Age, coloration and dominance in nonbreeding hummingbirds: A test of the asymmetry hypothesis

During the nonbreeding season, adult Anna and black-chinned hummingbirds ( Calypte anna and Archilochus alexandri ) have lower defense costs and more exclusive territories than juveniles. Adult C. anna are victorious over juveniles in aggressive encounters, and tend to monopolize the most temporally predictable resources.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46906/1/265_2004_Article_BF00300667.pd