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Identification and Status ofBald Eagles, Golden Eagles,

Turkey Vultures, andBlack Vultures in Ontario

byBruce W. Duncan

IntroductionIn flight., Bald Eagles (Haliaeetusleucocephalus) , Golden Eagles(Aquila chrysaetos) , Turkey Vultures(Cathartes aura), and Black Vultures(Coragyps atratus) all appear largeand black with varying amoun ts ofpaler or white markings here andthere in the plumage. Superficially,they are similar, but closerexamination reveals differences inshape, size, flight style, andmarkings that usually identifY each.

Two recen t books, A Field Guide

to the Hawks ojNorth America byClark and Wheeler (1987) andHaw~ in Flight by Dunne et al.(1988) cover the identification ofthese species very well. This paperadds or emphasizes certaindistinctions and providesinformation on the status of eachspecies in On tario; it is notintended to be a completediscussion of iden tification features.

SOIite helpful termsAll birds are not created equal. Inspite of appearing similar in the sky,

the four species considered herehave structural differences thatinfluence flight and can assist withidentification. The importantdifferences for large, soaringspecies include wing loading, aspectratio, and the number ofemarginated or slotted primaries.The definitions of these terms are:Wing Loading: Weight divided bywing area;Aspect Ratio: Ratio of wing span towing width;Emarginated Primaries: Primaryfeathers having one or both vanesreduced in width from the tipinwards.

For a much fuller discussion, seeRerlinger (1989), chapter 5.

How do they affect flight?(1) Wing loading:A soaring bird with a low wingloading '(i.e.. less weight per unit ofwing area) is able to fly more slowlyand still remain airborne (i.e., notstall). It also has a smaller turningcircle, and can soar on weakerthermals, an ability that is especially

Bruce W. Duncan, 1049 Kirkwall Road, R. R. #1, Dundas, Ontario L9H 5E1

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helpful early and late in the day.One with a high wing loading (Le.,more weight per unit ofwing area)is able to make high speed divesand has a lower rate of sink whengliding at high speed.

The Bald Eagle has a wingloading of 80.94 N/m2 (Kerlinger1989) while the others have wingloadings that are either unknownor unpublished. However, weightsand wingspans are given in Brownand Amadon (1968), and showGolden and Bald eagles havingdouble to triple the weights ofBlack and Turkey vultures, whilewingspans of eagles and TurkeyVultures are similar, and BlackVultures smaller (see Table 1).

This means that Turkey andBlack vultures have low wingloadings and the eagles, higher.

(2) Aspect ratro:

The higher the aspect ratio, thelonger and narrower the wing andthe more efficient it is forcontinuous gliding. Albatrosseshave aspect ratios of about 20, whilethe Sharp-shinned Hawk's(Accipiter striatus) is 4.57 (Kerlinger1989). A.:spect ratios of the fourspecies are indicated as similar byKerlinger and are considered low,although no figures are given. BaldEagles have a slightly higher aspectratio (somewhat narrower wingscompared to the other species).

Immature birds (Le., those intheir first year of life) have longerwing and tail feathers than adultsand therefore have slightly loweraspect ratios (Gerrard and

.ONTARIO BIRDS AUGUST 1990

Bortolotti 1988; Brown andAmadon 1968). This means thatimmatures may be slightly lessefficient gliders. However, it alsoprovides a technique for agingthese birds. Older birds will havemoulted some or all of the wingfeathers and replaced them withshorter ones. Eagles typically do nothave a complete annual flightfeather moult so that the trailingedge of the wing has some long andsome short feathers; it appearsragged compared to the even-edgedimmature's wing. This is often thecase with the tail as well.

The ragged edges are generallyan indication that an eagle is olderthan immature. On occasion animmature will lose a wing or tailfeather by acciden t and replace itbefore the annual moult. Thereplacemen t feather will be shorter.Immatures like this are few and farbetween.

(3) Emarginated primaries:All four species have six emarginat­ed outer wing feathers, providingsix slots at the tip of the wings.These slots do two related things:(a) lower the stalling speed (i.e.,the speed at which a soaring orgliding bird can stay airborne); and(b) add more lift to the wingswithout lengthening them.

Since the feathers are "cut" onboth vanes, the slots formed havesquared ends when the wings arefully spread; this is apparently moreefficien t than one-sided slots forproviding lift to the wing (Brown1976).

