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In cities, vegetation provides critical shelter, nesting, and foraging habitat for bird species of interest. Human actions---including development and landscaping choices---determine vegetation community composition and structure. Thus, human actions impacting vegetation are critically important to bird conservation in cities. A better understanding of how bird communities are impacted by parcel-scale actions that alter vegetation communities can help guide policy and management best practices to improve matrix habitat quality and quantity.
Here, I examined how bird habitat use varies along a vegetation gradient created by different development and landscaping choices. Where previous research focused on public green space and private residential property, I expand this research to twenty commercial office developments in King County, Washington, USA selected using stratified random sampling. All measures of the bird community are positively influenced by the presence of more native conifers, particularly old trees that are protected during development activities, and the presence of native shrubs. The bird community is negatively impacted by the presence of more non-native trees. Brown Creeper, Red-breasted Nuthatch, and Varied Thrush are among those species most impacted. In contrast to prior research, top-down neighborhood-scale variables did not explain variation in any measures of the bird community on office developments. Importantly, birds are associated with the same habitat on office developments as observed elsewhere. Together, my findings suggest an important role for developers, landowners, landscape architects, and tree protection policy in bird conservation. |
