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Bird Monitoring at Toronto'sExhibition Place Wind Turbine

Ross D. James and Glenn Coady

In December of 2002, a modern, tallwind turbine was installed atExhibition Place close to thelakeshore, in downtown Toronto.This was a joint venture of TorontoHydro and WindShare, with thecooperation of Exhibition Place. Bythe close of 2003, this turbine hadgenerated more than one millionkilowatt hours of electricity for thecity. This paper presents the resultsof a bird monitoring programundertaken in 2003 to assess thepotential impact of the turbine onbird populations.

The turbine is a Dutch LW 52Lagerwey 750 kw horizontal axismodel, with a tower standing 94 mhigh. The variable pitch blades are24 m long, and rotate at a maximumrate of 27 rpm. The generator isquiet enough that it would notinterfere with normal conversationright below it. The distant songs andcalls of White-throated and White­crowned Sparrows (see Appendix 1for scientific names of birds) wereaudible when standing right belowthe turbine. The blades swishthrough the air, but make littlemore noise at ground level than thewind would be making in the trees.The noise of the blades, however,might be loud enough higher in theair to alert birds at close range to

the presence of potential danger.The turbine is at the western

end of Exhibition Place, almost duesouth of the end of Dufferin Street,and just north of LakeshoreBoulevard. The turbine is surround­ed by paved roadways and parkinglots, and the open lawns with plant­ed trees and shrubs of theExhibition Place grounds. Buildingsare 50 m to the northeast, just morethan 50 m to the northwest, andabout 70 m to the east. The openwater of Lake Ontario lies about100 m south, beyond LakeshoreBoulevard. Within 50 m of thetower are mainly open lawns thatwere kept closely mowed, andpaved roadways. Immediatelyaround the turbine was a circle ofbark mulch. There were only a cou­ple of small shrubby patches thatwould have been more difficult tosearch. Part of the lawn was over­shadowed by the canopies of largertrees. About 15 percent of this areacould not be searched directlybecause of a chain link fence sepa­rating the Exhibition Place fromLakeshore Boulevard. The lawnsbeyond the fence could be scannedfrom inside the fence.

PROCEDURESDirect visual searches covered a 50 m

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Figure 1: Exhibition Place wind turbine, Toronto, Ontario. Photo by Toronto HydroCorporation.

Q TARIQ BIRDS AUGUST 2004

radius around the turbine (exceptbeyond the fence as noted).Searches started just after dawnand lasted about one hour each.The searcher (Coady) walked a pat­tern that covered the area at inter­vals of 5 m or less. The early startminimized the potential loss of anydead birds to diurnal scavengerssuch as crows, gulls, or squirrels, andavoided the possibility that peoplemight find something.

Searches in spring were con­ducted twice a week over fiveweeks, from 27 April to 31 May.Autumn searches were three times aweek for six weeks, 18 August to 27September. Searches were spaced toget fairly even coverage (less so inspring), but were random withrespect to weather. Many differentconditions from full sun to lightrain, and from calm to strong winds,were encountered. Notes weremade about live birds and potentialscavengers near the turbine.

A II removal by predators II

study was conducted in conjunc­tion with the searches, to assesspotential losses of dead birds topredators prior to their beingfound on searches. In total, 50 deadbirds were placed out within 50 mof the tower, 17 in spring and 33 inautumn. Thirty-one were small(warbler-sparrow size), 17 weremediurn-sized (thrush-jay size),and three were larger (woodcock­gull size). All birds were removedafter a week or more, when nolonger of much interest to a preda­tor because of the state of decay.

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RESULTSLiving birdsIn total, 44 species of birds werenoted on the ground or in treesand shrubbery near the ground, inor near the search area. The mostnumerous were Canada Goose,Ring-billed Gull, EuropeanStarling, Common Grackle, andHouse Sparrow. The most numer­ous and frequent were Ring-billedGulls in parking lots, on lawns, oron nearby breakwaters, at almostevery visit. They were found forag­ing on the lawns around the tur­bine at least a dozen times, with asmany as 46 present. Through theweeks the exhibition was operat­ing, they were attracted to thegrounds every day.

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European Starlings andCommon Grackles were presentalmost every day. Starlings wereobserved gathering nest materialson the lawns below the operatingturbine, and no doubt foraged closeby every day. Canada Geese wereclose to the turbine on at least halfthe visits in the autumn, with asmany as 31 present.

