brewoodringers

BIRD RINGING AT BELVIDE

The 2007 Report

Overview

For anyone interested in birds or wildlife generally, every year is different, and in many ways that is exactly what keeps us interested. As can be seen from the following report, ringing at Belvide in 2007 was very different from 2006, primarily as a result of the exceptionally high rainfall during June and July. In fact, we had almost abandoned any hope of ringing because even by mid July, the net rides were thigh-deep in water. Another local ringer, Dave Clifton, at Hams Hall abandoned all ringing when most of his net poles and guys were completely washed away! However, back at Belvide, by the end of July, most rides had drained sufficiently to allow nets to be set safely. As the water was let out of the reservoir we managed to have almost the same number of ringing sessions, during the main post-breeding period, using approximately the same number and length of netting as 2006. This means we now have an emerging picture based on a reasonably standard ringing effort—thereby enabling some robust year-on-year comparisons to be made. Although currently we can only do this for the last two years, this will obviously improve each year, and will satisfy one of the main aims of the ringing effort at Belvide.

We did improve coverage of other aspects this year, mainly on the winter roost in the Gazebo reed-bed, and around the feeding station outside the Gazebo hide. The effects of these on the totals are explained in the text.  

New birds ringed

Table 1 shows the total of birds which were newly ringed during 2007, and compares these numbers with those from 2006. The text which follows picks up and suggests explanations for some the issues which jump out from the numbers in the table.

TABLE 1

Analysis

Some species appear to have been unaffected by the weather conditions. Robin, Dunnock, Wren, Goldcrest, Chaffinch and Bullfinch were all caught in very similar numbers to last year. These species possibly bred before the poor weather hit, or nested in places less affected by the rain. For example, Goldcrest nests are usually quite high in conifers so assuming the birds sit tight during rain they should be relatively unaffected. The lower number of Goldfinch caught is not a reflection on population trends, but due to them roosting near a net site in 2006 and not in 2007.

Some other apparently interesting results can be explained quite easily. The large numbers of Reed Bunting and Starlings were due to the extra effort in catching them at their roosts in the reeds. Although we will continue in future, comparisons with Starlings may be impossible due to their erratic behaviour at roosts. The large number of Tree Sparrows was due to increased effort at the feeder station outside the Gazebo hide—this again may be continued to build up a more complete picture of just how many birds of this important species are being supported by the feeding station. The increased number of Greenfinches and Blue Tits ringed was due to the same reason.

However, the number of Great Tits gives some cause for concern. The expectation would have been for their numbers to have been largely unaffected by the weather in that they nest reasonably early and largely in boxes or holes in trees. However, we caught very few during the normal ringing sessions, and the only reason the numbers caught are as high as they are is due to the extra effort at the feeding station. On the positive side however, the ratio of adults to chicks was as it should be. This compares favourably with some reports from around the country where only adults are being caught, demonstrating very poor breeding. The low numbers of Long Tailed Tits is also difficult to explain. Their numbers generally have been increasing largely due to a series of mild winters. Indeed we caught lots of LTTs but a large proportion were re-traps from previous years which had clearly survived well ( see later section). For some reason it appears that their productivity this year was low; it could of course have been that any nests which were a little later than normal may have been washed out.

Blackbird and Song Thrush numbers are encouragingly high, with, as expected the majority of the new birds being birds reared during the year. Both species tend to nest early, and have several broods, so they probably missed the main deluge. Furthermore, wet weather can be very beneficial to both these species in that it keeps the ground soft enabling them to find worms more easily. The single Redwing signifies little other than a chance catch near the feeding station from what was a big influx of this species across the country.

The two most exciting birds of the year in some respects were the Pied Flycatcher and Cetti’s Warbler—both of which were new birds to be ringed at Belvide. The origins of the flycatcher are unknown, but it could have come from the small breeding population on Cannock Chase, or from the very large population throughout Wales. The timing is consistent with birds gradually moving off south, but catches away from the breeding range ( other than at coastal sites) are unusual. Our big hope is that it is recaptured, hopefully at a nest box in its natal area. The Cetti’s is potentially more exciting in that this is one of an increasing series of records as the species continues its northward spread in Britain. This individual was a female (based on wing length), which suggests it is a separate bird from the one heard singing briefly in Gazebo bay a couple of weeks later. With luck it may become a breeder at Belvide in the near future; the habitat certainly seems suitable when compared to other breeding sites in various parts of the country.

