A Survey of Breeding Black-Necked Grebes in the UK: 1973–2004 Brian Martin and Judith Smith

A survey of breeding Black-necked Grebes in the UK: 1973–2004 Brian Martin and Judith Smith

Jan Wilczur ABSTRACT Black-necked Grebe Podiceps nigricollis is a rare breeding species in Britain which favours shallow, eutrophic pools, preferably those which are undisturbed. The species first bred in Britain in 1904, and the number of breeding birds remained low for much of the twentieth century. Data from the Rare Breeding Birds Panel archives were analysed, and this paper provides a detailed regional summary of the ups and downs of Black-necked Grebes in the UK during the period 1973–2004. During that time, the population has increased, reflecting a wider expansion across northwest Europe, and the centre of gravity of the British population has shifted from southern Scotland to northern England; however, productivity remains generally low, and up to 40% of the population have bred at a single site. This paper discusses the possible factors underpinning the bird’s continuing rarity and speculates on what the future may hold.

lack-necked Grebes Podiceps nigricollis pits, reservoirs and even former sludge-deposit breed in shallow, eutrophic waters, which grounds. The species will tolerate a limited Btypically have extensive fringe vegetation amount of land-based disturbance but not and often floating aquatic plants such as water-based recreational activities (Boe 1992), Amphibious Bistort Persicaria amphibia, and it is clear that this greatly reduces the Bogbean Menyanthes trifoliata and water-lilies number of potential breeding sites. A common Nymphaea (Gibbons et al. 1993). Although factor at most, but not all, breeding sites is the undisturbed lakes are ideal, a variety of sites in presence of nesting Black-headed Gulls Larus Britain have been colonised, including gravel- ridibundus, which provide an early warning of

368 © British Birds 100 • June 2007 • 368–378 A survey of breeding Black-necked Grebes in the UK potential danger. It is this combination of (Temperley 1951), and a number of pairs bred requirements that may well explain the rarity of in Yorkshire (Mather 1986). It is doubtful, Black-necked Grebe as a breeding species in however, if the British population up to the Britain. period covered by this paper ever exceeded The bulk of the European population (esti- 15–20 breeding pairs, and it was frequently mated at between 37,000 and 142,000 breeding much lower. The period between 1950 and 1970 pairs) occurs from central Europe eastwards, saw the population in retreat, with Black- with over 70% in the Ukraine and southern necked Grebe barely retaining a foothold as a Russia (Hagemeijer & Blair 1997). A northwest- British breeding species. During 1968–72, Shar- erly expansion from this core area seems to have rock (1976) estimated the number of breeding begun in the later years of the nineteenth pairs in Britain & Ireland at fewer than 20, with century and was believed by Kalela (1949) to the population largely confined to a few sites in have been caused by the drying out of lakes in the Scottish lowlands. the Caspian region, mainly as a result of climate change. Adamian & Klem (1999) also reported Methods major losses from important breeding sites in Following a decision by the Rare Breeding Birds Armenia following the lowering of water levels. Panel (RBBP) to review the status of certain During this period of range expansion, species, the authors were permitted access to all breeding was first proved in Britain & Ireland in data held on Black-necked Grebes by the RBBP 1904, in Wales, followed by breeding records in for the period 1973–2004. In addition, county England in 1918 and Scotland in 1930. In addi- avifaunas, county bird reports and breeding tion, an unusually large colony was discovered atlases have been consulted. These provided in Ireland in 1930, at Lough Funshinagh (Co. further information, in particular of fluctua- Roscommon), which may have contained an tions in numbers in the years prior to 1973. extraordinary 300 pairs in 1932 but is now It became apparent at an early stage that extinct. With this one exception, however, pop- there was some inconsistency between records ulation levels remained low during the early held by the Panel and its annual reports pub- years of the twentieth century. A further period lished in BB. Where this was evident, enquiries of colonisation occurred in the 1930s and early were made to individuals with local knowledge to mid 1940s, when breeding was first proved in of the species and access to past records. These Cheshire (Guest et al. 1992), Co. Durham included County Recorders and specialist Bill Baston 150. Black-necked Grebe Podiceps nigricollis, Cavenham Pit, Suffolk,April 2007. A migrant bird, in full breeding plumage; Black-necked Grebes have never nested in Suffolk.

