Bewick's and "Vhooper Swans Cygnus Columbianus Bewickii and C

Bewick's and "Vhooper Swans Cygnus columbianus bewickii and C. cygnus: the 1994-95 season

J. BOWLER,L. BUTLER,c. HESKETH,R. HESKETH,c. LIGGETTand E. REES

The start of the 1994-95swan season at Washes with up to 905 birds on occasion Wildfowl & Wetlands Trust Centres was on the Welney refuge. later than normal because of the weath- The 1994-95 winter in Britain was er conditions in Iceland during October. exceptionally mild until early March, as A dominant southwesterly airflow with indeed it was throughout most of conti- associated heavy cloud-cover delayed nental Europe. Bewick's Swans conse- the departure of the bulk of the quently arrived both later and in small- Whooper Swans until a weather window er numbers than in recent years. The of clear skies and northerly winds on 26 first Bewick's Swans arrived on 17 and 27 October. The very first Whooper October at Welney, on 18 October at Swans appeared on 28 September at Martin Mere, on 19 October at both Caerlaverock and Martin Mere and Caerlaverock and on 20 October at on 4 October at Welney, but it was not Slimbridge. These were fairly typical until the end of October that numbers arrival dates but the subsequent rose to above 100 at any of the Wildfowl increase in numbers at all sites was slow & Wetlands Trust reserves. There were and peak counts during the winter were large influxes of Whooper Swans to the low. The maximum count of Bewick's British Isles in November and numbers Swans on the Ouse Washes at Welney continued to build up at Martin Mere was just 3,668 on 4 December, whilst and on the Ouse Washes at Welney peak counts of 548 at Martin Mere on 15 throughout November and December December and 286 in the Severn valley reaching record-breaking levels at both on 7 February were also disappointing. sites. A total of 738 Whooper Swans Larger numbers of Bewick's Swans than were present at Martin Mere on 13 normal (c.10,000) are known to have December which was a new reserve remained in The Netherlands this winter record, a further 35 birds were present (T. Haitjema pers. comm.) probably as a some 25 miles further north near Pilling result of the mild conditions. The mass on the Fylde bringing the Lancashire departure of Bewick's Swans from county record to at least 777 Whooper Britain was also earlier than normal. Swans. Not to be outdone, Welney Continuing mild weather with played host to 853 Whooper Swans on 4 favourable southwesterly 'tail-winds' December which with the 289 birds pre- encouraged the bulk of the Bewick's sent on the RSPBsection of the Washes, Swans to depart from the Ouse Washes produced a grand total of 1,142 and Martin Mere in early February, a full Whooper Swans for the whole of the two to three weeks earlier than usual. Ouse Washes, the largest single concen- The Bewick's Swans at Slimbridge lin- tration of the species ever recorded in gered a little longer but most had England. Whooper Swans have certainly departed by the end of February. benefitted from recent reserve manage- The proportion of Bewick's Swan ment at both Martin Mere and Welney; cygnets recorded at Welney and Martin around 700 Whooper Swans were to Mere indicated that 1994 was another remain at Martin Mere for much of the poor breeding season, with some 8-11% season, whilst over 1,000 Whooper juveniles in the population, well below Swans spent the winter on the Ouse the average of 15-16%cygnets recorded 176 Wildfowl 46 (1995): 176-187 Moulting Mute Swans 177 during the 1970s and 1980s. There have enth year she was accompanied by her now been four poor consecutive breed- second mate, Punter, with whom she ing seasons since the last above-average successfully raised two cygnets this sea- breeding season in 1990.As in the 1993- son. A fodder beet field, planted on the 94 winter, the proportion of cygnets at reserve specifically for the swans, Slimbridge was higher, however; 13.6% attracted the bulk of the birds through- of all Bewick's Swans recorded at the out November, whilst in December the site during the winter were juveniles, birds favoured a flooded pasture field suggesting a bias in the distribution of adjacent to the beet field and frequently family parties throughout the wintering commuted between the two fields dur- grounds. The Whooper Swans, on the ing the day. These two fields served to other hand, appeared to have had a hold the swans at Slimbridge and num- good breeding season in Iceland in 1994, bers were correspondingly low at with estimates on the wintering grounds Walmore Common, an important alter- ranging from 17%juveniles in the herds native feeding area lying some 10 km at Martin Mere and Welney, to 20.9% at north of Slimbridge, despite the pres- Caerlaverock. ence of extensive flood-w<;ltersat the site for much of the period. Only a hand- ful of birds were recorded feeding at Review of the season at WWT Centres Walmore Common before the New Year, with a peak of 23 on 18 December, and all returned to Slimbridge each evening Slim bridge to roost. A short period of freezing weather in The first Bewick's Swan to arrive at the New Year caused a small influx of Slimbridge was Auberon, who flew into swans, with numbers rising to 216 on 3 the European Pen early on the morning January. Numbers at Slimbridge then of 20 October, having first been seen on declined as birds began to make use of the River Severn at dawn. Auberon was flood waters at Walmore Common both also the first Bewick's Swan to arrive at for feeding and roosting purposes. A Slimbridge during the 1992-93 winter combined count on 10 January found