Geographic variation in the carotenoid plumage pigmentation of male house finches ( Carpodacus mexicanus )

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72538/1/j.1095-8312.1993.tb00685.x.pd

Comparative rates of natural osteological disorders in a collection of Paraguayan birds

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74983/1/j.1469-7998.1988.tb04994.x.pd

Historic genetic structuring and paraphyly within the Great-tailed Grackle

The Great-tailed Grackle (Quiscalus mexicanus) and Boat-tailed Grackle (Q. major) are sister species that have expanded their ranges during historical times. This expansion has created an area of sympatry between these species in Texas and Louisiana, and between distinctive Great-tailed Grackle subspecies in the southwestern United States and northern Mexico. We investigated the evolutionary histories of both species using mitochondrial DNA sequence data and modern phylogenetic methods. Our results reveal genetic structure within Great-tailed, but not Boat-tailed Grackles. Great-tailed Grackles are separated into two clades, but range expansion in the north has led to secondary contact between them. Boat-tailed Grackles are monophyletic and are embedded within the Great-tailed Grackle assemblage, rendering the latter paraphyletic. These results reveal a complex phylogeographic pattern caused by recent range expansion and secondary contact of once allopatric units

An experimental study of paternal behavior in red-winged blackbirds

The effect of brood size and female nesting status on male parental behavior was investigated in red-winged blackbirds Agelaius phoeniceus using brood size manipulation experiments. Male redwings allocated parental effort on the basis of brood size and nestling age. Males began assisting females only at nests with at least three offspring older than three days. Female nesting status had no singificant influence on male parental care. When females were unable to meet a brood's demand for food, males assisted females with nestling feeding. Females did not reduce the amount of food delivered to nestlings when males assisted. The amount of food brought to nestlings by the male was additional to the amount of food provided by the female. Male assistance increased fledgling success. When female provisioning was sufficient to meet a brood's demand for food males did not assist. The value of male parental care varied inversely with the ability of the female to meet nestling food demands. The ability of unassisted females to provide sufficient food and to raise a brood of nestlings successfully appeared to be influenced by resource abundance.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46891/1/265_2004_Article_BF00299713.pd