CHEW VALLEY RINGING STATION

by Reg Kersley.

The first recorded ringing at Chew Valley Lake took place on 4th. June 1961 when Roy Thearle trapped eight Reed Warblers and one Reed Bunting. He made 14 more visits in 1961, ringing 236 birds of 25 species. The success of these trial visits to the lake indicated its potential as a ringing site; ringing has occurred in every year since.

In January 1962 Roy Thearle, together with Miss D.M.Crampton, Mr and Mrs A. Dale, A.W. Diamond, T.B. Silcocks and Mrs Pam. Thearle, formed the Mendip Ringing Group. They ringed birds at a number of sites that year, particularly Saltford Sewage Farm, but it was not until 23rd December, after they had received permission from the Bristol Waterworks Company, that they visited Chew, when one Long-tailed Tit and two Chaffinches were ringed. Within a few days snow and freezing conditions had arrived and were to continue for another 10 weeks. Ringing restarted in April 1963 and the Group concentrated its efforts at Chew for most of the year. The subscription was £2.12s.Od. (£2.60).

They tried various sites, and by mid-summer had decided that the southern end of the lake, with its reed beds, was the most suitable area in which to base their activities. The year's total for Chew was 608 birds of 35 species including 107 Swifts, 69 Reed Warblers, 75 Sedge Warblers, 18 Blackcaps, 40 Whitethroats, 32 Willow Warblers and 24 Chiffchaffs. Roy quickly realised that Chew was an important feeding area for warblers in autumn and his emphasis on that aspect of ringing at Chew continues to this day. It soon became obvious that Chew offered so much potential that ringing at other sites would have to be abandoned. It was therefore decided to re-name the Group to fit its single-site status as the Chew Valley Ringing Station. The new name was officially adopted from the beginning 1964. Under Roy Thearle's enthusiastic leadership CVRS soon became one of the most important inland ringing stations in Britain. Sadly, Roy's early and tragic death in 1972 denied him seeing the full extent of his achievement.

I have extracted most of the following notes from the CVRS Reports  where many more details will be found, including the complete lists of birds ringed and recovered in each year.

Most of the 1,272 birds ringed in 1964 were dealt with either in the field or 'out of the back of a car' but in the closing weeks of the year CVRS moved into its first hut, really nothing more than a 10' x 4' garden shed. However, with its triple role as ringing laboratory, equipment store and shelter, the hut soon became a focus of attention for all visitors to Chew. The ringing hut proved to be an invaluable base and our activities in 1965 were soon consolidated with extra members and greater coverage during which 3,720 birds were ringed, tripling the 1964 figure. The number of warblers more than matched this increase and these included our first Aquatic Warbler .These birds are occasionally recorded at Chew, usually in the first week of August.

Subsequent foreign recoveries of Reed Warbler (one in Portugal) and Sedge Warbler (two in France) added icing to the cake. With the arrival of October any relaxing of ringing activity was forgotten as an influx of Bearded Tits (37 trapped) and Redpolls (35 trapped) kept us busy. Our first Water Pipit had been trapped in January.

The subscriptions for 1966 went up to £3.0s 0d but then everything was up in 1966, with high numbers ringed in both spring and autumn, thanks to a combination of unusual and good weather at Chew. The colossal total of 6,294 was achieved with a lot of hard work but helped, of course, by there being a lot of birds about. In fact, as it turned out, it was to be many years before this annual total was overtaken.

During August the vegetation was alive with Sedge Warblers (1062 ringed) Willow Warbler (562) and Chiffchaff (704). 518 Swallows were trapped in roosts (mainly) and these provided exciting recoveries from the Cameroun Republic and Cape Province, South Africa. Other notable recoveries included a Sedge Warbler in Morocco, Blackcaps in Spain and Corsica and Lesser Whitethroats in Austria and Italy.

During August the vegetation was alive with Sedge Warblers  with1,062 ringed, Willow Warbler (562) and Chiffchaff (704). 518 Swallows were trapped, mainly at roosts, and these provided exciting recoveries from the Cameroun Republic and Cape Province, South Africa. Other notable recoveries included; a Sedge Warbler in Morocco, Blackcaps in Spain and Corsica and Lesser Whitethroats in Austria and Italy.

