RECOGNIZING BONAPARTE'S. LITTLE, AND BLACK- HEADED GULLS -THREE SIMILAR SPECIES

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by Geoff Hogan

Identifying guTTs to species and age cTass is not difficuTt when using the usuaT fier marks, and is something that more peopTe are finding enjoyment in. No Tonqer are aTT guTTs simoTy “seaguTTs” (a tenn frowned upon by ornithoTogists) but instead we have Herring, Ring-biTTed, Greater bTack- backed, IceTand, GTaucous guTTs and others. To be more precise, we may observe two-year on IceTands, juveniTe Greater bTack-backs, or subaduTt Herring guTTs. P.E.I., because of its maritime Tocation, has an abundance of guTT species patroTTing our coastTine or foTTowing pToughs turning the soiT, not to mention scrounging the K-Mart parking Tot or city dump!

One smaTT species of quTT that is abundant on P.E.I. during migration in summer and faTT, and often seen in spring as weTT, is the Bonaparte's GuTT. Because of its smaTT size and unguTT-Tike behaviour it is often mistaken for a tern. The Bonaparte's GuTT beTongs to the group often referred to as the "smaTT hooded guTTs". During the breeding season the aduTts in this group aTT attain compTeteTy dark heads, usuaTTy bTack, but some species may be grey or dark brown, which gives the impression that they are wearing a hood. After the breeding season the 'hood' mouTts and the head becomes TargeTy white. One of the best fier marks to recognize an aduTt Bonaparte's GuTT in any pTumage however, is the Tong wedge of white, with narrow bTack borders, on the upper fore-edge of the wing, formed by the white primary feathers. This "window effect” is evident as the bird fTies and distinguishes it from aTT other terns and guTTs... except one. The BTack—headed GuTT is a European Species that has been seen frequentTy in eastern North America in the past few years and is known to have bred in NewfoundTand. They resembTe Bonaparte's GuTTs in aTT pTumages and frequentTy associate with then and hence, present a chaTTenne to ‘guTT-watchers'. There are differences however. The BTack-headed GuTT is Targer, Tess tern-Tike, has a Tonger, dark red biTT (bTack on Bonaparte's) and perhaps most important, shows much bTackish on underside of primaries (the underwing of Bonaparte's is paTe grey and white). In immature birds, the darker underwing of the BTack-headed GuTT is aTso present but Tess obvious than on the aduTts.

The LittTe GuTT, another European visitor, and rare North American breeder, that occurs in our area may aTso be confused with Bonaparte's GuTTs, which it resembTes and with which it often associates. The LittTe GuTT, however, is smaTTer and Tacks the distinctive white wedge on the end of the wing. In addition, the wings have a rather round appearance and, most important, the underside of the entire win is decidedTy bTackish. LittTe GuTTs aTso have the tern—Tike flight characteristic of Bonaparte's GuTTs. JuveniTe LittTe GuTTs have a bTacker "M" pattern across the back of the wings than Bonaparte's GuTTs, aTthough juveniTe Bonaparte's aTso exhibit distinct wing markings. Both juveniTe and aduTt LittTe

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