Less commonly seen speciesclose to or on the ground includedRock Pigeon, American Crow,Golden-crowned Kinglet, Ruby­crowned Kinglet, American Robin,

Cedar Waxwing, Chipping Sparrow,White-throated Sparrow, White­crowned Sparrow, Red-wingedBlackbird, Brown-headed Cowbird,House Finch, and AmericanGoldfinch. A pair of Red-wingedBlackbirds nested in the shrubberybelow the turbine blades.

Least often seen at or near theground were Ruby-throatedHummingbird, Downy Woodpecker,Northern Flicker, Warbling Vireo,Red-eyed Vireo, Blue Jay, White­breasted Nuthatch, Brown Creeper,House Wren, Swainson's Thrush,

ONTARIO BIRDS AUGUST 2004

Hermit Thrush, NorthernMockingbird, Brown Thrasher,Tennessee Warbler, Yellow Warbler,Chestnut-sided Warbler, MagnoliaWarbler, Black-throated BlueWarbler, Yellow-rumped Warbler,Blackburnian Warbler, Bay-breastedWarbler, Black-and-white Warbler,American Redstart, Ovenbird,Canada Warbler, and Song Sparrow.

On two occasions, Coady visitedthe Toronto Islands following amorning search at the turbine. Onthese occasions there were manywood-warblers seen on the islands,several hundred in one instance. But,only one species of wood-warblerhad been noted in the trees near theturbine on each of these days.Numbers of wood-warblers werealways small near the turbine.

In addition to birds seen on ornear the ground, 22 species werenoted flying near the turbine, at theheight of the blades, when in opera­tion. The most commonly seen wereRing-billed Gull, EuropeanStarling, Chimney Swift, AmericanCrow, and Rock Pigeon. Flocks ofRing-billed Gulls arriving to forageon lawns and parking lots soonafter dawn always took a flight paththat clearly avoided coming close tothe turbine. As with gulls, approach­ing Canada Geese took a flight paththat avoided direct approach, goingaround the turbine before landing.They had obviously also adapted tothe presence of the turbine prior tothe start of this study.

A flock of Bobolinks wasobserved flying directly at the rotat-

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ing blades, but easily changedcourse at close range and flewaround. A group of 15 ChimneySwifts was cruising about foragingfor some time one day, but theyseemed well aware of the turbineand avoided coming too close. Asingle Red-breasted Nuthatchapparently flew right between theblades turning at about 20 rpm andwas unharmed.

Other species seen flying nearthe turbine at blade height wereMallard, Double-crested Cormorant,Black-crowned Night-Heron,American Kestrel, Killdeer, Calidrissandpiper sp., Herring Gull, GreatBlack-backed Gull, CommonNighthawk, Northern Flicker, TreeSwallow, Cliff Swallow, BarnSwallow, Common Grackle, andAmerican Goldfinch.

Scavengers/predatorsThe mammalian predators seen inthe vicinity of the turbine weremainly Grey Squirrels (Sciurus car­olinensis), as many as 15 in one dayin autumn, and seen almost everyday. There were as many as threefree-roaming house cats (Feliscatus) seen in the vicinity. Raccoons(Procyon lotor) were seen twice.Striped Skunks (Mephitis mephitis)were possible, though none wereseen. The only one of these speciesregularly likely to be attracted tothe open lawns and roadways of theturbine area would be the squirrels.

Few people were seen close tothe tower in early morning. Morewere likely close-by during the 24th

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of May celebrations or during theCanadian National Exhibition(CNE), but few people will pick updead animals anyway. Dogs (Canisfamiliaris) were a possibility,though few were normally close,and they can be very inefficient atremoving dead birds (James 2003).

Potential avian scavengersmost likely were Ring-billed Gulls,present on many days and walkingon the grass. Crows were also a pos­sibility, but were fewer and typicallypassing at a distance.

Removal by predators studyAlthough fewer birds were placedout in spring, proportionately morewere removed then, at a time whenthere were far fewer gulls andcrows present. This suggests thesquirrels were the main agent, at atime when their alternate food sup­ply may have been scarce. Only 3 of17 (180/0) were removed within aweek of placement.