a and is a regular member of the group of total of 244 swans divided between the swans that roost on pools in the collec- two sites of which 66 were at Walmore. tion area. The arrival date was roughly The Walmore flock decreased in mid- average for Slimbridge, but the swan January, however, and numbers corre- departed the next day and it was not spondingly increased at Slimbridge; a until 4 November that the next seven total of 253 was counted at Slimbridge birds appeared. The build-up in swan on 15 January and some 130-150swans numbers was relatively slow with roosted each night on Swan Lake for counts rising from 48 on 6 November, to most of the month. Numbers declined at 63 on 21 November and to 120 on 28 the end of the month, to around 160, as November. Amongst these arrivals were swans returned to Walmore in order to Pedro and Weaver with four cygnets, take advantage of extensive flooding on returning for their second consecutive the common, following a period of winter at the site. Pedro now appears to unusually heavy rainfall. A count of 127 have forsaken Welney after ten years at Bewick's Swans at Walmore Common on the site in favour of Slimbridge, which is 24 January was the highest of the winter the traditional wintering site of his mate for this important alternative site. A few Weaver. new swans appeared at Slimbridge dur- Swans continued to arrive almost ing the first week of February and a daily in small groups throughout simultaneous count of Walmore and December with numbers rising to 140on Slimbridge on 7 February found a total 5 December and to 182 on 29 December. of 286 swans in the area of which 188 Amongst the December arrivals was were at Slimbridge. This was the highest Casino. Now in her twenty-fourth year, count of the winter for the Severn valley Casino was the oldest surviving flock. Around 90 to 100 birds remained Bewick's Swan to return to Slimbridge at Walmore until 9 February when the during the 1994-95 winter. For the sev- floods receded rapidly, encouraging the 178 Moulting Mute Swans

swans to leave the site. Not all of these tissues for lead shot; 33.3% of the adult birds returned to Slimbridge, however. swans were found to be carrying gun- Sightings of ringed birds revealed that shot in their tissues, a very similar fig- some, at least, moved north along the ure to previous estimates. None of the River Severn to make use of flooded pas- cygnets were found to be carrying shot ture in the Ashleworth and Coombe Hill however which suggests that the illegal areas. Over 100 Bewick's Swans were shooting of Bewick's Swans may be present on the floods near Coombe Hill more common in the spring. on 19 February whilst some 60 to 80 of Swans that had been ringed else- these birds moved on to frequent the where, but which were identified at Ashleworth area until the second week Slimbridge during the course of the win- of March. ter included Pedro from Welney, four Some 200 Bewick's Swans were pre- birds originally marked at Martin Mere, sent at Slimbridge in mid-February but and four birds that had been fitted with the mild conditions and persistent neck-collars in Russia. These included south-westerly "tail-winds" resulted in two birds (148P and 409P) which visited the birds leaving the site towards the Slimbridge during the 1993-94 winter end of the month. The first large depar- and another (430P) which had been ture occurred just after the second seen at a nearby site along the River afternoon feed at 1700 hrs on 26 Wye at Letton, Herefordshire, also in February when a group of 75 swans 1993-94. A further 49 swans ringed at departed north from Swan Lake. A total Slimbridge were not seen at the site dur- of 84 Bewick's Swans remained at ing the season but were reported else- Slimbridge the next day but numbers where. These included eight in the dropped to 32 on 2 March and to four on Welney area, two at Martin Mere, two at 7 March. The last Bewick's Swan other sites in England, three in remained until its demise on 26 March. Denmark, one in Germany and 33 in the A total of 330 individual Bewick's Netherlands. One of the swans Swans was recorded at Slimbridge dur- observed on the Ouse Washes near ing the winter, indicating that turn-over Welney, named Cry, is now in her at the site was unusually low. Some 45 twenty-fifth year and is the oldest (13.6%) of the birds were juveniles, Bewick's Swan known to be alive. which suggests that 1994 was another fairly poor breeding season. The mean Welney brood size was 2.14 cygnets per family which was very similar to the 2.12 The start of the Welney swan season cygnets per family recorded in 1993-94. was delayed by the rather late arrival of The proportion of new birds at the site the Whooper Swans from Iceland. The was lower than normal; 176 (61.8%) of first two birds appeared on 4 October, the adults and yearlings had been but there were few further arrivals until recorded at Slimbridge in previous the end of the month when a sudden years. influx pushed Whooper Swan numbers One of the highlights of the winter up to 446 by 23 October. Mild conditions season was the inauguration of the new prevailed and just 492 Whooper Swans swan-pipe at Slimbridge. This had been were present on 20 November. There built during the summer to replace the was a further influx at the end of old pipe, which had blown down during November, however and 853 Whooper the gales of December 1993. The pipe Swans were present on 4 December. proved to be an immediate success Amongst these late November arrivals when over 100 ducks were caught were a number of Welney regulars (including 61 newly-ringed