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Cited by 12Avian ecology and behaviorAnimal Behavior and ReproductionMarine animal studies overview

EFFECT OF AGE AND BREEDING STATUS ON MOLT PHENOLOGY OF ADULT AFRICAN PENGUINS (SPHENISCUS DEMERSUS) IN NAMIBIA

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KEMPER, JESSICA, ROUX, JEAN-PAUL, UNDERHILL, LES G.·2008·The Auk
DOI 10.1525/auk.2008.06262
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Abstract

We analyzed the seasonality of molt of African Penguins (Spheniscus demersus) in adult plumage and used information derived from banded individuals to examine the relationship between age, breeding status, and timing of molt in Namibia. Molt seasonality was bimodal, with a major molt peak in the austral autumn and a minor peak in midsummer. African Penguins younger than four years—and, therefore, unlikely to be sexually mature—molted in early January, at the same time as juvenile African Penguins. Birds aged between four and six years molted either in summer or autumn and were likely to be individuals making the transition from nonbreeder to breeder. African Penguins older than six years, considered to be breeders, molted, on average, in early May. Most birds that had been recorded breeding within 12 months of molt molted between March and May. Summer breeding in Namibia appears to force breeders to delay molt until autumn. There was individual variation in molt seasonality that we could not explain by age alone. Estimates of the proportion of potential breeders in the population derived from molt phenology and from the molt histories of banded, known-age individuals were likely to be underestimates and suggested that some adults of breeding age defer breeding.

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  • Unfledged African penguin chicks whose parents enter moult would starve in the nest.

    “However, moulting penguins are without adequate waterproofing and must fast for c.21 days [20]; unfledged chicks would thus starve in the nest [21].”

    From Hand-Rearing, Release and Survival of African Penguin Chicks Abandoned Before Independence by Moulting Parents (2014) · cites this paper as [21]

    The Discussion says molting African penguins cannot feed and that a simultaneous breeding attempt is unlikely to succeed. This supports the concern for unfledged chicks, but it does not establish that they would necessarily starve in the nest. (LLM, conf=0.86)

    Experimental — accuracy not yet measured

  • The acquisition of insufficient reserves prior to moult compromises survival.

    “Thus, the acquisition of insufficient reserves prior to moult compromises survival [21]”

    From Hand-Rearing, Release and Survival of African Penguin Chicks Abandoned Before Independence by Moulting Parents (2014) · cites this paper as [21]

    The Discussion (page not provided) says molting birds cannot feed and live on fat reserves, and that survival may be compromised if they have insufficient time to build fat before molt. The claim presents this possible consequence as a definite one. (LLM, conf=0.87)

    Experimental — accuracy not yet measured

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Research works printed but not linked: 7

  1. -Kemper, roux, and underhill - auK, Vol. 125
  2. Boersma, P. �. 1977. An ecological and behavioral study of the Galapagos Penguin. Living Bird 15:43-93.
  3. Hemming, M. 2001. The Treasure oil spill and its influence on moulting African Penguins Spheniscus demersus at Robben Island. M.Sc. thesis, University of Cape Town, Cape Town, South Africa.
  4. Kemper, J. 200�. Heading towards extinction? �emography of the African Penguin in Namibia. Ph.�. dissertation, University of Cape Town, Cape Town, South Africa.
  5. Murison, G. 1998. Nest site characteristics and breeding success in the African Penguin, Spheniscus demersus at Boulders Coastal Park, Simon's Town. B.Sc. thesis, University of Cape Town, Cape Town, South Africa.
  6. Williams, A. J., and J. Cooper. 1984. Aspects of the breeding bio- logy of the Jackass Penguin Spheniscus demersus. Pages 841-853 in Proceedings of the Fifth Pan-African Ornithological Congress (J. A. Ledger, Ed.). Southern African Ornithological Society, Johannesburg, South Africa.
  7. Wolfaardt, A. C., and �. C. Nel. 2003. Breeding productivity Breeding productivity and annual cycle of rehabilitated African Penguins following oiling. Pages 18-24 in Rehabilitation of Oiled African Penguins: A Conservation Success Story (�. C. Nel and P. A. Whittington, Eds.). BirdLife South Africa and the Avian �emography Unit, Cape Town.

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Authors
KEMPER, J., ROUX, J.-P., & UNDERHILL, L. G.
Affiliations
University of Cape Town (ZA)
ORCID
Venue
The Auk
Publisher
Oxford University Press (OUP)
Published
2008-10
Volume
125
Issue
4
Pages
809-819
ISSN
  • 0004-8038 (ISSN-L)
  • 1938-4254
DOI
10.1525/auk.2008.06262
OpenAlex
W2099076604
Cited by
12
References
44
Citations by year
2026: 2 · 2025: 2 · 2023: 1 · 2020: 1 · 2018: 1 · 2017: 1 · 2016: 1 · 2014: 1 · 2013: 2
FWCI
0.00
Type
journal article
Language
en
Open access
Locations
  • The Auk (publishedVersion)
  • BioOne Complete (BioOne) (submittedVersion)
Funders
National Research Foundation
Topics
  • Physical Sciences › Environmental Science › Ecology › Avian ecology and behavior
  • Life Sciences › Agricultural and Biological Sciences › Ecology, Evolution, Behavior and Systematics › Animal Behavior and Reproduction
  • Physical Sciences › Environmental Science › Ecology › Marine animal studies overview
Keywords
African penguin, Spheniscus demersus, age effects, breeding status, sexual maturity, interindividual variability, Namibia

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