Technical Report

Years 9 and 10 of a Long-term Monitoring Effort at a Marbled Murrelet Nest in Northern California

Marbled Murrelets (Brachyramphus marmoratus) have been endangered in the state of California since 1992 and continue to decline across their range. In recent years this has been primarily due to predation of eggs and young at the nest. Very few studies of murrelets have occurred at their nest due to the difficulty of locating and observing active nests. In northern California, a video camera was installed at one nest site in 2001 and each nesting attempt has been subsequently recorded. Additionally, in 2009 and 2010 a microphone was installed at the site as well. Herein, the 2009 and 2010 nesting seasons are reported for this nest site. In 2009, a nest was not detected at or near the monitored site. However, a murrelet landed at the monitored site and a leg-band was observed on the bird’s right leg. Additionally, a Steller’s Jay landed at the site on 5 separate occasions and a Gray Jay landed at the site once. In 2010, a nest was initiated outside the view of the camera on approximately 3 June, the egg hatched approximately 27 days later on 30 June. The chick was predated on 30 June by at least one Gray Jay. Following the predation of the chick, murrelets were recorded by the camera on 3 separate days before 06:00 (PDT). A pair of Steller’s Jays landed at the site on 6 July in 2010. Murrelets have initiated a nest on this branch during 7 of 10 years. Considering the 7 nesting attempts at this site, the nest has failed 71.4% of the time and each failure has been caused by predation. Finally, at least one member of this breeding pair was a minimum of 10-12 years old.