordinated a team of 15 partners to examine the spring migration ecology of shorebirds at 18 sites spanning 3 countries along the Pacific Flyway from northern Baja, California, Mexico, California, Oregon, Washington, British Columbia, to western Alaska.

From March-May 2004, we successfully radio-marked 47 Western Sandpipers at Punta

Banda, Baja California, Mexico and 41 Western Sandpipers at San Francisco Bay, California. Subsequently, we relocated 57% of the Punta Banda and 61% of the San Francisco radiomarked birds at least once past their banding site.

We documented 74 locations of Western Sandpipers at 9 sites past their banding sites.

We relocated significantly more adult birds (83%) than first year birds (42%). We found no significant differences in relocations between male and female Western Sandpipers or in relocations at Punta Banda vs. San Francisco.

The mean length-of-stay for Western Sandpipers banded at Punta Banda (x̄= 16.6 ± 6.6 days, n = 47) and San Francisco (x̄= 17.0 ± 5.0 days, n = 41) did not differ significantly by age, sex, body mass, or banding location (controlling for capture date).

Copper River Delta, AK had the highest recovery rates with 38% of the birds detected

(51% from San Francisco and 26% from Punta Banda), followed by San Francisco Bay (21%), Pt. Mugu, CA (13%), Willapa Bay, WA (9%), Grays Harbor, WA (9%), and Elkhorn Slough, CA (9%).

Western Sandpipers' mean length-of-stay past the banding site ranged from 1.0 – 7.9 days. Longest stopovers were at Pt. Mugu (x̄ = 7.9 ± 5.4 days, n = 6) and San Francisco Bay (x̄ = 7.8 ± 7.1 days, n = 10).

Travel rates to the Copper River Delta were 311 ± 162 km d-1 (n = 12 birds) for Punta Banda and 887 ± 471 km d-1 (n = 21 birds) for San Francisco.

Mean triglyceride levels of Western Sandpipers increased from Mexico to the Copper River Delta. Lowest levels were observed at San Francisco Bay in the winter and Punta Banda in the early spring

Triglyceride levels were significantly related to length of stay of Western Sandpipers banded at San Francisco, but not at Punta Banda.

Bivalves and polychaetes dominated invertebrate samples, with the highest biomass

at Elkhorn Slough and San Francisco Bay. Preliminary inspection suggests a positive relationship may exist between length of stay and invertebrate biomass at different stopover sites.

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Once again, our project was showcased on the list serve and web site of the Sister

Shorebird Schools, an environmental education program sponsored by the U. S. Fish and Wildlife Service.

Over the past decade, we have led a network of cooperators to examine the

importance of coastal habitats used by shorebirds during the spring migration. These studies have revealed the complexity of migration strategies used within and among shorebird species along the Pacific Flyway and highlighted the importance of how such information may improve the conservation and management of these populations.

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INTRODUCTION As a group, shorebirds of North America have experienced declines in populations over the last several decades (Morrison 2001, Morrison and Hicklin 2001). Reasons for the declines are unknown but habitat modification has figured prominently as a potential cause. As increasing amounts of habitats have been altered and destroyed, it is becoming critical for wildlife managers to understand how birds use habitats throughout their range. At present, we have little information on how individual birds use migration areas, especially during migration periods. Understanding the stopover ecology of shorebirds is also a critical component of understanding the complete life cycle of these birds (Skagen 1997). Conservation of migratory stopover sites relies not only on knowing how and when different areas of their migration landscape are used, but also on knowing what influences the use of and time spent at different areas of that landscape (Warnock and Bishop 1998). Research on shorebird migration is identified as a priority in the United States Shorebird Conservation Plan (Brown et al. 2001). For the past 14 years, the Pacific Flyway Shorebird Migration Program has worked to elucidate the migration ecology of shorebirds along the Pacific Flyway (Table 1). Table 1. Previous studies conducted by the Pacific Flyway Shorebird Migration Program. SF = San Francisco Bay, CA; YKD = Yukon Kuskokwim Delta, AK. Year Season Species Band Sites Search Regions References 19921 Spring Western

Sandpiper San Francisco, CA, Boundary Bay, BC, and Stikine River, AK

Coastal sites from SF to the YKD

Iverson et al. 1996

1995 Spring Western Sandpiper

San Francisco, CA, Honey Lake, CA; Grays Harbor, WA

Coastal sites from SF to YKD; western Great Basin Honey Lake North

Bishop and Warnock 1998, Warnock and Bishop 1998, Bishop et al. in press


San Francisco, CA, Honey Lake, CA; Grays Harbor, WA

Coastal sites from SF to YKD; western Great Basin Honey Lake North

Bishop and Warnock 1998, Warnock and Bishop 1998, Bishop et al. in press

2001 Spring Dunlin, Short- and Long-billed Dowitchers

San Francisco, CA, Grays Harbor, WA

Coastal sites from SF to western Alaska

Warnock et al. 2001; Warnock et al. in press

2002 Spring Western Sandpiper, Long-billed Dowitcher

Bahía Santa María, Sinaloa, Mexico

Western Mexico, limited Central Valley, Great Basin; coastal California to western Alaska

Warnock et al. 2002


San Francisco, CA, Punta Banda, Mexico

Northern Baja, Mexico, limited Central Valley, coastal California to Copper

This report

1Principal investigators –C. Iverson, U. S. Forest Service; and R. Butler, Canadian Wildlife Service.

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The migration strategies used by one of the best-studied shorebird species in North America, the Western Sandpiper (Calidris mauri), have been well described for the stretch between San Francisco and western Alaska (Iverson et al. 1996, Bishop and Warnock 1998, Warnock and Bishop 1998, Bishop et al. in press). Those studies, applying radio telemetry to document migration routes and timing, demonstrated that individual Western Sandpipers typically make short flights during their northward migration and use a variety of stopover sites. However, little is known about how Western Sandpipers migrate up the Pacific Flyway from areas south of San Francisco. In 2002, we radiomarked Western Sandpipers and Long-billed Dowitchers (Limnodromus scolopaceus) in Sinaloa, Mexico (Warnock 2002, Warnock et al. 2002) in order to begin to understand how shorebirds are migrating up through Mexico in the spring. This year, we expanded efforts on Western Sandpipers to look at migration from northern Baja, Mexico to Alaska. Additionally, this year we expanded our research and began assessing the quality of shorebird stopover sites. We sampled benthic invertebrates at different stopover sites to examine the availability of prey used by shorebirds during the migration. We also drew blood samples from radiomarked birds and other Western Sandpipers to evaluate the usefulness of plasma metabolite analysis as an indicator of habitat quality at migratory stopovers (Williams et al. 1999). During fat deposition, triglycerides increase in the plasma owing to transport of lipids to peripheral adipose tissue (Ramenofsky 1990). During mass loss (i.e. when birds are in negative energy balance), glycerol and free fatty acids increase in the plasma and are indicative of lipid catabolism (Jenni-Eiermann and Jenni 1994). Thus, measures of triglycerides and glycerol levels allow one to measure whether birds are gaining or losing mass at stopover sites, a potentially valuable indicator of habitat quality. Initial analyses by Williams et al. (unpubl. data) found significant site difference in plasma triglyceride levels in Western Sandpipers at a small (100 ha) stopover site at Sidney Island, British Columbia vs. a large stopover site (25,000 ha) at Boundary Bay, British Columbia. Study objectives for the spring of 2004 were to: 1. Determine the routes of migratory Western Sandpipers in spring between Punta

Banda, Baja California, Mexico and western Alaska. 2. Estimate the length-of-stay at stopover areas. 3. Evaluate interrelationships of stopover sites along the Pacific Flyway in spring. 4. Indirectly evaluate habitat quality of specific small and large stopover sites by: a) Determining whether blood plasma parameters are correlated with length of stay at

banding site and travel time to the Copper River Delta. b) Determining whether blood plasma parameters and invertebrate abundance (or

densities) at migratory stopover sites are correlated. c) Determining whether invertebrate densities are correlated with length-of-stay

estimates at migratory stopover sites. 5. Improve public awareness of shorebird conservation by featuring the project on the

USFWS Sister Shorebird School list serve and web site.

