MSBO UK Twite Study Project Introduction… Spring 2011

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MSBO UK Twite Study Project Introduction… Spring 2011
MSBO UK Twite Study Project
Introduction…
Spring 2011
During late summer 2010, Machrihanish Seabird Observatory (MSBO) joined
the UK Twite Study Project.
Historical data at MSBO reveals a light passage of Twite (carduelis flavirostris) in
spring then, throughout summer, a small breeding population has always been
obvious.
However, autumn (mid-August through to October) is prime time for the appearance
of many passage birds from the north; presumably from numerous W coast islands
and possibly also mainland Argyll.
Over many years, assemblies of up to 200 Twite have been logged in the area and
in recent years migrant flocks have been attracted to the immediate vicinity of MSBO
(just a few metres from observers) to gorge on nyjer seed.
On-going passage has always been assumed (see comment on retraps below).
This conclusion has often been reinforced by highly variable maximum daily counts
at the station coupled by brief sightings of loads of colour-ringed birds (majority
photographed) that originated mainly from ringing sites in NW England (Cumbria and
Lancashire) in previous winters.
A Twite colour-ringed in County Donegal in winter 2007 was photographed at MSBO
during autumn 2008.
Catching Twite at MSBO…
The trapping method involves a rather simple, near circular pull net (2m x 1.5m).
The back edge of the net is attached to a lead that is linked to a 1m high post. A pull
line is connected to the opposite end. The net is furled neatly in a semi-circle and
when the pull line is activated (from MSBO) it rises nippily, closing efficiently, almost
1m high over the birds (forming a tent shape) and is then lowered carefully.
No pegs are used; the net is 2m deep but rises only 1m allowing the net that remains
furled on the ground to act as a very capable barricade. In addition, a small drystone
dyke-type wall was built as a shelter to aid trapping operations.
The successful pull system was designed by the warden and constructed (very
professionally and at low cost) by Derek Goode (MSBO occasional assistant and ex
Campbeltown fisherman). The largest batch caught was around 30 birds.
Ringing totals at MSBO…
Trapping Twite began in earnest on 12th August 2010 and by the end of the month a
total of almost 200 birds sported our unique colour rings (sequence described
below). Throughout September the total rose (rather slowly) to 300 colour-ringed.
During October, very obvious passage/influxes of unringed birds occurred almost
daily; a further 194 were captured during this rousing period bringing the total colourringed this autumn (August – October) to 494 (our anticipated ringing total was
500+).
MSBO colour ring sequence…
All Twite captured were fitted with a green over white split ring on each leg along
with a statutory BTO metal ring which is positioned on the left leg above colour ring
(project identifier).
Winter destinations…
The project has verified that MSBO is unquestionably an outstanding passage site
for this species.
So, what has been discovered so far?
As at March 2011, we have received confirmation of birds in Ayrshire (2), Dumfries
and Galloway (3), Cumbria (1), Lancashire (1), Isle of Man (2) and Co Antrim, N
Ireland (2).
A total of 5 Twite were also controlled at MSBO during autumn 2010; these included
birds from Sanda Island (1), Cumbria (1), Lancashire (2) and Suffolk (1); see
Recoveries, Controls and Sightings below.
The controls reveal significant information on probable wintering areas and notably,
our first indication of natal origin; see Recoveries, Controls and Sightings below.
Retraps at MSBO…
Many birds acquired retrap histories; for example, a few retrapped in October had
been ringed in August.
This implied that the regular supply of nyjer seed was undoubtedly encouraging
some birds to adopt MSBO feeding station as a lengthy staging post (many adults
were in wing moult August/early September).
However, by the end of October, the majority had moved on and by early November
only a ‘handful’ of birds (<10: majority MSBO colour-ringed) were exploiting the
feeding station.
Five of our colour-ringed birds remained at the feeding station throughout NovemberDecember but, throughout January, none were present (J. McGlynn pers. comm.).
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Recoveries…
V879672 ringed on
August and retrapped at MSBO on 21st September
was controlled at Heysham Harbour North Wall (Lancashire) on 24 th/25th
October 2010 (‘most unusual for a controlled bird to be caught on consecutive
days’; Pete Marsh pers. com).
V879943 ringed on 11th October was controlled at Point of Ayre, Isle of Man
on 10th January 2011 (Sean Gray) (145 Km SE).
V879195 ringed on 23rd October was controlled at Point of Ayre, Isle of Man
on 17th January 2011 (Sean Grey).
28th
Controls…
X459621 (female) ringed at Corporation Marsh, Dunwich, Suffolk on 3 rd
January 2009 was controlled at MSBO on 27th June 2010 (597 Km NW –
apparently the longest movement of a UK ringed Twite).
X351628 (juvenile) ringed at Sanda Island BO off S Kintyre on 5 th July 2010
was controlled at MSBO on 27th August 2010 (21 Km NNW).
R687990 (male) ringed at Askam in Furness, Cumbria on 27 th November
2009 was controlled at MSBO on 25th October 2010 (213 Km NW).
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Sightings of MSBO colour-rings 2010 / early 2011…
One was photographed at Ramsey, Isle of Man on 16th October (Sean Gray).
One was seen very well at Walney Island BO (Cumbria) on 29 th-30th October
and 5th November with further sightings of 2 birds on 17 th November and
singles on 19th, 26th and 29th December 2010 (‘a most unusual colour
combination’; Colin Raven – warden).
One definite was photographed at The Wig, Loch Ryan, Dumfries and
Galloway on 19th November 2010 (‘however, at least three with green/white
rings were present in a large flock’; Gavin Chambers).
One was at Carsethorn Bay (Nith estuary) Dumfries and Galloway (inner
Solway) on 7th December and two were seen well there on 22 nd December
2010 (‘both birds in the ‘scope at the same time’; Richard and Barbara
Mearns).
One was photographed at Doonfoot, Ayrshire on 7th December 2010 (Chas
Moonie).
One was at Crook of Baldoon, Dumfries and Galloway on 11 th January 2011
(Paul Tarling – warden).
One (c/r sequence confirmed three times) appears to be wintering on Bird
Island (Kircubbin), Strangford Loch, Co Down, N Ireland; ‘colour rings seen
very well’; dates included 10th and 28th February and 14th March 2011 (Hugh
Thurgate / warden).
One was photographed at Black Neuk, Girvan, Ayrshire on 19 th April 2011
(Angus Hogg).
One was photographed on Rathlin Island, Co Antrim, N. Ireland on 22 nd April
2011 (Neal Warnock).
Notes; the majority of sightings reveal a SSE movement; however, the Doonfoot bird
moved directly east and the controlled Sanda ringed juvenile undertook a most
unexpected / extremely rapid post natal dispersal to the NW.
The birds observed well at Strangford Loch (photographed) and on Rathlin Island
(photographed) reveal that we still have much to discover about the potential winter
and possible breeding distribution of Twite in Northern Ireland.
X459621 a control from Suffok was very likely breeding by MSBO. Remarkably, this
female now has the distinction of undertaking one of the longest UK movements of
this species.
Twite sporting MSBO unique colour-ring sequence (October 2010)
Note metal above colour ring on left leg = project identifier
Askam in Furness (Cumbria) colour-ringed Twite at MSBO (October 2010)

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