Functions of extensive animal dung pavements around the nests of the Black Lark (Melanocorypha yeltoniensis)

We used observational and experimental approaches to assess the possible functional significance of the often extensive pavements of livestock dung constructed by female Black Larks (Melanocorypha yeltoniensis) around their nests. These pavements are conspicuous to human observers, suggesting that they may also attract predators. The size of the pavement was correlated with, but not limited by, the density of dung in the vicinity of the nest. The relationship between pavement size and local dung density did not differ significantly between habitats or years, suggesting that females might scale their pavements according to the perceived trampling risk. Even in heavily grazed areas nest trampling was rare, and nest survival rates were similar to those in areas with few grazing animals, suggesting that pavements may reduce trampling risk without incurring an additional predation risk or, alternatively, that trampling is currently not an important threat to lark nests. An experimental manipulation of grazing animals around artificial nests yielded equivocal support for a trampling-deterrent effect of dung pavements. Dung pavements might also provide thermal benefits; experiments on artificial nests suggested that dung pavements buffer nests against extremes of heat and cold, and there was equivocal support for a positive effect of pavement size on chick tarsus growth rates. These pavements may therefore be multifunctional, but identifying the adaptive drivers of the behavior requires further research.