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Table 1: Weights and wingspans of selected species

Species Wingspan (em) Weight (g)

Bald Eagle 1~244 3000-6300Golden Eagle 152-204 2900-5800Turkey Vulture 180 (average) 1400-1800Black Vulture 137-150 1181-19401

1 Brasiliensis race, which is about 7% smaller. Information for the atratus

race of our region is not available.

The flight styles of the birdsunder consideration are affected byall three of these factors together.The two vultures search for carrionover large areas and so need to beefficient soarers and gliders, andmay need to fly very slowly over anarea in order to detect food. Lowwing loadings and six emarginatedprimaries allow the vultures to dothis over land, including fairly earlyand late in the day when thermalsare too weak for eagles. The vultures,Turkey Vultures in -particular,seldom flap, an activity thatrequires more energy than soaring.

The two eagles, having higherwing.loadings, are able to makehigh speed dives, essen tial whenchasing prey, but with six slottedprimaries can also soar moreefficiently, important whensearching for food and migrating.The higher aspect ratio of the BaldEagle also makes it a more efficientglider, helpful when migrating.Because of their weight (and higherwing loading), the two eagles canglide or dive at much higher speedthan either vulture. A Golden Eaglewas once timed flying at 195 km/h

in a generally uphill direction(Brown 1976).

IdentificationThe following brief notes may addto or emphasize some aspects ofidentification. For a completetreatment, see the two booksmentioned at the beginning of thisarticle.

(1) Flight

Turkey Vultures fly with wingsuptilted in a pronouced dihedral,moving slowly, and rocking as theygo. They frequently give a half-flapwith the outer half of the wings,then straighten them out againquickly. Golden Eagles have slightlyuptilted wings, but not nearly sopronounced a 'V" as the TurkeyVulture. Bald Eagles and BlackVultures soar on flat wings. In fact,Bald Eagles look like flying planksbecause of their long, narrow wings.

When flapping, Black Vulturesgive half a dozen stiff, jerky flaps ata time; Turkey Vultures and eagleshave much slower, more deliberatewingbeats.

When g1iding, all species tuck

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their wings back more or lessdepending on wind and strength ofrising air. The eagles are able toglide more rapidly than the vulturesbut this may not be apparenLWatch carefully any single, fast­gliding, big black bird - TurkeyVultures are most often seen inflocks. It may be a Golden Eaglemigrating at the same time asvultures and looking very similarwhen in a half-tucked glidingposition; so similar, in fact, as to bedismissed as a Turkey Vulturewithout close scrutiny. The BlackVulture as the rarest of thesespecies in Ontario will be seenalone or with a group of Turkey.Vultures.

(2) Plumage:

BLACK VULTURE

This species is only two-thirds thesize of a Turkey Vulture and halfthe size of eagles. At a distance, itmay be confused - not with thedistinctive dihedral of the othervulture species - but with aneagle's fairly flat profile. However,its distinctive white primary patcheswill give it away.

TURKEY VUITURE

There is nothing new to add to theplumage descriptions already in theguides.

BAlD EAGLE

In immature and some subadultplumages, the Bald Eagle hasextensive white tipped with black­brown in the tail. This pattern is thesame for immature and subadult

ONTARIO BIRDS AUGUST 1990

Golden Eagles. However, in GoldenEagles, the white is a clear bandwith no dark sides on the outer tailfeathers. In Bald Eagles, the white isordered all around (tips and outertail feathers) with dark. Usually thewhite is marbled with dark like aHarlan's Hawk (Buteo jamaicensis

harlani) tail; in Golden Eagles thewhite appears immaculate.

GOLDEN EAGLE

The tawny and golden neck andhead feathers of the Golden Eaglecan appear white (like the head ofan adult Bald Eagle) when in fullsun. The extensive white in animmature Golden Eagle's tailcoupled with sun-lightened gold onthe head can bear a superficialresemblance to an adult Bald Eagle.At distances, the bird may easily bepassed off as the wrong species.

Nicoletti (1989) also pointed outsomething interesting aboutimmature Golden Eagles: some mayshow little or no white at the basesof the flight feathers. One of thisplumage was caught and banded atHawk Cliff, On tario, on 12November 1990; there was no whiteat all on the underwing flight orcovert feathers. These two whitepatches, in conjunction with thewhite patch in the tail, areconsidered standard field marks.Obviously, one must use great careand more than one or two fieldmarks when identifYing orattempting to age this species.

