Data from: Ecological and social factors constrain spatial and temporal opportunities for mating in a migratory songbird

Many studies of sexual selection assume that individuals have equal mating
opportunities and that differences in mating success result from variation
in sexual traits. However, the inability of sexual traits to explain
variation in male mating success suggests that other factors moderate the
strength of sexual selection. Extrapair paternity is common in vertebrates
and can contribute to variation in mating success and thus serves as a
model for understanding the operation of sexual selection. We developed a
spatially explicit, multifactor model of all possible female-male pairings
to test the hypothesis that ecological (food availability) and social
(breeding density, breeding distance, and the social mate’s nest stage)
factors influence an individual’s opportunity for extrapair paternity in a
socially monogamous bird, the black-throated blue warbler, Setophaga
caerulescens. A male’s probability of siring extrapair young decreased
with increasing distance to females, breeding density, and food
availability. Males on food-poor territories were more likely to sire
extrapair young, and these offspring were produced farther from the male’s
territory relative to males on food-abundant territories. Moreover, males
sired extrapair young mostly during their social mates’ incubation stage,
especially males on food-abundant territories. This study demonstrates how
ecological and social conditions constrain the spatial and temporal
opportunities for extrapair paternity that affect variation in mating
success and the strength of sexual selection in socially monogamous
species.