Landbird Monitoring at Channel Islands National Park: 2023 Annual Report

Larramendy, Peter; Hall, Linnea; Little, Annie

doi:10.36967/2316485

The National Park Service (NPS) has monitored landbirds at Channel Islands National Park (CHIS) since 1993 as part of its long-term inventory and monitoring program. Later, the landbird monitoring program became part of the NPS Inventory and Monitoring Division’s Mediterranean Coast Network long-term monitoring programs. In this report, we summarize landbird data collected during the 2023 breeding season and analyze trends since data collection began in 1993 for a select number of species. Landbird monitoring was conducted between 28 February and 16 May 2023. Using distance-based sampling methods in a standardized protocol, birds were counted at 334 of 335 permanent point count stations (99% of all stations) across CHIS. These surveys were conducted at 29 of 30 points on Santa Barbara Island, 8 of 8 on East Anacapa Islet, 112 of 112 on Santa Cruz Island, 40 of 40 on San Miguel Island, and 145 of 145 on Santa Rosa Island. Counts were not made at one station on Santa Barbara Island due to the presence of nesting California Brown Pelicans. For the first time, repeat visits were made to stations on Santa Barbara Island and East Anacapa Islet in 2023 to improve detection rates. Visits were spaced a month apart and all stations with access (i.e., no nesting seabirds) were counted twice. In 2023, a total of 53 bird species was counted at point count stations across all five islands, and parkwide, 40 of these species were breeders in CHIS. The ten most highly counted landbirds were, in descending order: Spotted Towhee, Song Sparrow, Horned Lark, Bewick’s Wren, White-crowned Sparrow, Orange-crowned Warbler, Western Meadowlark, House Finch, Common Raven, and Island Scrub-Jay. On Santa Rosa Island, Chipping Sparrow continued to show signs of overall decline and European Starlings continued to be detected. Recommendations for the 2024 landbird monitoring effort in CHIS include (1) changing monitoring on East Anacapa Islet to a spring area search rather than continuing the point counts, (2) conducting only one count timed either before or after seabirds nest on Santa Barbara Island (the best timing should be evaluated in the 2024 season), (3) adding a second count period on Santa Rosa Island to better determine Chipping Sparrow density, and (4) purchasing and deploying starling traps on Santa Rosa Island.

Landbird Monitoring at Channel Islands National Park: 2023 Annual Report

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