Pochard) in a including Cod, Cackle and Descant. lunch-time catch on 25 November. The It soon became clear that 1994 had first swan-catch was held on 27 January, been a good breeding season for the when a total of 58 Bewick's Swans were Whooper Swans. There were good num- caught, of which 34 were ringed for the bers of families amongst the herds and first time, including 15 cygnets. All of the largest brood was of six cygnets. the birds were X-rayed to examine their The proportion of juveniles in the popu- Moulting Mute Swans 179 lation on the Ouse Washes was estimat- estimated at 8%. ed at 17%.Following such a good breed- The International Bewick's and ing season it was perhaps not surprising Whooper Swan census on 21 January that the record count for Whooper found 3,480 Bewick's Swans on the Ouse Swans on the Ouse Washes was again Washes of which 2,906 were on the broken this year and, for the fir-st time Welney section. By late January, severe ever, topped 1,000. On 4 December an flooding was affecting the whole of the additional 289 Whooper Swans were reserve area, which resulted in the present on the RSPB section of the swans dispersing widely to roost. Some Washes, which when added to the 853 at Bewick's Swans moved to the Nene Welney gave a grand total of 1,142,shat- Washes at this time. The flooding per- tering the previous record of 986 set on sisted throughout February and, cou- 6 February 1994. The swans remained pled with the very mild conditions, quite mobile along the Washes, chang- caused a large number of the Bewick's ing their roosting and feeding sites in Swans to vacate the Washes during the response to changes in flood conditions. month, presumably embarking early on The peak count on the Welney reserve their spring migration. A number of the itself was 905 on 21 January. Numbers missing colour-ringed birds appeared at remained high throughout the winter sites near Great Yarmouth prior to and over 1,000 Whooper Swans were departing for the continental mainland still present on the Ouse Washes on 19 at the end of February. Just 723 Bewick's February. Swans remained at Welney on 19 The Bewick's Swans were also rather February. Very few Bewick's Swans slow in arriving at Welney this winter. remained into March with eight on 26 The first bird appeared on 17 October March and just two injured birds at the and numbers increased gradually to 150 end of the month. by 20 October, but then declined to 117 During the first half of the winter both on 21 October as birds moved away the Bewick's and Whoopers Swans con- from the site. Amongst those that centrated on agricultural fields sur- departed were two birds that had been rounding the Washes during the day, originally ringed in Russia and which feeding predominantly on the remains subsequently appeared, three days of sugar-beet and potato crops. The later, on the Wexford Slobs in south-east swans switched to feeding on freshly Ireland. There were further arrivals at sprouting wheat in January and dis- Welney at the end of October and a total persed over a wider area to sites up to of 173 Bewick's Swans were counted on ten miles away from the reserve. The 23 October. Mass migration of Bewick's switch from root crops to winter wheat Swans to the site occurred in November, occurred much earlier than in previous with numbers reaching 1,285 on 5 winters. This may have been due to rel- November and 2,462 on 20 November. atively dry conditions in autumn Further influxes occurred towards the enabling farmers to plough their fields end of November and 3,668 were count- following the harvest, thereby reducing ed at dawn, roosting on the reserve on 4 the supply of waste root crops as food December. Several Bewick's Swans that for the swans. had wintered regularly at Welney since As in recent years, the Whooper the early 1980's were again seen this Swans dominated the main lagoon at winter, including Bazaar, Burnie, Captoe Welney, and few Bewick's Swans came and Frappe. Panier arrived safely on 5 forward to feed on the grain in front of November together with his unringed the observatory. This situation was par- mate, and all four of their 1994 brood. ticularly marked during 1994-95as high The cygnets had been caught and flood levels encouraged the Bewick's ringed during the summer at Panier's Swans to roost at more distant sites on breeding territory near Khabuicka in the the reserve. Despite the flooding, the Nenetski State Game Reserve, Russia. regular swan feeds continued during the Breeding success amongst the Bewick's winter, thanks to the wardens who Swans was again disappointing this resorted to chest waders and life jackets year; the proportion of juveniles in the in order to brave the elements! Unlike in population on the Ouse Washes was previous winters, waste potatoes were 180 Moulting Mute Swans in short supply, particularly in the New as a cygnet during the 1991-92 winter Year. This reduction in supplementary and has returned regularly to the site feeding meant that even the Whooper ever since. It soon joined the five, most- Swans had to fly out to the surrounding ly injured and recuperating Whooper fields in search of food during the day. Swans, that had spent the summer on Numbers of Whooper Swans on the the Whooper Pond. The number of reserve remained high well into March Whooper Swans rose very slowly to a with 386 present on 26 March. More peak of 12 birds on 4 October, then favourable weather conditions for dropped back to just three birds the migration at the end of the month next day. Numbers remained in single encouraged the remaining birds to figures until 23 