Intermediate Egret at Midway Atoll

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SCOTT RICHARDSON* n 25June 1997 Jim Nestler awoke inthe field camp at Eastern Island,Midway Atoll NationalWildlife Refuge. Before sunrise, he set out on his shearwatersurvey route, winding throughthick standsof Golden Crown-beaM (Ver&esinaencelioides) and Ironwood trees(Casuarina equisetifolia). Along the way lira noticedan egret, registeredits defaultidentity•atfle--and returnedto surveying shearwaters.Only in full daylightwould the egret'strue identity becomeapparent. Threehours later and a coupleof milesto thewest, on Midway's SandIsland, lames Aliberti and Bart McDermottwere working in similarsurroundings when they, too, encountered an egret.It wasn't a Cattle Egret.Their tentativeidentification: Intermediate Egret ( Mesophoyxintermedia). I learnedabout the sightingsin lateafternoon, after many others had seenthe rarity,and went with a smallgroup of volunteersur- veyorsto find it. Aftersome anxious searching, we spied an egretfor- agingamong patches of leafyVer&esina. I studied it from 50 m away, using8-power Bausch & LombElite binoculars under an unbroken bluesky, and began taking notes: 25 lun 97 @ 1620.Small to medium-sized,not far from Cattle, probably,with paleyellow bill moreslender than Cattle(but notSnowy shape). At doserange, all-white plumage (including wingstretch) has peach or pinkcast when compared with the nearbyLaysan Albatrosses. Legs dark. Characteristic/habitual wiggleof neckside to sidenear base. Foraging in sunlightat 50 m. Peckingat shrubs,especially, and ground.Feathering on upperleg sleek.Nowhere on plumageis thereany plume-like adornment.Lores do not appearto contrastwith bill. After observingthe egret,1 consultedfidd guidesat the refuge office.I comparedBirds of Australia (Pizzey and Doyle 1980), Birds of ]apan(Wild BirdSociety of Japan1982), and Birds of Hawaiiand the TropicalPacific (Pratt et al. 1987).The lattertwo guidesmentioned a darktip to the Intermediate'syellow bill. Fewother hints to identifi- cation-and no warnings--wereissued by thesebooks. North Americanfield guides, of course,did not coverthe species. Refugemanager Rob Shallenbergerwas eagerto obtain docu- mentaryphotos of theegret, so I ledhim to thespot. We foundJames Aliberti alreadyphotographing the bird. As two camerasclicked, I resumednote-taking: Backw/Rob @ 1710.Head scratchshows black feet, maybe slightlypaler than legs. Bill tip dark.Iris yellow bright. As dose as 15 m. It isan IntermediateEgret. IntermediateEgret 25 June1997 on SandIsland, Hidway Atoll. Note the bird'sslender build and the gape line whichends * 29 KnoxLane, Be•wick, NE 03901 belowthe eye. Photograph/JamesAliberti

VOLUME53 (1999), ISSUE4 441 '- HAWAIIAN ARCHIPELAGO

MIDWAY ATOLL

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The HawaiianIslands with a detail of MidwayAtoll.

