Tweeters,

I realize that this is a bit far-afield for most of us, but thought that
Stuart MacKay would like a bit of news from "home".

Jon. Anderson
Olympia, WA
anderjda at dfw.wa.gov

---------- Forwarded message ----------
******** Swinhoe's Storm-petrel breeding in the North Atlantic? *********

The recent capture of at least six (?) Swinhoe's petrels in the North
Atlantic and Mediterranean must be one of the most unexpected birding
developments during the last decade. For those who have't followed this
emerging story, the records that I recall are as follows:

Trappings:
3 birds have been trapped at a single site in Tynemouth on the North Sea
coast of England, with 2 in 1989 and another being caught in 1990 and
retrapped every year until 1994.
also,
Brittany, France, date?
Islote de Benidorm on the Mediterranean coast of Spain,date?
Selvagem Grande in the Salvage Islands way back in 1983.

Potential sight records:
off Cornwall, England in August 1988.
off North Carolina in Aug 1993 (see Ned Brinkley's excellent piece in
Birding (April 1995 27(2) 95-97).

In trying to form my own opinion about the origin of these birds, I have
run into a few questions that maybe other BirdChatters, SeaBirders or
EuroBirdNet folk can help with.

Q1: Why are these Storm-petrels onshore in Tyneside? Is there a breeding
colony nearby? I didn't know petrels bred in the North sea or are they
scouting? Are there comparable storm-petrel banding efforts at other sites,
that so far have not recorded this species? In the back of my mind I recall
Storm-petrel ringing at headlands in eastern Scotland but I could be wrong.


Q2: Are there any banding programs for Storm-Petrels in north eastern North
America? Given the identification difficulty, banding or the lucky
collection of a specimen may be required to confirm the occurance of this
species off our shores. This certainly provides incentive for the
collection and careful examination of all corpses of storm driven
Storm-petrels. So the next time a hurricane hits........

My personal bias is that Swinhoe's Petrel must be breeding somewhere in the
North Atlantic, presumably in small numbers. The reasons for this opinion
are given below. Have I missed anything for or against?

- The scattered nature of the records which are spread over a 12 year
period (1983-). This doesn't sound like wandering vagrants, although most
seabird are admittedly long lived.

- The very large number of potential nesting areas that could hold a
colony, including such remote sites as the Cape Verde Islands, the Salvage
Islands, the Azores, the Canary Islands, many Mediterranean Islands,
islands off NE Canada, around the British Isles and on and on.

- This is currently a weak point but Ned Brinkley (and others?) have noted
that measurements of Swinhoe's Petrels caught in the Atlantic tend to be
slightly larger than data from the Far East. If this correlation turns out
to correct, and is not an artifact of measuring technique, it might suggest
a distinct population of birds. Obviously this would be very strong
evidence for an undiscovered breeding population.

- I am reminded of the Northern Soft-plumage Petrel Complex which has a
small to extremely small population (depending on race) but which seems to
be popping up increasing regularity off North Carolina and Southern
England/Netherlands. Although very tough, Soft-plumage P's would seem to me
to be an easier birds to spot than a few Swinhoe's Storm-petrels scattered
over an immense ocean.

- There is no evidence for seabirds crossing overland (or up the very
narrow Suez Canal) from the Red Sea to the Mediterranean. I guess the
presence of Cook's Petrels and Albatrosses on the Salton Sea, CA, argues
than anything goes!

In the latest issue of British Birds (July 1995 88, 342-348) Mark Cubitt
has another short piece with details and photos of Tynemouth birds. I was a
little suprised that his bias seemed to be towards wandering vagrants
rather than an undiscovered population. In an accompanying editorial, David
Parkin highlights the possibilities of birds jumping from the head of the
Red Sea into the Mediterranean or of a large push around the southern tip
of Africa into the S. Atlantic. Unfortunately these are short articles and
the thinking behind these views is not really layed out.

I hope people can fill me in on the gaps I have pointed out, and perhaps
let me know of their own opinions. I am sorry if some of the answers may
already be provided in the paper by Bretagnolle et al., 1991 in Ibis or
some of the Birding World articles but I don't have ready access to them.

Regards, Angus Wilson (wilson at cshl.org).