October when 14 birds depart with numbers dropping rapidly were present. Bewick's Swans no longer to 163 on 1 April and to 53 on 4 April. appear at Caerlaverock in the numbers Twelve birds were still present on the seen in the early to mid 1980's, when main lagoon on 23 April. some 30-40 birds regularly spent the Swan casualties due to collisions with winter at the site. It was therefore most overhead cables were very low this year. pleasing that a group of three unringed Although this reflected, in part, a shift in Bewick's Swans appeared at the back of feeding areas away from key power-line the Folly Pond on 19 October, increasing routes, and comparatively little freezing to four on 21 October, seven on 23 fog, it may also reflect the steady October and nine on 18 November, progress being made on the fitting of which remained in the area for much of bird diverters to the power-lines. the winter. These birds roosted on the Diverters were fitted to the earth-wire reserve and flew out to feed at neigh- above some of the national grid wires, bouring sites during the day, initially at which span the northern end of the Merkelands Farm near Bankend, some reserve, during the summer. Although three miles north of Caerlaverock, but progress was slow because the fields later at Newmain's Pond (about half a were very wet, it is hoped that the pro- mile north of the reserve) and at ject will be completed during summer Priests ide Farm. These birds became 1995. The only casualty recorded on a less easy to find in December but a power-line to the north of the reserve, a group of up to 13 Bewick's Swans, possi- Mute Swan, struck the section not yet bly including some of the earlier fitted with diverters. arrivals, made use of the Flood Field at A total of 200 ringed migratory swans Caerlaverock from the end of January were recorded on or near the Welney until 8 February. reserve during the winter; 100 Bewick's Unfavourable weather conditions for Swans and 100 Whooper Swans. Of the migration in October were thought to be Bewick's Swans, eight were originally responsible for the late arrival of ringed at Welney, 28 at Martin Mere, Whooper Swans this winter. A window eight at Slimbridge, 42 in Russia (includ- in the weather on 26 and 27 October, ing 13 leg-ringed birds and 29 with blue with wind directions predominantly neck-collars) and 12 on the continent by from the north, enabled many of the Dutch and German ringers (marked with swans to migrate south from Iceland yellow neck-collars). Of the Whooper towards the end of the month. A group Swans, six were originally ringed at of 21 Whooper Swans flew in at 1130 hrs Welney, eight at Martin Mere, ten at on 26 October, and swans continued to Caerlaverock, and 76 in Iceland (includ- arrive on the Folly Pond with 37 present ing 58 leg-ringed birds and 18 fitted with by the end of the day and 45 by dawn on yellow neck-collars by Danish and the following morning. A further three Icelandic ringers in August 1994). Whooper Swans were located nearby at Newmain's Pond. Further arrivals on 27 Caerlauerock October included the first of the two swans that had been fitted with satellite The first Whooper Swan of the winter transmitters in Iceland during the previ- arrived on 28 September. This bird had ous summer (JSC) together with her originally been ringed at Caerlaverock mate and five cygnets. By the end of the Moulting Mute Swans 181 day on 28 October a total of 100 declined rapidly in November to a more Whooper Swans were present including typical size of 20 to 30 birds and 27 (27.0%) cygnets. The second swan fit- remained so for the rest of the winter. A ted with a satellite transmitter (COD) number of the missing birds, including arrived with her mate during the night the Black Swan, were subsequently seen of 28 October and numbers rose to 110 at Caerlaverock, indicating a higher by 29 October. However, only eight than normal level of interchange Whooper Swans were present the next between these two generally discrete morning and this set the pattern for the flocks. A further 22 birds were present in next few weeks, with the swans flying the Kirkton/Gullyhill area, nearby in out early in the morning to feed on near- Cumbria, in January. by flooded pastures and stubble fields, A highly successful swan-catch was returning to Caerlaverock only to roost. held on 7 February when a total of 122 By 18 November there had been several Whooper Swans were caught, of which new arrivals of ringed swans but roost 49 were newly ringed including all 27 counts remained at just over 100 cygnets known to have been at the site Whooper Swans with the bulk of the at the time. The satellite transmitters fit- flock feeding on flooded potato fields ted to the Whooper Swans in Iceland east of Caerlaverock at Priestside Farm. last summer were successfully The number of swans roosting at removed, and two more were fitted to Caerlaverock rose to 170 on 20 two male Whooper Swans in order to November and to 176 on 26 November, monitor their return flights to Iceland in and there was an increase in the number the spring. We hope to track the birds of swans feeding on fields on the reserve back to their nest-sites, which are cur- at this time. The count of 176 Whooper rently not known, and to retrieve the Swans proved to be the highest of the transmitters during the swans' annual winter and was remarkably similar to moult in early August. the peak count of the 1993-94 winter, Up to 143 Whooper Swans were still with 175 Whooper Swans present on 18 using the reserve at Caerlaverock at the February 1994. end of February, including both of the