In the autumn, when searcheswere more frequent, only one of 33birds (3 %

) went missing within the2 to 3 days before a second visit wasmade. However, 3 of 33 (9 %

) wentmissing within one week. This wasat a time when gulls in particularwere more numerous and squirrelswere also more numerous, withyoung of the year. Apparently thesquirrels were now more interestedin seeds and nuts. Gulls, crows, andRaccoons were probably well sup­plied with junk food at the exhibi­tion for part of the time, and appar­ently had more readily available

ONTARIO BIRDS AUGUST 2004

food elsewhere. Given the potentialnumber of scavengers present, par­ticularly squirrels, there was rela­tively little scavenging.

If we consider all birdsremoved within one week of place­ment, only 12% were removed. Thisis probably a higher rate thanshould be used for the autumn peri­od, at a time when most casualtiesmight be expected (more nocturnalmigrants than in spring), sincesearches were more frequent (only3%- went missing between search­es). Search efficiency trials were notundertaken, since the area searchedwas almost all short grass or pave­ment that could be searched veryeasily. Even if something was over­looked one day, it probably wouldhave been found on the next visit.

Avian mortalityThe searches found one dead birdin spring and one in the autumnperiod. Both could have been localresidents and not migrants. Inspring, it was a European Starlingon 14 May, and in autumn, animmature American Robin on 30August.

DISCUSSIONGiven the ground conditions,search efficiency was probably veryhigh. Experience elsewhere hasshown that under such conditionseven individual feathers are readilyfound (James 2003). Nocturnalmigrants are considered to be atgreatest risk of collision with tallstructures (although still at low risk

at structures less than 150 m high)as they are travelling in low lightconditions. The chances of a colli­sion with a wind turbine in daylight,even in coastal situations, is virtual­ly zero (Crockford 1992, Pearson1992, Winkelman 1995). The search­es were conducted during periodsof heaviest nocturnal migration,and were more frequent in autumnwhen inexperienced young of theyear greatly enhanced numbers ofnocturnal bird migrants.

None of the larger birds placedout were touched. If any larger birdhad been hit by the turbine, it isprobable that it would have beeneaten in place, and remains wouldhave been readily visible. This wasthe result with larger birds found byscavengers at the Pickering turbine.If the number of birds found dead(two) is adjusted by a predatorremoval rate of 12% (using all thatdisappeared within a week, bothspring and autumn) and furtheradjusted by the 15% of the areathat could not be searched directly,the total projected mortality is stillfewer than three birds. The mortali­ty estimate, assuming all mortalitydid occur during the study period,would probably not have exceededthree birds. If any additional mor­tality did occur outside the studyperiod, it is unlikely to have beenmore than one additional bird.

Although mortality monitoringdid not span the entire year, it cov­ered the time of the year when mor­tality is most likely to occur. This isthe period of heaviest migration of

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small nocturnal migrants. MichaelMesure (pers. comm.) of Fatal LightAwareness Program has pointedout that the ten top species in tallbuilding kills in Toronto usually suf­fer the greatest mortality inOctober after the surveys atExhibition Place had finished.However, several of the species ofheaviest mortality at tall buildingsare warblers, the vast majority ofwhich have already left theprovince by the end of September.Why the remaining smaller num­bers should be more susceptible inOctober is uncertain.

Other species suffering highmortality in October at tall build­ings are later migrants. However,there is but a single flashing redlight on the Exhibition Place windturbine at night, and this is unlikelyto compare with lighted tall build­ings as an attractant to birds. Also,there were very few nocturnalmigrants attracted to ExhibitionPlace compared to the TorontoIslands, because there is little habi­tat of interest at Exhibition Place.The study at the Pickering wind tur­bine (James 2003) did continuethrough October and Novemberand no additional mortality of noc­turnal migrants was recorded.

Mesure also indicated thatmost of these migrants killed inOctober at buildings were daytimecasualties (860/0 in 2003). This clear­ly indicates that it is windows, andnot just obstacles, that are the pri­mary agent of mortality. Windowsare not a factor at the wind turbine.

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It seems unlikely to us that the latermigrants would have suffered anymortality at the Exhibition Placewind turbine.

Many of the diurnal raptormigrants also pass through Torontoin October and November.However, these birds are moving indaylight with good visibility, condi­tions under which collisions withanything other than glass are highlyunlikely. Many birds, particularlylarger ones, are known to avoid fly­ing within about 50 m of towers, par­ticularly if there are moving parts(Faanes 1987, James 2003, thisstudy). Even though diurnalmigrants may be abundant in areasnear communications towers, theyare almost totally absent from towerkills where tens of thousands of noc­turnal migrants are killed (Avery etal. 1978). Buteos and AmericanKestrels, for example, were com­monly observed flying at turbineblade heights in a Minnesota windfarm (73 turbines) and none wereknown to have been killed through20 months of continuous monitoring(Osborne et al. 1998).