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METHODS We captured shorebirds during daylight hours at Punta Banda, Baja California, Mexico (Fig. 1). Western Sandpipers were mist-netted during the day in shallow, open-ponded areas using taped alarm calls to lure them. We weighed each bird captured to the nearest 0.05 g. Other measurements (mm) that we took included exposed culmen. Individuals were sexed as males if their exposed culmen was ≤ 24.2 mm and as females if their exposed culmen was ≥ 24.8 (Page and Fearis 1971). We aged first-year birds based on extensive wear of the inner wing coverts relative to adults (illustrated in Warnock and Warnock 2001). All birds were marked with metal U. S. Fish and Wildlife Service (USFWS) bands. Ninety birds had 1.0-g radio transmitters (estimated life 6 weeks, Holohil Systems Ltd., Woodlawn, Ontario, Canada) glued to their lower backs (see Warnock and Warnock 1993). The radio transmitter weight was ~3% of their body mass. We affixed transmitters to the birds with cyanoacrylate glue (QuickTite Super Glue, Loctite Corp., Rocky Hill CT). Our ability to detect radios varied by method and equipment: range was <2 km from the ground with a hand-held antenna, 1-4 km from the ground with a truck mounted antenna (3-7 km from a 120-m hill), and <10 km from an airplane. We used radio transmitters at all major stopover areas to test aerial telemetry equipment. Trucks equipped with dual-Yagi, null-peak telemetry systems were used at San Francisco Bay. Hand-held, 3-element Yagi antennas were used at remaining ground monitoring sites. Aerial monitoring was conducted from planes equipped with exterior, dual-mounted antennas. Monitoring began north of banding sites (Table 2) as soon as radio-marked birds were suspected of departing. Flights were conducted at altitudes of 300-1500 m, with timing of flights varying by area. When a bird was located at a site, we monitored its presence until it had not been detected for at least 2 days, or the bird had been relocated at another site. All monitoring at a site ceased when either all radio-marked birds had departed, or when minimal migratory activity was observed. We assumed there was no difference in the probability of detection by method (ground or air), and that all radio-marked birds at a banding or monitoring site were detected on a given day. We defined relocations as the number of monitoring sites a bird was detected and migration time as the interval (full day increments) between successive sites that a bird remained undetected. Length-of-stay (LOS) for each site was the number of days from first to the last detection. We assumed a detected bird remained on a site the entire day, (i.e. LOS > 1 day), and it remained on site from the first to last detection day. For birds arriving or departing on days we were unable to monitor (usually because of weather, Table 2), we estimated the arrival or departure date by taking the midpoint between dates we monitored.

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Fig. 1. Location of banding sites and migratory stopover sites monitored for radiomarked Western Sandpipers during the spring of 2004.

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We used a subset of birds that were detected at the Copper River Delta to calculate rates of travel (km day-1). We defined rates of travel as the distance between two sites divided by the time (measured in 24 hr increments) between a radiomarked bird’s last detection at a site to its first detection at another site (in this case the Copper River Delta). We calculated travel rates of birds marked at San Francisco Bay and Punta Banda to the Copper River Delta (San Francisco to Copper River Delta = 3,250 km, Punta Banda to Copper River Delta = 4,240 km). We calculated distances with ArcView GIS 3.3 using the Equidistant Azimuthal (North Pole) projection. Distances between sites were calculated following the coastline. Blood was sampled (up to 150 µL) via brachial venipuncture, transported in coolers, centrifuged at 5000 RPM with portable centrifuges for three minutes within two hours of sampling, and the plasma was stored at -20°C until assayed. Free glycerol and triglyceride were assayed via sequential color endpoint assay (Trinder reagent A and B, respectively, Sigma-Aldrich Canada, Oakville, Ontario), using 5 µL of sample with 240 µL and 60 µL of reagents A and B respectively, with a reading taken at 540nm after 10 minutes of incubation at 37°C after the addition of each reagent. Triglyceride concentration (mmol L-1) was calculated by subtracting free glycerol from total triglyceride. Assays were run in 400 µL flat-bottom 96-well microplates (NUNC, Denmark) and read with a microplate spectrophotometer (Biotec 340EL). For triglyceride/glycerol each plate was run with a standard curve based on a serial dilution of 2.54 mmol glycerol (Sigma-Aldrich), and a 19-day old hen plasma pool used to calculate assay variation (CV%). Intra-assay CV% were 3.6% and 3.3% (n = 10), and inter-assay CV% were 12.5% and 5.2% (n=17) for glycerol and triglyceride, respectively. We controlled for body mass, time of day a bird was bled, and time between capture and handling as these have been important sources of variation of metabolite levels in Western Sandpipers in other studies (Williams et al. 1999, Guglielmo et al. 2002). Given that we have documented significant sex effects on stopover ecology in other studies (Warnock and Bishop 1998, Bishop et al. in press), we included sex as a variable in our triglyceride analyses relating to the stopover lengths of our radiomarked birds, even though others (Williams et al. 1999, Guglielmo et al. 2002) have failed to show sex differences in triglyceride levels. For this analysis, we used a more conservative significance level of P ≤ 0.10 since we had relatively small sample sizes (~30 birds per banding location), and because we wanted to determine the feasibility of relating blood plasma levels to individually tracked birds. Statistical analyses were performed using STATA (Computing Resource Center, Santa Monica CA 1999) and SAS. Significance was determined if P ≤ 0.05, unless otherwise indicated. We examined weather systems for 25 April – 5 May 2004 along the Pacific Coast from Baja, Mexico to Alaska using 12 Z surface analyses maps produced by NOAA, National Center for Environmental Predictions, Ocean Prediction Center. Formal analyses were not done on weather data.

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Table 2. Telemetry methods (A = aerial, G = ground) and number of surveys for monitoring migratory movements of Western Sandpipers, March - May 2004. Surveys indicate the number of searches conducted. Location Method Surveys Monitoring Dates Mexico Punta Banda, Baja Norte G 26 Mar 31, Apr 1-16, 18-25, 29, May 1 California San Diego Bay G 31 Mar 29-31, Apr 1-9, 12-30 Pt. Mugu G 43 Mar 30-31, Apr 1-10, 12-30, May 1-12 Elkhorn Slough A

G 14 16

Apr 7,11,13,21,23,25,27,29,30, May 1,4,5,7,10 Apr -6,,8,10,11,13,14,17,18,21-25, May 3,4,6

San Francisco Bay A 14 Apr 7,11,13,21,23,25,27,29,30, May 1,4,5,7,10 South Bay A

G 14 18

Apr 7,11,13,21,23,25,27,29,30, May 1,4,5,7,10 Apr 4-6,8-10,12,13-22,24,26,28, May 2,3,6,11,12

North Bay A 14 Apr 7,11,13,21,23,25,27,29,30, May 1,4,5,7,10 Suisun Bay A 2 May 1,10 San Joaquin Valley A 1 May 2 Sacramento Valley A 3 May 1,2,5 Tomales Bay A 13 Apr 7,11,13,21,23,25,27,29,30, May 1,4,5,7,10 Bodega Bay A 3 Apr 29-30, May 5 Oregon Bandon Marsh G 10 Apr 22-26,28,29,30, May 1,4 Coos Bay G 4 Apr 22,23,25,26 Washington Grays Harbor G

A 15 12

Apr 20,22,24,26,28,30, May 2-8,10, Apr 19,21,23,25,27,29, May 1,3,5,7,9,11

Willapa Bay G A

10 11

Apr 20,24,26,28,30, May 2,4,6,8,10 Apr 21,23,25,27,29, May 1,3,5,7,9,11

British Columbia Fraser River Delta G 10 Apr 26-30 May 1-3,5,6 Tofino Beach G 6 Apr 24,May 1,2,5,7 Alaska Juneau Wetlands G 14 Apr 30, May 2-6, 8, 10-15,17,20 Copper River Delta A 25 Apr 29, May 1-2, 4-25 Bristol Bay, Alaska Peninsula

A 2 Apr 29, May 3

We sampled the composition, abundance, and biomass of invertebrates at selected stopover sites along the migration route as an index to habitat quality (Appendix 1). Benthic samples were collected with a 10-cm diameter clam gun, 10 cm deep. At each site, 15 cores were randomly taken near where we set up our bird capture nets on mudflats on low tides and mid tides. Once collected, the samples were placed in a plastic bag labeled with the site name, date of collection, and tide sequence and either kept on ice or refrigerated until transportation to the Don Edwards San Francisco Bay National Wildlife Refuge in Fremont, California.

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Sorting and identification of the invertebrates occurred at the San Francisco Bay Estuary Field Station in Vallejo, California. Samples were washed with saltwater (tap water mixed to 20 ppt with Instant Ocean) onto a 0.5mm sieve. The contents of all remaining material on the sieve were preserved with a solution of 70% Ethanol/Rose Bengal . Invertebrates were sorted into taxonomic groups, enumerated, weighed (0.001g), and measured (mm). Sorters identified macroinvertebrates under stereoscopes with standard invertebrate keys. Invertebrate identification was restricted to taxonomic family with the exception of a few copepods and tanaids that were keyed to order. Identification of the specimens from Alaska, Washington, and Oregon was assisted by Marine Invertebrates of the Pacific Northwest (Kozloff 1996). Light’s Manual of Intertidal Invertebrates of the Central California Coastline (Smith and Carlton 1975) was used to identify macroinvertebrates from the California and Mexico sample sites to taxonomic family. Our results were recently completed; thus, they are presented here only as a preliminary evaluation. RESULTS BANDING Comparing body mass (log transformed) of birds, we found that radiomarked males were significantly lighter than radiomarked females (ANCOVA, sex, F1,84 = 5.68, P = 0.02; Table 3), but we failed to find significant differences in body mass between banding sites (F1,84 = 0.84, P = 0.36) or by age (F1,84 = 0.13, P = 0.72), holding date of banding constant (F1,84 = 5.68, P = 0.02). Within sexes, culmen measurements were similar between different aged birds and between banding locations (Table 3). RELOCATIONS Of the 88 radio-marked Western Sandpipers that we potentially could have detected (radios fell off two birds soon after marking and are not included here), we relocated 59% at one or more sites past their banding site (Table 4). Of the 17 sites that we monitored north of Punta Banda (Table 2), radio-marked birds were detected at 8 sites (Table 4). We did not detect birds at San Diego Bay, CA (search effort in days, n = 31, see also Table 2); Bodega Bay, CA (n = 3); Bandon Marsh, OR (n = 10); Coos Bay, OR (n = 4); Tofino Beach, BC (n = 6); Juneau, AK (n = 14); and Bristol Bay, AK (n = 2).

