The Leach’s Petrel Wreck
by Richard Smith
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The North West
is nationally renowned as being the premier area in the country for
seeing Leach’s Petrels, especially the mouth of the River Mersey and the
area immediately to the west – the north Wirral coast, Hilbre Island and
Point of Ayr. From the end of August and early October birds which are
moving southwards out in the Atlantic can get blown by north-west gales
through the North Channel in to the Irish Sea. Numbers vary greatly from
year to year with may be less than ten for the whole period one year and
hundreds in just one day the next.
Far more unusual are Leach’s Petrels appearing during the winter months.
This can happen after prolonged south-west winds when birds are blown up
from their wintering grounds through the southern entrance of the Irish
Sea, the St. George’s Channel. The last significant winter records for
Leach’s Petrels in the North West was in February 2002 when three or
four birds were seen between Criccieth and Porthmadog and another two
off the Little Orme. This winter we have what appears to have been two
separate occurrences of Leach’s Petrels, one in November which was
fairly typical of previous winter records, and another one in December
which resulted in large numbers of Leach’s Petrels all along the
country’s western and southern coasts, and many birds blown inland.
Leach's Petrel off North
Wirral, Steve Round ©
The story
begins on Nov 17th when the wind started to increase from the
south-west, blowing between Force 6 and 8 until about 0700hrs on Nov
21st. The only Leach's Petrel recorded in the country during this period
was one inland over Westwood Pool, Worcs, on the 19th. At 0700hrs on Nov
21st the wind swung from the SW quadrant to NW and within a few hours
seven flew past Hilbre Island. Again these were the only ones recorded
in the country on that day. It would seem that after four days of strong
SW winds the birds had been blown up in to the Irish Sea through the St
George's Channel from their wintering grounds way to the south. It was
not until the wind swung round to NW that they were then blown in
towards Hilbre Island. During the next 10 days the wind was relatively
moderate but, perhaps significantly, remained mostly in the southern
quadrant and this is what may have kept many Leach’s Petrels further
north than normal. But on Dec 2nd an intense low pressure system steamed
in from the south west, passing up the Irish Sea early on the 3rd,
bringing with it south-westerly Force 9 winds, a severe gale. Leach's
Petrels were seen from virtually first light on the 3rd from south-west
facing coasts in England and Wales. Ten went past Criccieth by late
morning and 12 went past Treaddur Bay on Anglesey in just one hour
around mid-day. Further south ones and twos were being observed along
the south coasts of Cornwall, Devon, Dorset and South Wales. A lot of
birds were being blown in to the Severn Estuary and one reached right up
the river beyond Slimbridge by mid-afternoon. Further north birds were
being blown in to Morecambe Bay and two got as far as the Scottish coast
of the Solway Firth.
As shown in the table birds were blown in to west and south-west facing
coasts on the 3rd right across the North West region from Porthmadog in
the south to the Solway Firth in the north, thus suggesting that a good
number of birds must already have been in the Irish Sea prior to the
storm system passing through on the night of Dec 2nd/3rd.
|
Date - December |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
11 |
12 |
13 |
14 |
15 |
|
Wind Direction |
SW |
SW |
SW |
SW |
SW |
NW |
NW |
SW |
SW |
SW |
SW |
SW |
W |
|
Wind Force |
9 |
8 |
6 |
7 |
7 |
5 |
6 |
8 |
7 |
7 |
8 |
7 |
5 |
|
Criccieth to Porthmadog |
21 |
1 |
100 |
|
182 |
|
|
2 |
|
2 |
|
|
|
|
Anglesey |
13 |
3 |
|
|
2 |
|
|
|
|
|
|
|
|
|
North Wales (Bangor to POA) |
1 |
1 |
1 |
|
|
9 |
11 |
|
|
|
|
|
|
|
North Wirral/Hilbre |
|
|
|
1 |
|
25 |
78 |
1 |
1 |
|
|
|
|
|
Crosby |
|
|
|
|
|
|
190 |
|
|
|
|
|
|
|
Lancs (Formby to Rossal Point) |
3 |
6 |
1 |
2 |
2 |
3 |
4 |
|
4 |
7 |
|
|
|
|
Morecambe Bay (Heysham
to Walney) |
5 |
102 |
6 |
2 |
27 |
|
|
|
4 |
4 |
2 |
|
1 |
|
Cumbria (Irish Sea
coast) |
3 |
4 |
|
|
|
12 |
|
|
|
9 |
|
|
|
|
Cumbria (Solway
Firth coast) |
8 |
11 |
6 |
|
|
|
|
1 |
4 |
1 |
|
|
|
On Dec 3rd
birds were blown on to south-west facing coasts as shown on the map. It
wasn't until Dec 8th and 9th that birds were blown in towards Wirral and
the Dee Estuary by north-west winds.