Mild, wet conditions throughout birds fitted with satellite transmitters in December and January encouraged the January. Numbers of Whooper Swans swans to spread out in the surrounding continued to remain high during March area, to feed on the flooded pasture, and with 150 birds present on 11 March, and numbers at Caerlaverock were conse- 142 on 24 March. The first big depar- quently lower. Around 100 Whooper tures took place at the end of the month Swans were present at Caerlaverock for with numbers dropping to 117 on 31 most of December, whilst in January March, 76 on 3 April and 26 on 9 April. A numbers fluctuated daily between 70 group of 16 birds were present on 16 and 150 birds. Sightings of ringed birds April of which six remained on 23 April. for the first time this winter suggested, Of the 119 ringed Whooper Swans however, that swans were continuing to observed at Caerlaverock during the arrive during this period. A count of 153 1994-95 season only thirty had been Whooper Swans on 4 January included ringed at other sites. Of these 18 32 (20.9%) cygnets, the highest number (including 5 cygnets) had been ringed of cygnets to be recorded at in Iceland and the remaining 12 had Caerlaverock during the winter. been ringed at Martin Mere. A further During the latter part of January it 50 birds were ringed for the first time at appeared that most of the birds roosting Caerlaverock during the winter. Some at Caerlaverock were flying further than 52 Whooper Swans ringed at usual to feed, since the number of birds Caerlaverock in previous years, but not located within a 20 mile radius of the seen at the site during 1994-95, were centre was lower than in previous years. reported elsewhere. These included The swan flock at the traditional three at flocks nearby in Dumfriesshire, Netherwood/Crichton sites was unusu- seven at other Scottish sites, four at ally large at the start of the season, with Martin Mere, nine at Welney, four else- up to 120Whooper Swans and one Black where in England, one in Wales, 21 in Swan present. However this flock Ireland and three in Iceland. Two of the 182 Moulting Mute Swans swans which returned to Caerlaverock was a new reserve and county record, during the winter had been seen earlier and the number of birds remained at in the season in Northern Ireland, around this level for the rest of the win- whilst two others which appeared ter. On 13 December a further 39 briefly at Caerlaverock in the autumn Whoopers were recorded on a field were relocated in Ireland towards the some 25 miles to the north of Martin end of the winter. Mere, near Pilling on the Fylde, bringing the Lancashire county record to at least Martin Mere 777 Whooper Swans. Of 723 Whooper Swans counted on 22 January, 125 Two Whooper Swans spent the summer (17.3%) were cygnets with a mean on the Mere in 1994; one was an adult brood size of 2.7 cygnets per family. that had broken its wing the previous Bewick's Swan counts reached 309 by winter and was unable to fly,the second 10 November, then increased very was one of its 1993 brood. The first four slightly to 329 on 24 November, and 409 migrating Whooper Swans to reach the on 27 November. There appears to have Mere arrived on the morning of 28 been an influx of Bewick's Swans September, and included two marked around 15 December, when a total of birds, one originally ringed as a cygnet 548 birds, including 61 (11.1%) cygnets, at Martin Mere during the 1993-94win- were recorded in the area. This proved ter and the other in Iceland. The build- to be the maximum count of the winter, up of Whooper Swans was much slower which was slightly lower than the 582 than normal, with only 32 present on 21 birds recorded in 1993-94.Up to 300 of October and 345 by the end of the the Bewick's Swans may have been month. The first Bewick's Swan of the roosting on the Ribble estuary at this season had been marked with a blue time, since the direction of morning neck-collar (300P) in Russia, in August flight to the fields was from the river 1992, and has since been a regular win- rather than Martin Mere. A flock of up ter visitor to Martin Mere. She arrived to 109 Bewick's Swans and 11 Whooper alone on 18 October, but by 22 October Swans, also roosted on the River 57 Bewick's Swans and 40 Whooper Douglas, a tributary of the Ribble. The Swans were present at the dawn count. swans were first seen using this roost It is very unusual to have more Bewick's during the 1993/4 winter. than Whooper Swans on the reserve at The number of Bewick's Swans in the this time of the year. By the end of area fell to 452 birds on 26 December, October there were 71 Bewick's in the and to 428 by the end of the year, area, including only three juveniles. although feeding birds were widely Whooper Swan numbers rose rapidly scattered and difficult to find. The num- in early November; 533 were counted at ber of Bewick's Swans counted at dawn dawn on 5 November and by 24 on Martin Mere at this time was low, November there were 651 birds at the either because the birds were still site. Less than one hundred birds roosting on the Ribble or because they remained on the reserve during the day, were leaving the Mere before first light. with the bulk of the swans feeding on In December less than 20 Bewick's stubble fields near the Ribble estuary. Swans remained on the reserve during From mid November to mid December the day, and only a handful fed on the some 450 Whooper Swans plus a vari- grain distributed twice daily. This may able number of Bewick's Swans fed on be due both to the abundance of food an unharvested potato field, which was in the