Effects of Experimental Malaria Infection On Migration of Yellow-rumped Warblers (Setophaga coronata)
Abstract
The potential of migratory animals to spread infectious diseases depends on how infection affects movement. If infection delays or slows the speed of travel, transmission to uninfected individuals may be reduced. Whether and how malaria (Plasmodium spp.) affects bird migration has received little experimental research. I captured 40 actively-migrating Yellow-rumped Warblers (Setophaga coronata) at a migration stopover site and held them in captivity. I inoculated 25 with P. cathemerium while 15 received sham inoculations. After 12 days the birds were released. Six P. cathemerium-inoculated birds (24%) developed P. cathemerium infections after inoculation. I radio-tagged all birds, and used radio signal strength variability as an index of activity before and after release. I radiotracked birds at the release site to measure stopover duration. Experimental groups (Infected, Exposed but uninfected, Sham) did not differ in activity levels before or after release, nor in stopover duration. This research suggests that birds do not alter the migratory stopover behavior in response to avian malaria.