Editors: Myrna Pearman, Judy Boyd September 2017

Seasonal Sights and Sounds of

Alberta: Osprey

Dr Sally Stuart

The Ospreys appeared for the first time in the summer of 2013. They

were almost certainly two-year olds. They were too young to breed but

they still built a huge precarious nest on the top of a transformer pole. In

2014, they returned. They descended on the trees, exhibiting incredible

strength as they broke off huge branches to construct their nest. They

then settled down to breed. That year they successfully raised three

young, followed by two in each subsequent year.

Ospreys are fascinating birds. There is a differences in the sexes (sexual

dimorphism) which is seen not in their appearance but in their behav-

iour. Among most bird species, the male and female have somewhat

different roles in the breeding season; the Osprey has taken these role

differences to the extreme. The male will do nearly all the fishing for a

four to five month period (imagine the quantity of fish needed to feed

both adults and to raise two young that will each attain a mature weight

of 1.5 kg. The female rarely leaves the nest, concentrating on egg laying

and incubation, and defending the nest and young, During this time, she

is entirely dependant on the male for food.

The remarkable breeding success enjoyed by our neighbourhood pair is

likely because there are no other Ospreys or Bald Eagles nearby. To find

fish, the male has to fly about five km to Sylvan Lake or even further to

the Blindman River.

Ospreys are well adapted for fishing. Unlike other perching birds(which

have three toes at the front and one at the back), Ospreys have zygodac-

tyl feet : two forward-facing and two rear-facing toes. This arrangement,

combined with massive curved talons and roughened scales on the soles

of their feet (spicules), allows them to grasp fish. The practice of fishing

is not without risks; birds may drown if they lock onto a heavy fish and

cannot get airborne Diving into the water to get fish requires extensive

water proofing of the feathers, so birds will preen themselves and smear

oil on their feathers from the uropygial gland located just above the base

of the tail.

While their anatomical specializations for fishing are remarkable, so is

the Osprey’s visual acuity. The ability for raptors to see fine detail is evi-

dent in research by Fox et al., who reported the American Kestrel can

see a 2- mm insect from the top of an 18-m high tree, quite incredible!

Osprey eyes are relatively large are of the optimum size-weight ratio.

The physiology and anatomy of eyes are fascinating. In order to see, light

must be focused by the lens on the retina, a thin membrane at the back

of the eye. Hawks and eagles have remarkable retinas (where the special-

ised rod and cones cells are found). Cones respond to bright light and are

responsible for colour vision. Raptor eyes have approximately five times

more cones per square

millimetre than human

eyes.

Eye retinas contain a de-

pressed area (fovea) which

have the highest concen-

tration of cones. Humans

have one central fovea,

which is important for image sharpness. Raptors have two fovea: the

deep and the shallow. The deep fovea provides excellent distant vision

with very high resolution (the ability to discriminate two separate points).

It is apparently directed at about 45 degrees to the side of the head, an

arrangement which provides the bird with binocular vision. The shallow

fovea is responsible for monocular and close-up vision.

All the cells in the retina require a vast supply of nutrients but— unlike

humans—birds do not have blood vessels in the retina because blood

may interfere with vision. Instead, they have a specialised structure called

the pectin. The pectin is attached to the retina near the optic nerve and

interferes less with visual function. In raptors, the pecten is large and

complex.

Another eye adaptation is the presence of a third eyelid, called the nicti-

tating membrane. This thin and transparent membrane is engaged when

the bird dives, acting much like swimming goggles.

Osprey behavioural sexual dimorphism has resulted in unique acoustic

and visual signals. These signals are important, especially for the female

who spends so many months defending and protecting young at the nest.

The sonogram, below, shows the typical alarm call which most people

are familiar with. The call, which consists of a series of short (about

0.05s) low frequency sounds with a series of harmonics, will carry a long

distance.

Osprey also have screaming and guard calls for protection, excitation and

copulation calls. These calls are made by both birds; however, as the

female is particularly dependant on the male for food she also has three

calls entirely devoted to solicitation for food!

In September the Ospreys leave Central Alberta and begin their migra-

tion south, often returning to the same wintering grounds each year.

Studies show that breeding pairs do not tend to migrate or overwinter

together, and that the female will often depart while the male continues

fishing for the offspring. Juvenile Osprey migration is remarkable: young

that have flown only short distances for short periods of time depart on

a first-time journey that will take them across the ocean for up to 35-54

hours of non stop-flight, often covering distances of over 2,000kms

October fades into November; still the nest continues to provide inter-

est. Occasionally, it is occupied by Canada Geese, even a comical group

of migrating Double-crested Cormorants pause there for a brief hour or

two. So we wait for spring and the day when the Ospreys will return.

