Road mortality in the blue‐black grassquit (Volatinia jacarina) is seasonally driven and sex‐biased

Abstract

Roads are responsible for different negative effects on wildlife, including the isolation of populations and the direct reduction of biodiversity. Millions of animals are killed in traffic every year. Despite that, the influence of animal behaviour on the probability of animal‐vehicle collisions has been overlooked by the literature. The blue‐black grassquit (Volatinia jacarina) is a small, migratory, dichromatic species. During the breeding period, males vigorously defend small, clustered territories. Here, we investigated how the number of roadkills varied spatially and temporally in relation to the breeding activity, density, and sex of grassquits. We demonstrated that the variation in the movement dynamics and reproductive behaviour of the grassquits are associated with a great number of casualties. Road mortality is higher during the breeding period but is not associated with juvenile dispersion. As expected, males have a higher probability of being road‐killed than females, suggesting that territory defence and mate searching may increase the risk of mortality. On the other hand, the clustering of individuals may not increase the risk of road fatalities, suggesting that other environmental attributes may influence the probability of being killed on roads.