Breeding birds arrive from mid-April and leave at the end of July. Chew is also an important stopping off' fattening up 'area and a large passage of adults and juveniles takes place in August and September.

1967 was a year sent to test us, with poor weather in spring and late summer and then Foot and Mouth Disease in November and December. Because of the latter we were not able to visit Chew so we diverted our activities, temporarily, to Berrow marsh and dunes. Under the circumstances we were moderately pleased to have ringed 3,434 birds with Tufted Duck, Little Ringed Plover, Black-tailed Godwit, Rook and Wood Pigeon new to the ringing list With the increased activity of CVRS it was clear to all that we had outgrown our small hut. So it was with great relief and satisfaction that we were able to move into a new much larger hut in 1968 . The 12' x 20' hut had four rooms; laboratory 12' x 8', office, kitchen and lobby, plus a loft for the storage of poles. Services now included electricity and running water (and soon after, Calor gas). Such facilities are costly, even allowing for the very low rental charged by BWW. Subscriptions went up to £4.0s.Od. and each daily visit to the hut would cost l/6d (71/2p). Birds ringed were up with the total of 4,790 including our first Bluethroat, Kestrel, Carrion Crow and Willow Tit. Recoveries included 3 Jack Snipe in Finland (ringed in 1967), two more Swallows in South Africa and a Song thrush (ringed at Berrow) in Denmark. (In October a few members combined with the Bristol Ornithological

During 1969 we had some notable additions to the ringing list: Curlew Sandpiper (three), Hobby  and Stock Dove (two). The latter two have not been in our hands since, although I suspect that many a Hobby has been very close to entering a net whilst chasing hirundines at dusk. In an attempt to protect their fishery interests BWW carried out a controlled shooting of Cormorants and two of the birds were carrying rings placed on them on Steep Holme and Puffin Island, Anglesey. A Lesser Whitethroat gave us a notable recovery when it was 'taken' at Latakia, Syria, on its return migration in spring but Whitethroats scarce during the summer!the 38 ringed being only a quarter of what we would have expected. We now know about the droughts in The Sahel (Bird Study 21 (1974): 1-14), but at that time we were mystified and shocked. Total number of birds ringed plunged to just under 2,000 and next year, 1970, the figure was only 400 higher. In 1970 a single Yellowhammer was ringed and it remains the only one in the totals.

1971 and 1972 produced a few first overseas recoveries; a Chiffchaff in Spain and a Blackcap in Morocco in 1971, and a Tufted Duck shot at Tyumen, USSR, (4,000km ENE) in 1972. These highlights contrasted with some very low totals for birds ringed - only 1,114 in 1971 and 1,804 in 1972. New to the ringing list for 1973 were Pied Flycatcher and Temminck's Stint. That year we paid £28 rental for our ringing hut, but this was doubled to £56 in 1974 during a period of unprecedented inflation. Even so, with the help of a grant from the BOC and other donations CVRS managed to remain solvent and activity continued at a reasonable level after its low point of the previous years. Curlew and Lesser Black-backed Gull were new to the ringing list.

1975 was notable for several reasons including our first African recovery of a Reed Warbler (in Morocco) and we added Cuckoo (two), Little Owl (one), Lesser Spotted Woodpecker (two), Cetti's Warbler (one) and Firecrest (two caught in the same afternoon in late winter, one of which was retrapped in the same area in the following autumn!) to the ringing list. We also started experimenting with using a tape recordings to attract roosting Swallows. The number of birds roosting at Chew in 1975 was low, similar to recent years, so the catch of 625 was considered a great success, being the second highest annual total. This augured well for the future. 1976 started well with a Little Bunting caught whilst trapping finches, Reed Buntings and sparrows in a kale field very close to the ringing hut. Other additions to the ringing list included Short-eared Owl, Wood Warbler and Red-backed Shrike. The subscription went up (to £6-00) that year and again in 1977 (to £7.00), when the 'hut tax' was also raised (from 10p. to 20p. per visit). The ringing totals for the previous two years had been quite high (3,273 in 1975 and 3,178 in 1976) and this better trend was maintained in 1977 with a total of 3,334 including Knot and Herring Gull as new species.

