140 • PhNiko toQon uiz Sponsored by Nikon Canada Glenn Coady

predominantly olive-gray and greenish above. It is uniformly plain and whitish below from the chin to the belly and flanks. Its back is not streaked and the rump is plain and close to concolour with the back. The wings are a slightly darker brown, with two narrow, white wing bars, formed by the fine white tips on both the median and greater secondary coverts. It has a dark iris sur - rounded by a prominent white eye ring, with white in the lores as well. Photo A The list of birds on the Ontario check list that might reasonably meet this Some readers are undoubtedly relieved to fairly general description includes several see that the subject of this quiz is an adult of the flycatchers of the genus Empidonax songbird, rather than a nest and eggs, a (including Acadian, Willow, Alder, Least, nestling, a juvenile bird, or some combi - Dusky and Gray), several of the vireos nation thereof. Other readers, having had (including Bell’s, White-eyed and Blue- a chance to puzzle over the photo a little, headed), Ruby-crowned Kinglet, several are probably beginning to appreciate how of the female wood-warblers of the genus little advantage this may confer upon Dendroica (including Chestnut-sided, them. Many readers, as usual, will find Pine and Bay-breasted) and Western Tan - the identification of this bird quite ager. straightforward. When trying to determine the identi - Let us begin by listing some of the ty of a bird species from such a disparate general characteristics of this bird that are group of possibilities, it is always useful immediately apparent and useful in nar - to begin by recalling the old maxim “you rowing the list of possibilities to a reason - are what you eat” (or perhaps more accu - able number of species. Our quiz bird is a rately, in the case of birds: “you are how rather small and drab songbird that is you eat”).

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Close examination of the bill structure ward curvature near the tip, which forms of many birds will help in the separation a distinct hook. Of the remaining species of species that otherwise exhibit many in our original list, this is most character - similarities. istic of the vireos, and rules out any of the Our quiz bird’s bill is much too long superficially similar female Dendroica and thick for it to possibly be a Ruby- warblers, which have rather pointed bills crowned Kinglet. It also lacks the dark bar lacking a hooked tip. that is easily noted at the base of the sec - So we know that our quiz bird is, ondaries in the kinglets. therefore, one of the Ontario vireo species The bird has a grayer upper back that with wing bars. Many will have also forms a “saddle” effect in its contrast with noticed the blue-gray legs on our quiz the lighter nape and the greener lower bird – this is another very good, but easily back. It also has a very pale wash of yel - overlooked, vireo field mark. lowish on the breast and its tertials are Of the Ontario vireo species that have broadly margined in white. Although barred wings, we can easily eliminate the these are all field marks that are similar to accidental Plumbeous Vireo from consid - a pale female Western Tanager, our quiz eration, since our bird is not uniformly bird’s bill is not stout enough at the base lead-coloured like that species. Similarly, for that species. Female Western Tanagers we need not consider the Yellow-throated tend to have more yellow-orange bills Vireo, since our bird lacks the bright yel - than the uniform horn-coloured bill on low throat and breast of that species. this bird. In addition, our quiz bird has The only remaining candidates are, much shorter primary projection than therefore, Bell’s Vireo, White-eyed Vireo one would expect for any Ontario tanager and Blue-headed Vireo. We can eliminate species. the Blue-headed Vireo because our quiz Another important aspect of this bird’s bird lacks the dark, blue-gray head with bill is that it appears to be laterally (or the boldly contrasting white “spectacles” sagittally) flattened. This is very useful in of that species. helping to distinguish it from the superfi - Our quiz bird lacks both the white iris cially similar Empidonax flycatchers, and yellow “spectacles” of an adult White- whose bills tend to be broad-based and eyed Vireo, but one must beware that more transversely flattened (top to bot - hatch year White-eyed Vireos have dark tom). Our bird is clearly not one of these eyes , and juveniles lack the bright yellow flycatchers. “spectacles”. However, White-eyed Vireos Closer inspection of the bill shape reveals that the upper mand ible has a very pronounced down-

