Mixed evidence for nest masquerading in the Blue Manakin (Chiroxiphia caudata)

Masquerading is a camouflage strategy in which the prey (here, the nests) have visual similarities to inedible objects or structures present in the surrounding environment to avoid correct identification by visually oriented predators. Here we investigate whether masquerading occurs in nests of the Atlantic Forest endemic Blue Manakin Chiroxiphia caudata, whose nests resemble pendent tufts of moss or debris. The number of tufts in a 3-m radius was the main parameter explaining nest-site choice, and nest monitoring with infra-red digital camera-traps revealed that the main nest predators were visually oriented. However, daily nest survival rate was negatively associated with the number of tufts around nests. Despite the mixed evidence for nest masquerading in this situation, it remains possible that this strategy is involved in the evolution of nest characteristics and of nest-site choice in bird species whose nests resemble nest-like structures present in their habitats, and we suggest developing further studies to test for the occurrence of masquerading.