In 1978 an experiment with wire traps designed to catch corvids worked well and significant numbers were trapped, particularly Jackdaws. Our first really successful round-up of Canada Geese in their flightless moult period, saw 55 ringed plus a retrap from 1976. This has now become a regular annual social event with the first Tuesday in July being traditionally set aside for the C. G. roundup with a barbecue to follow. This has provided us with some hilarious moments too with the combination of; keenness, boats, wild birds and water always a potential for some form of minor mishap. On a more serious note our now 18 year long database is one of the best records available for population studies of this introduced species. This has been made possible by the generosity of Bristol Water and the Chew Valley Lake Sailing Club in lending us their boats.  All this helped to put the year's total (3,111) at roughly the same excellent level of the previous three years. Greater Black-backed Gull and Black Tern were new species for the ringing list. Some members of CVRS deserted Chew on a few days in the winter to join members of the Wash Wader Ringing Group for the cannon netting of waders on the English side of the lower Severn, a stimulating, if exhausting, experience for all concerned. If the birds had not been warm blooded many fingers would have been lost to frostbite! 1,134 Dunlin, 94 Redshank, 35 Oystercatchers and one Knot were netted on 12th February: all in aid of Nigel Clarke's research on Dunlin along the Avon and Somerset coastline. During 1976 to 1978 improvements were made to the Ringing Hut - a storm porch, new equipment (including a small fridge for the kitchen) and more shelves and cupboards as well as a bookcase for our growing library.

1979 brought us all down to earth - it was a poor year with the spring passage being about the worst on record for trapped birds, and a below average autumn. Certainly, a distraction during the year was the setting up and installation of a GB radio system; the mobile units being identified as "Bird One" to "Bird Ten". It was hoped that the system would be useful for improving communications during Canada Goose round-ups and roost catching, for example. On the credit side, though, was the first South West Ringers' Conference held at Timsbury on 28th April, which was organized by CVRS on behalf of the BTO. About eighty ringers enjoyed  an interesting series of talks, helped along by excellent refreshments (including a lively bar!). A great success. Later in the year a highlight was the interesting series of talks, helped along by excellent refreshments (including a lively bar!). A great success. Later in the year a highlight was the retrapping of a Chiffchaff on 29th. July. It had been ringed (ring no. 183390) 7 years 11 months earlier, as a 3 (i.e., in its first year) on 29th. August 1971. The ring had worn down to about half its original thickness! The very low number of ringed birds in 1979 (1,528) was only slightly improved upon in 1980 (1849); another poor year., but with a new species, the 123rd. ringed - a Ruddy Duck. An interesting recovery, though, helped to brighten the year, our first overseas recovery of a Garden Warbler. It had been ringed in July and then travelled to Spain where it was found on 16th. October.

1981 continued the improvement of numbers ringed with the total creeping up to 2,161. Wryneck was a species new to the list. Extra effort in the autumn paid off with roost catches of over 200 Starlings and just under 300 Swallows. We organised the second South West Ringers' Conference. It again attracted around 80 ringers and was rated to be another interesting and successful day. In 1982 the total ringed slipped back to 1,772, partly due to bad weather, and the number of species ringed was only 41, well below the usual figure of between 50 and 60. 1983 reversed the low catch trend and turned out to be a tremendously successful year. Indeed, the total ringed of 4,404 was the third highest ever. During August alone 2,827 birds were ringed. New records were set for the highest day total of birds ringed: 333 (excluding a roost catch) and 441 (including a roost), the latter including 329 Swallows - another record. 685 Reed Warblers were ringed between June and September (inclusive). Unusual captures during the year included two Spotted Crakes, Green and Lesser Spotted Woodpecker, two Firecrests and 12 Bramblings. We also organized a third Conference, which was held on 26th March, but this time for Ringers and Birdwatchers in the South West. Although the total ringed in our 21st year, 1984, was down a little (to 2,938), we still enjoyed a successful year. A bonus, for us, was that the water level was below normal which gave us the opportunity to attempt to mist net waders (mostly at night). We did catch Greenshank, Little Ringed Plover and Curlew Sandpiper, amongst others, but we had hoped for more. Nevertheless more reed edge was accessible and this helped to keep the number of ringed Reed Warblers at nearly 600. A new record of 353 birds ringed in a day (excluding a roost) broke that set the previous year. Unusual captures included three Aquatic Warblers (we normally reckon we're lucky if we get one!) and two Wood Warblers (only one previously trapped). The subscription went up by £1.00 to £8.00, the first increase since 1977.

