Sexual size dimorphism and discriminant functions for predicting the sex of Atlantic Puffins (Fratercula arctica)

Abstract

Assortative mating is an important aspect of mate choice, especially in species where both sexes express ornamentation. Such ornaments could function as signals of individual quality and could result in individuals mating with partners of similar quality. We tested for assortative mating by measuring 63 pairs of Atlantic Puffins (Fratercula arctica) at two Canadian colonies (Gull Island, Witless Bay, Newfoundland and Labrador; and Machias Seal Island, New Brunswick), and constructed a function to predict the sex of puffins from Witless Bay. Male and female puffins have similar plumage, and both sexes have fleshy rosettes at the base of their bill, which are supposedly ornaments. We also examined changes in measurements over time in 5-30-year-old puffins recaptured at Machias Seal Island. Our discriminant function correctly predicted the sex of 88 % of puffins from Witless Bay. Overall, males were larger than females in all measurements, but within pairs, some females were larger in 4-27 % of individual measurements. We found no evidence of positive assortative mating or of assortative mating by rosette size, and rosette area did not increase with age. The importance of puffins' rosettes as indicators of quality requires further investigation.

Morphological measurements of Atlantic puffin (Fratercula arctica naumanni) in High-Arctic Greenland

“…Furthermore, the range of morphological measurements of High-Arctic Greenland puffins was greater than for any other breeding colony included in our study. Throughout their southern breeding range, puffins have been shown to demonstrate a high degree of sexual dimorphism, with males being larger than females (Corkhill 1972;Friars & Diamond 2011;Harris & Wanless 2011;Bond et al 2016). We found similar results for F. a. naumanni in High-Arctic Greenland; however, measurements overlapped considerably, and wing length differences were not significant between the sexes (Fig.…”

“…Age was determined using bill grooves, a technique described by Harris (1981Harris ( , 1984, and individuals with at least two bill grooves were considered adults. All puffins were sexed using a standard molecular method described elsewhere (Bond et al 2016), using primers 2550F and 2718R (Fridolfsson & Ellegren 1999) and DNA extracted from either blood or breast feathers using the DNeasy Blood and Tissue Kit (Qiagen Inc.).…”

Migratory movements of Atlantic puffins Fratercula arctica naumanni from high Arctic Greenland

“…After capture, puffins were banded (Danish government leg band and Darvic color band), weighed [ 15 ], sampled (feathers and blood), aged (adults possess two or more bill grooves) [ 18 ], tagged with an archival light tag (hereafter referred to as geolocators), and shortly after release were observed entering and exiting nests. Puffins were sexed using a standard molecular method as described elsewhere [ 56 ] using primers 2550F and 2718R [ 57 ] and DNA extracted from either blood or breast feathers with the DNeasy Blood and Tissue Kit (Qiagen Inc.). No information was collected on breeding success although individuals were regularly observed entering and exiting their apparent nests.…”