Winter is not a time we normally associate with Shearwaters in these parts. The vast majority of our Manx shearwaters spend the winter in the southern hemisphere in the sardine rich waters off Argentina, returning to Ramsey in March. However this year we have been seeing small numbers of its close cousin, the Balearic shearwater off the island in late December and early January.
The Balearic shearwater, as its names suggests, is to be found breeding on Mediterranean islands and remains in the northern hemisphere over winter.
The species distribution and movement has been part of an intense study by researchers under the banner of Seawatch SW, a project which ran from 2007-2011. The Balearic shearwater is classed as Critically Endangered with the total breeding population restricted to a few islands in the Med and estimated at between 10,000-30,000 individuals and declining
It is becoming clear that UK waters are becoming an important component of their life cycle with between 1,000 and 5,000 recorded annually in UK and Irish waters over the past 10 years. Most of these sightings occur between July and October and most are recorded off SW England. Reasonable numbers are recorded off the Welsh coast too in this period. Smaller numbers are recorded in winter, again mainly off SW England, but as we have seen over the past few weeks, there have been a small but regular number of birds off west Wales during this period. It will be interesting to see if sightings continue through January.
The same team from Oxford University who are involved with tracking our Manx shearwaters are also using the same technology on Balearics in Mallorca, along with researchers from Seawatch SW. A paper is due soon and will make fascinating reading. Click on the Seawatch SW link above for lots more info on this species.