surrounding fields, and to the partially flooded. Smaller numbers larger and more aggressive Whooper «200) of Whooper Swans and the Swans monopolising the two main feed- majority of the Bewick's Swans fed on ing sites. Although up to 80 Bewick's shooting cereals and left-over grain on Swans attended the grain feed in the stubble fields near the Ribble through- New Year, only around 20 birds out November and December. Whooper obtained much food from this source. Swan counts continued to increase dur- In contrast, at least 300 Whooper ing December and by 13 December Swans attended the grain feeds from there were 738 birds in the area. This early December onwards, and up to 600 Moulting Mute Swans 183 birds stayed on the reserve throughout from 514 on 9 March, to 390 on 11 the day in January and February. The March, and to 106 on 23 March. Just 26 Whooper Swans fed on grass fields birds were still present on 30 March such as Plover Field and Outer but there were no further departures Vinson's, and on re-sown grass fields until 6 April. Three injured/ill Whooper on neighbouring farms. Both species of Swans, including an adult and two swans also fed on Owl Marsh, a field on cygnets, remained on the Mere on 9 the reserve where extensive areas of April. rushes had been cut to provide better A total of 191 of the Whooper Swans pasture. In mid-January waste potatoes at Martin Mere was identified by ring were brought to the reserve by local number during the course of the win- farmers and these attracted 100-150 ter. Thirty two of these had been Whoopers and up to 50 Bewick's Swans caught and marked in Iceland, includ- for the following month. The majority ing seven birds fitted with neck collars of the Bewick's Swans used a winter in summer 1994. They also include nine wheat field near the Ribble, and also swans marked at Caerlaverock, one at grazed on flooded pasture, potatoes Welney and 16 which were newly and re-sown grass close to the reserve. ringed at the site during the winter. In early February some 100 to 150 Only 15 Whooper Swans which had Bewick's Swans remained on the been ringed at Martin Mere in previous reserve during the day where they fed winters and which did not return to the on waste potatoes and pasture. site during 1994-95,were reported else- Swans were present near Pilling on where during the season, highlighting the Fylde from November onwards. the high degree of site-fidelity exhibit- After Christmas up to 115 Bewick's and ed by these birds. Of the 13 swans seen 50 Whooper Swans used this area. away from the site there was one near- Sightings of ringed birds indicated that by at Pilling, Lancashire, five at Welney, the Whooper Swans had not visited three at Caerlaverock, four elsewhere Martin Mere during the winter, whereas in Scotland and one, most unusually, on some of the Bewick's Swans had been the Polder Pinjum in the Netherlands. in the Martin Mere area until late Ring-readers helped to record some December. The high number of migra- interesting movements in the autumn tory swans on the Fylde was most as the Whooper Swans returned from unusual and may have resulted from Iceland to Martin Mere. No fewer than the exceptionally wet winter which eleven Whooper Swans, originally allowed the birds to roost on flooded ringed at Martin Mere, were observed fields close to their feeding sites. in Northern Ireland prior to returning The Bewick's Swans wintering in to the site. A further eight stopped over Lancashire embarked on their spring at Caerlaverock, whilst two more first migration exceptionally early this sea- appeared in North Wales before arriv- son. On 22 January there were still 433 ing at Martin Mere. in the area, but numbers had dropped With fewer Bewick's Swans taking to 214 by dawn on 7 February, 137 on advantage of the grain feeds, there 14 February, and by 19 February just 27 were no large swan-catches at Martin birds remained. On 23 February only 2 Mere this winter. However a duck-catch Bewick's Swans (both cygnets) were on 2 February produced 18 Whooper left at Martin Mere, with a further 13 on Swans of which 16 were newly ringed the Ribble. There were still 93 Bewick's (including 11 cygnets), in addition to 50 and 15 Whooper Swans on the Fylde on Pochard, 46 Shelduck and a Pintail. 15 February, but by 20 February none Some 102 Bewick's Swans were iden- were found here either. The Whooper tified by ring number at Martin Mere Swans stayed later, as usual; on 21 during the winter. Of these, 96 had been February 734 roosted at Martin Mere, ringed at the site in previous years with 10 roosting on the Ribble. (including two of the seven birds Numbers declined slightly to 666 pre- ringed in January 1987), two at sent on 1 March, but the first major Slimbridge, one at Welney and three in departures did not occur until mid- Russia. Eighty-two Bewick's Swans March with counts dropping rapidly ringed at Martin Mere in previous win- 184 Moulting Mute Swans ters, but not seen at the site during annual wing moult in late July, and were 1994-95, were reported elsewhere dur- programmed to begin continuous trans- ing the season. These included 24 on mission in late September, in time for the Ouse Washes, four at Slimbridge, their departure from the breeding one in Yorkshire, one at Horsey, grounds. The operation was a complete Norfolk, one near Roxburgh, Scotland, success and both birds were tracked by one in Ireland, five in Germany, one in satellite from their nest-sites to their Denmark and 44 in the Netherlands. Caerlaverock wintering grounds. The two birds departed at different times. Arundel One left Skagafjordur