The ecological role of native-plant landscaping in residential yards to birds during the nonbreeding period

Residential yards are a form of urban land use that cover a considerable
amount of area in cities worldwide and provide important habitat for
wildlife, especially when landscaped with native plants. Nevertheless,
most native-plant landscaping and wildlife research in the northern
temperate regions of the world has been conducted during the spring and
summer breeding periods, leaving a gap in our understanding of the
importance of residential yards and native plants as habitats for animals
during the nonbreeding period. To fill this gap, we quantified the
ecological role of native-landscaped yards to avifauna throughout Greater
Los Angeles, California (L.A.) during the winter nonbreeding period, which
is a time of year when the region hosts a high abundance and diversity of
migratory and resident birds. We surveyed birds and habitat features from
October-March of 2020 and 2021 at 22 pairs of native and
nonnative-landscaped yards plus ten additional native-landscaped yards. We
had three objectives for our study. First, we compared avifaunal
communities, including feeding and nonfeeding behaviors, and habitat
features between native and non-native-landscaped yards. Second, we
quantified relationships between habitat features and bird richness,
abundance, and feeding and nonfeeding behaviors — focusing on species
affiliated with urban or natural terrestrial ecosystems of the region.
Third, we documented feeding and nonfeeding behaviors by birds with native
and non-native plants. Native-landscaped yards had a greater cover of
native trees, shrubs, and herbaceous plants, and a higher cover of natural
habitat elements, including leaf litter and bare-ground cover. Bird
richness and abundance — especially bird species affiliated with tree and
shrub-dominated ecosystems — were greater in native than
nonnative-landscaped yards. Further, yards with a higher cover of native
plants supported greater numbers of feeding birds, with individuals
focusing their foraging behaviors on distinct native trees and shrubs,
including Quercus spp. (oak), Heteromeles spp. (toyon), Arctostaphylos
spp. (manzanita), and Salvia spp. (sage). Our results suggested that
residential yards landscaped with native plants provide important habitats
for birds during the nonbreeding period and are a viable approach for
residents and cities if improving conditions for birds throughout the
annual cycle is a goal.