1985 was an important year for Chew Valley lake; it was declared as a RAMSAR site because of its international and national importance as a wetland for birds. During this, and the following year, more effort than usual was put into the maintenance of the ringing areas (i.e. removal, pruning or replanting of willows) and the BWW made some improvements to the area of Stratford Bay with the construction of two islands and a bund to retain water a times when the level of the lake is low. (These works are all part of a long term programme of changes to the habitat with the object of improving the breeding potential for birds). The 1985 figure of 2,834 birds ringed included ten Great Crested Grebes, a new species for the ringing list, all of which were trapped in the BWW outflow tower adjacent to the dam.

In 1986 the total for ringed birds increased to 3,365 and this included one new species for the list - Savi's Warbler, only the third record for Chew. Canada Goose round-ups had continued on an annual basis and in 1986 we drove 120 into the corral, the highest number so far. During this year we carried out our first season of Constant Effort Site (CES) ringing - this, after lengthy discussions since late 1985 about the new BT0 initiative at population monitoring. The commitment would be to netting to a standardized arrangement once in at least eight ten day periods during the breeding season, and for many years. Our fourth South West one day Ringers' and Birdwatchers' Conference was held on 22nd March. The financial state of CVRS was now good but even so we raised the 'hut tax' from 20p to 50p per day; the money contributed to the increasing costs of the upkeep of our ageing hut. During the year we discussed the possibility of a new hut; it needed replacing, not simply because of its deteriorating condition but mainly because we had outgrown it. We needed more room in the ringing laboratory particularly, but we also needed more storage space, a larger kitchen and so on.

During l987 we continued our discussions about the hut and put forward out thoughts to BWW and by the autumn they had agreed in principle to replacing the existing hut. Meanwhile, ringing continued apace and a healthy total of 4,141 birds were ringed during the year. The 279 Blackcaps ringed was a new highest years total. We held our first two day ringing course which helped the five participants to advance their ringing by gaining their next permits - a great success. Our CES had worked so well that the bold decision was made to start up a second one in the north east corner of the lake at Twycross (out of our usual ringing area). Unfortunately it had to be abandoned the next year. One immediate problem was that the reedbed had been ravaged by the Twin-spotted Wainscot moth. However, the main consideration was that any CES project would ideally need to be carried out over many years and there were plans afoot by BWW to bring a nature trail (now called the Bittern Trail) down into the Twycross area. Most of the Canada Geese caught in the annual round-up (which included our first Greylag and Barnacle Geese) contributed to a study of lead in the environment; they each gave a small sample of blood for analysis. (After several years of sampling the lake environment was declared as 'healthy', with low or normal levels of lead - not the case found with birds caught and tested in the industrialised Midlands!) A new effort was put into attempts to catch wildfowl in cooperation with the Wildfowl and Wetlands Trust.

This lead, in 1988, to the trapping (by cannon net) of 60 Wigeon. Dazzling of birds at night was another method used to catch wildfowl as part of Baz. Hughes Phd. study of Ruddy Ducks. These proved to be quite elusive but the 'spin-off' for CVRS was that 70 other birds were caught (mostly Coot and Moorhen) and the experiment was to continue to the winter of 1990/91.  The Wigeon and also Whimbrel (five were trapped) were new species for the ringing list. A Rook, which had been shot 4km. away at Compton Martin on 18th. May, was ringed at Chew ten years earlier, on 9th. April 1978 as a full adult which means that it must have been at least 12 years old (they can live to be over 18!). More visiting ringers were helped towards their A and C permits during our second successful ringing course. The ringing total for the year was 4,223, the fourth highest ever. All this despite feverish activity on the hut front. BWW had offered us a large (40' x 20') hut that was to be demolished at Old Sodbury. Contractors who should have 'deconstructed' it, nearly demolished part of it, but for the fortunate interception of certain CVRS members! The dismantled hut was delivered to Chew in February 1988 and various parts were repaired and cleaned up (thousands of rusty nails removed, for example). BWW laid the foundations in April and by June we had fitted the floor and by July the main shell was complete. The new roof, which took the major part of the fund-raising as the old one was not recoverable, was completed by the December. By this time the internal partitions were well under way and electrical work had started.