Although the wind moderated slightly to 'only' Force 6 to 8 over the
next four days Leach's Petrels continued to be seen in the same
south-west facing coasts as the 3rd, but in increasing numbers. Peak
counts included over 45 off Jenny Brown's Point in Morecambe Bay (4th),
36 past Sharpness in the Severn Estuary (4th), over 50 in Chesil Cove,
Dorset (5th), 100 at Black Rock Sands near Porthmadog (5th) with 136 at
nearby Borth-y-Gest on 7th and 132 past Porthcawl, South Wales (7th).
Interestingly numbers peaked in Morecambe Bay on the 4th, with a total
of 104, three days before peaking further south at Porthmadog/Bort-y-Gest
and Porthcrawl, suggesting birds may have come through in two waves.
Richard Smith ©,
Leach's Petrel rescued after being
found in a garden in Wallasey, December 2006.
Petrels reached
as far north as Loch Fyne in Scotland and as far east as Canvey Island
in Essex, with many also turning up over various inland reservoirs. By
the end of Dec 7th we birders who do our birdwatching from the usual
Leach’s Petrels hotspots of the River Mersey, north Wirral, Hilbre
Island and Point of Ayr were beginning to despair of seeing anything of
this remarkable influx. But at 4am on the 8th the wind swung round to
the north-west. The wind had eased down to force 5 but it was enough to
bring the birds in with about five observed passing along the north
Wirral coast and 20 past Hilbre that day. Elsewhere six flew west past
Towyn, North Wales, 12 flew out of the Solway Firth and 155 went past
Hartland Point, north Devon, as birds which had been trapped by the
south-westerlies in the Severn Estuary streamed out of the Bristol
Channel. The wind increased to Force 6 overnight and remained
north-westerly resulting in spectacular numbers at Crosby on the 9th
with at least 190 counted off the beach in the Mersey channel, the
highest total from a single site during this whole period. 74 were
recorded flying west along the north Wirral coast and many were also
seen off Hilbre and Point of Ayr.
On Dec 10th the wind went round to the south-west again and remained
strong (Force 6 to 8) for the next six days, but despite this numbers of
Leach's Petrels observed dropped right off with the only double figure
count for the whole country being 15 off Workington on the 11th. Most
records were of one or two in the northern half of the Irish Sea
although the most northerly record was one off the Outer Hebrides on the
11th. The last record of this remarkable influx was a single bird off
Heysham Harbour on the 15th.
It has been estimated that 2,000 birds were involved in total, making it
bigger than the "wreck" of December 1989 but not yet on the same scale
as the "wreck" of late Oct/early Nov, 1952, which apparently involved
more than 7,000 birds. The 1989 "wreck" involved relatively small
numbers of birds but the one in 1952 is still remembered when hundreds
of birds were washed up dead along the Wirral coast. It is believed that
Leach’s Petrels seen in the UK during winter are blown up from their
wintering grounds in the Atlantic, in particular the Bay of Biscay
which, according to Hémery and Jouanin (1988), hosts between 300,000 and
2 million wintering birds.
Although called a "wreck" the number of dead birds involved in
December's influx wasn't large compared with some previous "wrecks".
Undoubtedly some birds were under weight and many were reported as being
in moult, but the wind was probably not blowing strong enough for long
enough to cause wholesale deaths. Judging by the number of birds seen
making their way south on the 8th and 9th hopefully many will have made
their way safely back to their more usual wintering areas.
Sources of information for this article:
1. Sightings from www.birdguides.com.
2. Sightings sent to me directly from various birders.
3. Cheshire Bird Reports 1964 to 2005.
4. Two very informative emails forwarded to me, originally from Brian
Unwin.
5. BTO Migration Atlas..
6. Hilbre Island Weather Station, http://cobs.pol.ac.uk/cobs/met/hilbre/
which was used for all weather details in the article.
7. Hémery, G., C. Jouanin. 1988. 'Statut et origine géographique des
populations de pétrel culblanc (Oceanodroma leucorhoa leucorhoa)
présentes dans le Golfe de Gascogne.' Alauda 56: 238–245.
8. Slack, R., Dec 2006, Storm-bringer - An unexpected wreck of Leach's
Storm-petrels, www.birdguides.com.
9. Cambrian Bird Report, 2002.
Richard Smith.
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