Phylloscopus collybita – SIFF-SAFF/SIFF SIAFF – Breeding summer visitor, passage migrant and winter visitor
Since 2009, 2157 chiffchaffs have been ringed at various sites on the Pembrokeshire mainland. Another 2000 or so were ringed on Skokholm in that period.
These days, ringing is primarily for monitoring bird populations – their survival, reproductive rates, and so on. It is a very important tool in understanding how and when bird populations change.
A good proportion of the chiffchaffs ringed on the mainland are part of Constant Effort Site ringing, which is designed for population monitoring. Many of the birds ringed will be breeding, or will have hatched on that site. They will often be retrapped on the same site, in the same or subsequent years. These birds are not included in the map.
Chiffchaffs ringed on Skokholm are on migration. They may be heading north in spring, and south in winter, although occasionally a bird seems to be going in the wrong direction as it overshoots its destination. An example is a bird that was ringed on Skokholm in spring, but subsequently settled to breed in Cornwall that summer.
This map shows where birds ringed in Pembrokeshire went to, or where birds ringed elsewhere came from.
Ringing has been undertaken on Skokholm and elsewhere in Pembrokeshire for many decades, but the earlier data isn’t currently easily available.
The apparently low number of birds that have left mainland Pembrokeshire reflect the fact that a large proportion are ringed as fledgelings and juveniles, which are very vulnerable to predation. Birds that have made it as far as Skokholm before being ringed are a bit older, and so have a much better chance of survival.
Meanwhile, that chiffchaff from Keeston is the oldest, and the furthest-travelled, chiff-chaff from Pembrokeshire in the last decade at least.
Annie Haycock (BBS & WeBS local organiser)
Data from Mike and Theresa Sherman of the Pembrokeshire Ringing Group, from the Skokholm Island Annual Reports, and from the BTO website.