ELIMINATION OF OTHER SPECIES Tenother heron species are all white,either always or asjuveniles or morphs(Hancock and Kushlan1984). Only one,the CattleEgret (Bubulcusibis), is likelyto appearat Midway(Pratt et al. 1987).In basicplumage, it islargely white with a yellowto paleyellow bill, but hasdull yellowto greenishblack legs. At 48-55 cm,it issmaller than an IntermediateEgret (65-72 cm), and its profile---heavy-billedand short-necked--also differs from the graceful form of the Intermediate. An adult LaysanAlbatross provides a size reference for an IntermediateEgret at MidwayAtoll 25 June1997. The GreatEgret (Egretta alba, sometimes Great White Egret)is The albatrossmeasures about 80 cm (32 in) from headto tail. mostsimilar to the Intermediate;they are sometimes inseparable in A GreatEgret, by comparison,would measure 85-102 cm the field (Ali and Ripley1968, Hancock and Kushlan1984). Con- (33-40 in) andwould appear as longas or longerthan fusion can arise when birds are seen at a distance and without com- the albatross.Photograph/James Aliberti parativescale. Female Greats of the modestarace are saidto be the smallest,but at closerange any Great Egret (85-102 cm) oughtto impressan observeras large. Another feature eliminating modesta is I left Midwaya few dayslater without encountering the egret its bone-coloredtibia. An exaggeratedkink in the neck,a character again.It remained,however, for more than a month. In fact, Jim considerednoteworthy in the Greatby Hancockand Kushlan (1984), Nestlersaw two IntermediateEgrets on 27 and29 July.The lastsight- wasnot apparent in theMidway egret. The brownish bill tip provedto ing,of one individual,was on 31 July1997. be an unimportantclue; juveniles of bothspecies share this feature. Perhapsit is more characteristicof the Intermediate,as the Greats DESCRIPTION illustratedin Hancockand Kushlan(1984) are shownwithout it. The followingnotes refer to thefirst egret encountered, although the The mark that bestdistinguishes M. intermediafrom E. alba, secondcould be describedidentically. however,is the gape extension. On alba,a darkgape line extends well Size and Shape.A gracefulheron, structurally similar to Great behindthe eye,while on intermediathe line endsbelow the eye Egretor SnowyEgret, but nearerin sizeto the latter. (Hancock and Kushlan1984). This featurewas not known at the time Plumage.All white.A peachcast was noticed during early obser- of observationand wasnot noticed in the field. Photos,however, fail vations,but it disappearedin laterviews. A yellowishwash appeared to showan extendedgape line. on thebreast when it wasilluminated by directsun and seen at close Two other speciesare alwayswhite, but both SnowyEgret (E. range--possiblydue to reflectionof sunlightfrom the surrounding thula)and Swinhoe'sEgret (E. eulophotes)have yellow feet and, fre- grass. quently,black bills. Four other herons have white morphs: Reddish SoftPart•. Yellow bill with darkbrownish tip. Yellow lores closely Egret(E. rufescens),Great Blue Heron (Ardeaherodias), Eastern Reef resembledbill color.Bright yellow iris. Blackishlegs, with slightly Heron (E. sacra),and LittleEgret (E. garzetta).All four areeliminat- palertoes. ed by size,bill color,or legcolor. A ninth species,Little Blue Heron Vocalizations. None heard. (E. caerulea),is white in its first year,but at that stagehas a pale Movement/Behavior.Tended to remainin a relativelysmall area. bluishbill. Finally,the MalagasyPond Heron (Ardeola idae), besides Whileforaging, frequently "neck swayed" in themanner described by being extremelyunlikely at Midway, is all white only at its Kushlan(1978): a rapidside-to-side motion of the neck(and some- Madagascarbreeding colonies. timesbody) with the head held relatively stationary. "Walking quick- ly" (Kushlan1978) perhaps best described as prancing. Fairly rapid DISCUSSION and verticalascent when flushed;wingbeat rate moderate.Jim The IntermediateEgret ranges from Africaacross southern Asia to Nestlerdescribed the flightto be "not as choppyand bouncyas a lapan,Indonesia, and Australia. Three subspecies are recognized by Cattle,but smoothlike a Snowyor Great;' Hancockand Kushlan(1984), but onlythe nominaterace has dark

