Mark–recapture and the statistical analysis methods associated with it offer great potential for investigating fitness components associated with particular behavioral traits. However, few behavioral ecologists have used these techniques. We illustrate the insights that have come from a long–term mark–recapture study of social behavior in Cliff Swallows (Petrochelidon pyrrhonota). The number of transient swallows passing through a colony per hour increased with colony size and was responsible in part for increased rates of ectoparasite introduction from outside the group into the larger colonies. Annual survival probabilities of males engaging in extra–pair copulation attempts were lower than those of males not seen to commit extra–pair copulations, suggesting that males who engage in this behavior may be inferior individuals and that females do not benefit from copulating with them. Females engaging in intraspecific brood parasitism had higher annual survival probabilities than ones either parasitized by others or not known to be either hosts or parasites. This suggests that parasitic females are high–quality birds and that brood parasitism is an effective reproductive tactic for increasing their fitness. By estimating first–year survival of chicks, we found that a clutch size of 4 eggs is often the most productive, on average, as measured by recruitment of offspring as breeders, although birds laying the more uncommon clutch size of 5 fledge more young on average. This helps to explain the observed clutch–size distribution in which clutch size 4 is the most commonly produced.
Clutch size, Coloniality, Parasitism, Social behavior
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