The results for Chiffchaff and Willow Warbler are interesting on several counts. Willows were definitely more numerous this year than last, but it is debateable if the increase in Chifchaff is statistically significant. Whichever is true, neither species appears to have suffered from the bad weather. Both nest on or close to the ground, and so they both should have been affected. It is possible therefore that many of the individuals of these species nest close to the reservoir, in drier areas, and use the margins of the reservoir to feed up prior to migration. If this is the case then the reserve is no less important than if they do not actually breed, since pre-migratory fat deposition is a critical aspect of survival. The number of Willows also, undoubtedly, contains some migrants from further afield. The following table shows an unexpected trend difference between these two species. The high numbers of Willows earlier in the season fits with the notion of local birds wandering the natal area feeding up ready for migration, then as migration gathers pace, these birds move out, and are not replaced by migrants from further north ‘dropping in’ en route south. This is a little surprising because this species typically flies several short distances on migration. However, the period in question was typified by clear skies and following winds which presumably were ideal conditions for migration, and Willow Warblers left the country quickly. Chiffchaffs on the other hand typically migrate later than Willows, and the data show two peaks corresponding to two waves of birds passing through the reserve, with typically later dates for birds lingering into the Autumn.

Table 2

The varying fates of the ‘Sylvia’ warblers are very difficult to explain. Presumably, Whitethroats were unaffected by anything, and appear to have kept their small breeding population on the reserve. Given that their nest sites are very similar to Blackcap, it’s very difficult explain why the latter species appears to have done so badly this year. This is even more puzzling when the success of both Garden Warbler and Lesser Whitethroat are added to the equation. Garden Warblers were heard singing across the reserve and they appear to have bred successfully—and at last we managed to catch 2 adult birds proving that they do breed like other birds, rather than by spontaneous generation as we suspected last year! Lesser Whitethroat is an uncommon breeder in most places so it is doubly exciting to see their numbers looking so good. Two of the birds we caught were adults suggesting they bred nearby, so we can only hope that this is part of a trend, rather than a peculiar case in 2007—time will tell.

Clearly the most upsetting effect of the high water levels was the very poor breeding season experienced by Sedge and Reed Warblers. Sedgie numbers were down, but not disastrously so, partly we suspect, because they are less reliant on nesting over water than Reed Warblers. The effect on the latter can be seen in the stark numbers. What makes it even more significant is that almost half of the new birds ringed were adults, showing what a poor breeding season they had. We were unable to get into the reeds to look for nests for obvious reasons—but 3 nests were found in willow bushes, which the birds will use in dire circumstances. At least one of these nests was successful in that 3 chicks were fledged—the only Reed Warbler chicks ringed on the reserve in 2007. The fact that so many new adults were ringed does give some hope for the future, along with re-traps from previous years discussed later. This does show that the site is very attractive, and, given more normal conditions next year, we can be reasonably confident that numbers will be back where they were in 2006—we hope!

Keeping Track

One of the main purposes of marking individual birds, is that it allows us to keep track of them. This applies primarily to birds which are resident or nest at Belvide, but sometimes ‘our’ birds are recovered elsewhere—either dead or alive—thereby helping us to understand their movements. We are now starting to accrue some re-trap data, some of which is presented below.

 First, ‘our’ birds which have been found elsewhere:-

ChiffchaffAPK397, ringed as a juvenile bird on 23^rd August 2005, was found breeding in Buckinghamshire as a male the following year.

Sedge Warbler V228148, ringed as a juvenile on 27^th July 2006, was caught by ringers on its way to Africa on 27^th august 2006 in Sandouville, northern France, 397k from Belvide. From what we know about Sedge warbler migration it is very likely that the bird flew in one step—probably the night before, and was feeding up for the next stage of its migration.

Reed Warbler, V228258, ringed as a juvenile on 14^th August 2006, was found at a breeding site in Pocklington, Humberside. Clearly this bird was not faithful to its natal site. Having part of a breeding population move out is essential for species survival and for mixing gene pools.

Second, some of ‘our’ birds which have been found back at Belvide:-

 Sedge Warbler T569298, and Reed Warblers T569141, T569267, T569342 are all becoming ‘old favourites’ in that they were all first ringed as breeding adults in 2005, and they were all re-caught in 2007 at least trying to breed again. These are exactly the hard core of returning birds which we hope will return next year to help the recovery after this year’s bad breeding season.

