摘要
Egg recognition is a variable but common anti-parasitism defense among different species of birds with brood parasites.In contrast,nestling recognition is rare.Very few studies have found nestling recognition in brood parasite hosts and determined the rejection mechanism behind this behavior.Hosts may use the number of hatchling downfeathers to reject parasite nestlings.We tested whether hatchling down-feathers is a visual cue for the red-rumped swallow,a host that can recognize and reject parasite nestlings.Our results indicated that red-rumped swallows do not recognize foreign nestlings based on hatchling down-feathers.The closed nest structure and hatchling morph may explain the absence of such a mechanism.None of the rejection mechanisms found in previous studies could explain the nestling recognition in swallows.Olfactory cues,tactile cues,or other visual cues,except for single nestling or hatchling down-feathers,may provide nestling recognition in red-rumped swallows.More study is needed to evaluate these possibilities.
基金
the National Natural Science Foundation of China(Nos.31672303 to C.Y.and 31772453 to W.L.)
the current laws of China.Fieldwork was carried out under permission from Zhalong National Nature Reserve,P.R.China.
