The Grey-backed Shrike parents adopt brood survival strategy in both the egg and nestling phases

Abstract Background Great diversity exists in the parenting pattern of altricial birds, which has long been considered as an adaptive response to specific environmental conditions but not their life-history style. Methods We examined egg-laying and nestling-raising Grey-backed Shrike ( Lanius tephronotus ) that breeds only once a year on Tibetan Plateau. compared dietary composition its sympatric competitor, Brown-cheeked Laughing Thrush Trochalopteron henrici twice year. Results Female Shrikes produced fixed clutch size five, with increasing egg by laying sequence. The last offspring brood is disadvantageous hierarchy because it hatches later. However, they had largest fledgling body mass. These findings indicate adopt survival strategy both nestling phases. Moreover, males females exhibit no sexual division providing parental care made equal contribution total amount food delivered brood. This Shrikes, well items, differ significantly from those Thrush. Conclusions suggest differentiation style between competitors, rather than behavioral conditions, plays decisive role driving avian diversification.