British Birds 100 • June 2007 • 368–378 369 A survey of breeding Black-necked Grebes in the UK groups monitoring regional Black-necked there throughout August of that year, but Grebe populations. In addition, it became clear breeding was not confirmed. There was nest- that, in its early years, the RBBP was viewed building at Lade Pits in 1988 but both birds had with suspicion by some fieldworkers, who left by mid April, and the first confirmed feared that breeding sites might be disclosed breeding in Kent occurred in 2002, being and were uncertain as to what use their records repeated in 2003. In Essex, failed breeding might be put. Consequently, this led to some attempts were reported in 1991, 1999 and 2000, data being withheld. We are satisfied that, fol- but successful nesting finally occurred at one lowing our enquiries, any inconsistencies have site in 2001 and 2002. Between 1990 and 2004, been largely resolved and previously unsub- successful breeding took place at a site in Hert- mitted breeding information released. We are fordshire in five years, which included, remark- confident that a more complete database of ably, a pair of Great Crested Grebes P. cristatus Black-necked Grebe breeding records has been hatching and fledging a Black-necked Grebe achieved and that the following account accu- chick there in 2000. Latterly, this water has rately reflects the breeding population of Black- become the most important in the region, necked Grebes in the UK for the period having eight breeding pairs in 2004, and it is 1973–2004. hoped that the water company that owns the site will continue their positive management Regional summaries role, in conjunction with the local wildlife trust. Black-necked Grebe is a species targeted by egg- It is perhaps surprising that, given the collectors, and unfortunately we have had to number of gravel-pits in southeast England, withhold the names of many sites. Only coun- Black-necked Grebe remains so scarce as a ties where either breeding has been proved or breeding bird. Recreational pressures may be a birds have been present long enough to suggest key factor preventing colonisation of this region. probable or possible breeding have been included in the text. Southwest England (Avon, Dorset, Gloucestershire, Hampshire,Wiltshire) Southeast England (Essex, Hertfordshire, Kent) The south-coast harbours and estuaries, from Most records during 1973–99 were of migrants. Langstone Harbour (Hampshire/West Sussex) The William Girling Reservoir in Greater to the Fal estuary complex in Cornwall, are London held 11 birds in both October 1998 and important for Black-necked Grebes in winter. October 1999 (Musgrove et al. 2001). Since Double-figure counts have been regularly then, this water has become increasingly impor- recorded as part of WeBS surveys, but it is often tant for wintering birds, and a count of 27 in difficult to obtain accurate counts and numbers February 2005 was the highest in the UK for any fluctuate, e.g. 33 on the Fal in December 1997, site in the 2004/05 winter (Banks et al. 2006). none there in the two following winters and In Kent, a pair was seen at Dungeness in May then an average of 12 from 2000/01 to 2004/05. and June 1984, and up to three juveniles were Langstone Harbour and Tor and Babbacombe Bays (Devon) are also 60 important but other no. pairs confirmed breeding sites with confirmed, probable or possible breeding coastal sites such as 50 The Fleet (Dorset) and the Tamar (Corn- 40 wall/Devon) appear to 30 be declining in importance. 20 Despite this, breeding has been 10 recorded in only two southwest counties. In 0 73 75 77 79 81 83 85 87 89 91 93 95 97 99 01 03 Avon, a pair bred in 1998, followed by Fig. 1. The number of confirmed pairs of Black-necked Grebes Podiceps nigricollis possible breeding in breeding in the UK, and the number of sites at which confirmed breeding took place, 1973–2004. 1999; and in Hamp-

370 British Birds 100 • June 2007 • 368–378 A survey of breeding Black-necked Grebes in the UK shire, a single pair bred successfully at a sewage- intermittently in the following years, there was farm in 1987. At another site in that county, no confirmed breeding until 2004, when the four pairs plus an extra male arrived in 1995, single young did not survive. two pairs hatching young, and another pair In 1994, up to two birds were in Poole nest-building. Although birds were present Harbour (Dorset) in May, and up to three remained on The Fleet from mid May to mid 1973–82 June. Cotswold Water Park straddles the border of Wiltshire and Gloucestershire and birds at this site have thus been recorded in both counties, but no breeding has occurred. In 2004, a pair was successful at another site in Glouces- tershire and breeding was attempted close by.

Eastern England (Cambridgeshire, Lincolnshire, Norfolk, Northamptonshire, Suffolk) The Black-necked Grebe occurs only as a passage migrant in Suffolk and Norfolk, albeit 1–4 increasingly so in the latter county. There has 5–8 been one instance of successful breeding in 9–12 Cambridgeshire, in 1989, and two unsuccessful 13–16 attempts in 1992. In Lincolnshire, the first 17–20 breeding in recent times took place in 1998, at two sites, following display in 1996, and was repeated in 1999, 2001 and 2003–04 at one of these. Birds have visited 15 waters in Northamptonshire since 1981 with display, cop- ulation and nest-building noted in the county, but successful breeding has not been proved.