Blue TitsT569266, T569354, and Great Tits, T22646, T569371, T569321 are similarly becoming regular breeders. Although they don’t have the rigours of migration to overcome, they do have to survive our winters, and these were all ringed initially as adults in 2005, and were all re-trapped at the site during the Summer 2007.

Garden Warbler V228020, was originally ringed as a juvenile in July 2006, but obviously returned, as a ( presumably) breeding adult and was re-trapped in July 2007.

Chiffchaffs1U9114, 1U9115, BRV384, 1U9197, were all ringed during the Summer of 2006, and were re-trapped during the Summer of 2007, presumably part of the strong breeding population around Belvide.

Now a real gem! Reed Warbler P465670 is a very game old bird. She was initially ringed at Belvide as a recently hatched juvenile ( not sexed) on 14^th August 2001. We re-caught her on 18^th August 2007 with a brood patch showing that she was female and at least trying to breed. Hopefully she will now be spending the Winter in a safe reed bed somewhere in Africa getting ready to embark on her eighth period at Belvide. What a phenomenal feat that will be if she does make it. We shall certainly be keeping a sharp eye on every re-trap next season in case she turns up again!

We hope this report has been both interesting and informative. We believe it demonstrates the benefits of a systematic ringing effort, and we hope that further insights into the birds of Belvide will accrue as time goes on. Finally we would again like to thank the Belvide management team for their interest, enthusiasm, practical help and presence at many of our ringing sessions.

Colin McShane ( on behalf of the Bache, Shearwood and McShane ringing group)

January 2008

BELVIDE 2006 RINGING REPORT

 In General

This was a very successful year in terms of both numbers, and variety of species caught. The ringing effort (number of nets/number of visits/time nets open), in 2006 was a little under twice the effort in 2005. This is very important when trying to compare totals between years.

Ringing of Reed Warbler nestlings was not as good as expected, mainly because visits were not timed as well as they could have been, with several broods already fledged, while others were either too small or still in egg—of which there is more later in this report.

The clearing of rides helped the catch rate generally, but some willow sp. bushes had increased in height since 2005, which resulted in the nets beside these being less successful as birds flew over the nets. It will probably take a few more years before we have established exactly where the most productive sites are, and how best to manage the vegetation around them. What also helped generally was the weather, which provided a hot dry period during Summer which helped most relevant species in their breeding attempts; with reasonably still conditions during the main ringing period which helped the catch-rate. Those who experienced being caught in the heavy downpours may find this more difficult to believe!

 Specific species:-

Swallow, martins, and Yellow Wagtail

All but one of these were caught in one net during one morning when the weather conditions were such that the flies were very low, at the edge of the water, and very near to that particular net. We can therefore deduce nothing from this of a more general nature. 

Wren, Dunnock and Robin

The reasonable assumption here is that these birds are resident and numbers reflect the breeding population. Only 19 definite juvenile Wrens were caught, and overall the numbers compare unfavourably with 2005, we suspect they were not very successful in their breeding attempts in 2006. About twice as many Dunnock and Robin were caught this year—consistent with the extra effort—probably they did as well as 2005.

Grasshopper Warbler 

This was an unexpected catch as there were no records of the bird breeding this year. The bird was a juvenile, so we must assume that it ‘dropped in’ to the area on its southward migration—or was on an exploratory flight near to its nest site near to Belvide?

Sedge Warbler

Only 10 adults were caught this year (14 last), from which a total of 43 juveniles were ringed. We suggest that most of the birds were hatched at Belvide since most were caught in July and early August; however there may have been some immigrants from passage birds. Although only 28 juveniles were ringed in 2005, given the extra effort this year, we feel that this species has not done as well as in 2005.

Reed Warbler

Again we feel that most birds relate to those breeding at Belvide—we even caught two freshly fledged birds as late as the first week in September. However, we also know there is some immigration as we have records of birds ‘commuting’ between the site and Chillington.

