Parental care and chick growth rate in the Mediterranean Storm-petrel Hydrobates pelagicus melitensis

Few studies on parental care in monomorphic seabirds are available, whether or not differences between sexes are reported. We studied the Mediterranean subspecies of Storm-petrel Hydrobates pelagicus melitensis from 2007 through 2012 to determine the nature of parental care for each sex and to evaluate the birds' breeding behaviour. We found that parents' investment is equally divided during incubation and first days after hatching. When chicks grow older females invest more time in taking care of their offspring. The variability in parents effort observed in the five years lead us to conclude that parental care changes from year to year is an adaptation to variability in environmental conditions and food availability balancing long lived species vulnerability.