Award Date

1-1-1996

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Biological Science

Number of Pages

104

Abstract

Population structure and ecological morphology of four species of raptors were studied in three migratory populations. Sharp-shinned Hawks (Accipiter striatus), Cooper's Hawks (A. cooperi), Red-tailed Hawks (Buteo jamaicensis), and American Kestrels (Falco sparverius) all migrate through three major flyways in North America: the Goshute Mountains of Nevada, the Manzano Mountains of New Mexico, and Cape May Point in New Jersey. Restriction fragment analysis of mitochondrial DNA was used to elucidate population structure, and analyses of morphological characteristics provided information on ecomorphology of raptors. Geographic population structure was found only in Red-tailed Hawks with Cape May individuals having a different haplotype than western individuals. The other three species did not exhibit obvious phylogeographic population structure with most individuals of these three species having one common haplotype. All four species exhibited size and shape differences consistent with predictions of morphological variation related to migration distance and/or habitat. Those individuals migrating through western flyways had longer wings and tails and lower body weights than eastern individuals; autumn flights being much longer in the west than in the east. I predicted that individuals from the Manzano Mountains would be capturing more mammalian and ground-dwelling prey on the breeding grounds than individuals from the other flyways. Male Cooper's Hawks and female Sharp-shinned Hawks from the Manzano Mountains differed significantly from those in other flyways for characteristics, such as short, stout tarsi, related to hunting ground-dwelling prey. Red-tailed Hawks and American Kestrels exhibited no significant differences between flyways for morphological characteristics related to hunting. In spite of low or non-existent levels of phylogeographic structure, raptors exhibit morphological variation across flyways consistent with predicted adaptations unique to different flight or predatory habits on the breeding grounds. Natural selection of wing and tail length as a response to migratory distance could account for variation across flyways in all four species. Response to selection may be through rapid morphological evolution or through phenotypic plasticity.

Keywords

Accipiter; Accipiter Cooperi; Accipiter Striatus; America; Buteo; Buteo Jamaicensis; Cooperi; Falco; Falco Sparverius; Jamaicensis; Migratory; Molecular; Morphological; North; Raptors; Sparverius; Species; Striatus; Variation

Controlled Subject

Zoology; Molecular biology

File Format

pdf

File Size

2590.72 KB

Degree Grantor

University of Nevada, Las Vegas

Language

English

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