Killdeer 138 
The Killdeer is perhaps the commonest of all the waders in Colorado ; 
it is a summer resident, arriving from the south early in March and 
breeding throughout the State, from the plains to about 10,000 feet, 
between April and June. It leaves again for the south late in October. 
Breeding records are: Barr (Hersey & Rockwell), Hl. Paso co. 
(Aiken) and Baca co. (Warren), in the plains; Breckenridge (Carter) 
and Twin Lakes (Scott), in the mountains ; Mesa co. (Rockwell) and 
La. Plata co. (Morrison), on the western slope. H. G. Smith in- 
formed Henderson that he saw three just east of Boulder, 
December 31st, 1904; possibly w few individyals winter in the 
State. 
Habits.—This little Plover, which gets its common 
name from its shrill two-syllabled whistle, is commonly 
found in Colorado, not only near water but in high, dry 
prairies and mesas. It is not specially gregarious, and 
is generally met with in pairs, except at migration time. 
As a rule it isnot very shy and is easily approached, 
while it is bold and most demonstrative in defence of 
its young. 
It makes its nest on the ground, very generally near 
water on the sand, but at other times in meadows or 
cultivated fields and even in quite dry, high places. 
The nest, a poor affair of a few twigs is arranged in a 
depression. The eggs, almost always four in number, 
are buffy or drab, with spots and heavy blotches of 
dark purplish or blackish-brown, most numerous at 
the larger end. In shape they are very pyriform and 
pointed, and they average 155 x 1°05. The nesting 
time appears to extend over a long period in Colorado. 
Gale found eggs exceptionally early in April, and gives 
as an average date, April 20th to May 20th; an egg in 
the Colorado College Museum, presented by I. C. Hall, 
was taken so late as June 24th, near Greeley, and is 
stated to have been fresh and unincubated. Possibly 
two broods are raised. Both parents share in the labours 
of incubation. 
