First recorded breeding attempt of Redfooted Booby Sula sula on St Helena Island, South Atlantic

Annalea Beard1* and Philip Lambdon2

1 Marine Section, Environmental Management Division, St Helena Government, Essex House, Jamestown, St Helena Island, South Atlantic;

2 St Helena Nature Conservation Group, PO BOX 32, Jamestown, St Helena Island, South Atlantic.

Full paper

Abstract

Red-footed Boobies Sula sula are a wide ranging species that used to have a significant breeding population on both Ascension and St Helena Island in the South Atlantic. It was thought that only a small remnant population existed at Ascension Island until now. Five breeding attempts on the southern coastal windward side of St Helena by white morph Red-footed Boobies were recorded using an infra-red motion sensitive camera during 2014–2015. Of the minimum of nine eggs laid, none hatched suggesting more than one female was involved in nesting efforts and they were infertile and/or inexperienced breeders. Theories as to where these birds may have come from are discussed.

Introduction

Red-footed Boobies Sula sula have a wide range, occurring on tropical islands in most oceans (del Hoyo et al. 1992) where they nest predominantly in trees and shrubs. The sub-species, S. s. sula is restricted to the Atlantic, predominantly the Caribbean with outposts around the Brazilian Islands of Trinidade and Fernando de Noronha (Harrison 1985), and further east on Ascension Island. The South Atlantic population is approximately 4,000 individuals (den Hartog 1987) and holds both white and white-tailed brown morphs, although the relative proportions of each morph are not known (Nelson 1978). The small, remote islands of Ascension and St Helena, which lie in the South Atlantic Ocean close to the mid-Atlantic Ridge, once harboured significant breeding populations (Ashmole 1963a,b). The introduction of predators following discovery of the islands in the 16th century, and subsequent deforestation of St Helena after human colonisation, reduced the Red-footed Booby populations to a tiny remnant on Boatswain Bird Island, an offshore islet off the southwest coast of Ascension Island (Stonehouse 1962; Simmons 1990). Here we report recent breeding attempts of this species, previously thought to be absent on mainland St Helena, including additional individual observations of non-breeding birds from 2010 to 2015.

Acknowledgements

We thank Graham Sim, Ivan Henry, Emma Fowler, Edward Thorpe, Sophy Thorpe and Remi Bruneton for additional observations; St Helena Government for help producing the map and Richard Sherley for advice and comments on the manuscript.

References

Amerson, A. B. & Emerson, K. C. 1971. Record of Mallophaga from Pacific birds. Atoll Research Bulletin 146: 1–30.

Ashmole, N. P. 1963a. The extinct avifauna of St Helena Island. Ibis 103b: 390–408.

Ashmole, N. P. 1963b . The regulation of numbers of tropical oceanic birds. Ibis 103b: 458–473.

Ashmole, N. P. 1963c. Sub-fossil bird remains on Ascension Island. Ibis 103b: 382–389.

Bolton, M., Watt, R. E. F., Henry, L. & Clingham, E. 2011. Re-colonisation and successful breeding of Masked Boobies Sula dactylatra on mainland St Helena, South Atlantic, in the presence of Feral Cats Felis catus. Seabird 24: 60–71.

del Hoyo, J., Elliot, A. & Sargatal, J. 1992. Handbook of the Birds of the World, vol. 1: Ostrich to Ducks. Lynx Edicions, Barcelona.

den Hartog, J.C. 1987. A record of a Red-footed Booby from Cape Verde Islands, with a review of the status of this species in the South Atlantic Ocean. Zoologische Mededelingen 61: 405–419.

Diamond, A. J. 1974. The red-footed booby on Aldabra Atoll, Indian Ocean. Ardea 62: 196–218.

Fisher, H. T. 1951. The avifauna of Niihau Island, Hawaiian Archipelago. Condor 53: 31–52.

Harrison, P. 1983. Seabirds. An identification guide. Christopher Helm Ltd., Bromley, UK.

Lambdon, P. 2012. Guide to the flowering plants and ferns of St Helena. Pisces Publications, Newbury.

Simmons, K. E. L. 1990. The status of the Red-footed Booby Sula sula at Ascension Island. Bulletin of the British Ornithologists' Club 110: 210–222.

Stonehouse, B. 1962. Ascension Island and the British Ornithologists Union Centenary Expedition 1957–59. Ibis 103b: 107–123.

Nelson, J. B. 1969. The breeding ecology of the Red-footed Booby in the Galápagos. Journal of Animal Ecology. 38: 181–198.

Nelson, J. B. 1978. The Sulidae: gannets and boobies. Oxford University Press, Oxford.

Oppel, S., Beard, A., Fox, D., Mackley, E., Leat, E., Henry, L., Clingham, E., Fowler, N., Sim, J., Sommerfeld, J., Weber, N., Weber, S. & Bolton, M. 2015. Foraging distribution of a tropical seabird supports Ashmole’s hypothesis of population regulation. Behavioural Ecology and Sociobiology 69: 915–926.

Verner, J. 1961. Nesting activities of the red-footed booby in British Honduras. Auk 78: 573–594.