Nicoletti also added that onbirds in later plumages thanimmature there is a tawny bar

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Table 2: Dates and locations of Black Vulture sightings in Ontario

Date16-17 Feb 198431 Mar 19842-3 July 1986

29July 198217 Aug 198124 Aug 197420 Sep 197926 Dec-3 Jan 1987-88

LocationLong PointPointPeleeWalsingham and Turkey Point, Haldimand­NorfolkHighway 402, east Lambton CountyPoint PeleeCayuga, Haldimand-Norfolknear Kingsville, Essex CountyAldershot, Halton

across the upper wing coverts. Thisbar fades over time and is verypronounced in spring migran ts. Bythat time, immatures may have aslightly pale area here due tofading; however, the bar is a verygood mark to aid in aging GoldenEagles.

Status of the species in OntarioBlack Vulture

This is the rarest of these speciesreported in the province, with eightrecords accepted by the On tarioBird Records Committee Games1983; Wormington 1985, 1986,1987; Coady and Wormington1989). The dates are listed inTable 2.

There appears to be no patternto the times of the sightings,al though four may have beenwandering non-breeders duringsummer. The locations were all inthe southwest of the province, closeto Lake Erie in most cases,J\ldershot being the furthest northand west (at the western end ofLake Ontario).

In the Black Vulture's breedingrange further south, it is considereda permanent resident althoughindividuals wander or withdrawseasonally from the northern areas(Palmer 1988a). It is currentlyspreading northward east of theMississippi River.

Turkey Vulture

McTIwraith· (1894) reported that theTurkey Vulture "... is a rare visitor tothe southwest of Ontario, and tothe east I have not heard of itsbeing observed." Today it is acommon nesting species across thesouth and west of the province(Cadman et at. 1987), and thenumber seen in migration issteadily increasing, with 12 365sighted at Holiday Beach in the fallofl988 (Benoit 1989).

The Turkey Vulture entersOntario beginning around midMarch, and peaks during the springmigration in the last week of thatmonth and the first two weeks ofApril (pers. obs.). These dates applyto the extreme south of the

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province.During the nesting season it can

be seen almost daily in rural areasaway from unbroken foresL Mterthe breeding season, the movementout of Ontario begins in earlySeptember to the north and lateSeptember along the Lake Ontarioand Lake Erie shores. These birdsexit in largest numbers from about5 to 20 October, with the last fewgoing in mid November. However,in the past five years, there havebeen a number of sightings ofTurkey Vultures in December,January, and February in southernOntario, an indication, perhaps, ofits expanding population. Withmore birds in the province, it ismore likely that there will be someunable to move south because ofillness or injury, along with anadditional few who may inherit adefective migratory orientation thatresults in them migrating tosouthern Ontario rather than withthe rest of the population.

Ba/dEag/eThe Bald Eagle had declined inOntario due to habitat loss, directpersecution and DDT poisoning. Inthe late 1970s and throughout the1980s, however, its numbers haveslowly increased with theelimination of DDT andreintroduction programs. Ontario'swestern population in the RainyRiver District has remained quitelarge even though reproductivesuccess declined during the DDTyears (Grier 1985), but thesouthern Ontario population

ONTARIO Bums AUGUST 1990

reached a low of seven active nestsin 1983 (McKeating 1985) fromwhich it is slowly recovering(Cadman et aL 1987; Gerrard andBortolotti 1988).

The migration of Bald Eagles iscomplicated by the fact thatirnmatures and subadults from thesoutheastern United States alsomove into the province in springand out in faU. Ontario (andprobably some Quebec) breedersmove into the province fairly early,in March and April (Nicoletti andDodge 1986, 1987). Youngercohorts return north later ingeneral (Palmer 1988a) , althoughoccasional adults are seen even inJune - a few might be southernbreeders. For example, at BraddockBay on the south shore of LakeOntario in June 1987, one adult,one four-year old, five subadult(two- and three-year olds), sevenone-year olds, and two of unknownage were sighted. Although outsideOn tario, many of these birds mayhave been on their way into theprovince.

Southern birds of the year(immatures) from Florida, as wellas west along the Gulf Coast, and asfar north as Chesapeake Bay, becomeindependent of their parents fromMarch toJune. Palmer (l988a) stated

'Their northern movemen t israpid, and they spread out fromnear the Atlantic coast to inland

.well west of the main axis of theAppalachians ... The young, intheir first calendar year, aredominated by older cohorts. Bygoing north, presumably they

can find room to feed where theyare free of aggression from theirown kind; those still surviving infall return south and enter roost­ing assemblies of other pre­breeders - a better social situa­tion that prevails un til reproduc­tive maturity, when the birdsbecome territorial(pp.204-205)."

