New Passage - September 1988: © A. Merritt.

On September 12th 1988 the south-westerly gales that had been blowing the previous day were still in evidence at dawn. As a good selection of seabirds had already been seen in Avon that month, several observers gathered at New Passage in anticipation. At about 09:00 I picked out a dark shearwater wheeling up the Estuary towards the Severn Bridge. Over the next ten minutes it slowly drifted back down river with the tide, regularly sitting on the water. It was probably never less than 500 metres away, but it was also kept in view by Paul Bowerman, Brian Lancastle and Harvey Rose.

On detailed inspection the bird, which was fairly small and short winged most closely resembled a Manx Shearwater, Puffinus puffinus. However the following features of its plumage differed from those of the nominate race: dusky under wings with paler centres and lacking a black trailing edge. recalling a Sooty Shearwater; muddy grey upperparts; and dirty white rather than silky white under parts. The lack of contrast in the plumage was made more apparent when an ordinary Manx Shearwater flew past in similar light about an hour later.

These characters identified the bird as one of the rather variable race Puffinus mauretanicus, colloquially known as Balearic Shearwater, which had not previously been identified in the Avon recording area. This individual was at the pale end of the spectrum; many have rich chocolate brown upper parts, and some show completely dusky under parts. They are slightly larger and stockier than the nominate race, and darker individuals can be mistaken for Sooty Shearwaters.

After breeding on islands in the western Mediterranean, Balearic Shearwaters disperse into the Atlantic. Between late June and October substantial numbers may feed as far north as the English Channel and the Irish Sea. In Britain they are mainly seen from headlands from Cornwall to Dorset. Recently there has been some discussion as to whether these Mediterranean shearwaters, together with the race P. yelkouan, may in fact represent a completely separate species; if this theory is ever accepted as correct. the Avon bird list will be one species better off!

A. Merritt - September 1988.