MAY 27, 28 Species Count Summary

Snow Goose 2

Cackling Goose 2

Canada Goose 1332

Trumpeter Swan 1

Gadwall 155

American Wigeon 20

Mallard 709

Blue-winged Teal 387

Cinnamon Teal 19

Northern Shoveler 217

Northern Pintail 18

Green-winged Teal 60

Canvasback 39

Redhead 120

Ring-necked Duck 133

Lesser Scaup 239

Bufflehead 153

Common Goldeneye 61

Hooded Merganser 1

Common Merganser 15

Ruddy Duck 134

Gray Partridge 7

Ring-necked Pheasant 1

Ruffed Grouse 4

Common Loon 5

Pied-billed Grebe 2

Horned Grebe 7

Red-necked Grebe 33

Eared Grebe 87

Western Grebe 2

American White Pelican 22

Double-crested Cormorant 33

American Bittern 2

Great Blue Heron 15

Turkey Vulture 9

Osprey 7

Bald Eagle 8

Northern Harrier 7

Cooper's Hawk 1

Broad-winged Hawk 1

Swainson's Hawk 11

Red-tailed Hawk 78

Rough-legged Hawk 1

Sora 19

American Coot 185

Sandhill Crane 6

Killdeer 23

American Avocet 26

Spotted Sandpiper 16

Solitary Sandpiper 2

Greater Yellowlegs 2

Willet 11

Marbled Godwit 2

Wilson's Snipe 24

Wilson's Phalarope 51

Bonaparte's Gull 9

Franklin's Gull 1

Ring-billed Gull 154

California Gull 1

Black Tern 44

Common Tern 11

Forster's Tern 13

Rock Pigeon 86

Eurasian Collared-Dove 15

Mourning Dove 13

Great Horned Owl 14

Great Gray Owl 1

Long-eared Owl 5CW

Short-eared Owl 1

Northern Saw-whet Owl 5

Ruby-throated Hummingbird 4

Belted Kingfisher 2

Yellow-bellied Sapsucker 6

Downy Woodpecker 8

Hairy Woodpecker 4

Northern Flicker 8

Pileated Woodpecker 5

American Kestrel 8

Merlin 4

Prairie Falcon 1

Western Wood-Pewee 6

Alder Flycatcher 1

Least Flycatcher 42

Eastern Phoebe 7

Western Kingbird 2

Eastern Kingbird 1

Warbling Vireo 8

Red-eyed Vireo 5

Gray Jay 3

Blue Jay 13

Black-billed Magpie 151

American Crow 224

Common Raven 77

Purple Martin 59

Tree Swallow 374

Northern Rough-winged Swallow 15

Bank Swallow 372

Cliff Swallow 844

Barn Swallow 55

Swallow species 15

Black-capped Chickadee 58

Boreal Chickadee 4

Red-breasted Nuthatch 18

White-breasted Nuthatch 12

House Wren 84

Marsh Wren 20

Ruby-crowned Kinglet 5

Mountain Bluebird 71

American Robin 189

Gray Catbird 9

European Starling 517

Cedar Waxwing 3

Common Yellowthroat 6

Yellow Warbler 184

Yellow-rumped Warbler 21

Spotted Towhee 1

American Tree Sparrow 2

Chipping Sparrow 38

Clay-coloured Sparrow 154

Vesper Sparrow 36

Lark Sparrow 1

Savannah Sparrow 90

Song Sparrow 52

Lincoln's Sparrow 2

White-throated Sparrow 23

White-crowned Sparrow 14

Dark-eyed Junco 5

Rose-breasted Grosbeak 8

Red-winged Blackbird 778

Western Meadowlark 56

Yellow-headed Blackbird 123

Brewer's Blackbird 290

Common Grackle 14

Brown-headed Cowbird 50

Baltimore Oriole 29

Purple Finch 8

House Finch 27

Pine Siskin 8

American Goldfinch 44

Evening Grosbeak 2

House Sparrow 100

COMPILER: JUDY BOYD

Participants: 39 – Jana Biber, Karin Bjorge, Myron Bjorge, Helene Boulan-

ger, Jim Boyce, Judy Boyd, Larry Boyd, Alexandra Braun, Colleen Caddy,

Jerry Caddy, John Caddy, Anto Davis, Bev Ewanchuk, Bertha Ford, Eileen

Ford, Jordan Ford, Laurel Ford, Stewart Ford, Jane Grenier-Frank, Laura

Fritz, Ben Giese, Bill Heinsen, Scott Hoyland, Carol Kelly, Keith Kline, Joyce

Lemke, Shelley Macauley, Laura Oomen, Myrna Pearman, Doug Pedersen,

Bonnie Potter, Jim Potter, Brooke Rafferty, Marg Ramsay, Brooklyn Rose,

Kim Siebold, Joanne Susat, Rick Tallas, Rick Varjassy

Area Covered: Zone 1 (Red Deer), Zone 2 (Sylvan Lake), Zone 3 (Gull Lake),

Zone 4 (Lacombe), Zone 6 (Pine Lake), Zone 7 (Penhold), Zone 8 (Dickson,

MRWC), Zone 11 (Rimbey/Bluffton), Zone 12 (Crestomere), Zone 16

(Lousana), Zone 17 (Bigelow Reservoir), Zone 25 (Three Hills), Zone 26 (Dry

Island Buffalo Jump), and Zone 27 (Rocky Mountain House).

