Rare Shearwaters off the Dee Estuary

Richard Smith

Six species of shearwater are on the British List; the most numerous by far is the Manx Shearwater (see the June 2007 Newsletter). All six species have been recorded within sight of the Dee Estuary and/or the north Wirral Coast and I describe the occurrence of the five rarer shearwaters below. I also include a possible sighting of a Yelkouan Shearwater; a species which is not yet on the British List. The data for the sightings mainly comes from Cheshire and Wirral Bird Reports and other historical publications for the same area - see References at the end. I have also used Clwyd Bird Reports for records from Point of Ayr and Gronant but the number of printed reports I have for this area is very limited. Due to lack of Clwyd Bird Reports in particular, and the possibility that some Cheshire and Wirral records may have been overlooked it is likely that the list of records described below is incomplete, for which I apologise.
 

Cory's Shearwater Calonectris diomedea
Five accepted records, one record rejected by BBRC, one record not submitted to BBRC.

There are two subspecies of this large shearwater, the Mediterranean subspecies C. d. diomedea, and the Atlantic subspecies C. d. borealis; there is no indication from the reports which subspecies have been observed here. They breed mainly on remote islands, the Mediterranean subspecies throughout the Mediterranean and the Atlantic subspecies on islands around the Azores, Madeira and Canary Islands. Both subspecies seem to be doing well with a total population estimated to be around 350,000. Most birds overwinter off South Africa, many non-breeders spend the summer in the North Atlantic although mostly to the south of the British Isles.

One which flew past Meols and Hilbre (assumed to be the same bird) on Aug 30th 1980 was the first accepted record for Cheshire and Wirral. Singles were also recorded on Sep 14th 1986 (Hilbre), Jul 15th 1991 (Red Rocks), Sep 4th 1992 (Hilbre) and Jun 21st 1999 (Gronant). One reported from Hilbre on April 13th 1975 was rejected by BBRC and one the following year on May 16th was not submitted.
 

Great Shearwater Puffinus gravis
Two records, both accepted.

This large shearwater breeds in the South Atlantic on the islands of Tristan da Cunha and nearby Gough Island. The number of breeding pairs is at least six million. The birds spend the northern summer in the North Atlantic with many following a circular route, flying up the eastern seaboard of America, moving past Greenland and eastwards towards Europe before returning south. This species moves further north than Cory’s Shearwater and stays further offshore than the Sooty Shearwater. Rarely seen from the coast which is why, despite large numbers in the North Atlantic in the summer, very few have been recorded in Liverpool Bay. Adults return to breed during August so birds observed off European coasts in September and October are likely to be non-breeders.

One observed off Hilbre on Oct 31st 1971 was the first Cheshire and Wirral record. The only other record was also one seen from Hilbre, on Sep 12th 1980. The lateness of these dates suggests that these were both non-breeding birds. We are somewhat overdue for another one! Right - Great Shearwater, © Bryan Thomas
 

Sooty Shearwater Puffinus griseus
Forty records involving sixty five birds between 1964 and 2006, several additional records not submitted.

They move closer in to the coast than the other large shearwaters such as Cory’s and Great and are therefore our second commonest shearwater after the Manx. Even so, they are scarce in the Irish Sea with typically only one or two a year being seen off the Dee Estuary/ north Wirral coast. The histogram above shows the sighting dates for Sooty Shearwaters from 1964 to 2006. There is only one spring record which was on May 28th 2006 off Leasowe Gunsite. It is probable that the bulk of the sightings are of adult birds on their way south with the stragglers in late October and November being non-breeding birds.
 

Balearic Shearwater Puffinus mauretanicus
Eight records between 1964 and 2006, all accepted.

Reports are as follows: One on Sep 7th 1974 off Meols; one Aug 24th 1989 off Red Rocks; three July 31st 1993 off Red Rocks; one Sep 8th 1997 off Dove Point, Meols; one Aug 22nd 1998 off Hilbre; one at Point of Ayr on Sep 30th 1999; singles on Oct 4th and 6th 2003 off Hoylake. Although none were sighted here in 2006 there was a big influx in to the Irish Sea with 14 past Anglesey on Aug 20th and 46 off New Quay on Sep 18th. There was some discussion about these unusually high numbers with some blaming global warming for a shortage of food which meant birds had to travel further north than usual, others reckoned that most of the birds appeared to be juveniles and thus it would seem this species may well have had a good breeding season.
 

