The risk of brood parasitism does not affect levels of extra-pair paternity in a cuckoo host

In socially monogamous bird species, extra-pair paternity is common, but its level varies considerably within and among species. For hosts of brood parasites, the risk of brood parasitism may influence the costs of engaging in extra-pair copulations (e.g., leaving the nest undefended) and the benefits of having extra-pair young (e.g., spreading the risk of nest predation). However, whether brood parasitism risk affects extra-pair behavior in host species has rarely been tested. We investigated whether variation in the risk of brood parasitism affected levels of extra-pair paternity in Daurian redstarts, a socially monogamous passerine. As a common host of the common cuckoo, the redstart is unique in that its first clutch of the year takes place before the arrival of cuckoos. As a consequence, redstarts experience large seasonal variation in cuckoo parasitism risk, with no parasitism in the first egg-laying period and a high risk in the second period. We genotyped 995 nestlings (and unha..., , , README

The key columns for dataset

year = study year

nest_id = nest identity

clutch = egg-laying period (first/second)

plot = subplot of the study site

treatment = manipulation of perceived brood parasitism risk (cuckoo/control); 'NA' indicates nest from 2018, when we did not conduct the manipulation

clutch_size = clutch size; 'NA' means the clutch size is unknown

typed_young = number of offspring genotyped

epy_yn = whether the brood includes extra-pair young or not

epp_loss = number of extra-pair young in the brood

prop_epy = proportion of extra-pair young in the brood