Weather: Day 1: Temp. 8 to 25 C; Wind speed: 0 to 40 km/hr. Wind direc-

tion: variable; Cloud cover: 0-50%

Day 2: Temp. 14 to 24 C; Wind speed: 0 to 35 km/hr. Wind direction: varia-

ble; Cloud cover: 0-50%

Team Distance/Hours: Total Team Mileage: 1318.9 km; by vehicle 1256.7

km; on foot 56.2 km; by bicycle 6 km. Total Team Hours: 121 hr; by vehicle

67 hr.; on foot 27.5 hr, by bicycle 2 hr, by canoe 1 hr; feederwatch 23.5 hr.

Number of Species: 143 + 1 CW; Number of Birds: 10381 + 5 CW

Highlights: Highest recorded numbers since 2000: 2 Belted Kingfisher (tied

with 2008), 15 Eurasian Collared-Dove, 372 Bank Swallows. This was the

first time since 2000 that a Cackling Goose and Great Crested Flycatchers

were counted. This was only the second time Broad-winged Hawk and

Snow Goose were counted (both times were last counted in 2013).

Count Week birds were 5 Long-eared Owls seen on May 31.

Number of participants was down from last year's 47 to 39. The number of

bird species went up from last year's 140 to 143. (The highest recorded

number of species since 2000 was in 2008: 153.) The count of individual

birds was down from last year's 1,3126 to 1,0381.

Thanks to Judy Boyd for organizing RDRN bird counts!

Front cover designed by Doug Pederson

In Memoriam: Long-time RDRN mem-ber, Dorothy Hazlett, passed away on Au-gust 15. A celebration of her life will take place on Saturday October 14 at 2:00 PM at Gaetz Memorial United Church Hall, 4758 Ross St., Red Deer. A tribute to Dor-othy will be included in the November newsletter.

The Red Deer River Naturalists, the first natural history organization to be

established in Alberta, was incorporated as a society in 1906. The objec-

tives of the society are to foster an increased knowledge, understanding

and appreciation of natural history, and to support conservation measures

dealing with our environment, wildlife and natural resources.

Annual membership is $15.00 for individuals and $30.00 for families.

Membership period: January 1—December 31.

Regular meetings are held at 7:30 p.m. on the fourth Thursday of most

months at the Kerry Wood Nature Centre, 6300-45 Ave., Red Deer, AB.

Non-members are welcome.

Members are encouraged to contribute to this newsletter. Deadline is the

last Friday of the month.

Box 785 Red Deer, AB T4N 5H2

Phone/Fax: 403.347.8200

rdrn.nature@gmail.com www.rdrn.ca

http://wearenaturalwise.blogspot.com

May Species: Other Animals

Mammals: Beaver, Coyote, Elk, Mule Deer, Muskrat, Red Fox, Red Squirrel, Richardson's Ground Squirrel, Thirteen-lined Ground Squirrel, White-tailed Deer,

Amphibians: Boreal Chorus Frog, and Wood Frog

Insects: Alfalfa Butterfly, Boreal Bluet, 2 queen bum-blebees, bumblebee, Cabbage Butterfly, Canadian Tiger Swallowtail, Cherry-faced Meadowhawk, drag-onflies, damselfilies, Field Cricket, fritillary, Green Comma, Hudsonian Whiteface, Red-winged Click-hoppers, Whirligig Beetle, Wood Ant

Birding hikes

Photos by Myrna Pearman unless otherwise noted

NOTE: In September, hikes will start at 10:00 AM. From October 7 to December 9, hikes will start at 1:30 PM.

September 2— Heritage Ranch. Meet in the first parking lot.

September 9—Hazlett Lake. # 27432 West on Hwy 11 A . Take the last entrance before Hwy 2. I’ll be standing at the entrance.

September 16 - Slack Slough and Cooty Pond

September 23—O’Brien Wetland

September 30—Nova Nature Walk. Google for di-rections.

October 7—Maskapatoon

October 14—Three Mile Bend Meet in the first park-ing lot on your right.

October 21—River Bend Golf Course. Meet in the parking lot on your right at the bottom of the en-trance to River Bend

October 29—Heritage Ranch

November 4—Mackenzie Trails

November 18—Bower Woods. Meet on Selkirk Drive in front of #35.

November 25—Kin Kanyon. Meet at the Rotary pic-nic parking lot.

December 2—Gaetz Lakes Sanctuary. Meet at KWNC

December 9—Gaetz Lake.Meet at KWNC