Yelkouan Shearwater Puffinus yelkouan
One possible record.

Like the Balearic Shearwater this species breeds in the Mediterranean but is more widespread across the central and eastern ‘Med’, the number of breeding pairs is difficult to estimate but is at least 15,000 and may be as high as 50,000. The Yelkouan Shearwater was given species status when it was split from the Balearic Shearwater in 2002. It is undoubtedly overlooked in this country as it is difficult to distinguish from the Manx Shearwater.

One possible record, I quote from the 2000 Hilbre Bird Observatory Report: “A single bird moved west during a heavy passage of Manx Shearwaters on 6th June. The bird showed characteristics which the observer felt more closely fit eastern birds (Levantine) rather than Balearic”. Levantine is an alternative name to Yelkouan.
 

Macaronesian Shearwater Puffinus baroli (formerly known as Little Shearwater, also now known as North Atlantic Little Shearwater).
Two inland Cheshire records accepted by BBRC. Four records rejected. One record initially accepted then withdrawn. One bird accepted for Lancashire which was also seen from Wirral, but not submitted to Cheshire & Wirral.

The status of the Macaronesian Shearwater as a species seems to be somewhat confused and disputed, as does its relationship with its close relative the Audubon’s Shearwater. However, it is accepted as a separate species by the BOU. There are two sub-species, P. b. baroli which breeds in Madeira and the Canary Islands and P. b. boydi which breed in the Cape Verde Islands. There is very little in the literature about population size but there appears to be a total of a few thousand pairs. This species tends to spend most of the time in tropical and sub-tropical waters; there have been a total of only 57 records for the United Kingdom between 1958 and 2005.

Rather bizarrely for a bird which spends most of it’s time out on the ocean the only accepted records for Cheshire and Wirral are both inland. One was found moribund on May 10th 1958 at Stockport and a sick individual was present at Rostherne Mere from Jun 29th to Jul 3rd 1977 when it was picked up and later died.

Four records have been rejected with dates as follows: one on Oct 20th 1971 off Meols; one on Sep 1st 1976; one on Sep 21st 1985; one on Sep 6th 2000, the latter three all Hilbre records. These birds were seen by experienced and reliable observers so it is difficult to believe that these were not Macaronesian Shearwater except for the possibility that they were some other small shearwater, such as Audubon’s; so that may be is where the problem lies. Another Hilbre record was of one on Sep 2nd 1984 which was accepted by BBRC but subsequently withdrawn by the observer after reading an article on Shearwaters in British Birds; another example of how difficult it is to precisely identify this species.

What was undoubtedly a Macaronesian Shearwater was seen flying over the River Mersey several times between Sep 1st and 5th 1992. Apparently it was well seen from New Brighton on the 4th but was never submitted to BBRC as a Cheshire and Wirral bird. The following day it was well observed from the Liverpool side and subsequently accepted by BBRC for Lancashire.

References:
1. British Ornithologist's Union Species list, http://www.bou.org.uk/.
2. Cheshire and Wirral Bird Reports 1964 to 2005.
3. Lancashire Bird Report 1992.
4. Clwyd Bird Reports, 1989, 1991 & 1992, 1993 to 1995, 1999, 2000, 2001, 2002 and 2004.
5. Hedley Bell, The Birds of Cheshire, 1962 (and 1967 supplement).
6. Allan Conlin and Steve Williams, Rare Birds in Cheshire & Wirral, CAW Birding, 2004.
7. Sightings communicated directly to me.
8. Wikipedia (The online Encyclopedia - http://en.wikipedia.org/), a surprisingly rich source of information for birds.
9. Cramp & Simmons, Birds of the Western Palearctic, 1977, (and updated version on CD/DVD).
10. The IUCN Red List of Threatened Species, http://www.iucnredlist.org (the website gives the status, including population details, for each species).
11.BirdLife International Website, http://www.birdlife.org/datazone/species/index.html.

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