on 16 October but then remained for over a week in south- A small number of Bewick's Swans vis- ern Iceland before departing finally on ited Arundel during the course of the 26 October. The other flew directly from winter from their more traditional Skagafjordur to Britain on 26 October haunts in the Arun valley at without stopping off at a staging area. Pulborough and Amberley. The first Although the timing of the flights of the Bewick's Swan which arrived at two birds differed, they followed a very Arundel on 2 January, had been marked similar route over the first leg of the with a neck-collar (235P) in Russia in journey as they struck out across the 1992. A second neck-collared bird open ocean from Iceland. Both birds (l09P) arrived on 12 January and was flew in to Britain through the Outer subsequently observed nearby on the Hebrides and then proceeded down the floods at Amberley on 25 January. This west coast of Scotland, prior to arriving swan has now spent three consecutive safely at Caerlaverock; one with its mate winters in the Arun valley. The swans and five cygnets on 27 October and the visited Arundel in order to roost on the other with its mate on 28 October. pools within the enclosures and were There has always been much specula- present from 2 to 16 January, with a tion about the height at which swans fly peak of at least 26 birds on the night of during migration. Altimeters fitted to 3 January. Around 50 birds were known the transmitters of the two swans in this to have spent the winter in the valley. study revealed that they flew the entire journey just above the waves, and that both actually spent some time resting International Research projects on the sea itself. Although we have not proven that Whooper Swans never migrate at high altitudes, given Iceland favourable atmospheric conditions, the study has clearly demonstrated for the A new dimension was added to the first time that they can cross from study of Whooper Swan migration this Iceland to Scotland without needing to year when, as part of a collaborative fly high. These exciting results encour- project with Bristol University, aged the team to fit transmitters to two Professor Colin Pennycuick fitted satel- male Whooper Swans at Caerlaverock lite transmitters to two adult female during the winter. The two original birds at Skagafjordur, north Iceland. The transmitters were successfully removed two swans selected were both regular from the swans during their winter at visitors to Caerlaverock, and were cho- Caerlaverock and two new transmitters sen so that the transmitters could be were fitted to two carefully selected retrieved upon their return this winter. male birds during the swan-catch on 7 Prior to this study, information concern- February. The two swans will be tracked ing the timing, duration, and direction of from Scotland back to Iceland, firstly to the migratory flight from the Icelandic see how the return migratory flight com- breeding grounds to wintering grounds pares with that in the autumn, and sec- in Britain and Ireland was based, less ondly to help locate the nests of some precisely, on sightings of colour-marked Caerlaverock birds whose nesting areas individuals. are currently unknown. The satellite transmitters were fitted As well as helping with the satellite upon catching the swans during their tracking, our Icelandic colleagues were Moulting Mute Swans 185 also very busy with more traditional their final clutch size. The spring was ringing and monitoring of the breeding particularly late this year with snow and success of known pairs. For the seventh ice remaining well into June, and initia- year running, surveys were made of tion of nesting was delayed by at least a clutch size and fledging success for week compared with 1993, and by two Whooper Swans nesting in the two main weeks compared with 1992. Large sec- study areas at Skagafjordur in north tions of the study site remained inacces- Iceland and Jokuldals-heidi in the east of sible to the scientists but a total of ten Iceland. In the Skagafjordur lowlands nests were reached and were found to breeding success was again very high have a mean clutch size of 3.3 eggs. This with a mean clutch size of 4.6 eggs per figure is a little higher than in 1993but is nest and a mean brood size of 3.7 down on both 1991 and 1992, and may cygnets. Breeding success at the high- be attributable, in part, to low food land study site of Jokuldals-heidi was availability caused by the late blanket again lower than at Skagafjordur, with a covering of snow and ice. mean clutch size of 3.8 eggs per nest A second team of Wildfowl & and a mean brood size of 2.8 cygnets. Wetlands Trust and Russian scientists However these figures are higher than in returned to the study site in August, 1993 and suggest that 1994 was a good where they joined Dutch and Danish sci- breeding year for Whooper Swans in entists who had been present since late Iceland. In addition, Oli Einarsson, July. A total of 25 broods were relocated Sverrir Thorstensen and Danish scien- in the study area with a mean brood size tist Bjarke Laubek, together with a ster- of 2.4 cygnets. Although there were ling band of Icelandic volunteers, good numbers of cygnets present, they caught a total of 623 birds during the were generally smaller in size than late summer moulting period, of which expected for the time of year, presum- 522 were ringed for the first time. ably because of the late spring. Food Ring-readers throughout the British supply in the form of sedges, grasses, Isles and Iceland were kept busy by the pondweeds and a bumper crop of tun- large