Long-Term Occupancy of Home Ranges and Short-Term Changes in Use of Habitat by California Towhees (Pipilo crissalis)

Abstract

California towhees (Pipilo crissalis) defend all-purpose, type-A territories throughout the year and are believed to remain on home ranges for successive breeding seasons. I present the first data regarding use of space by California towhees from a long-term study of a color-banded population. I examined individual site-fidelity to home ranges over 5 breeding seasons and combined this information with radiotelemetry data to assess sizes of home ranges and use of habitats. California towhees exhibited strong site-fidelity to breeding territories. All (n = 31) individuals located >10 times in a season were site-faithful across years for up to 4 years. Average size of home range was 0.83 ± 0.31 ha. Size of home range did not differ by sex, and paired birds occupied similar home ranges. All home ranges were composed of a variety of habitats, including open field, dense forest, and riparian areas. California towhees used habitat types differentially throughout the breeding season, and nested in a variety of plants. Prior to and following nesting, they were most often in open areas that provided good forage. While nesting, males and females were most often in dense vegetation. Because they defend type-A territories year-round, potentially for their entire lives, California towhees may benefit from settling on home ranges with high diversity of habitats that can meet fluctuating needs for resources.