Distribution of the Marbled Murrelet at Inland Sites in California

Abstract

We conducted transect surveys from the Oregon border to Monterey County in 1988 and 1989 to determine the distribution of marbled murrelets (Brachyram- phus marmoratus) at inland sites in California. This seabird uses the coastal redwood (Sequoia sempervirens) forests of the northern half of California, but little is known of its distribution away from the ocean. We identified potential inland habitat from remote sensing data and then conducted systematic surveys of forest stands based on this inventory. Murrelets were detected on 74 of 170 (44%) transects, with a patchy distribution concentrated in three regions in Del Norte, Humboldt, San Mateo, and Santa Cruz Counties: (1) east of Crescent City to Redwood Creek in Redwood National Park; (2) lands east of Humboldt Bay to Humboldt Redwoods State Park on the Eel River; and (3) state parks in southern San Mateo and northern Santa Cruz Counties. The primary habitat type where birds were detected was old-growth dominated forest, with 1.05 detections/station, compared to 0.02 detections/station on second-growth transects. Transects with high activity levels tended to be in or west of old-growth stands ~250 ha. The farthest inland we observed murrelets was 39 km from the coast.