Meeting Abstract
In seasonally sympatric species, migratory and sedentary (resident) populations may exhibit overlapping distributions in winter and early spring but become allopatric when breeding. In this case, choosing a mate that exhibits similar reproductive timing may be critical, especially for residents. While males are typically less choosy than females, resident males that are selective in allocating courtship may benefit. In the dark-eyed junco, a species that exhibits seasonal sympatry, we predicted that resident males would exhibit a preference for resident females over migrant females. We tested this prediction by conducting simulated courtship interactions (SCIs), in which we presented a free-living male with a live, female lure (migrant or resident), paired with a population-specific pre-copulatory trill. We then recorded all of the male’s courtship behaviors. Trials were conducted 22 May-16 July in 2014 (peak breeding season), and 19 April-13 May in 2016 (early breeding season). Males exhibited no preference for either female type during peak breeding season. However, early in the breeding season, when presented with resident females, males sang more short-range song, a song highly associated with overall courtship effort, approached more closely, and exhibited more visual displays than when presented with migratory females. We conclude that males distinguish between migrants and residents but only early in the breeding season, when risk of interacting with a non-reproductive migrant is high. Males may be less choosy when migrants are no longer present and a cost of choosiness could be the loss of a potential extra-pair copulation.