44Z NORTH AHERICAN BIRDS INTERMEDIATE EGRET

tibia.The breeding range of M. i. intermediaincludes southeast Asia AmericanOrnithologists' Union (AOU). 1998.Check-list of NorthAmerican andJapan (Hancock and Kushlan1984). Birds,7th ed.American Ornithologists' Union, Washington, D.C. Brooks,A. 1923.A commenton the allegedoccurrence of Mesophoyxinter- Bothpost-breeding disperal and annual migrations occur in M. i. media in North America. Condor25: 180-181. intermedia.Birds breeding in Japantypically fly southto winterin Campbell,R. W., N. K. Dawe,I. McTaggart-Cowan,J. M. Cooper,G. W. Kaiser, the Philippines;one banded individual was recovered 3520 km (2200 andM.. C. E.McNall. 1990. The Birds of BritishColumbia, vol. 1.University mi) from its breedingcolony (McClure 1974, cited in Hancockand of British Columbia Press,Vancouver. Hadden,E C. 1941.Midway Islands.The HawaiianPlanters' Record 45: Kushlan1984). Althoughthis recoverysuggests that Intermediate 179-221. Egretsare capable of long-distancemovements, such a migrational Hancock,J., and J. Kushlan.1984. TheHerons Handbook. Harper and Row, path includeslarge land massesfor stopovers.Both the 4400 km New York. (2800mi) from Japanto Midwayand the 6100km (3800mi) from Kermode,E 1923.Notes on the occurrenceof the PlumedEgret (Mesophoyx the southernPhilippines to Midway are mostlyopen oceanwith intermedia)in BritishColumbia. Murrelet4: 3-5. [An identicalarticle was publishedthe sameyear in CanadianField-Naturalist 37: 64-65.] occasionalsmall islets and atolls.Stopovers on theseisolated land- Kushlan,J. 1978.Wading birds. In ResearchReport Z NationalAudubon formswould have been possible--perhaps necessary--for the egrets Society,New York. to havereached Midway, unless they were aided in theirjourneys by McClure, E. 1974.Migration and Survivalof the Birdsof Asia. U.S. Army vesselstraversing the Pacific. MedicalComponent, SEATO, Bangkok. IntermediateEgrets usually are found along water margins, but Pizzey,G., and R. Doyle. 1980.A Field Guideto the Birdsof Australia. PrincetonUniversity Press, New Jersey. they also frequent grasslandswith water nearby (Hancock and Pratt,H. D., P.L. Bruner,and D. G. Berrett.1987. The Birds of Hawaii and the Kushlan1984). The Midwaybirds were seen on mowedgrass with TropicalPacific Princeton University Press, New Jersey. adjacentshrubs and trees (specifically, at the parade grounds, below Pyle, E 1984.Observations of migrant and vagrantbirds from Kure and the watertower, and nearthe hangar).They were not observedat the Midwayatolls, 1982-1983. 'Elepaio 44:107-111. Wild BirdSociety of Japan.1982. A FieldGuide to the Btrds of Japan. Kodansha two freshwaterponds on SandIsland (the catchmentbasin and the InternationalLtd., Tokyo. "dumppond"). Fewardeids have been recorded at MidwayAtoll. The first Cattle --Received10May 1999, accepted 2November 1999. Egretat Midwaywas reported by CraigHarrison on 19October 1978 (U.S.Fish and Wildlife Service files). Cattle Egrets have been reported from Septemberthrough May duringseveral years of the subse- quenttwo decades.Single birds have been the norm, but up to five Allß Weather. havebeen seen (Pyle 1984). None were present during summer 1997. BirdingGear The only otherardeids referenced for Midwayhave been "bitterns" www.kopico.com %,, blown in on winter stormwinds (Hadden 1941). The IntermediateEgret has been reported onlyonce before in North America.The record 2000 pertainsto a white heroncollected in 1879at Burrard Inlet, British Columbia (Kermode 1923).The specimenassociated with thisinci- BIRDING dent,an [ntermediateEgret in alternateplum- age,was believedby Brooks(1923) to have beenan importedskin innocentlysubstituted for theoriginal specimen, which may have rep- resenteda residentNorth Americanspecies. S•ctacle 4- 20 May Therefore,the IntermediateEgret has remain- edhypothetical in BritishColumbia (Campbell OHI• •2 et al. 1990) and North America (American Manchuria,Inner Mongolia Ornithologists'Union 1998). "the 17May-ll June operator•••••••of 7;3//// The• ' '.' Beidaihe Migratio, ACKNOWLEDGMENTS ornithologicalfff Asia I thankthe OceanicSociety for makingpossible my tours on I/I • . -. presenceat Midwayduring June 1997, the U.S. Fish /// Specialists Mr. Kinabalu and Wildlife Servicefor facilitatingaccess to refer- Arthur •tl/ Writefor 24June-16 July ences,Robert Pyle for encouragingme to preparethe Frommet •{ itineraries manuscript,James Aliberti for providing pho- INDONESIA #1 tographs,Jim Nestler for sharingfield notes, and Jean Greater Sundas Radesovichfor tellingme immediatelyof the egrets 2001 BIRDING TOURS Java, Bali presence.Thanks also to SteveMlodinow, Steve 7-30 July Stedman,Tom Will, PeterYaukey, and an anonymous THAILAND SRI LANKA reviewerfor suggestingrevisions. Special thanks to 6- 28 January 26 January-12 February INDONESIA #2 Irmgard,Jill, Ernie, Sandy, and Michelefor patiently PHILIPPINES Sumatra sharingthe momentß NW INDIA 2 February-5 March 5-27 August Rajasthan,Gujarat,Bharatpur LITERATURE CITED 4-27 January VIETNAM Ali, S.,and S. D. RipIcy.1968. Handbook of theBirds Forest Owlet Pretour North, South BHUTAN of India and Pakistan,vol. 1. OxfordUniversity 31 December-5 January 8 March-1 April 6- 29 April Press,Bombay.

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