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Table 3. Measurements of culmen length (mm) and body mass (g) of radiomarked Western Sandpipers captured at Punta Banda, MX and San Francisco, CA during Mar-May 2004. Measurements include mean ± SD, n. Sex determined by exposed culmen measurements: males ≤ 24.2 mm, females ≥ 24.8 mm. Adult Juvenile Punta Banda, MX Mass Male 24.8 ± 1.2, 18 24.4 ± 1.7, 24 Female 28.3 ± 1.2, 3 26.6 ± 0.7, 2 Culmen Male 22.4 ± 1.0 22.4 ± 0.8 Female 26.4 ± 0.8 26.7 ± 1.5 San Francisco, CA Mass Male 26.7 ± 2.9, 7 27.7 ± 2.2, 21 Female 29.2 ± 3.3, 8 27.6 ± 3.2, 6 Culmen Male 22.9 ± 0.9 22.9 ± 0.7 Female 27.1 ± 0.7 26.8 ± 0.5 We relocated 57% of the birds marked at Punta Banda and 61% of birds marked at San Francisco. Age, but not sex, influenced whether or not a radiomarked bird was relocated (logistic regression, Punta Banda, χ2

2 = 9.06, P = 0.01, n = 47; San Francisco, χ22 = 6.95, P =

0.03, n = 41). Past the banding site we relocated 81% adults and 38% first-year birds marked at Punta Banda and 87% adults and 46% first-year birds marked at San Francisco. For birds marked at Punta Banda, coastal sites along the Pacific Flyway were frequently used with 13% of birds detected at Pt. Mugu, CA; 9% at Elkhorn Slough, CA; 21% at San Francisco Bay, CA; 4% at Tomales Bay, CA; 9% at Willapa Bay, WA; 11% at Grays Harbor, WA; 2% at Fraser River Delta, BC; and 26% at Copper River Delta, AK. Table 4. Relocation sites with mean length-of-stay and number of birds (length-of-stay ± SD days, n) of Western Sandpipers radio-marked at Punta Banda, MX and San Francisco, CA Mar-May 2004. Only sites where at least one bird was detected are listed. Females Males Combined Adult First-year Adult First-year California Pt. Mugu 4.8 ± 1.4, 3 11.0 ± 6.6, 3 7.9 ± 5.4 Elkhorn Slough 3.4 ± 3.4, 4 3.4 ± 3.4 San Francisco Bay 11.5 ± 13.4, 2 9.6 ± 6.0, 5 2.3 ± 0.3, 3 7.8 ± 7.1 Tomales Bay 3.0 ± 1.4, 2 3.0 ± 1.4 Sacramento Valley 4.0 ± 0.0, 1 1.0 ± 0.0, 1 2.5 ± 2.1 Washington Willapa Bay 1.0 ± 0.0, 1 2.5 ± 1.3, 3 2.8 ± 1.2, 4 2.4 ± 1.2 Grays Harbor 1.5 ± 0.0, 1 2.1 ± 1.2, 5 5.0 ± 4.2, 2 2.8 ± 2.3 British Columbia Fraser River 1.0 ± 0.0, 1 1.0 ± 0.0 Alaska Copper River 1.8 ± 0.9, 8 3.7 ± 1.2, 3 2.7 ± 0.9, 12 2.1 ± 1.0, 10 2.3 ± 1.1

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For birds marked at San Francisco Bay, CA, coastal sites along the Pacific Flyway were also frequently used with 10% detected at Willapa Bay, WA; 7% at Grays Harbor, WA; and 51% at Copper River Delta, AK. Birds marked at Punta Banda and San Francisco also used interior sites. We relocated one bird from each site in the Sacramento Valley, despite limited search effort there. LENGTH-OF-STAY AT BANDING SITE The mean length-of-stay (LOS) of Western Sandpipers at their banding sites (Punta Banda and San Francisco), varied by banding location, sex, and age of birds (Table 5), but not significantly (ANCOVA, model, controlling for banding date, F4,86 = 0.73, P = 0.58). The mean length of stay at Punta Banda was 16.6 ± 6.6 days (n = 47) and at San Francisco 17.0 ± 5.0 days (n = 41). Table 5. Length-of-stay of radiomarked Western Sandpipers at Punta Banda, MX and San Francisco, CA banding sites by age and sex. Length-of-stay reported as x̄, SD, n. Sex First year Adult Punta Banda, MX Female 19.5 ± 3.5, 2 9.7 ± 6.8, 3 Male 17.5 ± 7.3, 24 16.2 ± 5.3, 18 San Francisco, CA Female 20.5 ± 5.1, 6 18.1 ± 2.0, 8 Male 15.0 ± 5.9, 19 17.9 ± 3.0, 7 LENGTH-OF-STAY PAST THE BANDING SITE We were able to determine 70 LOS estimates based on relocations of 52 birds detected north of their banding sites (Table 4). Mean LOS ranged from 1-7.9 days, with mean LOS of birds stopping at Pt. Mugu and San Francisco Bay more than double other stopover sites (Table 4). Within sites, LOS at stopover sites varied by age and sex (see Table 4). At the Copper River Delta, where sample size was sufficient for testing, a linear model incorporating age, sex, banding location, and an age by sex interaction, explained significant amounts of variation in LOS (square-root transformed) (ANOVA; adjusted r2 = 0.35, F4,28 = 5.23, P = 0.003). While age and sex were not significant (age, F1,28 = 1.73, P = 0.20; sex, F1,28 = 0.28, P = 0.60), we did detect a significant interaction effect between age and sex (F1,28 = 17.05, P < 0.001) and a banding location effect (F1,28 = 7.54, P = 0.01). Birds radiomarked at Punta Banda had shorter mean LOS at the Copper River Delta than birds radiomarked at San Francisco (Punta Banda, x̄ = 2.0 ± 0.8, n = 12, San Francisco, x̄ = 2.6 ± 1.2, n = 21). At San Francisco Bay, LOS at Punta Banda was significantly related to arrival date (adjusted r2 = 0.61, P = 0.005, n = 10; Fig. 2). On average, early-arriving birds stayed longer than late-arriving birds. However, we failed to find a significant relationship between LOS and arrival date of Western Sandpipers at the Copper River Delta (ANOVA, F1,32 = 1.21, P = 0.28).

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0

5

10

15

20

25

8-Apr 13-Apr 18-Apr 23-Apr 28-Apr 3-May 8-May

Leng

th-o

f-sta

y (d

ays)

Figure 2. Relationship between arrival date and length-of-stay of Western Sandpipers at San Francisco Bay, California, Spring 2004. Birds originally marked at Punta Banda, MX. RATE OF TRAVEL After leaving Punta Banda, birds traveled on average 311 ± 162 km d-1 (n = 12 birds) to reach the Copper River Delta, while birds leaving San Francisco Bay traveled 887 ± 471 km d-1 (n = 21 birds) to reach the Copper River Delta. Using our sample of birds that were banded at San Francisco and detected at the Copper River Delta, controlling for the effects of weight and banding date, we failed to detect a significant effect of either a sex*age interaction or an age effect (ANCOVA, model, F5,15 = 1.21, P = 0.35). Dropping the effects of age, an age*sex interaction, and body mass at banding, while controlling for banding date, we found that the number of days it took females (x̄ = 3.9 ± 2.4, n = 8) to get from San Francisco to the Copper River Delta was significantly less than the number of days it took males (x̄ = 5.3 ± 2.2, n = 13) to get from San Francisco to the Copper River Delta (ANCOVA, sex, F1,18 = 4.45, P = 0.05). Sample sizes precluded us from doing these analyses for birds marked at Punta Banda. The mean arrival date at the Copper River Delta for birds banded at Punta Banda was 8 May (± 4.8 days, n = 12) while for San Francisco birds the mean arrival date was 5 May (± 3.2 days, n = 21). These differences were not significant (Kruskal-Wallis, χ2

1 = 2.1, P = 0.14). VARIATION IN PLASMA METABOLITE LEVELS In 2004, we measured triglyceride and glycerol levels of 87 wintering Western Sandpipers at San Francisco Bay between 12 Jan – 30 Apr, and 371 Western Sandpipers at various sites between Apr-May (Table 6). Among the radiomarked Western Sandpipers, we measured triglyceride levels for 34 Punta Banda and 32 San Francisco birds. From our overall sampling of blood plasma at a broad geographic scale, we confirmed several sources of variation in metabolite values identified in previous studies (Williams et

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al. 1999, Guglielmo et al. 2002): 1) plasma triglyceride was positively related to body mass (F1,450 = 8.81, P < 0.001, b = 0.011), and negatively related to bleed time (F1,450 = 5.08, P < 0.001, b = -0.002), although both relationships were weak; 2) plasma glycerol was independent of both mass and bleed time (P > 0.25); 3) there was no effect of age or sex on either metabolite, for all data pooled or by site; and 4) time of day of blood sampling affected plasma triglyceride levels but not glycerol levels. We therefore controlled for mass, bleed time, and time of day in subsequent analyses. Using data from all birds that we captured and collected blood samples (n = 450) we found a highly significant "site" effect for plasma triglycerides (F5,450 = 25.9, P < 0.001). We observed a linear trend for increasing residual triglycerides as birds migrated north. Triglyceride levels were lowest for San Francisco in the winter and next lowest in Punta Banda, Mexico, our earliest spring and most southern research site. Plasma triglyceride levels, controlling for body mass, bleed time, and time of day, were higher in the spring at San Francisco than in the winter, and levels increased through Oregon, Washington, British Columbia, and Alaska (Fig. 3). Glycerol levels also varied with site (F5,450 = 3.69, P < 0.01) but no pair-wise comparisons between sites were significant and this variation was not systematically related to latitude.