Approximately the same number of adults were caught as last year. Catching adults is not susceptible to the same effect of increased effort as juveniles, since they are at the site continuously and tend to be more static in their behaviour—if they are there then we will catch most of them quite early in the ringing effort, after which the catch drops off as the older, wiser birds learn where the nets are. ( see graph below). A total of 116 juveniles/nestlings was caught which is approximately twice as many as last year—in line with the extra ringing effort. Their appearance after fledging can be seen from the graph below—as can the length of time fledging occurs with 2 and sometimes 3 broods being reared. The apparent drop in period 4 is mainly a function of a period of poor weather when little ringing was carried out. The 10 day periods are as follows:-

Only 11 nestlings were ringed although an estimate of productive nests was carried out. We estimate that in the reed bed by the first hide there were about 8 pairs, one or two pairs around the shore between there and the Gazebo bay, where we estimate there were 7 pairs. This equates to somewhere around 17-20 pairs of Reed Warblers on the site. 

Whitethroat

2 adults and 14 juveniles were ringed, which is in line with last year—probably 2 or 3 breeding pairs.

Lesser Whitethroat

We believe that one pair bred this year. One adult and 4 juveniles were ringed; none were ringed in 2005.

Garden Warbler

25 birds were ringed which is about double last year, indicating a steady state for this species. What is fascinating however, is that while this should indicate that at least 4 pairs were present, over the last 2 years we have not caught a single adult Garden Warbler! (Answers on a postcard please.)

Blackcap

63 individuals were ringed indicating a steady state for this species also. Adult Blackcaps do seem easier to catch than their plainer Garden cousins for some reason.

Chiff-Chaff

Perhaps surprisingly, this was the most numerous species to be ringed, taking over from last year’s ‘winner’ which was Reed Warbler.  However, the difference is marginal, and there would appear to be about the same number of pairs around—possibly 10-12, with 95 juveniles being caught, some of which undoubtedly have moved into the area from breeding nearby.

Willow Warbler

The position seems about the same as last year, although trying to relate numbers to breeding pairs is particularly tricky with this species because juveniles especially begin to migrate very early in August.

No particular patterns could be established on the remaining species due to relatively small numbers—although their catch rates do appear to be reasonably in line with last year.

The future

We hope to continue exploring net sites and to make as many as possible ‘permanent’ for future comparative analysis, and to make net erection and management easier. This would mean having some permanent poles installed with hooks for the net loops. We would also like to continue and if possible expand the involvement of visitors to the site, which was successful, if limited in numbers this year. Better planning and advertising should help—although the vagaries of the weather are always a stumbling block. We hope to join some of the work parties during the winter to clear rides/ lop bushes and help with general site management.

Retraps and Controls

Note that a retrap is a bird which was originally ringed and then recaptured at the site, whereas a control is a bird which was originally ringed or recaptured at another site.

Controls 

Unfortunately we have only had a couple of controls this year—both of which were ringed locally:-

TH 46574 :- a Greenfinch adult female ringed 07 April 2006, at a garden feeder in Brewood, recaptured 27 July 2006 at Belvide.

T227891:- a Reed Warbler ringed as a juvenile bird in Chillington on 9^th August, controlled at Belvide on 19^th August. Obviously checking out its local area for the future.

 A selection of re-traps

R495437:- a Reed Bunting ringed as an adult bird on 31^st December 2004 when trying to catch Snipe, was re-trapped on 2^nd May 2006 obviously a resident breeding bird.

1U 9019:- a Long Tailed Tit, ringed as a juvenile bird on 11th July 2004 in a large flock, re-trapped on 1^st August 2006. This bird has survived 2 mild winters and stayed in the same site.

T569185/187/191:- are 3 adult Sedge Warblers which were all ringed on the same day—10^th July 2005, and were all re-trapped on the same day, 4^th July 2006. These are obviously experienced breeding birds returning to the same site each year. We do not know for how many years because they were ‘adult’ when first ringed.

APK 392:- a Long Tailed Tit first ringed as an adult on 5^th August 2005, retrapped on 17^th January and again on 2^nd May 2006. Again a bird that has survived a mild winter and stays close to the same area.

Acknowledgements 

We would like to thank the Belvide Management Committee for their continuing support and encouragement—especially to Steve for his regular interest and visits. We hope these notes are both interesting and helpful to the continued improvement of Belvide as a first class reserve.

Special thanks to Glynn Middleton for keeping all the electronic records and producing the appendices tables.

Colin McShane; Pete Bache; Glynn Middleton; Paul TenHoeve

(See Appendices below) :- Please note that adding the juvenile total to the adult total does not add up to the overall total. This is because there are around 100 individual birds whose age could not be determined so are not accounted for on the age specific tables. Long Tailed Tit and Wren are classic cases, both of which are commonly caught at Belvide                                                                                               

BELVIDE TOTALS 2005