OCCURRENCES OF KITTLITZ'S MURRELETS SOUTH OF THEBREEDING RANGE ALONG THE WEST COAST OF NORTH AMERICA

摘要

Even though Kittlitz's Murrelets (Brachyramphus brevirostris) remain almost entirely within the species' breeding range throughout the year, 20 records were obtained south of the breeding range along the west coast of North America between 1969 and 2010. Eight records between southern British Columbia and southern California (1969-2010), within the California Current region (33°-49° N), were considered to be vagrants, occurring far from the nearest breeding areas (1060 to 2920 km). Twelve records in southern Southeast Alaska and northern British Columbia (1994-2001) were relatively close to southernmost breeding areas (<730 km), still within the southern Alaska Current region (51°-56° N), and were considered to reflect occasional use of the southern part of the non-breeding range. With no records south of breeding areas prior to 1969, vagrancy and movements just south of the breeding range may have increased in recent decades because more qualified observers have covered the coastal areas, as well as due to changes in weather, reproduction, and movements. Increased search effort and better documentation of records will facilitate future confirmation and identification of changes in the type or frequency of these occurrences.