Fig. 3. Variation in residual plasma triglycerides in relation to site at San Francisco (winter) and between Mexico and Alaska on spring migration in 2004. ● = variation in residual triglyceride including time of day as covariate. ∆ = variation in residual triglyceride excluding time of day as covariate.

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We found no significant relationship between the effects of triglyceride levels and sex on LOS of birds from Punta Banda, MX (n = 34) controlling for body mass and time of bleeding (Table 6). Using this same model with birds radiomarked at San Francisco, we found that triglyceride levels were significantly and positively related to LOS of males and females (Figs. 4 and 5, Table 6). Since we have previously shown that LOS is significantly related to banding date (Warnock and Bishop 1998), we re-ran the analysis holding banding date constant. While the model was still significant, the relationship between LOS at the banding site and triglyceride levels was not significant (P = 0.11, San Francisco2, Table 6). Dropping the variable contributing least to this model, bleed time, the relationship between length of stay at the banding site and triglyceride levels was significant (P = 0.10, San Francisco3, Table 6). Table 6. Linear models showing the effects of triglyceride levels and sex on length of stay of Western Sandpipers radiomarked at Punta Banda, MX (n = 34) and San Francisco, CA (n = 32) in the spring of 2004, controlling for body mass, time of bleeding, and date banded. Significant models (P ≤ 0.10) in bold. Punta Banda San Francisco1 San Francisco2 San Francisco3 Model F4,29 = 0.56

P = 0.70 F4,27 = 2.40 P = 0.07

F4,27 = 2.34 P = 0.07

F4,27 = 3.03 P = 0.03

Triglyceride Level F1,29 = 0.54 P = 0.47

F1,27 = 3.45 P = 0.07

F1,27 = 2.69 P = 0.11

F1,27 = 2.87 P = 0.10

Sex F1,29 = 0.64 P = 0.43

F1,27 = 6.37 P = 0.02

F1,27 = 3.17 P = 0.09

F1,27 = 3.28 P = 0.08

Mass F1,29 = 0.09 P = 0.77

F1,27 = 1.40 P = 0.25

F1,27 = 1.76 P = 0.20

F1,27 = 1.84 P = 0.19

Bleed time F1,29 = 0.21 P = 0.65

F1,27 = 0.15 P = 0.70

F1,27 = 0.01 P = 0.92

Date banded F1,27 = 1.79 P = 0.19

F1,27 = 2.01 P = 0.17

adj. r2 0.15 0.18 0.21 Figure 4 – Relationship between triglyceride levels (square root transformed) and length of stay at the banding site (log transformed) of female (F) and male (M) Western Sandpipers radiomarked at San Francisco Bay, California, in the spring of 2004.

0.5

11.

5

1 2 3 4 1 2 3 4

F M

stri

ldayGraphs by sex

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Figure 5 – Relationship between triglyceride levels (square root transformed) and length of stay at the banding site (log transformed) of female (F) and male (M) Western Sandpipers at Punta Banda, Mexico, spring 2004.

.4.6

.81

1 2 3 4 1 2 3 4

F M

stri

ldayGraphs by sex

MACROINVERTEBRATE COMPOSITION, ABUNDANCE, AND BIOMASS We collected and sorted 206 benthic cores from 9 capture sites (Appendix 1). This included sites in Mexico (1), California (3), Oregon (1), Washington (2), and Alaska (1). The largest numbers of invertebrates were found at California stopover sites (Fig. 6), with the greatest biomass at Elkhorn Slough that supported large numbers of polychaetes (Fig. 7). Bivalves and polychaetes dominated the samples, with increased biomass of Crustacea in northern samples (Appendix A). Invertebrates migrate downward from the surface on falling tides to avoid dessication, and we generally observed lower biomass in mid-tide samples, although not at some sites (Punta Banda, Bandon Marsh; Fig. 6). A preliminary visual inspection of these invertebrate results in comparison with LOS of the migrating sandpipers (Table 4) may indicate a weak positive relationship between LOS and available wet biomass. Assuming sandpipers have equal preference for all prey, the highest overall biomass was observed at Elkhorn Slough, and it had the second longest mean LOS (3.4 d) of sites where we had both LOS and invertebrate data. San Francisco Bay had the second highest biomass and the longest LOS (7.8 d). The lowest biomass was found at Grays Harbor, and it had the second shortest LOS.

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Fig. 6. Biomass (wet weight, g/m3) of macroinvertebrates at Punta Banda, Mexico (MX); Elkhorn Slough, California (ES), San Francisco Bay (SFB), and South Bay salt pond (Pond B1C); Bandon marsh (BM) and Bandon mud flats (B), Oregon; Grays Harbor (GH) and Bottle Beach (BB), Washington; and Hartney Bay, Alaska (HB2). Each site code is followed by a letter indicating samples at mid (M) and low (L) tide. Major invertebrate classes in samples are indicated by color in the legend.

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

MX

M

MX

L

ESM

ESL

Pond

B1C

SFB

M

SFB

L

BM BL

BB

M

BB

L

BO

TM

BO

TL

HB

2

Sites

Tot

al W

et B

iom

ass (

g/m

3 )

Bivalvia Crustacea Arthropoda Oligochaeta Polychaeta

Fig. 7. Mean number (individuals/m3) of macroinvertebrates in core samples from Mexico (1 site), California (2), Oregon (1), Washington (2), and Alaska (1). Major invertebrate classes in samples are indicated by color in the legend.

0

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PUBLIC OUTREACH AND EDUCATION Research results were featured on the Shorebird Sisters web page. At Hartney Bay on the Copper River Delta more than 50 high school biology students from the Cordova Alaska school district observed capture and banding operations in May. In Mexico, five biologists from various institutes including Centro e Investigación Cientifíca y de Educación Superior de Ensenada; Universidad Autonoma de Baja California Sur, Departamento de Biologia Marina; and, El Colegio de la Frontera Sur were trained in radiotelemetry techniques. Additionally, we gave talks on our research to various groups including the Waterbirds Around the World conference held this spring in Edinburgh, Scotland (Warnock, N., J. Y. Takekawa, and M. A. Bishop. Shorebird Migration along the Pacific Flyway), and the Alaska Shorebird Conference. DISCUSSION SITES USED IN MIGRATION Over the past decade, we have built a network of cooperators to examine the importance of coastal habitats used by shorebirds during the spring migration. The 2004 spring shorebird migration study marks the sixth season (Table 1) that we have successfully radio-marked and followed shorebirds over large areas of the Pacific Flyway. These studies have revealed the complexity of migration strategies used within and among shorebird species along the Pacific Flyway. For the first time, we marked birds in Baja, Mexico. Little had been known about how individual shorebirds migrated from Mexico, especially from Baja, through western United States and Canada. Our recoveries in the study this past year were informative. For example, at San Diego Bay, no Western Sandpipers were detected despite a substantial search effort (31 days). These results were perplexing because this is a small site, easy to check from the ground, and the bay and its adjacent salt ponds host thousands of Western Sandpipers in the spring (Page et al. 1992, Terp 1998). Given our search efforts there, we would have predicted relocations of some birds if they stopped at San Diego after leaving Punta Banda. However, it may be that San Diego simply is too close to Punta Banda (approximately 130 km), and birds are not ready to stop there after leaving Punta Banda. Our lack of detections at San Diego may have been confounded by problems with transmitters. Since we began tracking Western Sandpipers, we have consistently used the same brand and model of transmitters. This year, we suspect that the power of our radios was not as high as in previous years, resulting in lower ability to detect birds from the ground. At San Francisco Bay where we conducted ground and air surveys, we had higher detection rates from the air than from the ground. Similarly, at Grays Harbor, 15 days of ground searches yielded no detections whereas aerial surveys during the same period detected 8 birds.

