Warbler Update

I always find it interesting to compare ringing totals with the previous years as with similar effort from year to year they give an indication of productivity. To early to do this for most species but  with all the data in it is possible to look at warbler trends in this year which saw  poor weather early in the breeding season but better weather later.

Blackcap at 116 is just slightly up on both 2012 (102) and the five year average of 97. Chiffchaff at  180 has a similar trend, up on 2012(159). The species which has seen the greatest decline though is Willow Warbler with 349 ringed this year compared with 510 in 2012 and a five year average of 476.  This fits in well with the general feeling that the breeding population was down this year. On the surveyed part of Warton Crag the breeding population was down from 29 pairs in 2012 to 21 this year. By contrast Whitethroat were up from  just 70 in 2012 to 173 this year as were Lesser Whitethroat from 30 last year to 48 this year.

Two other species which several members of the group have commented on as being scarce this autumn are Long-tailed Tit and Goldcrest. So far this autumn we have caught only 37 Long tails compared with 108 in 2012 and 27 Goldcrest compared with 184 in 2012 but there is still time for these to appear.

John

New Twite Colour Combinations

Hopefully, Twite will begin arriving on passage at Heysham Harbour very soon.  Colour ringing that has been undertaken here since 2002 will be continuing.  From now onwards however, a new scheme of site colour plus numbered colour rings will be utilised such that each bird will be uniquely identified.
 

The combination for this winter will be:  Right Leg below tarsal joint – Pale Blue over BTO Metal,  Left Leg below tarsal joint – White with dark engraved number between 1 and 99.

Sightings where the colours only are recorded will be attributable to Site and Season, but individual birds will be identifiable too if the numbers can be read (by telescope, digital camera etc) so I urge everyone to keep their eyes open for Twite wearing colour rings and report any combinations, and hopefully engraved numbers to Alan Draper.

All sightings will of course be eagerly awaited whether or not the colour ring numbers are known.  There will also hopefully be birds wearing the colour combinations from previous seasons (Right Leg: BTO Metal,  Left Leg: Pale Blue over a two-colour striped ring) and sightings of any of these are also very welcome.

Thank you in advance.

 

ajd

Grey Wagtail Sighting

This year at Heysham we have trapped and colour ringed 82 Grey Wagtails during the autumn passage (including four trapped nearby at Middleton NR).  The first was caught on the 3rd September and the last just 6 days ago on the 8th October.  One individual has possibly chosen to remain in the area as it was ringed on 9th Sptember and retrapped on the 8th October - this has been the only retapped bird.

This morning, whilst at the hut, my phone bleeped with a text message from Skokholm Island telling me that one of 'our' birds had just been sighted there. The colour combination was that of a bird caught on the 4th October - the last but one caught this year.  This is the only sighting so far this season although it is early yet and hopefully more will be reported.

ajd

Reed Warbler End of Term Report

Have at last got round to working out the results of  our Reed Warbler Study for this year at Leighton Moss RSPB Reserve. This is run as a spin off to our main study of Bearded Tits. During the four months June to September we made 59 visits to our five sites spread  throughout the reed bed, around our normal number of visits over the past five years.

The adults were late in arriving this year and the population certainly appears to have been down on recent years. This year we caught 146 adults (88 new birds and 58 retraps from previous years). This compares to an average of 192 for the previous five years. The late arrival and an early departure may well have reduced the catch but even so the breeding  population does appear to have been lower.

However the excellent late spring and summer weather appears to have been good  for productivity for despite the apparent drop in the breeding population we ringed 743 young birds, well up on the 504 in the poor weather of 2012 and also up  on the five year average of 598.

Departure of adults was certainly earlier than usual, many apparently leaving in late July/ early  August. We only caught 15 adults in August compared to  an average of 70 over the past few years. I wonder if the late spring arrival  meant that  very few birds attempted a second brood. Also the good productivity suggested fewer re-lays after a failed attempt.

Sedge Warblers also appear to have  had excellent productivity with a catch of 326 compared with an average of 270 over the past five years.

John

It's All Go

A busy weekend with conditions good for mist netting at Leighton Moss RSPB Reserve. One highlight was the catching of two Reed Warblers. Numbers drop off steeply by October but these late birds are obviously getting ready to migrate. One  weighed 15.2 grams almost  half as much again as they weigh in summer and it's  breast was completely  covered in fat. The second bird weighed in at 13.8. I thought the first bird was the heaviest Reed Warbler we have ever caught but a quick search with the aid of IPMR brouught up one at 17.2 grams on October 6th 2005. The majority of the 105 birds ringed in previous Octobers were putting on weight but a few were as low as 9.9 grams.

Our main study species is Bearded Tit and with a catch of 17 birds and grit tray sightings of colour ringed birds we logged up a total of 33 different birds. Most satisfying was the catching of three previously un-ringed birds, from the pale iris colour we could age them as birds of the year- this brings our total of young birds for this year to 42, well up on last years poor show of just 17. Of the 33,  19 were this years birds and 14 were adults. This reflects the finding that adult birds start to visit the grit trays  a week to 10 days before the bulk of the juveniles.

Earlier in the autumn I reported on the low numbers of Blue Tits we were catching and surmised  that they were still in the woodlands where there was plenty of natural food.  Numbers have really started in pick up now in the scrub and reed bed and this was  reflected in our catch this weekend.
John 

Bearded Tit Gritting Season Gets Underway

I have just returned from watching the superb sight of at least 11 Bearded Tits busily gritting on the specially provided grit trays just off the Public Causeway at Leighton Moss RSPB Reserve. They have started gritting this year a few days later than normal but it got underway with a bang with 13 birds seen on  September  30th. After a period of warm weather with lots of  insects around a sudden drop in temperature brought the birds to the trays so they have grit in their gizzards to grind up the reed seeds which they turn to once insects decline. In most previous years adults have been the first to visit followed by juveniles a few days later. But  this year about half the birds identified by their colour rings were  birds hatched this year and ringed as juveniles. Possibly this is a reflection of a better breeding season this year with 40 juveniles caught this year compared to only 17 in  2012.

The colour rings enable us to identify the birds individually as part of a population study which started when the Bearded Tits first colonised The Moss in 1973 with just one pair. To date we have identified  10 adult males and 11adult females but we usually pick up quite a few more during the gritting season. We identified two new ones yesterday.

Perhaps the most interesting sighting yesterday was a pair seen together on the tray at 11.45. This pair occupied one of our wigwam nest boxes this year. You  may have watched the RSPB Web Cam shots from the nest box in late April early May when they reared  four young. Last gritting season they visited the grit trays together on 13 occasions and were obviously a pair. They nested together  and have returned to the  grit trays together this season. This again shows that Bearded Tits once paired remain together throughout the year.

Today another pair which also used our nest boxes turned up again together  and had been seen together on the trays 10 times last autumn.

The RSPB Web Cam is now installed on one of the trays so you can watch in comfort. Today though they seemed a little camera shy and used the other two  tables more although on one occasion five were on view from the camera.

Thanks to Alan Gallagher for the photos
John