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1 December 2018 Sex Determination by Morphological Measurements of Young Rockhopper Penguins (Eudyptes chrysocome) during the Crèche Phase
Virginia Morandini, Miguel Ferrer, Lynelle Perry, Marc Bechard
Author Affiliations +
Abstract

To provide an easy and reliable work tool to identify the sex of Rockhopper Penguin (Eudyptes chrysocome) chicks, we weighed and measured 95 nestlings in the crèche phase during 24-31 January 2017 on the Falkland Islands, Argentina. Sex was subsequently determined using DNA analyses of blood from the same individuals. Significant differences were found in bill length (exposed culmen), bill depth and width, flipper length, and diagonal tarsus, but stepwise discriminant analysis showed bill length to be the best predictor for sex determination. Our model correctly classified 82.7% of males and 90.2% of females (overall correct classification 86.2%). Threshold bill length was 36.64 mm, with values above this point being males and values below being females. Therefore, it appears that measuring bill length is an easy, immediate, and accurate method to sex Rockhopper Penguins during the crèche phase.

Virginia Morandini, Miguel Ferrer, Lynelle Perry, and Marc Bechard "Sex Determination by Morphological Measurements of Young Rockhopper Penguins (Eudyptes chrysocome) during the Crèche Phase," Waterbirds 41(4), 434-437, (1 December 2018). https://doi.org/10.1675/063.041.0407
Received: 23 February 2018; Accepted: 19 April 2018; Published: 1 December 2018
KEYWORDS
bill length
crèche phase
culmen
discriminant analysis
Eudyptes chrysocome
morphometric
nestlings
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