Brood desertion in Kentish plover: the value of parental care

To understand the evolution of parental care, one needs to estimate the pay offs from providing care for the offspring and from terminating care and de serting them. In this study we estimated the payoff from care provision, an d in a companion paper we analyze the payoff from offspring desertion. In t he current study we experimentally investigated the influence of the number and sex of attending parents on growth and survival of offspring in the Ke ntish plover Charadrius alexandrinus, in two sites (A and B). Either the ma le or the female parent was removed from some broods at hatching of the chi cks (female-only and male-only broods, respectively), whereas in control br oods both parents were allowed to attend their young. At site A survival of the chicks was lower in uniparental (male-only and female-only) broods tha n in control broods, whereas we found no difference in brood survival at si te B. Brood survival decreased over the season. Removal of either parent di d not influence the growth of the young, although growth varied over the br eeding season, and it was significantly different between the sites. These results suggest that the payoff from parental care decreases over the breed ing season and that the value of parental care (i.e., the contribution of p arents to the survival of their young) may depend on the environment.