1983–92 1993–2004

1–4 1–4 5–8 5–8 9–12 9–12 13–16 13–16 17–20 17–20

Fig. 2. The regional distribution and spread of breeding Black-necked Grebes Podiceps nigricollis in the UK. The data show the maximum number of pairs proved breeding, by county, in any year in three time periods, 1973–82, 1983–92, 1993–2004.

British Birds 100 • June 2007 • 368–378 371 A survey of breeding Black-necked Grebes in the UK

Central England (Derbyshire, Leicestershire & 1997 moved between this and a nearby site that Rutland, Nottinghamshire, Shropshire, Staffordshire, had also been partly destroyed, but no breeding Warwickshire,Worcestershire) occurred. In 2002, a pair failed to hatch a clutch Confirmed breeding has occurred in all coun- laid late in the season at an exposed site with ties except Derbyshire and Worcestershire on at little vegetation. In 2004, a pair managed to least one occasion during the period under fledge two young at an unprotected site, despite review. In Leicestershire & Rutland, breeding human disturbance. In Warwickshire, a pair was has occurred at Rutland Water, with chicks seen unsuccessful in 1984 and although birds visited in 1978, 1983, 1987 and 1988, but has not been three other sites in the period 1990–96, only in confirmed since. 1994 did a pair stay longer than a few days, but In Nottinghamshire, the first confirmed without any evidence of breeding. In 2000, an breeding was in 1979, when one pair fledged two agitated adult was seen at a new site in May, but young. Although two birds returned in 1980, this record was not followed up. breeding did not occur. A pair was successful in In 1983, a pair frequented a reedbed in Der- 1985 and breeding attempted in 1993, followed byshire until it was flooded in early June. In by success in four years since at four different 1994, two pairs displayed at a new gravel-pit site sites. At one of these, in 2000, seven pairs hatched in that county, but left as the pit was pumped at least 16 chicks, of which up to ten fledged. In dry to make way for a link road to the M1 2001, five pairs were thought to have bred at one motorway. In Worcestershire, a pair was site but only three chicks were seen, and there recorded at the same site in both 1986 and 1996 was probable breeding at a second water. In but water-skiing, sailing and fishing made the 2002, two pairs bred at one site, producing three site unsuitable for breeding. The 1988 RBBP or four young, but a family at another location Report addenda stated that confirmed breeding was thought not to have been bred there. In both took place at two central England localities in 2003 and 2004, there was successful breeding at 1984 and at one in 1995, with presence at one site by two pairs again, raising three juveniles another water. Unfortunately, further details of in each year, and 1–2 other pairs either non- these records could not be traced. breeding or unsuccessful. Some disturbance was suspected at this site. Northern England (Cheshire, Cleveland, Co. Some of the meres in Shropshire are in Durham, Greater Manchester, Northumberland, private ownership and, during 1987–89, con- Yorkshire) firmed breeding took place by one pair at an This region is undoubtedly the main breeding unidentified mere. In Staffordshire, breeding area in the UK, with three major clusters, in took place at Barton Gravel-pit in 1996. This site Cheshire, Northumberland and Yorkshire. At was later partly infilled and birds returning in one point during the period under review, one Ian Fisher 151. Black-necked Grebe Podiceps nigricollis, Northumberland,April 2006.

