The preferred nest sites are on cliffs, steep banks or rocky islets and are often close to water. Ledges on tall buildings and trees have been used as well as quarries, church towers, bridges and assorted other sites such as hummocks, dirt slopes or dykes. The most common nest in North America is a scrape on a rocky ledge, often with a bit of an overhang and some dirt or debris on the ledge to scrape a laying site. The site is not necessarily on the highest cliff face in the area. If alternate sites are available, mated pairs may rotate amongst several over the course of years. Nest sites are traditional and some have been used for hundreds of years.
Tree-nesting has been infrequently documented in North America, such that a small population of pealei using old Bald Eagle nests and tree cavities along the coast of British Columbia is of interest. Six such nests within 15 miles (24 kilometers) of each other suggests the possibility of a genetically-related population that has adopted the strategy in the absence of suitable cliffs and the presence of large numbers of alcids nesting at the same sites.
The clutch size varies from three to four eggs. Rarely, clutches have reached seven eggs. The egg-laying interval is normally 48 hours but it may extend to 72 hours and can take place anytime during the day. The Peregrine Falcon is single-brooded, but replacement clutches may be initiated within two to three weeks and as many as four replacements have been noted in wild birds. By removing clutches, a female may be induced to lay up to 20 eggs. The egg ground color varies from creamy through browns and reddish, overlain by dots and blotches of warm browns with considerable variation. The shell is smooth and the eggs are subelliptical in shape. In the largest race, F. P. pealei, egg size ranged from 1.91 to 2.28 inches (48.5 to 58 millimeters) in length and 1.54 to 1.69 inches (39.1 to 43 millimeters) in width and averaged 2.10 inches (53.3 millimeters) long and 1.60 inches (40.6 millimeters) wide Eggs for F. p. anatum ranged from 1.91 to 2.24 inches (48.5 to 57 millimeters) in length and 1.52 to 1.71 inches (38.5 to 43.5 millimeters) in width and averaged 2.09 inches (53.23 millimeters) long and 1.62 inches (41.26 millimeters) wide. Eggs of the race F. p. tundrius average slightly smaller.
The age at first breeding is generally two years. The males arrive at the nest site first and following the laying of the last egg, incubation is mainly by the female. Captive males have incubated for up to one-quarter of the daylight hours. The male hunts for the female and the young as most of the brooding of the nestlings is done by the female. He will cache food nearby and the female will retrieve it during her brief forays from the nest. The incubation period varies from 33 to 35 days. Nestlings are brooded continuously for 10 to 14 days afterwhich the downy feathers are well-developed and brooding time decreases steadily. Activity outside of the nest by the young increases by about day 28 and fledging occurs from 40 to 49 days after hatching. Once the young are on the wing, there is close association for up to 60 days in some populations. Behavior during this period is varied and includes feeding, hunting, aerial acrobatics and practice flights. In some cases, the onset of migration may terminate the family bond, but it is not universally so. Young have been seen with parents as far south as the Gulf coast of Texas.
#Which species lays this egg?;question\Q32\Q32.wav
