Assortative mating for carotenoid colouration but not size in the Yellow-legged Gull (Larus michahellis)

Hammouda, A., Hamza, F., Ayadi, T., Pearce-Duvet, J. & Selmi, S. (2016). Assortative mating for carotenoid colouration but not size in the Yellow-legged Gull Larus michahellis. Bird Study 63: 289–292. doi: 10.1080/00063657.2016.1185087
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Abstract:

Mediterranean Yellow-legged GullsYellow-legged Gulls mate assortatively according to carotenoid-based colouration but not in relation to size

In conclusion, our results suggest that carotenoid-based colouration plays a more important role in mate choice than does body size in Mediterranean Yellow-legged Gulls. However, these results might have been impacted by the study’s small sample size. Moreover, our data are descriptive in nature and reveal nothing about potential underlying processes. We thus believe that additional studies involving larger data sets obtained from marked birds and field experiments are necessary to clarify mate choice mechanisms in this species.

Morphometric sexing of Mediterranean Yellow-legged Gulls in Gabès, Tunisia

Hammouda, A. & Selmi, S. (2013). Morphometric sexing of Mediterranean Yellow-legged Gulls Larus michahellis michahellis breeding in the Gulf of Gabès, southern Tunisia. Ostrich 84 (2): 119-122.

Abstract:

Discriminant analysis functions have previously been determined for sexing Mediterranean Yellow-legged Gulls Larus michahellis michahellis from the western Mediterranean basin. However, data from eastern Mediterranean populations are lacking. In this work, we used morphometric data from a sample of 81 Mediterranean Yellow-legged Gulls (39 males and 42 females) breeding in the Gulf of Gabès in south-eastern Tunisia to (1) determine a dscriminant function useful for sex discrimination, and (2) assess the accuracy of previously published functions in sexing Mediterranean Yellow-legged Gulls from our study area. Our results showed marked sexual differences in all morphological measurements, with males being significantly larger than females. The best discriminant function included head length, bill depth and wing length, and accurately classified 93% of sampled birds. We also found that Mediterranean Yellow-legged Gulls from the Gulf of Gabès could accurately be sexed using discriminant functions determined for another North African population, but not with a function determined for a South European population, although distances between sites are almost the same.

Yellow-legged Gull (Larus michahellis)

Larus michahellis – Goéland leucophée – Yellow-legged Gull (Sébastien Bertru, license: CC-by-sa)