She ain't heavy, she's my sister

Not all brood parasites are on the hunt for an unsuspecting bird of another species to take advantage of. In fact, there are many bird species who lay the occasional egg in the nest of a same-species neighbor. But is this behavior actually parasitic? For many waterfowl species, it may be that both host and egg-layer benefit from the arrangement. Join us for part II of our brood parasite mini-series, as we discuss "Brood parasitism, relatedness, and sociality: a kinship role in female reproductive tactics" (Andersson, Ahlund & Waldeck, 2019).