Parental care in a sexually monomorphic Picid, the Red-headed Woodpecker

Parental care is energetically costly and is thus shared by parents in many bird species. Little is known about how parental care is shared in pairs of sexually monomorphic species. Red-headed Woodpeckers (Melanerpes erythrocephalus) are a sexually monomorphic and socially monogamous species in an almost exclusively dimorphic family (> 99% of species; Picidae). We assessed duration of diurnal incubation and brooding and frequency of nestling provisioning and nest cleaning for individually marked breeding Red-headed Woodpeckers at Fort A.P. Hill, Virginia, USA. Individuals were genetically sexed using DNA from feather samples. In addition to parent sex, we evaluated the influence of nestling characteristics (brood size and nestling age) and exogenous factors (habitat type, date, and maximum daily temperature) on parental care behaviors. We recorded and analyzed video at nests during the incubation and nestling stages. We found that females diurnally incubate more than males and males almost exclusively remove fecal sacs from nests. Using generalized linear mixed models, we found females brood young nestlings more than males, but males are the only parent to enter the cavity when chicks are > 10 days old. We found provisioning peaked during the middle of the nestling period, and provisioning frequency was higher in early summer (before 7 July) compared to late summer. The seasonal reduction in provisioning could be related to resource availability but warrants further study. This division of reproductive roles is common in dimorphic woodpecker species and supports the existence of energetic constraints to successfully fledge altricial offspring.