Alaska Science Center
Attendance patterns and population monitoring of crevice-nesting Horned Puffins and Parakeet Auklets in the North Pacific
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Full Publication: https://alaska.usgs.gov/products/pubs/2002/2002_Harding_etal_CrevicenestingHOPU_USGS_ASC.pdf
Product Type: Report
Authors: Harding, A. M. A., J. F. Piatt, G. V. Byrd, S. A. Hatch, N. B. Konyukhov, and E. U. Golubova
It is difficult to monitor populations of crevice-nesting seabirds because nest sites are hard to identify and count. To complicate matters further, the number of adult birds attending a colony can be extremely variable within and between days. Horned Puffins and Parakeet Auklets generally nest in crevices throughout their range. There is no standardized method for censusing either species and consequently little is known about absolute numbers or population trends. This paper examines within- and among-year variation in the colony attendance of Horned Puffins and Parakeet Auklets at five breeding colonies in the North Pacific. Using 11 colony-years of data, we examined variance in attendance at colonies and consider the implications for detecting changes in population size. Due to breeding failure we were unable to suggest firm monitoring guidelines for Parakeet Auklets. We therefore focused on developing a population monitoring protocol for Horned Puffins, using the halflife of a puffin population at two rates of decline as a yardstick for measuring the performance of various monitoring protocols. In order to monitor Horned Puffins at individual colonies, we suggest that investigators a) first identify the colony-specific period of peak diurnal attendance, b) count birds once daily during the narrow window of peak diurnal attendance, c) count birds resting on the water adjacent to the colony, d) count birds daily during the census period, e) define the 30 days at the end of incubation as the census period, and, f) census colonies annually. Future research should focus on measuring interannual variability in Horned Puffin attendance.