296 LIFE HISTORIES OP NORTH AMEBIC AIT BIRDS. 



were building their nest; some 70 yards from it was the nest of the Black 

 Rough-legged Hawk (Archibuteo lagopus sandi-johannis), while some 300 yards 

 to the north was the nest of a Raven (Corviis corax sinuatus), and near it the 

 beginning of the nest of the Labrador Falcon (Falco rusticolm ohsolefus). Just 

 beneath the latter were the deserted nests of the preceding year of the White- 

 bellied Swallow (Tacliycineta hicolor)." 



Several eggs of this species from Greenland, where it is not uncommon, 

 are also in the U. S. National Museum collection. T think the Duck Hawk 

 remains paired during life, and that when a nesting site is once selected it 

 is usually resorted to from year to year, even should the eggs be taken 

 regularly each season. They appear very much attached to certain localities, 

 and if persistent persecution during the nesting season should cause them to 

 abandon the original site they nearly always select another on the same 

 cliff, or if one cannot be found there, as near to it as possible. A site once 

 selected is valiantly defended against interlopers, and as a rule no other pair 

 of Hawks is allowed to nest in close proximity to it. Each pair seems 

 also to have its proper hunting range during the season of reproduction, 

 and any infringement on this is stoutly resisted. At other seasons they are 

 usually seen alone, and they are' at all times rather a silent bird, except- 

 ing when their homes are invaded; then they are noisy enough, and give 

 vent to loud screams and cacklings. 



Nidification in the southern and middle portions of its range begins in 

 the latter half of March, in New York and the New England States usually 

 about the beginning of April, in Colorado, Montana, and Oregon about the 

 latter half of April, and correspondingly later in Labrador and the Arctic 

 regions, where eggs have been taken throughout the month of June, and a 

 set of four at Fort Chimo, Ungava, as late as July 6, 1884. But a single 

 brood is raised in a season. Incubation lasts about four weeks and both 

 parents assist in this duty. The eggs are usually four in number, occasion- 

 ally but three, and very rarely five. These are deposited at intervals of 

 two or more days, and generally laid on the bare rock or soil, if the eyrie 

 is on a cliff or clay bank. The Duck Hawk can scarcely be said to build 

 a nest, and if there is occasionally a semblance of one, it is but very slight. 

 Sites in hollow trees are only used when cliffs or suitable bluffs are wanting, 

 and old nests of other Raptores are still more rarely resorted to. 



The eggs of the Duck Hawk vary considerably in shape as well as in 

 coloration. The most common forms are short and rounded ovate, and occa- 

 sionally a specimen is distinctly elliptical ovate. 



The ground color when visible, which is not often the case, is pale 

 creamy or yellowish white; in some specimens this is evenly overlaid with 

 coloring matter, giving it a light chocolate colored appearance, in others it 

 approaches a pale yellowish brown, and in one it is a decided fawn color. 

 The eggs are irregularly blotched, streaked, smeared, and spotted with vari- 

 ous shades of claret brown, vinaceous rufous, and brick red. In some the 