number of leg-ringed swans cur- dra berries, was abundant this summer, rently in the Icelandic breeding popula- however, allowing the cygnets to grow tion. By the end of the winter some 538 rapidly. Timing of the onset of winter individuals had been identified includ- may have been critical since many of ing 72 in Iceland only, 132 in Scotland, the cygnets would have been too small 104 in England, two in Wales and a to fly if freezing conditions started early, record-breaking 228 in Ireland thanks to as happened in 1992. the concerted efforts of a network of The main aim of the second expedition observers, most notably Graham was to catch and ring the swan families McElwaine, Jim Wells and Kendrew in the study area and, with the help of Colhoun. (Swans seen at several sites our Russian, Dutch and Danish col- during the winter were allotted to their leagues, a total of 88 swans had been final mid-winter destination for this caught by the end of the month, includ- analysis). More unusually, one Whooper ing 73which were ringed for the first time Swan marked with a leg-ring in Iceland, (29 adults and 44 cygnets). Following the was observed at the Lauwersmeer in the discovery of the nest belonging to Netherlands in January 1995. Croquet (a Martin Mere-ringed bird) in the study area in 1991, the team were Russia most surprised to capture Panier (a Welney-ringed bird) together with his There were two expeditions to the family of four cygnets in the northern breeding grounds of the Bewick's Swan part of the study area on 26 August. in the Russian arctic in 1994.DafilaScott Panier was first ringed as an adult at and Eileen Rees returned to the Welney back in the 1982-83winter, and is Khabuicka study site in the Nenetski now at least 15 years old. He arrived at State Game Reserve in late May together Welney safe and well with his mate and with our Russian colleagues, in order to all four cygnets on 5 November. monitor the establishment of nesting Of the 124swans that have been fitted territories by known pairs and to record with conventional darvic leg-rings since 186 Moulting Mute Swans

1992 at the Khabuicka study site, a total ing and feeding area on both the spring of 48 were observed during the period and autumn migrations. Over half of the June 1994- March 1995.Ofthese, 12were Western European wintering population identified on the Ouse Washes near of Bewick's Swans have, in previous Welney, one at Martin Mere and two in autumns, used the shallow Gulf of Northern Ireland. In addition, seven were Korovinskaia (immediately north of the observed in Germany and 23 in the delta) as a migratory stop-over site, and Netherlands; whilst three were seen back the consequences of a large oil-spill on the breeding grounds at Khabuicka reaching the Gulf could be very serious. but not subsequently. One of the first Together with the World Conservation cygnets to have been colour-ringed at Monitoring Centre, the United Nations Khabuicka in August 1992, a female now EPjDHA Environment Unit and other in its third year, was observed with a concerned conservation organisations mate at Welney in November. we continue to follow developments closely. A team from WWT plans to re- Russian oil spill visit the area north of the Pechora Delta in June 1995 and will keep a careful News broke in October 1994 of a serious watch for any signs of oil on the fragile oil spillage from a leaking pipeline in the tundra ecosystems. far northeast of European Russia. The Our work is greatly helped by the spill, near the city of Usinsk in the Komi efforts of voluntary ring-readers district, was reported to be spreading throughout the British Isles, in Iceland into the Kolva River, a tributary of the and on the continent, as well as by the River Pechora. Although the spill is like- staff at all WWT Centres. To all who ly to have a serious local effect on the report their observations of swans we taiga habitat, it was some 150 miles extend our grateful thanks. In addition south-east of the Nenetski State Game we would like to thank the many swan Reserve and its high densities of breed- supporters and members who gave to ing Bewick's Swans. By March 1995 it the Slimbridge Swan Pipe Appeal. The was still uncertain whether migratory appeal raised 11,000 pounds. Thanks to swans were going to be affected in large this generosity, and to the hard work of numbers. Continental Whooper Swans the Slimbridge grounds staff, a new breed throughout the taiga and shrub swan pipe has now been built to replace tundra belts and would be at risk when the one which blew down in the severe they returned to their nesting areas in gales of December 1993. The Iris spring 1995. The greatest threat howev- Darnton Foundation and PSTERICkindly er would be if the spill were to flow supported our Whooper and Bewick's unchecked into the River Pechora itself. Swan research respectively. Special The delta of the Pechora is an important thanks go to the British Airways' breeding area for Whooper Swans, and Assisting Nature Conservation pro- is used by very large numbers of both gramme for their support of the WWT's Whooper and Bewick's Swans as a rest- Bewick's Swan project.

Jonathan M. Bowler, The Wildfowl & Wetlands Trust, Slimbridge, Glos, GL2 7BT,UK. Linda Butler, The Wildfowl & Wetlands Trust, Welney, Hundred Foot Bank, Nr. Wisbech, Cambridgeshire, PE14 7TN, UK. Carol Hesketh and Richard Hesketh, The Wildfowl & Wetlands Trust, Eastpark Farm, Caerlaverock, Dumfriesshire, DGI 4RS, UK. Eileen C. Rees and Charlie Liggett, The Wildfowl & Wetlands Trust, Martin Mere, Burscough, Ormskirk, Lancashire L40 OTA,UK.