Palmer also noted that bandingevidence indicates that only afraction of second-year and olderBald Eagles migrate in the mannerof the immatures. These southern­hatched birds probably comprisethe bulk of early spring immaturesseen on migration while birdshatched the previous year in Ontarioand Quebec come north later.

During the fall migration, BaldEagles are seen from early Septemberto late November along the LakeErie north shore. There are twopeaks, in mid September and earlyto mid October (Benoit 1987, 1988,1989), perhaps indicating returningsouthern-hatched immatures earlyin the season followed by northernbirds. later. However, the evidenceavailable does not include ages and.is based on 122 birds over onlythree autumns at Holiday Beach,Ontario. It is known, according toPalmer again, that in general,young northern birds go southearlier than their elders - apattern typical of many birds ofprey.

A few Bald Eagles winter inOntario (e.g., along the NiagaraRiver, near Peterborough, inHamilton Harbour, along the lower

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Grand River), usually below dams atrapids or falls where open waterproduces injured or dead fish andbirds.

Golden EagleCadman et aI. (1987) showed onlythree breeding locations in theprovince and, of these, only one wasa confirmed Golden Eagle nestingsite. Like the Bald Eagle, it is listedunder the Endangered Species Actof On tario. To the west inmountainous country, its typicalhabitat, it becomes much commoner.

During spring migration,Golden Eagles, like all the otherspecies described here, are mostreadily seen along the southshoreline of one of the Great Lakes.Spring passage along Lake Ontarioruns from 10 March to 5 May atDerby Hill at the eastern end(Palmer 1988b); 5 March to 26 Mayat Braddock Bay near Rochester,New York (Nicoletti and Dodge1986,1987; Dodge 1989, 1990); and24 February to 23 May at BeamerConservation Area near Grimsby,Ontario at the western end (Dodge1989, 1990; Grimsby Hawkwatcher1981-88; unpublished data1975-80). The majority passthrough from 21 March to 5 Maybut there is no clearly-defined peak.

In the fall, based on HolidayBeach data, Golden Eagles are firstseen in early October but few passby until late in the month. From 24October to 11 November, 102 of thethree seasons' total of 129 wereseen. The IS-year average andrange at Holiday Beach (1974-88)

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is 27 per year (0-58). Some of thesecould be immatures from the westthat have wandered to Ontario afterdispersal from the nesting area.

It is of interest to note thatduring both spring and fallmigrations, almost all GoldenEagles are seen from 1100 to 1400h(Nicoletti and Dodge 1987; pers.obs.). This is a more restricted timethan that of Bald Eagles andvultures, and probably indicates theneed this species has for thermallift during migration.

Few Golden Eagles are sightedduring winter in the province,although two areas do report themwith some regularity: PetroglyphsProvincial Park and Sault Ste.Marie.

ConclusionOf these four species, three areknown to have increasingpopulations, and will probablyspread to areas of the provincewhere they have previously beenuncommon or absent. The fourthspecies, the Golden Eagle, has apopulation that in Ontario is notwell known at any season.

AcknowledgementsMy thanks to all my friends at HawkCliff and Beamer who over theyears have made raptors ever morefascinating for me. Special thanksto Margaret Bain, who suggested Iput these thoughts in writing forOntario Birds, and to Bob Curry andAlan Wormington for providinginformation on Black Vultures.

ONTARIO BIRDS AUGUST 1990

Literature citedBmoit, D. 1987 Eastern Great Lakes report.

Newsletter of the Hawk MigrationAs5ociation of North America 12: 42-44.

Bmoit, D. 1988 Eastern Great Lakes report.Newsletter of the Hawk MigrationA550ciation of North America 14: 52-54.

Bmoit, D. 1989 Eastern Great Lakes report.Newsletter of the Hawk MigrationA550ciation of North America 15: 71-74.

Brown, L H. 1976. Eagles of the World.Univer5e Books. New York.

Brown, L H. and D. Amadon. 1968. Eagles.Hawks. and Falcons of the World. CountryLife Books. London.

Cadman, M. D., P. FJ. Eagl8s, and F. M.H,l1Iiner. 1987. Atlas of the Breeding Birdsof Ontario. University ofWaterloo Press.Waterloo.

Clarlt, W. S. and B. K W/wltr. 1987. A FieldGuide to Hawks of North America.Houghton Mimin Company. Boston.

