Movements and habitat selection of fledgling Boreal Chickadees in lowland conifer forests

Abstract

Avian habitat associations during the post-fledging period are lacking for many bird species which impairs the development of management plans that address the full annual cycle of birds. We used radio telemetry to study the post-fledging movements and cover type associations of 22 broods of fledgling Boreal Chickadees (Poecile hudsonicus) at both the microhabitat and landscape scales in northern Minnesota, USA from 2020 - 2022. We used habitat measurements taken at fledgling locations and at paired random points to compare habitat use versus availability at the microhabitat scale via generalized linear mixed effects models. We also used compositional analysis, modified with age-specific movements to assess cover type selection by fledglings during the post-fledging period. These analyses were conducted on the entire post13 fledging period as well as during dependent (with parental care) and independent (without parental care) periods. Fledgling Boreal Chickadees of all ages used habitat disproportionately with respect to its availability. Cover types that contained productive and/or stagnant black spruce were strongly preferred, and areas with deciduous trees were strongly avoided. Within black spruce cover types, Boreal Chickadee fledglings selected microhabitats that contained higher percent canopy cover. Fledglings did not shift cover types at any time in the post-fledging period. Results from this study can be used by managers to develop conservation strategies that will provide and/or maintain critical habitat to support this species.