The fact that gives the great-crested flycatcher a unique interest among all North American birds is that it invariably lines its nest with snake-skins if one can be had. Science would scarcely be worth the studying if it did not set our imaginations to work delving for plausible reasons for Nature's strange doings. Most of us will doubtless agree with Wilson (who made a special study of these interesting nests and never found a single one without cast snake-skins in it, even in districts where snakes were so rare they were supposed not to exist at all), that the lining was chosen to terrorize all intruders. The scientific mind that is unwilling to dismiss any detail of Nature's work as merely arbitrary and haphazard, is greatly exercised over the reason for the existence of crests on birds. But, surely, may not the sight of snake-skins that first greet the eyes of the fledgling flycatchers as they emerge from the shell be a good and sufficient reason why the feathers on their little heads should stand on end? "In the absence of a snake-skin, I have found an onion skin and shad scales in the nest," says John Burroughs, who calls this bird "the wild Irishman of the flycatchers."
[Illustration: BOBOLINK (Upper Figure, Male; Lower Figure, Female)]
_Length_--7 to 7.5 inches. About an inch longer than the English sparrow.
_Male and Female_--Dusky olive or grayish brown above; head darkest. Wings and tail blackish brown, the former sometimes, but not always, margined and tipped with dusky white. Throat yellowish white; other under parts slightly lighter shade than above. Olive-gray on sides. A tuft of yellowish-white, downy feathers on flanks. Bristles at base of bill.
_Range_--From Labrador to Panama. Winters in the tropics. Nests usually north of United States, but it also breeds in the Catskills.
_Migrations_--May. September. Resident only in northern part of its range.
Only in the migrations may people south of Massachusetts hope to see this flycatcher, which can be distinguished from the rest of its kin by the darker under parts, and by the fluffy, yellowish-white tufts of feathers on its flanks. Its habits have the family characteristics: it takes its food on the wing, suddenly sallying forth from its perch, darting about midair to seize its prey, then as suddenly returning to its identical point of vantage, usually in some distended, dead limb in the tree-top; it is pugnacious, bold, and tyrannical; mopish and inert when not on the hunt, but wonderfully alert and swift when in pursuit of insect or feathered foe. The short necks of the flycatchers make their heads appear large for their bodies, a peculiarity slightly emphasized in this member of the family.