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At Pt. Mugu, 430 km north of Punta Banda, we detected six radiomarked birds from the ground. Detections at Pt. Mugu as well as at Elkhorn Slough, San Francisco Bay, and sites north indicate that at least a significant number of birds migrating up through and from Baja stay on the coast during their northward migration. However, as we observed in 2002 with birds marked in Sinaloa, Mexico (Warnock et al. 2002), at least some birds forego the coast and switch to interior sites during spring migration. At interior sites in the Central Valley of California, with limited search effort, we found two of our radiomarked birds, including one bird banded in Baja. This indicates that some birds from Baja, Mexico migrate north through the Central Valley and then move to the coast. Our 1995 and 1996 studies showed that radiomarked birds in the Great Basin were not detected on the coast until the state of Washington (Warnock and Bishop 1998, Bishop et al. in press). Thus, this year we made an a priori prediction that if birds banded in Baja took an interior Great Basin route we would observe a pattern where interior migrants would not be detected until Grays Harbor or Willapa Bay, WA. In fact, five birds did fit this pattern (being first detected in Washington) and four others were first relocated at the Copper River Delta, AK. In future years it would be interesting to increase monitoring in the western Great Basin to confirm if some Baja birds are migrating up through that region. This season, our southern sites with the most recoveries were at Pt. Mugu and San Francisco Bay (21%). Our results reconfirm previous results (Page et al. 1992, Page et al. 1999) that in southern California, Pt. Mugu generally has the highest number of Western Sandpipers during the spring migration, and San Francisco Bay is perhaps the single most important coastal spring site for Western Sandpipers in the western United States with the exception of the Copper River Delta. North of San Francisco, we failed to detect any radiomarked birds at the two sites in Oregon we monitored, whereas in 2002 we recovered birds at various coastal sites in Oregon. Since we suspect that our radios were not as powerful as in the past, we cannot rule out that we missed radiomarked birds that did stop there. However, numbers of birds using the Oregon coast during spring migration can greatly vary among years (Warnock 2002) and perhaps this was a low use year. Along the Washington coast at Willapa Bay and Grays Harbor, our radio work from previous years and this year confirmed the importance of this area as a stopover site (Iverson et al. 1996, Warnock and Bishop 1998, Warnock et al. 2002). North of Washington at the Fraser River Delta, we only detected a single bird, even though this site is known for its concentrations of Western Sandpipers and other shorebirds in the spring (Butler 1994, Butler et al. 2002). At the Fraser River Delta in 1995 and 1996, we relocated 25 Western Sandpipers from three banding sites: San Francisco, Grays Harbor, and Honey Lake (Warnock and Bishop 1998, Bishop et al. in press). However, in the recent years of work (2001 and 2004), we have only detected two Western Sandpipers at this site. This result is undoubtedly in part due to a decreased search effort. In 1995 we had 24 days of ground effort there while in 1996 we had 23 days of aerial searches. In recent years we have had limited ground efforts, but it is also true that at least some areas in British Columbia have

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suffered significant declines in Western Sandpiper numbers in the spring (see web page http://www.ecoinfo.ec.gc.ca/env_ind/region/wsandpiper/wsandpiper_e.cfm). The majority of the estimated world's population of Western Sandpipers passes through the Copper River Delta in the spring (Bishop et al. 2000). In previous years, we recovered 70-90% of the birds that we radio-marked at this site compared to 26% recovered there this year. Search effort was similar as in the past, suggesting that our lower recovery rates may be a result of decreased detectability of radios as well as radios falling off prior to birds reaching the Copper River Delta. This year, we began marking birds in Baja at the end of March and in San Francisco in early April, so some radios would have undoubtedly fallen off since glue on radios will begin falling off from a few weeks after attachment to a few months (Warnock and Takekawa 2003). However, this year, birds traveled on average extremely quickly to the Copper River Delta compared with past years. It is likely that a certain proportion of birds bypassed the Copper River Delta on their way to an early breeding season on the Alaska Peninsula, the Yukon-Kuskokwim Delta, and further north (Bishop and Warnock 1998), partially accounting for our lower recovery rates. This year, we were twice as likely to relocate adult birds (83% relocated) as first year birds (42% relocated). This striking difference held true for birds banded at San Francisco and Punta Banda. Why we had this pattern is unclear. A certain number of first year shorebirds do not breed and often forego or shorten their migrations including Western Sandpipers (Hockey et al. 1998, O’Hara 2002) and this may explain part of the differences. However, it is generally thought that individuals at sites further from the breeding grounds are more likely to forego migration and this does not fit the pattern that we observed where detection rates of first year birds from Punta Banda and San Francisco, almost 1,000 km to the north, were approximately the same. Another potential explanation is that first year birds are using areas that we did not monitor. It is possible that these birds are more likely to use interior routes, for instance along the western Great Basin. However, currently we lack data to test this hypothesis. LENGTH-OF-STAY AT BANDING SITES Birds marked at Punta Banda and San Francisco Bay stayed on average just over 16 days and we failed to detect any influence of banding location, age, or sex of birds. These LOS estimates are long compared to results from 1991, 1995, 1996, and 2002 (for San Francisco) that ranged from 2-9 days (Iverson et al. 1996, Warnock and Bishop 1998, Warnock et al. 2002) but similar to the average length of stay of 16 days in Sinaloa, Mexico (Warnock et al. 2002). Several factors may help explain the longer mean length-of-stay this year at San Francisco Bay and at Punta Banda. First, inclusion of birds that are not actually migrating may inflate estimated length-of-stay for Punta Banda and perhaps San Francisco birds, although at both sites, all radiomarked birds appeared to have left (based on surveys at the end of the monitoring period where no birds were detected). Second, our length-of-stay estimates at banding sites are also not as accurate as in past years because of the presumed lower detection distances of the

19

radiotransmitters. At Punta Banda, we appeared to be missing birds during our ground searches. As a result, for a number of birds we had to conservatively estimate the departure date. Third, longer LOS at Punta Banda and San Francisco versus other sites to the north (in past years) may also be a factor of our early banding dates for Punta Banda (late March, early April) and San Francisco (early April – about a week earlier than our past efforts). Birds arriving too early to Alaska face potential snow-covered landscapes (Holmes 1971, 1972). As has been the case in the past (Warnock and Bishop 1998, Warnock et al. 2001, 2002), we failed to find any significant effects of sex, body mass, or banding date on length-of-stay at the banding site (although we had few females to compare at the Punta Banda site). Additionally, we found no significant effect of age. Part of these effects may be masked by the banding effect that we have documented in the past (Warnock and Bishop 1998, Warnock et al. 2001), that causes birds to stay longer at the site where they are banded than they would if they were not handled. Past the banding site, we also failed to find significant effects of sex or age on LOS. LENGTH-OF-STAY PAST BANDING SITES With the exception of stopover lengths at Pt. Mugu and San Francisco Bay, Western Sandpipers that departed from banding sites moved rapidly through stopover sites, spending on average a few days per site. There does appear to be a latitudinal pattern in mean LOS along the coast (Table 4), with estimates for sites from around San Francisco Bay and to the south all averaging over 3 days while those further north averaged less than 3 days. While we are just beginning to collect data for sites south of San Francisco Bay, north of there, our estimates are similar to those we have recorded for previous years of study (Iverson et al. 1996, Warnock and Bishop 1998, Warnock et al. 2002). Compared to the rapid turnover estimates at other sites, mean LOS at San Francisco Bay and Pt. Mugu was on average about 5 days longer than other sites. These data support the idea that these sites serve as staging sites rather than stopover sites (Warnock and Bishop 1998). There are probably few true staging sites for shorebirds in North America, sites where birds spend relatively longer amounts of time increasing their body mass in response to a superabundant food resource (see Warnock and Bishop 1998). At San Francisco Bay it is likely that the combination of relatively large tracts of mud flats in juxtaposition with large expanses of salt ponds offer opportunities for intense periods of feeding. With the salt ponds present, Western Sandpipers can and do feed through the day and night, switching between habitats depending on tide height (Warnock and Takekawa 1995, 1996). It is currently unknown how the invertebrate community at Pt. Mugu compares to San Francisco Bay and other sites. At sites north of San Francisco, birds moved rapidly through wetlands, generally staying less than three days. Along the Washington coast, they used Grays Harbor and Willapa similarly, stopping generally for 2.4–2.8 days before continuing. Previous turnover estimates for these birds at these sites in Washington have also been rapid (Iverson et al. 1996, Warnock and Bishop 1998). In comparison with Western Sandpipers, Dunlin and Short and Long-billed Dowitchers marked in 2001 used Grays Harbor and Willapa Bay differently. Dowitchers

