Associating Landscape Variables with Nesting Occupancy and Success of Songbirds Using Nest Boxes in Semi-urban Greenspaces

Habitat fragmentation and loss of biodiversity due to urbanization is happening at a rapid pace. Greenspaces within our cities can provide habitat for native species, and effective management of urban and semi-urban parks is an increasingly important way to support these species. I compared landscape metrics surrounding nest boxes used by five avian species in four semi-urban parks of central coastal California, USA, to determine which land cover elements best predicted nest box occupancy and success. Five species were included in this study – Ash-throated Flycatcher (Myiarchus cinerascens), Chestnut-backed Chickadee (Poecile rufescens), Oak Titmouse (Baeolophus inornatus), Violet-green Swallow (Tachycineta thalassina), and Western Bluebird (Sialia mexicana). Data on nest box occupancy and success from 96 nest boxes at four study sites were collected over five years. The landscape variables influencing box occupancy and success differed among the species, but tree cover was a high-ranked predictor for all species. The influence of human-made land cover and distance to water also differed among species but had less influence on box occupancy and success than tree cover. My research on landscape preferences among secondary cavity nesting birds in semi-urban greenspaces matched previous research conducted in natural environments, suggesting that these species have potential to nest in semi-urban environments given specific tree cover parameters. This information can be used to support avian biodiversity through appropriate land management practices at the study sites themselves and in other urban and semi-urban greenspaces