372 British Birds 100 • June 2007 • 368–378 A survey of breeding Black-necked Grebes in the UK site in Northumberland became the most 1992 found the site dry, and they scattered important in the country. It was established in across northwest England, displaying at two 1977, when one pair bred, and numbers then other Cheshire sites but there was otherwise no increased steadily to reach 17 confirmed evidence of breeding. Three displaced pairs breeding pairs in 1989, when 28 young were arrived at a small site in Greater Manchester and seen. In 1990–91, there were approximately 16 all bred successfully, and there were also sight- pairs here, but productivity was poor. At this ings at two sites in Lancashire, but no breeding. site, breeding Black-necked Grebes are This event demonstrates the ability of this dependent on Amphibious Bistort for nest- species to seek out and colonise newly suitable building, and cannot breed until this develops waters when necessary. During 1993–94, water sufficiently to support the nest. In some years, levels were still too low at Woolston Eyes, but plant growth is poor and therefore breeding gradually the drainage ditches silted up and suffers correspondingly, and at all times second water returned. A pair bred at a nearby site in broods are rare. American Mink Mustela vison 1993, but this proved to be an isolated event. In (or possibly Otter Lutra lutra) caused wholesale 1995, two pairs bred successfully at Woolston desertion by 11 pairs in mid July 2000, leaving Eyes, and as the former habitat returned, two pairs with young and one other pair. In numbers grew to ten successful pairs in 1998, 15 2001, seven pairs bred at this site but only four pairs in 2001, a peak of 20 pairs in 2002, 11 pairs young were reared, and just one pair was in 2003 and ten in 2004, with two and then one present at another site. A return to better times also successful at a second site in 2003 and 2004. was seen in 2002, when nine pairs hatched 12 The propensity for this species to breed young and just two nests failed, but again only colonially was shown by the breeding history in four chicks fledged; at two other sites in 2002, Greater Manchester. As already noted, the first single pairs fledged one and two young respec- breeding here in 1992 was a direct result of dis- tively. In 2003, a breeding attempt was thwarted persal from Woolston Eyes and two sites were by Common Coots Fulica atra at the main site occupied in 1993, when the water level at one of and also at another site in the county. these was raised to a permanent summer level. From 1990, Black-necked Grebes began to Breeding occurred at both of these private and colonise other Northumberland sites and, up to undisturbed sites in 1994 and 1996–98, and at 1993, breeding was proved at three further sites the first site also in 1995. Subsequently, birds and adult birds were seen at two more. From have withdrawn to Woolston Eyes, with only the 1994, there was retrenchment to the major site, second, larger, site regularly retaining up to five with expansion again from 1996 when two pairs, sometimes double-brooded. In 2004, this additional sites were used successfully, followed site achieved remarkable success when four by a fourth new site used in 2000. In 2002, pairs, all double-brooded, fledged 16 of 18 single pairs fledged one and two young respec- young hatched. Because the threat to Woolston tively at this site and at one of the 1993 sites, Eyes has by no means gone away, it is felt that which is now the pre-eminent water in the the nearby Greater Manchester sites should be county, 5–6 pairs fledging young in both 2003 protected in case of further problems. and 2004. In Yorkshire, there was successful breeding in In Cheshire, there were records from eight 1982–84 at a site near Sheffield. From 1993, sites during the breeding season in the period colonisation of the Lower Derwent Valley NNR 1980–83, with probable breeding taking place at began, five pairs nesting in the first year, Nunsmere in 1982 and 1983, followed by suc- increasing to 14 in 1994, 13 of which produced cessful breeding there in 1984. The introduction young; then nine pairs in 1995 hatched 15 of water sports at this site in 1985 caused the young; 15 pairs in 1996 hatched 34 young; 11 birds to desert, and although they returned in pairs in 1997 hatched 11 young, and 4–6 pairs 1986, they did not stay. Colonisation of what is in 1998 on two adjoining sites produced 11 now probably the most important site in the young. Fluctuating water levels in 1999–2000 UK, Woolston Eyes SSSI, began in 1987, with then precluded breeding here, but suitable con- successful breeding by one pair, progressing to ditions returned in 2001, when three proven eight broods from four pairs by 1991. Disaster attempts produced nine young, at least seven of struck in late 1991 when the owners drained the which fledged; up to four more pairs may have main breeding pool. Returning birds in spring bred, but monitoring is extremely difficult at

