Assessing the number of known-age chicks required for accurate age estimation of growing Atlantic Puffin (Fratercula arctica) and Razorbill (Alca torda) chicks
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Date
2022-04
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University of New Brunswick
Abstract
At Machias Seal Island, chick age is used to estimate hatch dates and predict fledge dates of growing seabirds. A small percentage of chicks have a known hatch date, as the number of nest checks required to capture hatch date is limited to reduce colony disturbance. The goal of this study is to find the minimum number of known-age chicks required to accurately estimate ages of unknown-age chicks in Atlantic Puffins (Fratercula arctica) and Razorbills (Alca torda). To do this, I collected measurements of known-age chicks from the time series at MSI (1995-2021), separated these data into training and test datasets, created a series of annual linear growth models, estimated the ages of known-age chicks, and calculated the accuracy of these estimates. My results suggest that a minimum of three chicks are required to estimate chick age with 85% accuracy of puffins and four chicks for 80% accuracy in Razorbills.