So, the new hut was on target for use during 1989 (it was in a useable condition by April). Mike King gives a more detailed account of the progress and problems during the building of the hut in the 10th. Report, 1987-89. Despite this considerable distraction, ringing continued with an excellent year total of 4,387 birds ringed and the two CES were manned during the summer. 325 geese were rounded up at Chew in early July, mostly Canadas, but including four Greylags. Two days later 75 Canadas were rounded up at Blagdon Lake. Three Pochard, two Goldeneye and a Long-eared Owl were new species for the list.

During 1990 the interior of the hut and the furnishings were completed in readiness for the official opening which was performed by Sir John Wills Bt., Chairman of Bristol Water plc. on 15th September.  Chris Mead of the Ringing Office, and many CVRS members and guests came to partake of the wine and refreshments kindly laid on by Bristol Water. The construction of the new hut is a great tribute to the hard work of a minority of members, but thanks should also be handed out to those who did some work or contributed in other, not necessarily lesser, ways. The new hut was a great spur to members and the larger ringing laboratory was tested out thoroughly with our second highest annual total of ringed birds - 5,273. Over 1,800 hirundines (including 1,510 Swallows) trapped at roosts were a major contribution to this total as were good catches of Sedge and Reed Warblers. The most exciting catch, though, was an Aquatic Warbler carrying a polish ring. This was the first control of this species and, astonishingly, only one hour after our bird was trapped a second control was caught in Cornwall This bird was carrying the consecutive ring to ours; both had been ringed in the same nest in northern Poland that summer! During 1990 a few members started operating a moth trap and by the end of 1992 a total of 174 species had been identified.

Above average catches were maintained during 1991 and 1992 even though the expected roost of hirundines failed in 1992 There were two notable breeding records in 1991. Grasshopper Warblers bred near the Ringing Station, the first time for several years; four were ringed. The other record was the first for CVL (and Avon) of breeding Bearded Tits. A pair raised two broods and a total of eight were ringed including six Juveniles, three from each brood . Six members joined ringing expeditions to northern Senegal, organised by The Wetlands Trust, held in the winters from 1990/91. This has since produced an interesting crop of controls of Sand Martin, Sedge Warbler, Reed Warbler and Chiffchaff.

The two CES, Canada Goose round-up and the Ringing Course were carried through successfully in these years as well as in the 30th year, 1993, which became the new second highest annual total, with 5,508 birds ringed. This was achieved despite an almost non-existent Swallow/Sand Martin roost. Reed Warblers were the highest ever at 1,017, topping even the huge 1991 total of 889. Sedge Warblers were also well up at 565, being the first time over 500 for ten years. Two more records were broken, 33 Kingfishers  and 353 Blackcaps were ringed in the year. Of note, three of our Sedge Warblers went to France and a Chiffchaff came from the Netherlands. But the star was PV6056, another Chiffchaff, which came from Senegal. It was also carrying black and red colour rings. Since the completion of the new hut in 1990 the excellent facilities have been used on many occasions by local natural history groups and schools and by the University of Bristol Extra Mural course on bird censusing. Twice yearly all day visits have been made by the RAF Ornithological Society.

The most significant feature of 1993 was, however, the acquisition of a computer, which was made possible by the generosity of many people who gave donations, and especially to BWW. This has revolutionised our record keeping and improved the accuracy of the data extracted from those records. One great piece of help was a grant from the British Ecological Society to input our long and almost unique Sedge and Reed Warbler data sets. There should be around 30,000 entries when completed and they will be used by the British Trust for Ornithology in population studies monitoring these two significant reedbed inhabitants.

In our 30th. year, then, we have entered the computer age and there will be no turning back. But there will be more looking back as we endeavour to make the best use of the valuable information stored away in 30 years of ringing schedules, nearly 100,000 ringed, not to mention the tens of thousands of retraps and controls.

That some birds migrate and others follow a more sedentary life-style was a known and accepted fact at the turn of this century. Since then, however, the ringing scheme has filled in a great deal of the detail about the movements of many different birds and has discovered where they come from - and go to. At Chew Valley Lake we have played our part in this quest . And so, finally, here are a few facts and figures summarising some of the data collected in our first 30 years that has added to this broad picture.