Mesure has also pointed outthat Ring-billed Gulls usually justgrab small birds and depart, leavingno trace such as feathers, evidentwith mammalian predation.However, while gulls regularly for­aged on lawns and parking lotsadjacent to the search area, they didnot ordinarily come into the searcharea. They typically avoided the tur­bine, as they also did at Pickering(James 2003). They certainly were

ONTARIO BIRDS AUGUST 2004

not a factor in removing placed-outbirds through September. They aremuch more likely to be a removalfactor where they have learnedthere is a more constant supply offood, such as at tall downtownbuildings.

The mortality experienced at thewind turbine is only a tiny fraction ofthe numbers of birds regularly occur­ring in the area. The local birdsseemed well aware of the turbineand lived around it much as usual.Nocturnal migrants were probablyrelatively few in the immediate vicin­ity because of the built-up nature ofthe area. The mortality is closer tothat of individual houses where birdshit windows at a rate of between oneand 10 per year on average, andmuch higher at some rural areahomes surrounded by trees (Klem1990, Dunn 1993).

The level of mortality experi­enced at the Exhibition Place windturbine is absolutely insignificantwhen compared with the thousandsof birds killed annually in Torontoat tall buildings (Evans Ogden1996; www.flap.org). Each of thefree-roaming cats seen are capableof killing as many as 1000 small ani­mals per year, including birds(Coleman and Temple 1993). Eachfree-roaming cat in Toronto proba­bly kills more birds per year thanthe Exhibition Place wind turbinedid in 2003.

Although mortality at the tur­bine is likely to vary from year toyear, it is unlikely to exceed the lowlevel of 2003 by any significant

amount and could be lower. Largemortality events at wind turbines inNorth America have never beenreported, and they are unlikely infuture (Erickson et al. 2001). TheExhibition Place wind turbine willnot have a significant direct impacton bird populations, but could have avery significant indirect impactthrough providing clean energy tothe city.

Literature CitedAvery, M.L., P.F. Springer, and J.F. Cassel.

1978. The composition and seasonal varia­tion of bird losses at a tall tower in south­eastern North Dakota. American Birds 32:1114-1121.

Coleman, J.S. and S.A. Temple. 1993. A sur­vey of owners of free-roaming domesticcats in rural Wisconsin. Wildlife SocietyBulletin 21: 381-390.

Crockford, N.J. 1992. A review of the possi­ble impacts of windfarms on birds andother wildlife. Joint Nature ConservationCommission (JNCC) Report No. 27,Peterborough, United Kingdom.

Dunn, E.H. 1993. Bird mortality from strik­ing residential windows in winter. Journalof Field Ornithology 64: 254-269.

Erickson, W.P., G.D. Johnson, M.D.Strickland, D.P. Young, Jr., K.J. Semka,and R.E. Good. 2001. Avian collisions withwind turbines: a summary of existing stud­ies and comparisons to other sources ofavian collision mortality in the UnitedStates. National Wind CoordinatingCommittee Resource Document.

Evans Ogden, L.J.1996. Collision course: thehazards of lighted structures and windowsto migrating birds. World Wildlife FundCanada and Fatal Light AwarenessProgram, Toronto.

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AcknowledgementsJoyce McLean of Toronto Hydro,and Ed Hale of WindShare, alongwith Chip Weseloh of EnvironmentCanada, were involved in planningand conducting the study. Joyceacted as a main contact with all par­ties, and arranged access to the site,with Dianne Young of ExhibitionPlace. We thank Glenn Murphy forhis help in this project, and MichaelMesure for his helpful comments.

Faanes, C.A. 1987. Bird behavior and mor­tality in relation to power lines in prairiehabitats. Fish and Wildlife TechnicalReport No.7, United States Fish andWildlife Service, Washington, D.C.

James, R.D. 2003. Bird observations at thePickering wind turbine. Ontario Birds 21:84-97.

Klem, D., Jr. 1990. Collisions between birdsand windows: mortality and prevention.Journal of Field Ornithology 61: 120-128.

Osborne, R.G., C.D. Dieter, K.F. Higgins,and R.E. Usgaard. 1998. Bird flight char­acteristics near wind turbines inMinnesota. American Midland Naturalist139: 29-38.

