NLRG was formed in 1957 to help in the study of birds in the Lancaster and District Birdwatching Society area. There are currently 12 active ringers. Species currently being studied include: Pied Flycatcher, Bearded Tit, Sand Martin, Twite, Goosander, Oystercatcher and Grey Wagtail. Migration has been studied for 28 years at Heysham. We welcome anyone who wants to observe, help or perhaps wish to become a ringer. Photo: A Heysham-ringed Twite on the Mull of Kintyre (thanks to Eddie Maguire)

Saturday, 7 February 2009

Twite ringing – late winter update

The ringing of previous influxes of Twite to Heysham and nearby coastal sites to the south has resulted in several recoveries to and from the inner Hebrides and nearby Scottish mainland along with one from South Uist. Given this evidence, there has been a logical interchange of birds between Askam-in Furness (Cumbria) and Heysham. This picture was ‘complicated’ by evidence suggesting that the occasional bird of south Pennine origin at the very least passed through Heysham and Askam on late autumn passage and also wintered in small numbers on the south Ribble marshes. The jury is out as to whether the two Heysham recoveries involving the Lincolnshire coast, or indeed the recent Walberswick control, were of south Pennine origin or could be birds of Scottish origin. Two of these were in the same autumn-winter. Therefore this presumably involved either south Pennine birds reorientating towards the "correct" wintering area after initial autumnal dispersal in the 'wrong' direction or Scottish birds "ending up with" (how?) south Pennine birds and being "dragged" kicking and screaming to the east coast! There has not been an east-coast-ringed bird found on the western Scottish breeding grounds or vice-versa.

After two rather lean winters with very few birds at the Heysham feeder and rather low numbers along the coast, it was a surprise to find a significant influx of mainly juvenile birds during late October-mid November 2008. The west Scottish Twite population had seemingly enjoyed the “poor” summer in terms of breeding success. Or have a higher percentage simply come further south than in the previous two winters? In this respect, at this current time, there does not seem to be a great deal of evidence of sizeable flocks on the Cumbrian coast c/p winters 2006/7 and 2007/8. This is, however, the sort of comment which could be contradicted tomorrow!

This influx resulted in about 130 birds being ringed at Heysham north harbour wall feeder between 31/10/08 and the end of January 2009. Over one-third of these were trapped on 5/11/08.

The retrap data from previous winters has seen a certain amount of interchange between birds at Heysham north wall and other flocks scattered along the Fylde coast. However, there was always a “core” of up to c20 birds, which were regularly retrapped. This winter has been different. First of all, there was only ONE bird seen which was ringed at Heysham prior to February 2008. Therefore there was NO ‘core population’ of regularly returning birds and this is perhaps reflected in the retrap data tabled below. In other words, the presence at Heysham in winter 2008/9 is simply due to a significant number of mobile birds knowing about the feeding station, not due to a ‘resident group’ using this source and occasionally being joined by others. The Heysham retrap data and observation of ringed birds elsewhere suggests a metapopulation of scattered coastal flocks which vary in size and location as the individuals ‘mix and match’ sites. It must be emphasised that catching of Twite at Heysham tends to be an "all or nothing" under a whoosh net. Therefore there is no obvious bias towards birds which have not been retrapped on a regular basis and are therefore not net-shy. Therefore catching sessions are not accompanied by significant numbers of net-wise birds sitting on a nearby fence. Also, in previous winters, when there was a "core population", some individuals were retrapped as many as five times.

'Mixing and matching' certainly appears to be the case between Heysham and Bank End and is also probably the case between Heysham and perhaps as far south as Knott End (although ringing data from this flock not available). Unfortunately we have no idea of the location of overnight roosts, possibly the most likely ‘mixing ground’. However, the roosts may be separate entities at each location and therefore any mixing is simply, as has been observed on occasions, due to roaming around in daylight hours. Observed roaming e.g. purposeful flight over Potts corner, half way between the Heysham and Conder, has tended to involve small flocks, not singletons.

