Parental Care, Male Desertion, and Reproductive Success in the Spanish Sparrow, Passer hispaniolensis

Parental care in altricial birds is costly, and mate desertion can occur due to sexual conflict over the level of parental investment in the offspring. This cessation of parental care by 1 parent can affect the success of the current reproduction. In the Spanish Sparrow (Passer hispaniolensis), the nests can either have bi-parental or female-only care. Males desert early in the breeding cycle. This study quantifies parental feeding effort and brooding behavior in nests with bi-parental or femaleonly care, and describes the impact of desertion on reproductive success. The absence of differences between sexes in bi-parental care nests suggests that males generated feeding efforts similar to females, but females performed a greater number of brooding visits. Bi-parental care nests presented higher total feeding effort compared to uni-parental care nests, but the average feeding care received by each nestling did not significantly differ between the 2 types of nests, due to the higher number of nestlings present in the bi-parental nests. From these results, we expect, as was observed, that nestling conditions were similar between uni- and biparental nests. Only hatching success differed between uni- and bi-parental nests, while other breeding success parameters did not significantly differ between nest types. Single females invested significantly more per nestling than did coupled female, having to provide more in order to feed the same number of offspring. These results suggest that single females compensated for the absence of male parental care in order to maintain their short-term fitness.

Paulo A. M. Marques, Zoological Studies 43(1): 123-131