VOLUME 26 NUMBER 2 142 of all ages tend to have considerably dark - Vireo field mark, and one which gives er (almost blackish) greater secondary them a more Warbling Vireo-like appear - coverts than the brownish coverts of ance to the head. Indeed, they are often Bell’s Vireos. This tends to present a visually mistaken for Warbling Vireos by much higher contrast appearance to the those who don’t notice the barred wings. barred wing of the White-eyed Vireo The White-eyed Vireo, on the other than the Bell’s Vireo. Our quiz bird has hand, does not have any hint of a post- light brownish greater secondary coverts ocular line, but rather a strikingly solid and wing bars with a very weak contrast. head colour behind its bold “spectacles”, It also has a much more prominent lower imparting a more “Solitary” Vireo-com - wing bar and a fainter upper wing bar. plex type of head pattern. Our quiz bird These are both characteristics that favour also exhibits a broken eye-ring that is Bell’s Vireo. White-eyed Vireo tends to more in keeping with a Bell’s Vireo than a have a much darker moss-green back White-eyed Vireo. than the Bell’s Vireo, which can be quite The bird in photo A is an adult male variable from a plain grayish to a paler, Bell’s Vireo. The photo was taken near a olive-green back. Our quiz bird also con - nest on the campus of Ohio State Univer - forms better with Bell’s Vireo in this sity in Columbus, Ohio ,on22 June regard. Another field mark we can see is a 2008 by Mikey Lutmerding. very faint, dark post-ocular line on our I chose this photo particularly because quiz bird. This is another very good Bell’s of its deceptive nature. The nominate

Photo B

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“eastern” Bell’s Vireo ( Vireo bellii bellii ) tends to be brighter (greener dorsally and more yellowish ventrally — see photos B and C for examples of more typical eastern individuals) and shorter-tailed than the three more western subspecies in North America. However, very drab, worn and faded adults like this one also occur in the east. This bird is also in a fairly vertical pos - ture that gives it more of a flycatcher Phot o C “gestalt” than the typically more horizontal postures one normally associates with the small numbers in Columbus and other vireos. counties across Ohio. In the recently com - This quiz serves as a good example of pleted Ohio Breeding Bird Atlas, there was how bird identification from a single a confirmed breeding record not very far photo, from a lone angle, is often fraught inland from the south shore of Lake Erie, with much more difficulty than bird iden - directly across from Point Pelee National tification in the field, where several angles, Park. An interesting paradox is that, repeated viewings, ranges of lighting condi - although the Bell’s Vireo is an exceedingly tions, habits, vocalizations and comparison rare vagrant species in Ontario (with very with other available species, help to form few recent accepted records), it is probably the basis for a more solid identification. also a good candidate to be one of the next Accuracy of colour saturation in photo - newly-confirmed breeding species in graphs can strongly bias first impressions, Ontario. Birders in Ontario, particularly often producing identification dilemmas those living in the southwest counties, that may be much more easily sorted out should make a point to become familiar “in the field”. This quiz clearly presented with its distinctive song, and be sure to give that challenge as well. ample coverage to its dense, early succes - Fortunately, the drab, secretive, and sional, scrubland habitat in spring and often chameleon-like Bell’s Vireo has a very summer. distinctive and unmistakable song, which Photo B was taken at the Catalina makes its detection and identification pret - Woods Forest Preserve in Orland Park, Illi - ty simple. nois, on 2 July 2008, by Paul Dacko. Photo For the past 50 years, the “eastern” Bell’s C was taken at the Cook County Forest Vireo has been undergoing a slow, but Preserve in suburban Chicago, Illinois, on steady, eastward and northward range 30 June 2008, by Craig Thayer. expansion. It was first detected nesting in Ohio in the Cincinnati area in 1968. Since Glenn Coady , 604 – 60 Mountview Avenue, the mid-1980s it has bred annually in very Toronto, Ontario M6P 2L4

VOLUME 26 NUMBER 2