Pearson, D. 1992. Unpublished summary ofSouthern California Edison's 1985 birdmonitoring studies in the San GorgonioPass and Coachella Valley. Presented atPacific Gas and Electric Company/California Energy Commission Workshopon wind energy and avian mortality, SanRamon, California.

Winkelman, J.E. 1995. Bird/wind turbineinvestigations in Europe. Pp. 43-48 inProceedings of the National Avian-WindPower Planning Meeting, 20-21 July 1994,Denver, Colorado.

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Appendix 1: Scientific names of bird species.

Double-crested Cormorant, Phalacrocorax auritusBlack-crowned Night-Heron, Nycticorax nycticoraxCanada Goose, Branta canadensisMallard, Anas platyrhynchosAmerican Kestrel, Falco sparveriusKilldeer, Charadrius vociferusAmerican Woodcock, Scolopax minorRing-billed Gull, Larus delawarensisHerring Gull, Larus argentatusGreat Black-backed Gull Larus marinusRock Pigeon, Columba LiviaCommon Nighthawk, Chordeiles minorChimney Swift, Chaetura pelagicaRuby-throated Hummingbird, Archilochus colubrisDowny Woodpecker, Picoides pubescensNorthern Flicker, Colaptes auratusWarbling Vireo, Vireo gilvusRed-eyed Vireo, Vireo olivaceusBlue Jay Cyanocitta cristataAmerican Crow, Corvus brachyrhynchosTree Swallow, Tachycineta bicolorCliff Swallow, Petrochelidon pyrrhonotaBam Swallow, Hirundo rusticaRed-breasted Nuthatch, Sitta canadensisWhite-breasted Nuthatch, Sitta carolinensisBrown Creeper Certhia americanaHouse Wren, Troglodytes aedonGolden-crowned Kinglet, Regulus satrapaRuby-crowned Kinglet, Regulus calendulaSwainson's Thrush, Catharus ustulatus

Hermit Thrush, Catharus guttatusAmerican Robin, Turdus migratoriusNorthern Mockingbird, Mimus polyglottosBrown Thrasher, Toxostoma rufumEuropean Starling, Sturnus vulgarisCedar Waxwing, Bombycilla cedrorumTennessee Warbler, Vermivora peregrinaYellow Warbler, Dendroica petechiaChestnut-sided Warbler, Dendroica pensylvanicaMagnolia Warbler, Dendroica magnoliaBlack-throated Blue Warbler, Dendroica caerulescensYellow-rumped Warbler, Dendroica coronataBlackburnian Warbler, Dendroica [uscaBay-breasted Warbler, Dendroica castaneaBlack-and-white Warbler, Mniotilta variaAmerican Redstart, Setophaga ruticillaOvenbird, Seiurus aurocapillaCanada Warbler, Wilsonia canadensisChipping Sparrow, Spizella passerinaSong Sparrow Melospiza melodiaWhite-throated Sparrow, Zonotrichia albicollisWhite-crowned Sparrow, Zonotrichia leucophrysBobolink, Dolichonyx oryzivorusRed-winged Blackbird, Agelaius phoeniceusCommon Grackle, Quiscalus quisculaBrown-headed Cowbird, Molothrus aterHouse Finch, Carpodacus mexicanusAmerican Goldfinch, Carduelis tristisHouse Sparrow, Passer domesticus

Ross D. James, R.R. 3, S1480, Concession 7, Sunderland, Ontario LOC IHO

Glenn Coady, 604-60 Mountview Avenue, Toronto, Ontario M6P 2L4

OFO Annual Convention and BanquetOakville, Ontario

2 and 3 October 2004

Plan to attend the OFO Annual Convention and Banquet at the Pavilion On ThePark in Oakville on 2 and 3 October 2004. On both Saturday and Sunday, experi­enced OFO birders will lead field trips to hotspots such as Dundas Marsh, VanWagners Beach, Tollgate Ponds, Fifty Point, Grimsby Lagoons, Bronte Harbour,LaSalle Marina, and High Park Hawkwatch.

Saturday's events will include Ron Scovell's book sale, the evening banquet, and aspecial presentation by expert birder Bruce Mactavish on "Newfoundland Birds:Land, Sea and Vagrants".

Send your $50 registration (includes banquet, program and field trips), payable by cheque toOntario Field Ornithologists, to: Chris Escott, 1 Shouldice Court, Toronto, ON M2L 2S3

ONTARIO BIRDS AUGUST 2004