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stayed on average up to 5 days at these sites, and dowitchers stopped longer at Willapa Bay than Grays Harbor while Dunlin stopped longer at Grays Harbor than Willapa Bay (Warnock et al. 2001). Our mean two-day stopover lengths at the Copper River Delta are comparable with results from previous years (Iverson et al. 1996, Warnock and Bishop 1998, Warnock et al. 2002). As in 2002, at San Francisco Bay, arrival date had the largest effect on stopover length with late-arriving birds staying shorter periods than early-arriving birds (Fig. 2). However, we failed to find this relationship at the Copper River Delta this year. In other years, the LOS of males was negatively related to arrival date, whereas we failed to find this relationship in females (Warnock and Bishop 1998, Warnock et al. 2001). Farmer and Wiens (1999), in a study of Pectoral Sandpipers (Calidris melanotos) migrating through the Central Flyway in the spring, showed a similar relationship with birds banded at more northerly sites having shorter lengths of stay the later they were banded in the season. Undoubtedly, this is related to the need for late-arriving shorebirds to get to the breeding grounds in time to breed. Shorebirds migrating towards breeding grounds in the subarctic and Arctic face time constraints, and males probably face tighter constraints than females the closer they get to the breeding grounds, as has been suggested for Western Sandpipers (Warnock and Bishop 1998) and Pectoral Sandpipers (Farmer and Wiens 1999). Eggs laid too early in the season face freezing (Green et al. 1977), while for chicks hatching too late in the short breeding season there is an increased probability of food shortages (Holmes 1972) and, in some years, greater predation (Oring and Lank 1986, Jönsson 1991). However, energetic costs for females may be equally or more important than time considerations because egg production is energetically expensive (MacLean 1969, Blem 1990). At the Copper River Delta, we failed to find significant differences in length-of-stay by sex or age, although we did detect a significant age-by-sex interaction. However, the patterns are difficult to interpret (see results in Table 4). Additionally, we found that birds originally banded at Punta Banda that passed through the Copper River Delta had significantly shorter LOS than birds banded at San Francisco. It may be that these birds represent different breeding populations resulting in different time constraints on migration although this hypothesis remains untested. It may also be a function of Punta Banda birds arriving at the Copper River on average 3 days later than San Francisco birds, although these differences were not significant. TRAVEL RATES This year, travel rates from San Francisco to the Copper River Delta were over twice as fast on average than in previous years. In past years, radiomarked birds took about 10 days to reach the Copper River Delta after leaving San Francisco Bay. This year, females took on average 4 days and males a little over 5 days to reach the Copper. In previous years, we have only had one bird that traveled from San Francisco to the Copper River in less than 2 days, whereas this year 5 birds did. Four of the 5 birds left on either 3 or 4 May, suggesting that weather and or climate patters may have been a factor. On the Yukon Kuskokwim Delta, AK, the 24-year mean date for first sighting of a Western Sandpiper is 7 May while this year it was 30 April, the earliest ever (Brian McCaffery and Craig Ely unpubl. data). Their rapid movements to Alaska may have been a response to early breeding conditions, although we

21

lack direct evidence of this. The rapid migration may also have been triggered by a large high-pressure system that stretched between California and Alaska VARIATION IN PLASMA METABOLITE LEVELS This is the first study to measure variation in plasma triglycerides (i.e. predicted fattening rates), for a migratory species on a geographical or flyway-level scale in a single year. We were able to show, first, that plasma triglycerides levels increased between winter and migration at San Francisco Bay. Second, we found that there was a near-linear increase in plasma triglyceride levels with increasing latitude through the spring migration period going from lower levels in Mexico to progressively higher levels up to the Copper River Delta in Alaska. This suggests that birds are fattening more rapidly as they move further north and get closer to the breeding grounds. These data are consistent with decreased LOS that we observed with increasing latitude. This suggests that as birds move north, they remain at stopover sites for shorter periods and consequently have to fatten at higher rates. For the first time, we were able to relate triglyceride levels of individual birds to one of their migration variables, LOS at a stopover site. While not entirely conclusive, our results suggest that further research in this area will be fruitful. At Punta Banda, reflecting the generally low triglyceride levels, we found no significant relationship between LOS at the banding site and triglyceride levels; however, at San Francisco, a site with higher mean triglyceride levels than Punta Banda, we did find significant relationships between LOS at the banding site and triglyceride levels. Sex also explained significant variation in our models, despite the fact that previous studies (Williams et al. 1999, Guglielmo et al. 2002) have failed to find a relationship with larger sample sizes. It may be that this relationship is confounded by the fact we typically catch females later in the migration period than males, but our results hint that something else, still not understood, is in effect. Our results suggest that the relationship between triglyceride levels and LOS at a site may be more pronounced farther north, and as a consequence, closely related to the mean date of arrival at the breeding grounds. FUTURE RESEARCH Over the past decade, the Pacific Flyway Shorebird Migration Program has been very successful through its wide-scale project and its use of an international network of partners. In the near future, the program is preparing an integrated proposal to complete analyses on wetland quality, bioenergetics, and connectivity, and to conduct one more radio-telemetry field season in 2006, focusing on the Pacific Flyway and Western Sandpipers. In our efforts to understand the northward migration of Western Sandpipers, we have developed a much better understanding of how sites along the Pacific Flyway are connected from the perspective of individual sandpipers, and also how these birds use the sites during their migration stopovers. The one area where we would like to collect more data is in the Central Valley and along the western Great Basin. We have collected bits of information in these regions, but a more comprehensive picture is needed. In the future, we also hope to add information on use of stopover sites by fall migrants, and general migration information on other shorebird species, representing other migration strategies

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in the Pacific Flyway. We believe these large-scale collaborative efforts are invaluable in generating data to protect key shorebird migration habitats in the Pacific Flyway.

ACKNOWLEDGMENTS A study of this breadth would not have been possible without the significant help and cooperation from multiple people and organizations. We thank the many individuals and organizations that helped us with monitoring, funding, public outreach, and logistics. Guillermo Fernandez is thanked for helping organize our work and permits in Mexico. We received logistic support, analysis support, and helpful comments from Nicole Athearn on the draft report. She and Jill Bluso organized the complicated blood and invertebrate sampling schedules, while Kate Goodenough sorted all of the invertebrate samples. Todd Thompson is thanked for help on generating figures. Bob Gill and Gary Hufford are thanked for help with weather maps while Craig Ely and Brian McCaffery are thanked for their long-term perspective on Yukon-Kuskokwim Delta breeding conditions. None of our work would have been possible without help from the following: COOPERATORS AT BANDING AND MONITORING SITES Estero de Punta Banda, Mexico CICESE Edna Sanchez, Horacio de la Cueva Universidad Autonoma de Baja California Sur, Departamento de Biologia Marina Luis Sauma, Daniel Galindo El Colegio de la Frontera Sur Jorge Correa Sandoval, Alejandro de Alba Simon Fraser University Guillermo J. Fernandez Aceves PRBO Conservation Science Diana Stralberg USGS Jill Bluso San Diego Bay, CA Tijuana Slough National Wildlife Refuge Brian Collins, Todd Stands Pt. Mugu, CA US Navy, Environmental Division Emilie Craig, Ken Gilliland, Nathan Lang, Lyn Perry, Martin Ruane, M. Saeland

Elkhorn Slough, CA Moss Landing Marine Laboratories Josh Adams, Hannah Nevins

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Ecoscan Services Bob Van Wagenen San Francisco Bay, CA and surrounding areas San Francisco Bay National Wildlife Refuge Joelle Buffa, Margaret Kolar, Clyde Morris, Natalie Wilson San Francisco Bay Estuary Field Station, US Geological Survey

Nicole Athearn, Jill Bluso, Kathleen Henderson, Christina Kereki, Luke Naylor, Shannon Page, Susan Wainwright-De La Cruz, Matt Wilson

Ecoscan Resource Data Bob Van Wagenen PRBO Conservation Science Mark Herzog, Sarah Warnock, Hanna Mounce Coos Bay, OR Oregon Coast NWR Complex Kathy Castelein, Dave Lauten, Dave Ledig, David Pitkin PRBO Conservation Science Hanna Mounce Willapa Bay and Grays Harbor, WA Cascadia Research Joe Buchanan Nisqually National Wildlife Refuge Marian Bailey, Kristie Bushman, Lisa Godina, Chuck McCoy, Jean Takekawa Willapa Bay National Wildlife Refuge, WA

Marie Fernandez, Rudy & Winona Schuver, Charlie Stenvall, US Fish and Wildlife Service, Region 1 Migratory Birds and Habitat Programs

Sue Thomas San Francisco Bay Estuary Field Station, US Geological Survey Jill Bluso PRBO Conservation Science Hanna Mounce Tofino Beach, British Columbia Adrian Dorst Fraser River Delta, British Columbia Canadian Wildlife Service, Pacific Wildlife Research Centre Rob Butler, Mora Lemon, R. Will Stein, A. Pomeroy Juneau, AK USDA Forest Service, Juneau Ranger District, Tongass National Forest Gwen Baluss, Dennis Chester, Jesse Reebs

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Copper River Delta, AK Adam Kenyon, Gerry Koechling, Susanna Marquette, Susan Ogles, Paula Payne Fishing and Flying

Larry Hancock, Gayle Ranney, John Tucker Eyak Corporation

Jim McDaniel, Steve Ujioka Prince William Sound Science Center

Signe Fritsch, Nancy DiNapoli, Allen Marquette, Sean Meade, Brad Reynolds San Francisco Bay Estuary Field Station, US Geological Survey Jill Bluso University of Alaska, Fairbanks Audrey Taylor Bristol Bay, AK US Fish and Wildlife Service, Becharof National Wildlife Refuge

David Cox, Susan Savage, Sarah Schuster PUBLIC OUTREACH AND EDUCATION Our efforts to educate people to the marvels of shorebird migration were greatly aided by: Sister Shorebird Schools, US Fish & Wildlife Service Hilary Chapman PRBO Conservation Science Sarah Warnock EQUIPMENT: We thank the following individuals and agencies for advice or loan of equipment:

Fred Anderka, Holohil Systems David Irons and Shawn Stephensen, US Fish and Wildlife Service, Region 7, Migratory Bird Management Gayle Ranney, Fishing and Flying

FUNDING SOURCES: This research would not have been possible without funding from the following sources: Chase Wildlife Foundation National Fish and Wildlife Foundation Royal Caribbean Cruise Lines Settlement Fund US Fish & Wildlife Service

Nisqually National Wildlife Refuge Willapa Bay National Wildlife Refuge Pacific Coast Joint Ventures Region 1, Ecological Services, Coastal Program - San Francisco Bay Program Region 1, Migratory Birds and Habitat Programs. Puget Sound Program, Western Washington Fish and Wildlife Office.