One of the difficulties has been to determine the end of the passage period and the start of the winter ‘mixing and matching’, especially in relation to the unringed birds appearing at Heysham in variable numbers during the winter. The Heysham ringing data, allied to observations, suggests that the 2008 autumn passage as such was probably over by about 20/11/08, therefore subsequent unringed birds were part of the winter ‘mixing and matching’ and presumably not a dribble of southbound new arrivals during the course of the winter. Difficult to be absolutely certain as this species is NOT obvious on ‘vis’, perhaps due to off-passage birds at the feeder & regular commuting to and from Ocean Edge saltmarsh confusing matters.

The flocks, many of which appear to contain “at least some” Heysham-ringed birds, can be found at the following sites. As already implied the numbers are extremely variable as befits a mixing and matching metapopulation.

Location of flocks in Lancashire and Merseyside winter 2008/9
Bolton-le-Sands saltmarsh

The only flock recorded to the north of Heysham was of 5 (at least one Heysham-ringed) on Bolton-le-Sands marsh on 10/1/09. This was a regular site, with daily commuting to and from Heysham north wall in e.g. winter 2003/4.

Heysham north harbour wall & Ocean Edge
Reasonably easy to see ringed percentages at the feeding station. Very variable unringed/ ringed ratios, sometimes as low as 1/40 in early December, but as high as 21/85 on 23/12 and about 16/60 in mid-January. In general, the smaller flocks of 30-40 contained about 4-7 unringed birds during December-January, but a flock trapped on 4/2/09 contained 6 unringed birds out of a flock size of just 15. This supports the suggestions above re-mixing

Conder Estuary and area
Maximum of 55+ on 6/2/09 (only 2 at Heysham on this date). 50+ on 23/1, all other counts being 25 or below. Very hard to observe legs but percentage of Heysham birds presumed high

Maxima of 50+ on 1/1/09 & 5/1/09, 41 on 2/1/09, otherwise 13 or below. “Some” Heysham birds, with some counts suggesting as high as 80%

Bank End
46-55 on several dates 30/11-11/12/08. c50 on 5/1, otherwise absence of records. At least 50% Heysham birds on the few occasions able to observe the legs

Fluke Hall to Cockers Dyke
Difficult to be sure here – maximum of 20-30 but Linnets confuse the picture. “Some” Heysham birds

Knott End
Build up during November from 1 on 5/11, 30+ on 14/11 and 50+ on 23/11 & 28/11. Irregular high counts reported with a maximum of 62, but under 40 since 1/1/09. Number of Heysham birds completely unknown

South Ribble Estuary
Numbers unknown – no data available. Previously, this flock has perhaps surprisingly contained several south Pennine-ringed birds along with at least two from Heysham, or in one case, ringed on the South Ribble and controlled at Heysham. There is no evidence that the Heysham-ringed birds were of Scottish origin, given the history of small numbers of south Pennine or presumed south Pennine (see ringing recoveries) birds mixing with the inner Hebridean/west Scottish mainland birds

Birkdale and rest of Sefton Coast
There is absolutely no evidence of these birds mixing with any further north during the course of the winter. The grand total appears to be about 130 with the largest flock, of up to 56, at Birkdale One Heysham-ringed bird present – ringed during the known passage period [& one from Askam – see recoveries]. Otherwise at least 50 unringed, probably as many as 90, with the rest unknown. 33 have been metal-ringed here by John Gramauskas. As far as I am aware, the usual amount of ringing was undertaken in the south Pennines in 2008, so the lack of ringed birds may suggest another origin, perhaps logically, Scottish birds avoiding the whoosh nets at Askam and Heysham (apart from one from each site)

Thurstaston, Wirral
A small seemingly isolated and self-contained flock exhibiting a ’10 green bottles’ winter survival syndrome as it has gradually reduced from 15 to about 11. No ringed birds.