Goady, G. and A. Wormington. 1989. OntarioBird Records Committee report for 1988.Ontario Birds 7: 43-54.

Dodgw,j R. 1989. Eastern Great Lakes Regionreport. Newsletter of the Hawk MigrationA550ciation of North America 14: 46-51.

D()(/.gw,j R. 1990. Eastern Great Lakes Regionreport. Newsletter of the Hawk MigrationAs5ociation of North America 15: 75-84.

Dumu, P., D. Sibley and C. Sutton. 1988. Hawksin Flight. Houghton Mimin Company.Boston.

eer.,a.,d,j M. and G. R. BD"ftolotti. 1988. TheBald Eagle: Haunts and Habits of aWilderness Monarch. Western ProducerPrairie Books. Saskatoon.

on,."J 1985. The status of Bald Eagles nestingin northwestern Ontario. pp. 49-51 InGerrard,J. M. and T. N. Ingram (eds.).The Bald Eagle in Canada: Proceedings ofBald Eagle Days. 198~. White Horse PlainsPublishers, Headingly, Manitoba.

Ja'lf&lS, R. D. 198~. Ontario Bird RecordsCommittee report for 1982. Ontario Birds1: 7-15.

&rlin~ P. M. 1989. Flight Strategies ofMigrating Hawks. University of ChicagoPreS5, Chicago.

Mcllzmaith, T. 1894. The Birds of Ontario.Second Edition. William Briggs Company,Toronto.

McKeating, G. 1985. Charles Broley: Eaglesthen and now in southern Ontario.

pp. 2>341n ~rrllrd,J.M. and T. N.Ingram (ed!l.). The Bald Eagle in Canada:Proceedin~of Bald Eagle Days, 198~.

White Horse Plains Publishers, Headingly,Manitoba.

NicoUUi, F. 1989. A caution to beware whenaging Colden Eagles in flight. HawkMigration Studies 14: 22-24.

Nicolltti, F. and) Dodge. 1986. Summaryreport of the 1986 spring raptor count atBraddock Bay, New York. Braddock BayRaptor Research. Unpublished. 56 pp.

NicoUUi, F. and) Dodge. 1987. Summary reportof the 1987 spring raptor coun tatBraddock Bay, New York. Braddock BayRaptor Research. Unpublished. 50 pp.

Pal""" R. S. 1988a. Handbook of NorthAmerican Bird!l. Volume 4. DiurnalRaptors (Part 1). 'hie University Press,New Haven.

Pal-. R. S. 1988b. Handbook of NorthAmerican Bird!l. Volume 5. DiurnalRaptors (Part 2). Yale University Press,New Haven.

WOnIIingwn, A. 1985. Ontario Bird Record!lCommittee report for 1984. Ontario Birds~: 2-17.

WOnIIingwn, A. 1986. Ontario Bird Record!lCommittee report for 1985. Ontario Birds4: ~18.

Wonningwn, A. 1987. Ontario Bird Record!lCommittee report for 1986. Ontario Birds5: 42~~.

69

Nesting of White-wingedCrossbills in Oxford County

byJames M. Holdsworth and Don S. Graham

The White-winged Crossbill (Loxia

leucoptera) normally breeds in theBoreal Forest zone. However,breeding has been confirmed as farsouth as Presqu'ile Provincial Park,Victoria Coun ty, and the Waterlooarea (Smith and Lumsden 1987;Weir 1989a). This article details abreeding attempt by White-wingedCrossbills in Oxford County. Thenesting was at Wildwood Lake, anartificial reservoir in Oxford'snorthwest corner, and is among themost southerly known nest recordsin the province.

In the win ter of 1989-90,Holdsworth and Grahamrepeatedly observed about 40White-winged Crossbills feeding in

spruce (Picea spp.) plantationslocated at the eastern end ofWildwood Lake. As spring arrived,breeding behaviour becameapparent. On 17 March 1989,Holdsworth observed several malesperforming the species'characteristic flight song anddisplaying strong territorialbehaviour. By 29 March 1989,20White-winged Crossbills remained,all of which appeared to be pairedand very sedentary. These pairscould be found in the same smallspruce plantation for several days.

On 7 April, Holdsworth and. Graham observed a female White­winged Crossbill carry nestingmaterial into a Norway Spruce

James M. Holdsworth, R. R. #1, Woodstock, Ontario N4S 7V6Don S. Graham, P. O. Box 1719, Atikokan, Ontario POT 1CO

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