Age at first breeding and change in plumage of kelp gulls Larus dominicanus in South Africa
Crawford, R.J.M.; Dyer, B.M.; Upfold, L. (2000). Age at first breeding and change in plumage of kelp gulls Larus dominicanus in South Africa. S. Afr. J. Mar. Sci./S.-Afr. Tydskr. Seewet. 22: 27-32
In: South African Journal of Marine Science = Suid-Afrikaanse Tydskrif vir Seewetenskap. Marine & Coastal Management: Cape Town. ISSN 0257-7615, meer
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| Auteurs | | Top |
- Crawford, R.J.M.
- Dyer, B.M.
- Upfold, L.
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| Abstract |
In South Africa, kelp gulls Larus dominicanus first breed when 4 years old. At least 50% of 4-year-olds breed annually; virtually all older birds breed annually. Most chicks leave natal colonies in the austral autumn and winter, when about 6 months old, and 60% of them may not return until aged 2 or 3 years. One 3-year-old showed signs of defending territory, but birds only attain full adult plumage when aged 4. The plumage of 3-year-olds is similar to that of adults, but the white spots on the outer primaries are less well developed and the secondaries and inner primaries have no white trailing edge. Chicks are dark, whereas birds aged 1 and 2 years gain increasing amounts of pale or white plumage on the face, neck, underparts and tail. |
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