Ringing in 2016

In 2016, long-term ringing studies of Manx Shearwaters and breeding Wheatears continued, and spring and autumn migrants were ringed during twelve days in April and six weeks in autumn. With a total of 1,868 birds ringed, catches were lower than in 2015. This was because of significantly lower numbers of migrants caught, with ringers’ visits not generally coinciding with good conditions for migration and mist-netting.

The year’s ringing totals are shown in the table below. Manx Shearwaters were ringed in the highest numbers, while Goldcrest topped the passerine totals with 265 caught, followed by Blackcap (244), Swallow (194) and Chiffchaff (170). Unusual species included Jack Snipe, Wryneck, Pallas’s Warbler, Common Rosefinch and Lundy’s second Blyth’s Reed Warbler. Also noteworthy in a Lundy context were two Woodcock, six Snipe and six Long-tailed Tits. In previous decades five Yellow-browed Warblers would have been impressive too, but there have been three higher Lundy totals in the last ten years, reflecting the rapidly growing numbers reaching Britain.

Siskin numbers fluctuate greatly from one autumn to the next and their absence from the 2016 list is not a great surprise. Lesser Whitethroat and Redstart are also missing. This may simply reflect the lower levels of migrant ringing, but with averages between three and four ringed per year on Lundy over the past ten years, these are vulnerable species to watch in the future.

Lundy ringing data have been submitted to the British Trust for Ornithology (BTO) in digital form since 1997. To facilitate analysis of long-term data sets, the process of digitising earlier records has begun, using paper records which survive from 1972 onwards. An important bonus will be the inclusion of all recaptures in the same files as ringing data. This facilitates analysis of weight changes, survival rates and other information relevant to conservation issues.

In late May and early June, 107 new adult Manx Shearwaters were ringed, then between the end of August and late September a further 19 adults, four recently fledged young and 291 chicks were ringed. In addition, almost 100 previously ringed adults were caught during the year, including 17 originally ringed as chicks, all contributing to our understanding of recruitment and survival of breeding birds.

In Lundy’s natural burrows it is not possible to establish with certainty which pairs lay eggs and which are just prospecting. So 30 nestboxes designed for shearwaters were installed in March 2016 in the hope that some will be used by birds ringed as chicks, to provide further information on their age of first breeding and survival. It is not surprising that no eggs were laid in the boxes in 2016 because pairs spend a year or two prospecting burrows and bonding before they lay, but in the longer term the boxes should be a very valuable asset (for further details, see Manx Shearwater Nestboxes, 2016 LFS Annual Report, p.101). Two ringed shearwaters showed movements between Lundy and Wales. One ringed near Aberystwyth in July 2013, away from any breeding colony, was likely to be a sub-adult. It was caught twice on Lundy, in May and June 2016, by which time it was probably committed as a Lundy breeder. The other was ringed as a chick on Lundy in September 2007 and caught on Skokholm in 2016, having already reached breeding age. It seems that the sight, sound and smell of a very large colony was strong enough to draw it away from its natal site on Lundy.

The Wheatear Retrapping Adults for Survival (RAS) project continued, with three weeks of intense fieldwork in late May and early June. Forty-eight breeding birds were newly colour-ringed and 29 birds colour-ringed in previous years were re-sighted. Six were from 2013, six from 2014 and 17 from 2015.

Survival estimates currently stand at 61% from 2013 to 2014 and 55% from 2014 to 2015. Perhaps because of difficult weather conditions in spring, the spread of laying dates was greater in 2016 than in the previous three years, and males were harder to catch and re-sight than females at the time of fieldwork. So it is likely that some older males not seen in 2016 will reappear in 2017, raising the survival estimates.

The minimum number of breeding females present in the study area, including at least one unringed and one with a metal ring only, was 46. This represents the highest number of pairs recorded, so the population is very healthy and may still be growing after rat eradication.

Many thanks to all observers who reported colour-ringed birds before and after the main study period, adding to our knowledge of the birds’ life histories. Any 2017 records will be much appreciated.

Recoveries and Controls

In addition to the two Manx Shearwaters mentioned above, seven other ringed birds showed movements to or from Lundy in 2016. One was the Lesser Black-backed Gull colour-ringed as a chick in 1995 which has continued to visit the south-west coast of France in winter. Though it has done very well to reach its current age, it still has some way to go before passing the record for a ringed Lesser Black-back, which is almost 35 years.

Migrating passerines included four Chiffchaffs. Two of these showed rapid movements in spring, from Alderney and to Somerset, and one was on Lundy and Bardsey in North Wales in successive springs. The fourth, on the Lincolnshire coast in May and on Lundy in mid November, could perhaps be a bird that breeds on the continent and winters in south-west Britain.

A Blackcap controlled in spring on Hilbre Island, Merseyside, after being on Lundy the previous autumn is likely to breed further north in Britain. A Chaffinch found dead in North Wales was probably also migrating north via Lundy when it was ringed three springs earlier.

Numbers in brackets indicate pulli – i.e. chicks/nestlings – ringed in 2016. The number of pulli is included in the main total.