(Download) "Effects of Parasitism by Brown-Headed Cowbirds (Molothrus Ater) on Reproductive Success of Three Frequent Hosts in New Mexico (Report)" by Southwestern Naturalist * Book PDF Kindle ePub Free
eBook details
- Title: Effects of Parasitism by Brown-Headed Cowbirds (Molothrus Ater) on Reproductive Success of Three Frequent Hosts in New Mexico (Report)
- Author : Southwestern Naturalist
- Release Date : January 01, 2009
- Genre: Life Sciences,Books,Science & Nature,
- Pages : * pages
- Size : 229 KB
Description
Evidence that many populations of songbirds in North America are not reproducing at self-sustaining levels has drawn considerable attention to the brood-parasitic, brown-headed cowbird (Molothrus ater, Morrison et al., 1999; Smith et al., 2000; Ortega et al., 2005). The brown-headed cowbird is an obligate brood parasite that lays its eggs into nests of 200 species (Friedmann and Kiff, 1985). Parasitism by cowbirds may reduce reproductive success of hosts through removal of eggs of the host, reduced hatching success of the host, and through competition between nestlings of the cowbird and host (Rothstein, 1975x; Payne, 1977). In some habitats, cowbirds parasitize a considerable portion of the available hosts' nests (e.g., Elliot, 1978; Robinson, 1992; Goguen and Mathews, 1998). Further, parasitism by cowbirds may be an important limiting factor in some populations of endangered species (Robinson et al., 1995). Although brood parasitism generally reduces nesting productivity of hosts (Payne, 1977), studies of nesting dynamics of hosts have demonstrated that outcome of a parasitism event depends upon a complex of interactions between parasite and host. Size of host, life-history traits (e.g., length of incubation, diet), and behavior may influence the impact of parasitism on a given host (Robinson et al., 1995; Ortega, 1998; Lorenzana and Scaly, 1999). For example, some hosts rarely are able to raise any of their own young from nests that are parasitized (Marvil and Cruz, 1989; Harris, 1991; Ortega and Ortega, 2003), while others suffer smaller costs (Weatherhead, 1989; Eckerle and Breitwisch, 1997; Clotfelter and Yasukawa, 1999; Ortega and Ortega, 2001). In addition to characteristics of hosts, decisions made by the cowbird, such as whether to remove an egg of the host or to multiply parasitize a host, may also affect success of the host, but these behaviors are poorly understood. An improved understanding of how these traits and behaviors influence outcome of a parasitism event would be useful in predicting demographic implications of parasitism on populations of the host (May and Robinson, 1985). Further, knowledge gained of these relationships from studies of common species may be applied practically as models for rare or threatened species.
 "Effects of Parasitism by Brown-Headed Cowbirds (Molothrus Ater) on Reproductive Success of Three Frequent Hosts in New Mexico (Report)" by Southwestern Naturalist * Book PDF Kindle ePub Free){kind=link}