Heysham north harbour wall retrap data
Retraps of birds ringed during the 2007/8 winter
Ringed 12/2/08 (last three digits of ring numbers=619-640)
628 26/11
629 31/10
630 26/11
631 31/10
633 26/11
638 12/11
640 31/10
Ringed 16/2/08 (641-646)
643 15/12
644 1/11
646 5/11

Ringed 31/10/08 (647-677)
648 26/11
649 5/11
650 26/11
651 12/11
653 15/12
654 5/11
655 5/11
658 26/11
659 5/11
661 26/11
662 5/11
663 26/11
664 26/11 & 4/2/09
666 4/2/09
667 15/12
668 16/11 & 15/12
670 4/2/09
671 26/11
672 5/11 & 16/11
674 5/11
677 5/11
Ringed 1/11/08 (678-691)
680 26/11
684 26/11 & 4/2/09
685 4/2/09
686 16/11
688 5/11
690 5/11
Ringed 5/11/08 (692-743)
697 26/11
702 26/11
705 15/12
706 26/11
709 4/2/09
712 15/12
713 12/11
716 12/11
719 12/11 & 26/11
722 12/11
724 12/11
725 12/11
726 26/11
730 26/11
732 16/11
738 26/11
741 4/2/09
742 16/11
Ringed 10/11/08 (744)
744 4/2/09
Ringed 12/11/08 (745-746)
Ringed 16/11/08 (747-754)
753 26/11
754 15/12
Ringed 26/11/08 (755-770)
Ringed 15/12/08 (771)
Ringed 4/2/09 (772-777)

As has already been alluded to, the low number of double, as opposed to single, retraps does suggest that the Heysham winter population involves mixing and matching with at least the birds as far south as Bank End. The notable exception appears to be the Askam-ringed R687936! See above re-comment on net-shyness.

Selected ringing recoveries relating to winter 2008/9
Ringed: Askam-in-Furness SD205775 c27/10/08
Seen: Birkdale beach 12/11/08

Ringed: Heysham north harbour wall SD399604 31/10/08
Presumably same bird seen: Birkdale beach 12/11/08 & 4/1/09

Ringed: Askam-in-Furness SD205775 end of Oct 2008
Seen Glasson Marsh 17/11/08

Possibly one of those already seen/trapped at Heysham

Ringed: Heysham north harbour wall autumn 2008
Seen: Bolton-le-Sands shore; only bird/5 where legs seen 10/1/09

The only Morecambe Bay-east flock seen to the north of Heysham as far as we know

Ringed: Heysham north harbour wall autumn 2004
Seen: Heysham north wall 22/11/08

The only Heysham-ringed bird seen/caught which was ringed prior to February 2008! (None ringed 2006/7)

Ringed: Askam-in-Furness autumn 2006
Seen: Heysham north harbour wall 13/11/08

Just seen the once rather briefly and not possible to read metal ring

Heysham controls of birds ringed at Askam in Furness late October 2008:
R687936: caught 26/11/08 & 15/12/08, also presumably this partially read in 2009
R687948: caught 5/11/08
R687944: caught 5/11/08 & 12/11/08

All sightings of Askam birds at the Heysham feeding station since mid-November 2008 have been singletons and, on two occasions [last on 31/1/09], partial-reading has suggested, but not absolutely confirmed, R687936.

Ringed: Walberswick, Suffolk 3 female 23/12/06
Caught: Heysham north harbour wall 5/11/08 & 4/2/09

This has obvious wintered! Why would a south Pennine bird orientate correctly to Suffolk in its first winter (as a potentially lost and inexperienced immature) yet go “the wrong way” in its third winter? Perhaps it was a Scottish bird which ended up ‘lost’ at Walberswick (with known south-Pennine birds) as a youngster, then found the ‘correct’ wintering area in 2008/9? Is it from a fragmented population in the north Pennines without a strongly flock-cohesive migration pattern?

Further information required
The ringed birds have a metal ring on one (usually the right) leg and a single colour and a two-colour (with each colour half the width of the single colour) rings on the other leg. The most common combination of colour rings will involve a Heysham LIGHT BLUE single ring which is the SITE CODE and a variety of two-colour rings.

WE are not that bothered about the individual details as you will probably get very little time to observe the flock. Therefore please prioritise checking the approximate ringed to unringed ratio and check for any SINGLE colour rings which are NOT LIGHT BLUE. If you do come across one with a site ring not from Heysham, please try and get details of the two-colour ring and in an ideal world digicam the metal ring (last three numbers might be enough in conjunction with accurate reading of the two-colour ring)

Thanks very much and good luck!

To Alan Draper for ably conducting the ringing effort at Heysham and to all the various people who have assisted in ringing and providing photographs of ringed birds. Could someone upload a Twite pic to accompany this article, please?

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