Marbled Murrelet Activity Patterns and Survey Efficiency at Inland Sites in Southeastern Alaska

Abstract

We measured activity levels of marbled murrelets (Brachyramphus marmoratus mar- moratus) at 4 inland locations in southeastern Alaska from December 1992 through November 1996. Activity levels were measured by recording the number of times marbled murrelets were detected during dawn surveys (n = 281). Detection rates peaked during the last half of July, following or coinciding with fledgling periods reported elsewhere. Post-sunrise detections and length of activity periods also peaked in July, possibly because of increased activity by breeding birds. Marbled murrelets were absent during September through October, corresponding to the pre-basic molt. Detection rates were also low in April during the pre-alternate molt. Throughout the rest of the year marbled murrelets were present during 90% of the surveys. Variability in detection rate did not decrease in winter. Our results support monitoring during the breeding season. We examined survey efficiency and found that the survey period in southeastern Alaska could be shortened substantially (31%) with only a small loss of detections (3%). Because few detections are made during some portions of the standard intensive survey (Ralph and others 1994), we recommend that other researchers examine their data to determine whether changes in the survey protocol for southeastern Alaska should be made.