BurNns—Own Broap-wINGED HaAwkK. 251 
On the 27th the nest contained a second egg which showed no 
incubation, while the hen’s egg upon being broken exhibited 
incubation of about a week. 
Datres FoR CompLete Sets—Audubon states that the eggs 
“are deposited as early as the beginning of March . . . but not 
_ until a fortnight later in mountanious parts of the districts in 
which the birds most frequently breed. Yet the only set of 
eggs he mentions having seen, was as late as May 30. Some 
of his immediate successors compromised upon “early April,” 
and a host of later writers, even up to the present time, either 
boasting of their utter lack of personal experience with the 
domestic calendar of the species or distrusting their own ob- 
servations; blindly accept the rather general statement of Au- 
dubon or his imitators, causing endless confusion in the ranks: 
of the amateurs. The number of sets of eggs of Buteo lineatus 
and other early breeding Accipitrines innocently masquerading 
under the name of B. platypterns is appalling. Any one con- 
sulting the Bibliography at the end of this paper will see a 
number of corrections, preferably by the collector or writer 
acknowledging erroneous identification; and there can be little 
doubt that others would be discovered were it possible to have 
an expert handle the specimens. 
The date for fresh eggs in complete sets varies according to 
locality, of course, but it is coincident with the bursting of the 
leaf buds on the surrounding deciduous timber, and right here 
it might be remarked that the immunity from persecution en- 
joyed by this species during the breeding season is as much 
due to the thickening screen of leaves nature speedily throws 
around its habitation as the birds’ inoffensive habits. As C. L. 
Rawson says: "Not one farmer in fifty has ever seen the bird 
to know it. ... Even the Lillibridges whose homestead has 
lone been hetween two of the best breeding stretches of chest- 
nut timber in many a furlong, did not know it, though they 
had shot, trapped and robbed nests of all the other local birds 
of prey.” 
Some latitude is to be expected in my averages through the 
probable inaccuracies in the reported state of incubation, there- 
