Parental care by Black-backed Woodpeckers in burned and unburned habitats of eastern Canada

Abstract

Nest care is an important parental contribution to offspring. In woodpeckers, males often have an equal or greater contribution to parental care, including nest sanitation. The Black-backed Woodpecker (Picoides arcticus) is a North American boreal woodpecker for which both parents are highly involved in parental care. By modifying their territory size in optimal and suboptimal habitat (e.g. burned vs unburned habitats), this species seems to have a large tolerance to variation in prey abundance at a landscape scale, and could provide a useful biological model to investigate the adaptability of parent care, particularly to relative contribution of each sex. We investigated sex- and habitat-specific parental care behaviour of Black-backed Woodpeckers at 9 nests by daily monitoring during the nestling period. Specifically, we examined two different aspects of parental care: 1) time spent at the nest, and 2) food delivery. We also compared relative contribution between sexes to nest sanitation. Despite our small sample sizes, our results show that males are more involved in nest sanitation and spend longer at the nest, and both sexes exhibit higher food delivery rates and spend less time at the nest in burned habitat. This latter result may suggest that greater effort is needed to provision Black-backed Woodpecker nestlings in unburned habitat compared to burned habitat.

Black-backed Woodpecker occupancy is extensive in green conifer forests of the southern Cascade Mountains, Oregon

“…High-severity fires create relatively high initial prey availability and are reported to be particularly important for Black-backed Woodpeckers (Smucker et al 2005, Hanson and North 2008, Hutto 2008, whereas other disturbance types such as widespread beetle infestations do not provide the same magnitude of resource (Bonnot et al 2008, Tingley et al 2020. Tremblay et al (2016) found that both male and female Black-backed woodpeckers had higher food delivery rates and spent less time at the nest per delivery in burned forests compared to green forests, which suggests that greater effort may be needed to raise young in green forests. Forests in our study area did not have recent fire or beetle damage, and we assumed they would have fewer prey resources, which would lead to lower occupancy.…”

Nestling provisioning behavior of Black‐backed Woodpeckers in post‐fire forest

“…Therefore, variation in our measured habitat covariates may not have been sufficient to reveal an effect of burn severity, as previously described for Black‐backed Woodpeckers (Tremblay et al. 2016). These woodpeckers likely seek out high‐quality habitats for nesting and foraging, which can limit detection of habitat‐based effects (Stillman et al.…”

“…However, some investigators have found that females provision nestlings more frequently than males (Kilham 1966, Short 1974), whereas others have reported no differences between the sexes (Tremblay et al. 2016). In boreal forests in Quebec, provisioning rates of Black‐backed Woodpeckers were lower in unburned than in burned forests, reflecting the need for greater foraging effort in unburned areas and potential negative effects on nestling survival (Tremblay et al.…”

“…In boreal forests in Quebec, provisioning rates of Black‐backed Woodpeckers were lower in unburned than in burned forests, reflecting the need for greater foraging effort in unburned areas and potential negative effects on nestling survival (Tremblay et al. 2016). Woodpeckers also capture larger prey when foraging in burned forests than in other types of disturbed forests (Rota et al.…”

“…In particular, males may incubate eggs, brood young at night, and perform most of the nest sanitation duties (Wozniak and Mazgajski 2003, Tremblay et al. 2016). In some species, males provision young more (Gow et al.…”