Publication Date

Summer 2014

Degree Type


Degree Name

Master of Science (MS)


Biological Sciences


Scott A. Shaffer


Cassin's auklet, egg loggers, egg turning, incubation behavior, nest boxes, seabird conservation

Subject Areas

Biology; Ecology; Wildlife conservation


Nest attendance behaviors are critical to hatching success for most bird species. Yet, details of avian incubation behaviors are still not well understood, especially for species that nest in burrows and crevices. Cassin's auklet (Ptychoramphus aleuticus) is a burrow-nesting seabird found throughout the northeastern Pacific Ocean, including Southeast Farallon Island, California (SEFI). Artificial nest boxes have been used to monitor Cassin's auklets (hereafter auklet) breeding on SEFI. Temperatures in un-shaded nest boxes can increase significantly during extreme heat events. The effects of these elevated temperatures on auklet incubation behaviors and egg viability are not clear. In this study, egg data loggers were used to measure egg temperatures and turning rates of auklet eggs in natural burrows, shaded nest boxes, and un-shaded nest boxes on SEFI during the 2012 and 2013 breeding seasons. Nest temperatures were highest and most variable in un-shaded nest boxes. Egg temperatures were highest in un-shaded boxes. Egg turning rates and egg temperature decreased during the night. During the day, egg turning rates increased with nest temperature. Overall, the results of this study show that nest habitat type can influence auklet incubation behaviors and temperatures. Increasing environmental temperatures could affect breeding Cassin's auklets, and mechanisms to further mitigate these effects should be considered.