Planet of Birds

American Kestrel (Falco sparverius) Science Article 3 abstract The degree of dimorphism between males and females has been examined in a number of raptors (Storer 1966, Reynolds 1972, Balgooyen 1976, Snyder and Wiley 1976), but few studies have reported the amount of dimorphism between mated pairs of birds. If the maintenance of a size difference […]

American Kestrel (Falco sparverius) Science Article 16 abstract An Eastern Screech-Owl (Otus asio) was found incubating her own egg and that of a Southeastern American Kestrel (Falco sparverius paulus) in late March 1995. Three owlets and the kestrels uccessfully hatched in early May; all appeared normal. The kestrel was not present in the nest box […]

American Kestrel (Falco sparverius) Science Article 18 abstract Although it is well documented that hatching asynchrony in birds can lead to competitive and developmental hierarchies, potentiallygreatly affecting growth and survival of nestlings, hatching asynchrony may also precipitate modulations in neuroendocrine developmentor function. Here we examine sibling variation in adrenocortical function in postnatally developing, asynchronously hatching […]

American Kestrel (Falco sparverius) Science Article 2 abstract Unspecified species of Haemoproteus have been recorded from American Kestrels in Texas, Colorado and Panama; and Haemoproteus elani de Mello, 1935 has been recorded from kestrels in Oklahoma. However, there are no published identifications of Haemoproteus tinnunculus in this avian host in North America. This investigation reports […]

American Kestrel (Falco sparverius) Science Article 1 abstract The American kestrel, Falco sparverius, has sex-related differences in habitat use during thenon-breeding season, with females occupying more open habitats than males. Two competinghypotheses have been proposed to explain this phenomenon: (1) males and females prefer differenthabitats, and (2) males and females prefer similar habitats, but larger […]

American Kestrel (Falco sparverius) Science Article 7 abstract We studied the acoustical characteristics of calls made by nestling American Kestrels (Falco sparverius). A total of 563 vocal samples was obtained from 88 chicks (49 males and 39 females) from 20 broods. Thirteen frequency, three numerical, and two temporal characteristics were measured using audio spectrography. Discriminant […]

American Kestrel (Falco sparverius) Science Article 5 abstract The effect of rainfall on the metabolism of birds is poorly understood. We measured the metabolism as rate of oxygen consumption (V? O2)of four male and four female American kestrels (Falco sparverius) using open-circuit respirometry. We measured V? O2 during the spring atambient temperatures (Ta) of 5, […]

American Kestrel (Falco sparverius) Science Article 6 abstract Bright coloration in birds is typically a sexually selected trait. Expression of suchtraits is sensitive to environmental factors, so they can function as bioindicators ofenvironmental contamination. Of particular value may be carotenoid-based colorationbecause it is commonly used as a social signal and these pigments have importanthealth functions. […]

American Kestrel (Falco sparverius) Science Article 15 abstract The American Kestrel (Falco sparverius) is widely distributed across mostof the United States and is one of the most abundant of all North Americanraptors. Two subspecies of kestrels occur in the southeast, F. s. sparverius andthe rarer F. s. paulus. Amanda Allen Beheler and John B. Dunning, […]

American Kestrel (Falco sparverius) Science Article 8 abstract The Southeastern American Kestrel (Falco sparverius paulus), anon-migratory subspecies of the widespread American Kestrel, has declined tothe point that it is listed as threatened in Florida, the state in which it is mostcommon. We studied the nesting biology of Southeastern American Kestrels in1999 and 2000 at Eglin […]