Center for Wildlife Ecology, Simon Fraser University, BC

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SPECIAL THANKS TO: Lynn Chase, Chase Wildlife Foundation Mary Mahaffy, US Fish & Wildlife Service, Puget Sound Program, Western Washington

Fish and Wildlife Office. Rick Morat, US Fish & Wildlife Service Coastal Program - San Francisco Bay Program Sue Thomas & Tara Zimmerman, US Fish & Wildlife Service, Migratory Birds and Habitat

Programs Jean Takekawa, Nisqually National Wildlife Refuge Carey Smith, US Fish & Wildlife Service, Pacific Coast Joint Ventures Krystyna Wolniakowski and Jennifer Taylor, National Fish and Wildlife Foundation LITERATURE CITED Bishop, M. A., and N. Warnock. 1998. Migration of Western Sandpipers: links between their

Alaskan stopover area and breeding grounds. Wilson Bull. 110:457-462. Bishop, M. A., P. M. Meyers, and P. F. McNeley. 2000. A method to estimate migrant

shorebird numbers on the Copper River Delta, Alaska. J. Field Ornithol. 71:627-637. Bishop, M. A., N. Warnock and J. Y. Takekawa. In press. Differential spring migration by

male and female Western Sandpipers at interior and coastal sites. Ardea. Blem, C. R. 1990. Avian energy storage, p. 59-113. In D. M. Power [ed.], Current

Ornithology. Plenum Press, New York. Brown, S., C. Hickey, B. Harrington and R. Gill. 2001. The U. S. Shorebird Conservation

Plan, 2nd ed. Manomet Center for Conservation Sciences, Manomet, MA. Butler, R. W. 1994. Distribution and abundance of Western Sandpipers, Dunlins and Black-

bellied Plovers in the Fraser River estuary, p. 13-23 In: R.W. Butler and K. Vermeer [eds.], Abundance and distribution of birds in estuaries in the Strait of Georgia. Can. Wildl. Serv. Occas. Paper No. 83, Ottawa.

Butler, R. W., P. C. F. Shepherd, and M. J. F. Lemon. 2002. Site fidelity and local movements of migrating Western Sandpipers on the Fraser River Estuary. Wilson Bull. 114:485-490.

Farmer, A. H., Jr., and J. A. Wiens. 1999. Models and reality: time-energy trade-offs in Pectoral Sandpiper (Calidris melanotos) migration. Ecology 80:2566-2580.

Green, G. H., J. J. D. Greenwood, and C. S. Lloyd. 1977. The influence of snow conditions on the date of breeding of wading birds in north-east Greenland. J. Zool. 183:311-328.

Guglielmo, C., P. D. O’Hara, and T. D. Williams. 2002. Extrinsic and intrinsic sources of variation in plasma lipid metabolites of free-living Western Sandpipers (Calidris mauri). Auk 119:437–445.

Hockey, P. A. R., J. K. Turpie, and C. R. Velásquez. 1998. What selective pressures have driven the evolution of deferred northward migration by juvenile waders? Journal of Avian Biology 29:325-330.

Holmes, R. T. 1971. Latitudinal differences in the breeding and molt schedules of Alaskan Red-backed Sandpipers (Calidris alpina). Condor 73:93-99.

Holmes, R. T. 1972. Ecological factors influencing the breeding season schedule of Western Sandpipers (Calidris mauri) in subarctic Alaska. Am. Midl. Nat. 87:472-491.

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Iverson, G. C., S. E. Warnock, R. W. Butler, M. A. Bishop, and N. Warnock. 1996. Spring migration of Western Sandpipers (Calidris mauri) along the Pacific coast of North America: a telemetry study. Condor 98:10-21.

Jenni-Eiermann, S., and L. Jenni. 1994. Plasma metabolite levels predict individual body-mass changes in a small long-distance migrant, the Garden Warbler. Auk 112:888-899.

Jönsson, P. E. 1991. Reproduction and survival in a declining population of the southern Dunlin Calidris alpina schinzii. Wader Study Group Bull. 61:56-68.

Kozloff, E. N. 1996. Marine invertebrates of the Pacific Northwest. Univ. of Washington Press. Seattle. 539pp.

MacLean, S. F., Jr. 1969. Ecological determinants of species diversity of Arctic sandpipers near Barrow, Alaska. Ph.D. diss., Univ. California, Berkeley, CA.

Morrison, R. I. G. 2001. Trends in shorebird populations in North America using Breeding Bird Survey data. Bird Trends 8: 12-15. Canadian Wildlife Service, Ottawa.

Morrison, R. I. G, and P. Hicklin. 2001. Recent trends in shorebird populations in the Atlantic Provinces. Bird Trends 8: 16-19. Canadian Wildlife Service, Ottawa.

O’Hara, P. D. 2002. The role of feather wear in alternative life history strategies of a long-distance migratory shorebird, the Western Sandpiper (Calidris mauri). Ph.D. dissertation, Simon Fraser University, Burnaby.

Oring, L. W., and D. B. Lank. 1986. Polyandry in Spotted Sandpipers: the impact of environment and experience. Pages 21-42. In (D. Rubenstein and P. Wrangham, Eds.). Ecological aspects of social evolution. Princeton Univ. Press, Princeton, NJ.

Page, G., and B. Fearis. 1971. Sexing Western Sandpipers by bill length. Bird-Banding 42:297-298.

Page, G. W., W. D. Shuford, J. E. Kjelmyr, and L. E. Stenzel. 1992. Shorebird numbers in wetlands of the Pacific Flyway: a summary of counts from April 1988 to January 1992. Unpublished progress report, Point Reyes Bird Observatory, Stinson Beach, CA 94970.

Page, G. W., L. E. Stenzel, and J. E. Kjelmyr. 1999. Overview of shorebird abundance and distribution in wetlands of the Pacific Coast of the contiguous United States. Condor 101: 461-471.

Ramenofsky, M. 1990. Fat storage and fat metabolism in relation to migration. Pages 214-231 in (E. Gwinner, Ed.) Bird migration: physiology and ecophysiology. Springer-Verlag, Berlin.

Skagen, S. K. 1997. Stopover ecology of transitory populations: the case of migrant shorebirds. Ecol. Studies 125:244-269.

Smith, R. I., and J. T. Carlton. 1975. Light’s Manual: intertidal invertebrates of the central California coast. University of California Press, Berkeley. 716pp.

Terp, J. M. 1998. Habitat use patterns of wintering shorebirds: the role of salt evaporation ponds in south San Diego Bay. M.S. thesis, San Diego State University.

Warnock, N. 2003. Western Sandpiper Calidris mauri. Pages 235-237 in ( D. B. Marshall, M. G. Hunter, and A. L. Contreras, Eds.) Birds of Oregon: a general reference, Oregon State University Press. Corvallis.

Warnock, N., and M. A. Bishop. 1998. Spring stopover ecology of migrant Western Sandpipers. Condor 100:456-467.

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Warnock, N., and J. Y. Takekawa. 2003. Use of radio telemetry in studies of shorebirds: past contributions and future directions. Wader Study Group Bull. 100: 138-150.

Warnock, N. and S. Warnock. 1993. Attachment of radiotransmitters to sandpipers: review and methods. Wader Study Group Bull. 70: 28-30. Reprinted 1993. Stilt 23: 38-40

Warnock, N., and S. Warnock. 2001. Sandpipers, phalaropes, and allies. Pages 273-287 in The Sibley guide to bird life and behavior. Chanticleer Press, Inc., NY.

Warnock, N., M. A. Bishop, and J. Y. Takekawa. 2001. Spring migration of Dunlin and dowitchers along the Pacific Flyway. Unpublished progress report, Point Reyes Bird Observatory, Stinson Beach, CA 94970.

Warnock, N., M. A. Bishop, and J. Y. Takekawa. 2002. Spring shorebird migration, Mexico to Alaska. Final report 2002. Unpubl. Prog. Rep., Point Reyes Bird Observatory, Stinson Beach, CA and U.S. Geological Survey, Vallejo, CA.

Warnock, N., J. Y. Takekawa, and M. A. Bishop. In press. Migration and stopover strategies of individual Dunlin along the Pacific Coast of North America. Canadian Journal of Zoology.

Warnock, S. 2002. Herding dowitchers. Observer 149: 3. Warnock, S. E. and J. Y. Takekawa. 1995. Habitat preferences of wintering shorebirds in a

temporally changing environment: Western Sandpipers in the San Francisco Bay estuary. Auk 112: 920-930.

Warnock, S. E. and J. Y. Takekawa. 1996. Wintering site fidelity and movement patterns of Western Sandpipers Calidris mauri in the San Francisco Bay estuary. Ibis 138: 160-167.

Williams, T.D. C.G. Guglielmo, O.E. Egeler, and C.J. Martyniuk. 1999. Plasma lipid metabolites provide information on mass change over several days in captive western sandpipers (Calidris mauri). Auk 116: 994-1000.

