Dräktförändring hos en intersex gräsand Anas platyrhynchos över en sexårsperiod

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DOI:

https://doi.org/10.34080/os.v31.22427

Nyckelord:

Anatidae, and, fältstudier, stegvis maskulinisering, longitudinella observationer, fenotyp, fotografisk dokumentation

Abstract

Intersex individuals with a mixture of female and male plumage traits are reported regularly, but at low frequency. Here we describe the changes in plumage in a Mallard Anas platyrhynchos intersex individual over six years (2015–2020), from a mixed female–male phenotype to a predominantly male phenotype. Already at the first observation, typical male characteristics were present, such as greyish-white tail with two central curved black rectrices and a greenish tinge to parts of the head. The bird attained a more male-like plumage with the next moult and maintained that plumage for the rest of the study period. However, presence of female-patterned body feathers continued until 2019, but in reduced frequency, except for the cheeks and ear-coverts, which displayed a variation in colour. The bill remained female-patterned throughout and the bird did not enter eclipse plumage.

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Referenser

Andersson S, Bengtsson D, Hellström M & Waldenström J. 2016. Age and sex determination of Mallards Anas platyrhynchos in autumn. Ornis Svecica 26: 61–81. https://doi.org/10.34080/os.v26.22530

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Major AT & Smith CA. 2016. Sex reversal in birds. Sexual Development 10: 288–300. https://doi.org/10.1159/000448365

Reeber S. 2015. Wildfowl of Europe, Asian and North America. Helm Identification Guides. Bloomsbury Publishing, London. 656 pp.

Smith CA. 2010. Sex determination in birds: a review. Emu 110: 364–377. https://doi.org/10.1071/MU10030

Wirdheim A (red). 2020. Sveriges fåglar 2020. BirdLife Sverige, Stockholm & Svensk Fågeltaxering, Lunds universitet, Lund. 28 sidor. Tillgänglig från https://www.fageltaxering.lu.se/sites/default/files/files/Rapporter/sveriges_faglar_2020.pdf.

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Publicerad

2021-06-04

Referera så här

Sjögren, A.-K., & Jonas. (2021). Dräktförändring hos en intersex gräsand Anas platyrhynchos över en sexårsperiod. Ornis Svecica, 31, 68–74. https://doi.org/10.34080/os.v31.22427

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