98-100 OB Vol 16#2 Aug1998.Pdf

98 Photo Quiz Bob Curry Rather few of our birds sit length groups. Two species of nighthawks wise along branches as this bird is in the genus Chordeiles have doing. What we have is a dark and occurred in Ontario: the Common light bird with mottled, intricate Nighthawk, which unfortunately is plumage. It displays no legs and far less common than it once was, feet, a tiny somewhat hooked bill, a and the Lesser Nighthawk, which large-headed and no-necked occurred once at Point Pelee associ appearance, and rather long, point ated with a late April push of tropi ed wings. Moreover, it is sleeping! cal air. The other three are true Our only birds which combine nightjars, although two genera are these features are the Caprimulgi involved. Alas, the Whip-poor-will dae or nightjars. It is surprising to also is heard by fewer than it once consider that in a north temperate was in Ontario, but is nonetheless a eastern jurisdiction such as is widespread breeding inhabitant of Ontario, five species of goatsuckers southern and central Ontario. The have been recorded. Poorwill, a western species, has These may be divided into two occurred accidentally on the shore ONTARIO BIRDS AUGUST 1998 99 of James Bay, and the Chuck-will's and light buffy spots, whereas the widow, a denizen of the hot, humid somewhat less cryptic nighthawks southeastern U.S., has occurred in have plain black primaries. The summer (and bred) at a few wide underparts on nighthawks are spread locations, but remains an strongly barred blackish on white extremely rare bird, being recorded or pale buff. far less than annually in the Being scrub and forest edge province. hunters, the nightjars have shorter, All these birds have a white or more rounded wings and longer buff slash across the throat, tails for increased maneuverability. although the pattern, position and On close examination, what this extent of these varies from one means results from two structural species to another. On all three features. First, the outermost nightjars, the white slash is around (tenth) primary is shorter than the base of the neck, whereas on the those immediately inward from it. nighthawks it covers the throat and On the folded primaries of a sitting chin. Of course, on our subject the bird, this difference tends to disap relaxed head is sunk into the neck pear. Second, each of the outer pri such that only a portion of the maries is more rounded and blunt, white mark may be seen. Nightjar whereas in the nighthawks these plumage is a composite of subtle are more tapered to points. The net browns, golds and blacks offering effect is that on these nightjars the superb camouflage as they sit on folded wings end short of the tail the forest floor. Nighthawks, which tip, whereas in the nighthawks the frequent open country such as wingtips reach to or beyond the tail grasslands, deserts, and, in Ontario, tip. Shield outcrops, alvars, sand plains, So the subject bird with the forest burns and hydro cuts, present rather contrasty plumage, barred a more pale appearance with more flanks and the long, black, tapered contrasts of light and dark. The sub wings is a nighthawk. But which tleties on the one hand and the con one? This bird was photographed trasts on the other are the result of by Michael Runtz at Point Pelee in distinctive patterns on specific May, just the time and place for feather tracts. The nightjars have another vagrant Lesser Nighthawk several rows of black-centred to turn up! The slightly smaller size, scapulars. The nighthawks tend to as is implied in the name Lesser, is more uniform feathering in these useless in species determination. areas, with broader light or white Common Nighthawk tends to be margins to the feathers. The night more heavily barred underneath, jar primaries are buffy or grey and there is more contrast with brown, but with blackish cross bars white, whereas Lesser is buffier. VOLUME 16 NUMBER 2 100 Again, however, these are tenden which we will return briefly in a cies only and cannot be used as moment). On Lesser, the patch is proof of identity. The critical diag positioned approximately opposite nostic feature is the position and the tip of p5, whereas in Common it extent of the white patch on the pri falls about opposite the tip of p4. maries of both species. But in our Count downwards from the outer sleeping bird, the tertials are relax most primary on our bird. You will ed and have dropped down to cover see that the tip and most of the the white patch. So is the bird exposed portion of p5 is visible. On unidentifiable as to species? a Lesser Nighthawk, the distal edge Perhaps not. Will Russell, in his of the white patch on the folded own ID Frontiers discussion group outer primaries should just be visi entitled BIRDWG01 (available at ble, whereas on this Common http://nbhc.com/birdmail.htm) Nighthawk the white patch remains offers an excellent analysis of this covered by the tertials. feature based upon his examination Controversy surrounds the point of museum specimens, prompted by that primary 9 in Lesser Nighthawk a controversial nighthawk photo in is longer than p10, whereas p10 is Living Bird, the Cornell University longer than p9 in Common publication. To understand this fea Nighthawk. This feature is well ture, it is important to know that the illustrated for both species on page primaries are numbered (1 to 10) 251 of the National Geographic from innermost to outermost. On Society guide. The problem is that Common Nighthawk, the patch is photos and observations (again, see larger, extending from p10 to p6, ID Frontiers) indicate that this fea while on Lesser, it extends from p10 ture is not diagnostic, and that on at to p7. This could be seen on a rest least some Common Nighthawks, ing bird if the tertials were not p9 can be longer than p10. Try relaxed, as they are in the Runtz studying nighthawks closely, espe photo. cially during fall migration when The guide books make much of flocks are overhead (which will not the point that the patch is farther be easy given the erratic flight of out on the wing in Lesser than in nighthawks), keeping in mind that Common. This, as it happens, is real primary proportions may vary even and not just an artifact of the more more with juveniles. rounded wing of Lesser (a point to Bob Curry, 50 Young Street, Apt. 308, Hamilton, Ontario L8N 1V2 ONTARIO BIRDS AUGUST 1998.

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