28

Appendix 1. Percent found, mean length (mm), wet weight (g/m3), and number of individuals from 10 cm diameter core samples taken 10 cm deep in benthic sediments at Western Sandpiper migration sites in Spring, 2004. Order and family of invertebrates sampled are reported.

North Site, Mexico Mid-Tide North Site, Mexico Low-Tide Elkhorn Slough Mid-Tide Elkhorn Slough Low-Tide

Order Family

% Occurrence in Samples

n=15

Mean Length (mm)

Mean Wet BM/Sample

(g/m3) No. Ind.


n=15

Mean Length (mm)

Mean Wt BM/Sample

(g/m3) No. Ind.


n=15

Mean Length (mm)

Mean Wt BM/Sample

(g/m3) No. Ind.


n=15

Mean Length (mm)

Mean Wt BM/Sample

(g/m3) No. Ind.

Oligochaeta Tubificidae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 26.67 6.88 48.51 46

Tubificoides 0.00 0.00 0.00 0 6.67 5.00 15.26 1 53.33 15.11 49.44 44 13.33 10.50 52.52 6

Ampharetidae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Polychaeta Capitellidae 0.00 0.00 0.00 0 6.67 11.00 7.63 1 33.33 11.81 93.10 13 86.67 26.83 294.19 183

Cirratulidae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 40.00 9.14 12.08 10 46.67 13.30 56.87 30

Glyceridae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Goniadae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 20.00 5.00 10.56 16

Nephytidae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Nereidae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Onuphidae 0.00 0.00 0.00 0 6.67 — 26.71 2 0.00 0.00 0.00 0 20.00 42.75 900.03 7

Phyllodocidae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 6.67 5.00 1.27 1

Sabellidae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Serpulidae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 6.67 6.00 1.27 1

Spionidae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 13.33 6.00 3.82 2

Unknown 6.67 — 5.09 1 0.00 0.00 0.00 0 0.00 0.00 0.00 0 6.67 — 1.27 1

Bivalvia Cerithidae 86.67 8.27 82.37 74 0.00 0.00 0.00 0 20.00 14.60 3061.79 13 6.67 18.00 602.86 1

Mactridae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Myidae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Olivellidae 33.33 2.70 0.91 12 20.00 2.33 1.47 11 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Tellinidae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Veneridae 6.67 38.00 662.81 2 0.00 0.00 0.00 0 60.00 7.32 52.99 43 0.00 0.00 0.00 0

Crustacea Corophiidae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 20.00 7.39 96.21 3 0.00 0.00 0.00 0

Copepoda 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Tanaidacea 0.00 0.00 0.00 0 0.00 0.00 0.00 0 6.67 11.37 1.27 1 0.00 0.00 0.00 0

Gammaridae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Insecta Ceratopogonidae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Ephydridae 13.33 15.00 3.82 2 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

29

SF Bay Mudflats Mid-Tide SF Bay Mudflats Low-Tide Pond B1C, CA Bandon,OR Mid-Tide

Order Family


n=15

Mean Length (mm)

Mean Wt BM/Sample

(g/m3) No. Ind.


n=15

Mean Length (mm)

Mean Wt BM/Sample

(g/m3) No. Ind.


n=15

Mean Length (mm)

Mean Wt BM/Sample

(g/m3) No. Ind.

% Occurrence in Sample

n=9

Mean Length (mm)

Mean Wt BM/Sample

(g/m3) No. Ind.


Tubificoides 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Ampharetidae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 6.67 6.00 2.54 1


Cirratulidae 0.00 0.00 0.00 0 40.00 7.83 1.70 6 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Glyceridae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Goniadae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Nephytidae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Nereidae 53.33 28.75 110.49 13 100.00 17.43 65.88 56 0.00 0.00 0.00 0 0.00 0.00 0.00 1

Onuphidae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Phyllodocidae 0.00 0.00 0.00 0 13.33 7.00 3.18 4 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Sabellidae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Serpulidae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Spionidae 0.00 0.00 0.00 0 13.33 12.00 1.91 2 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Unknown 6.67 — 2.54 1 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0


Mactridae 0.00 0.00 0.00 0 13.33 6.00 26.97 3 0.00 0.00 0.00 0 13.33 10.00 44.89 3

Myidae 0.00 0.00 0.00 0 6.67 5.00 1.96 1 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Olivellidae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Tellinidae 6.67 4.00 3.42 3 20.00 6.33 7.71 13 0.00 0.00 0.00 0 40.00 11.64 95.45 12

Veneridae 0.00 0.00 0.00 0 93.33 2.35 13.42 247 0.00 0.00 0.00 0 0.00 0.00 0.00 0


Copepoda 0.00 0.00 0.00 0 6.67 3.00 1.27 1 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Tanaidacea 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Gammaridae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0


Ephydridae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 6.67 13.00 11.45 1 0.00 0.00 0.00 0

30

Bandon, OR Low-Tide Bandon Marsh, OR Mid-Tide Bandon Marsh, OR Low-Tide Bottle Beach, WA Mid-Tide

Order Family


n=7

Mean Length (mm)

Mean Wt BM/Sample

(g/m3) No. Ind.


n=5

Mean Length (mm)

Mean Wt BM/Sample

(g/m3) No. Ind.


n=5

Mean Length (mm)

Mean Wt BM/Sample

(g/m3) No. Ind.


n=15

Mean Length (mm)

Mean Wt BM/Sample

(g/m3) No. Ind.


Tubificoides 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Ampharetidae 0.00 0.00 0.00 0 20.00 7.00 2.54 1 0.00 0.00 0.00 0 0.00 0.00 0.00 0


Cirratulidae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Glyceridae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Goniadae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Nephytidae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 6.67 7.67 11.45 4

Nereidae 0.00 0.00 0.00 0 40.00 28.00 119.53 2 0.00 0.00 0.00 0 6.67 10.00 5.09 1

Onuphidae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Phyllodocidae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 6.67 9.00 1.27 1

Sabellidae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Serpulidae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 40.00 — 3.82 1 0.00 0.00 0.00 0

Spionidae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 5.00 8.90 9

Unknown 0.00 0.00 0.00 0 0.00 — 3.82 1 0.00 0.00 0.00 0 0.00 0.00 0.00 0


Mactridae 0.00 0.00 0.00 0 80.00 8.00 30.79 7 100.00 8.00 49.94 4 0.00 0.00 0.00 0

Myidae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0

Olivellidae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 — 0.00 0

Tellinidae 28.60 5.50 12.22 6 0.00 0.00 0.00 0 0.00 0.00 0.00 0 73.33 6.65 50.05 25

Veneridae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0


Copepoda 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Tanaidacea 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Gammaridae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 40.00 4.83 23.11 11


Ephydridae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

0.00

31

32

Bottle Beach, WA Low-Tide Bowerman Basin, WA Mid-Tide Bowerman Basin, WA Low-Tide Hartney Bay, AK

Order Family


n=15

Mean Length (mm)

Mean Wt BM/Sample

(g/m3) No. Ind.


n=15

Mean Length (mm)

Mean Wt BM/Sample

(g/m3) No. Ind.


n=15

Mean Length (mm)

Mean Wt BM/Sample

(g/m3) No. Ind.


n=15

Mean Length (mm)

Mean Wt BM/Sample

(g/m3) No. Ind.


Tubificoides 6.67 5.00 1.27 1 0.00 0.00 0.00 0 0.00 0.00 0.00 0 6.67 21.00 79.60 1

Ampharetidae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0


Cirratulidae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Glyceridae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 26.67 21.25 62.64 5

Goniadae 20.00 57.00 36.04 3 0.00 0.00 0.00 0 13.33 11.00 36.04 3 13.33 26.50 58.06 3

Nephytidae 26.67 10.40 15.01 7 0.00 0.00 0.00 0 33.33 10.40 15.01 7 0.00 0.00 0.00 0

Nereidae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Onuphidae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Phyllodocidae 6.67 11.00 10.18 2 6.67 9.00 1.27 1 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Sabellidae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Serpulidae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Spionidae 6.67 7.00 2.54 1 6.67 5.00 8.90 9 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Unknown 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 6.67 11.00 36.11 1


Mactridae 26.67 11.00 71.86 2 0.00 0.00 0.00 1 6.67 5.16 23.22 12 0.00 0.00 0.00 0

Myidae 6.67 4.00 4.24 2 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Olivellidae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Tellinidae 26.67 5.62 46.55 3 0.00 0.00 0.00 0 13.33 5.63 9.29 7 46.67 8.13 141.36 23

Veneridae 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0


Copepoda 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Tanaidacea 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0 0.00 0.00 0.00 0

Gammaridae 0.00 0.00 0.00 0 46.67 4.83 23.11 11 0.00 0.00 0.00 0 0.00 0.00 0.00 0


Ephydridae 0.00 0.00 0.00 0 13.33 11.50 25.44 3 0.00 0.00 0.00 0 0.00 0.00 0.00 0

[PS1]

Documents

Pacific Flyway Shorebird Migration Program: Spring Western … · Spring Western Sandpiper migration, Northern Baja California, Mexico to Alaska Final Report 2004 NILS WARNOCK1, MARY