NOTES
A WHITE GREEN HERON IN SOUTHERN CALIFORNIA
KIMBALL L. GARRETT, Sectionof Vertebrates,Natural History Museumof Los AngelesCounty, 900 ExpositionBlvd., Los Angeles, California 90007
Albinism,leucism, and otherpatterns of pigmentreduction are widespreadamong birds,with exampleshaving been documented for 50 avianfamilies in NorthAmerica alone,representing well over 245 species(Ross 1963). Recurringpigment reduction within populationsmay have interestingbehavioral and evolutionaryimplications (Graves1992, Holyoak 1978), but most publicationsdocumenting albinism and leucismseek simply to addto a growingregistry of affectedspecies. Of more direct concernto the field ornithologistare casesin which albinisticindividuals resemble other species,confusing species-level identification (Garrett 1990). Here I report a leucisticor "partialalbino" Green Heron (Butoridesvirescens) at Malibu Lagoon, LosAngeles County, California, and discuss implications of thisunusual plumage for speciesidentification. A reviewof Palmer(1962), Ross(1963), Hancockand Elliott (1978), Cramp and Simmons(1977), Brown et al. (1982), and Marchantand Higgins(1990) revealedno previousrecords of albinismor leucismin the Butorides striatusspecies complex, within which B. virescensis againconsidered specifically distinct(Monroe and Browning 1992, AOU 1993). I didnot undertakean exhaustive searchof regionalliterature. I discoveredthe unusualheron at this smallcoastal estuary on 15 August1992; sevennormally plumaged Green Herons were present at the lagoonthe sameday. Kiff and Nakamura(1979) consideredthis speciesa "commonresident" there. Hal Spearobserved and photographed(Figure 1) the birdthe sameday. In size,shape, and behaviorthe bird was a typicalButorides; it was not heardto call. Its plumage was entirelypure whiteexcept for an inconspicuousline of darkleathering on the forecrown,extending back just posterior to the eye.The followingbare-part and soft- part colorswere recorded in the field:bill brightyellow basally and somewhat duller yellowdistally, with dusky along the culmenand at the baseof the maxilla;eyes bright yellow;a patchof brightgreen skin between the eyeand the bill;legs bright yellow- green. Many speciesof heronsand egretsare essentiallypure white in plumage,either in all plumages(Great Egret, Casmerodiusalbus; many speciesof œgretta),as immatures(Little Blue Heron, œgrettacaerulea), in basicplumage (Cattle Egret, Bubulcusibis), or as one particularmorph (e.g., ReddishEgret, E. rulescerts).Apart fromthe inconspicuousarea of darkleathering on the forecrown,the MalibuLagoon heronmatched the purewhite plumage of otherlocal white small herons (Snowy and CattleEgrets) and could easily have been dismissed as one of thosespecies. Bare-part colorsvary notably with age andseason within the Ardeidae(Hancock and Kushlan 1984, Palmer 1962, McVaugh1972) and must be usedcautiously for species identification.However, the bare part colors of the Malibu Lagoon heron, as describedabove, fall outsidethe range of the Snowyor Cattle Egret or any local ardeidbesides Butorides. The extensiveyellow on the bill may suggesta hatching- year bird or be the resultof the unusualmelanin reduction. The bird'sshape, includingthe relativelylarge bill, shortlegs, and hunchedposture were the most 198 Western Birds 25:198-200, 1994 NOTES
.o
Figure1. White Green Heron (Butoridesvirescens) at MalibuLagoon, Los Angeles County. California. 15 August1992. Photos by Hal Spear 199 NOTES obviousfactors confirming its identificationas a GreenHeron. The foragingbehav- ior,slow stalking and motionlessprey-searching at the water'sedge or in veryshallow water,was also typical for thisspecies. I thankNancy Spear for additionalinformation on thissighting and for permission to publishthe photographs.The photographswere cheerfullyobtained, at my request,by the late Hal Spear. Hal's contributionsto field ornithologyand bird conservationin the Los Angelesarea were many, and he is missed;this note is dedicatedto his memory.
LITERATURE CITED
AmericanOrnithologists' Union. 1993. Thirty-ninthsupplement to the American Ornithologists'Union Check-list of North American Birds. Auk 110:675- 682. Brown, L. H., Urban, E. K., and Newman, K. 1982. The Birds of Africa, vol. 1. Academic Press, London. Cramp, S., and Simmons,K. E. L. 1977. Handbookof the Birdsof Europe, the MiddleEast, and North Africa,vol 1. OxfordUniv. Press,Oxford, England. Garrett,K. L. 1990. LeucisticBlack-vented Shearwaters (Puffinus opisthomelas) in southern California. W. Birds 21:69-72. Graves, G. R. 1992. The endemic landbirdsof Henderson Island, southeastern Polynesia:Notes on naturalhistory and conservation.Wilson Bull. 104:32-43. Hancock,J., and Elliott,H. 1978. The Heronsof the World. Harper and Row, New York. Hancock,J., and Kushlan,J. 1984. The HeronsHandbook. Harper and Row, New York. Holyoak,D. T. 1978. Variablealbinism of the flightfeathers as an adaptationfor recognitionof individualbirds in somePolynesian populations of Acrocephalus warblers. Ardea 66:112-117. Kiff, L. F., and Nakamura,K. 1979. The birdsof MalibuLagoon. Audubon Imprint 4(2): 1-13. Marchant,S., and Higgins,P. J. 1990. Handbookof Australian,New Zealandand Antarctic Birds, vol. 1, Ratites to Ducks. Oxford Univ. Press Australia, Melbourne. McVaugh,W. 1973. The developmentof four North Americanherons. Living Bird 11:155-173. Monroe, B. L., Jr., and Browning,M. R. 1992. A re-analysisof Butorides.Bull. Br. Ornithol. Club 112:81-85. Palmer, R. S., ed. 1962. Handbook of North American Birds, vol. 1. Yale Univ. Press, New Haven. Ross,C. C. 1963. Albinismamong North Americanbirds. Cassinia 47:2-21.
Accepted 30 July 1994
2OO