Departure of Manx Shearwater Puffinus puffinus fledglings from Bardsey, Gwynedd, Wales, 1998 to 2013

Mike Archer1*, Peter Hope Jones2 & Steven D. Stansfield2

1 14 Fulwood Park Mansions, Chesterwood Drive, Sheffield S10 5DU, UK;

2 Bardsey Bird and Field Observatory, Cristin, Bardsey, off Aberdaron, via Pwllheli, Gwynedd LL53 8DE, UK.

Full paper

Abstract

Very little has been published about how soon Manx Shearwater Puffinus puffinus fledglings leave the area around the natal colony, clearly because of the difficulty of re-catching them after they are first ringed and of knowing whether or not recaptured birds had flown (Perrins et al. 1973; Perrins 2014). Fledglings are thought to depart southwards promptly after they finally leave the natal burrow because the food supply near the colony is deteriorating as the breeding season draws to a close, as suggested by the earlier departure of the adults and the lighter weights of later fledglings, and also as evidenced by the paucity of recoveries immediately after fledging, gale-wrecked birds apart (Brooke 1990). Catching Manx Shearwaters on Bardsey, Gwynedd, Wales at lighthouse attractions within the perimeter of the lighthouse complex, and re-catching them there and on the ground elsewhere on the island, showed that not all fledglings left the area immediately, with a few remaining for up to five/six days. The data published here relate to the numbers initially attracted to the lighthouse and later re-attracted or otherwise caught again in late August and September, between 1998 and 2013.

Acknowledgements

Thanks are due to Professor Chris Perrins, the Wildlife Trust for South & West Wales (its current name) and Skokholm Bird Observatory for providing the Skokholm data in Table 1 with commentary. Members of the Bardsey Bird Observatory staff and visitors caught, re-caught, ringed and processed the fledglings at attractions and elsewhere on the island. Martin Heubeck, Professor Chris Perrins and another, anonymous, referee greatly improved the manuscript with their comments.

References

Brooke, M. 1990.The Manx Shearwater. Poyser, London.

Brown, R. & Stansfield, S. 2011. Breeding birds on Bardsey and Ynysoedd Gwylan. Bardsey Bird and Field Observatory Report 54: for 2010: 98-110.

Cramp, S., Bourne, W. R. P. & Saunders, D. 1974.The Seabirds of Britain and Ireland. Collins, London & Glasgow.

Else, R. 2009. Census of the breeding population and productivity of Manx Shearwaters Puffinus puffinus on Bardsey in 2008. Bardsey Bird and Field Observatory Report 52: for 2008: 92-96.

Else, R. 2010. Manx Shearwater breeding population census 2009. Bardsey Bird and Field Observatory Report 53: for 2009: 105-107.

Else, R. 2011. Manx Shearwater population census and productivity monitoring. Bardsey Bird and Field Observatory Report 54: for 2010: 111-113.

Leaper, G. 2000. Census of the breeding population of Manx Shearwaters Puffinus puffinus on Bardsey 2001. Bardsey Bird and Field Observatory Report 45: for 2001: 93-99.

Newton, S. F., Thompson, K. & Mitchell, P. I. 2004. Manx Shearwater Puffinus puffinus. In: Mitchell, P. I., Newton, S. F., Ratcliffe, N. & Dunn, T. E. (eds.) Seabird Populations of Britain and Ireland: 63-80. Poyser, London.

Perrins, C. M., Harris, M. P. & Britton, C. K. 1973. Survival of Manx Shearwaters Puffinus puffinus. Ibis 115: 535-548.

Perrins, C. M. 2014. Factors affecting survival of fledgling Manx Shearwaters Puffinus puffinus. Seabird 27: 62-71.

Stansfield, S. 2010. Bardsey. In: Archer, M., Grantham, M., Howlett, P. & Stansfield, S. (eds.) Bird Observatories of Britain and Ireland: 29-57. Poyser, London.