No change in Atlantic Yellow-nosed Albatross (Thalassarche chlororhynchos) egg size over 160 years

ABSTRACT

Biotic and abiotic conditions in the world’s oceans have changed considerably in the last two centuries as a result of anthropogenic factors, including whaling, sealing, fishing, and climate change. For species that have limited variation in life-history traits, life-history characteristics may impede the ability to adapt to changing environmental conditions. Albatrosses are one such group, where breeding investment is limited to a single egg every one or two years. At a coarse level, individuals may decide whether to breed or not, or whether to incubate an egg or not, but one of the only finer-scale adjustment in parental investment involves altering egg size, along with parental foraging and chick provisioning. We investigated changes in egg size in Atlantic Yellow-nosed Albatrosses (Thalassarche chlororhynchos) breeding at Tristan da Cunha, South Atlantic Ocean, from 1856 to 2015. We found no change in egg length, or breadth, which may suggest that with regards to this life-history parameter, Atlantic Yellow-nosed Albatrosses appear to have been able to buffer the effects of the trophic, climatic and oceanographic changes in the South Atlantic Ocean.

KEYWORDS:

• Albatross
• egg size
• life-history
• maternal investment
• Tristan da Cunha

Acknowledgements

We thank J. Bradley, D. Davies, B. Dilley, D. Fox, C. Jones, W. Kuntz, J. Mcgillan, A. Mitham, M. Risi, E. Sommer, G. Swain, and C. Taylor for assistance in the field, D. Russell (Natural History Museum) and B. McGowan (National Museums Scotland) provided access to historical collections, and Ovenstone Agencies (Pty) Ltd, and the South African National Antarctic Program (SANAP) provided logistical support and transport on the MFV Edinburgh, MV Baltic Trader, and SA Agulhas II. The Administrator and Island Council of Tristan da Cunha approved this research, and the Royal Society for the Protection of Birds, the UK partner in BirdLife International, provided funding. Data are available on figshare at https://doi.org/10.6084/m9.figshare.9784085. Comments from M. Carroll and three anonymous reviewers improved this manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary material

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