British Birds 100 • June 2007 • 368–378 373 A survey of breeding Black-necked Grebes in the UK this complex site. Three pairs returned in most years to 2003, and an exceptional four March 2002 but were not seen after 7th April. In pairs fledged eight young in 2001, although the 2000, a pair bred for the first time in recent birds were hampered by egg-collectors in years at Fairburn Ings RSPB reserve, and pairs 1990–91, and possibly by aggression from Little were also present in 2001 and 2002. Since 2000, Grebes Tachybaptus ruficollis in 1995. The there has been confirmed breeding at three second site in that county, where a pair bred other sites and possible/probable breeding at successfully in 1973, and which attracted seven two further sites. pairs in 1977, from which four broods were Breeding records in Co. Durham in the late reported, now appears to have been deserted 1940s have never been repeated. In Cleveland, because of disturbance from fishing boats. Four there was a promise of first breeding in 2004 pairs bred there in 1978, fledging four young, but Common Coots harassed the pair before while three pairs fledged six young in 1979. At a eggs could be laid. third site in Fife, breeding occurred in 1995 only, but the water is subject to disturbance Scotland, South (Borders, Dumfries & Galloway, from water-skiing. Lothians) In Perth & Kinross, the key site held 12–14 The first confirmed breeding for the Borders pairs in 1973, of which five were proved to breed; region was in 1992, when a pair bred success- ten pairs in 1974 of which six bred; eight pairs in fully at a site where a prospecting bird had been 1975 and ten pairs in 1976, when the outcomes noted the previous June. This site was not occu- were unknown. From 1977 to 1985, numbers pied again until 1995, when a pair again bred there were reduced, but breeding by two pairs successfully. Also in 1995, another site was was proved in both 1981 and 1985. Numbers colonised by a single pair, with breeding con- were back to nine pairs in 1986, but breeding firmed. From then until 2004, one or both sites details were not known. The following year, were occupied annually, and at least one pair 1987, was a successful year, with seven pairs pro- was successful in each year. Both were successful ducing 12 young, but in 1988, although 11 pairs in 2001 and in 2002 six pairs bred at one site, were present in April and six adults still there in but only four young were fledged. One of these late June, no breeding outcome was established. sites is threatened because of the loss of emer- In 1989, 1991 and 1992, four, two and six pairs gent vegetation. In Dumfries & Galloway, a sus- respectively were present but no outcome was pected breeding attempt in 1993 was thought to known, while in 1990 two pairs were seen with fail because of flooding of the nest. The only two young and in 1993 five pairs had four young. breeding-season records in the Lothians refer to A maximum of six pairs was present in July migrants. 1995. The last confirmed breeding record here was in 1996, when a pair with two young was Scotland, Mid (Angus, Fife, Perth & Kinross) seen in July; since then, there have been only In 1973, the year of the first RBBP report, the passage records. The reason is thought to be a small British population of Black-necked combination of predation by Otters, which Grebes was confined to this region, with a total arrived in the late 1990s, and competition from of four pairs breeding at two sites in Fife and Little Grebe, Great Crested Grebe and Common 12–14 pairs at the main site in Perthshire. The Coot, but research is needed to determine the two principal sites, one in Fife, the other in extent of possible changes in water quality, Perthshire, continued to be pre-eminent macrophyte and invertebrate populations (M. V. throughout the remainder of the 1970s, Bell pers. comm.). At a second Perth & Kinross although difficulties of access to the important site, birds were present every year from 1984 to Perthshire site meant that accurate data on pop- 1988 and probable breeding was recorded in two ulation size and breeding success were difficult of those years. Two further sites also supported to obtain in some years. Nonetheless, it is clear single pairs in 1987, each of which raised one that the population at this Perthshire site fell chick. At a new site, four pairs bred in 1999 and from the 1973 peak to an average of 3–4 pairs six young were seen, of which at least three between 1977 and 1979. fledged. Two pairs bred here in 2000 but no The main Fife site showed less fluctuation in young fledged. There was probable breeding by breeding numbers, but has suffered in recent one pair of two in 2001. years from flooding. One or two pairs bred in In Angus, records are mostly from the

374 British Birds 100 • June 2007 • 368–378 A survey of breeding Black-necked Grebes in the UK

RSPB’s Loch of Kinnordy reserve, a site with an Northern Ireland abundance of Bogbean among which the grebes Single adults have been recorded between breed. The first record was in 1987, when a March and September at Lough Beg or Lough single pair hatched young from two breeding Neagh in most years since 1994. In 1997, one attempts; none survived and it was believed that displayed to a Slavonian Grebe P. auritus in they were predated by Pike Esox lucius. A pair May. There have been no proven breeding raised two chicks in 1988, and in 1989 one records since 1944, however (G. Gordon pers. young survived from each of two broods from comm.). one pair, while another adult was also seen to feed the young. Five pairs fledged nine young in Discussion 1990, and in subsequent years in this decade up The status of the Black-necked Grebe in Britain to 11 pairs were present. Productivity has been prior to the first proven breeding attempt in low, with only one or two chicks fledging in 1904 is unclear. Any suggestions of earlier some years. Numbers declined to two pairs in nesting must be treated with caution, since con- 1998 and just one pair in 1999–2001. Manage- fusion with Great Crested Grebe, formerly ment work was carried out in 2001 to remove known as ‘Eared Grebe’ in some areas, cannot Branched Bur-reed Sparganium erectum and be ruled out. However, Brown & Grice (2005) silt. Following on from this, a Recovery Project, stated that Pennant’s (1771) description of birds to address many problems which have led to the in the fens, described as ‘Lesser Crested Grebe’, site losing much of its conservation interest, ‘clearly identifies [them] as Black-necked including Black-necked Grebes, is now in Grebes.’ Up to the early 1970s, the species was progress and expected to last until 2009. In an annual, but rare, breeding bird with the 2001, a pair, probably from Kinnordy, arrived stronghold of the small UK population centred and bred successfully at a second site in Angus, in southern Scotland. Nesting in the rest of the but in 2002 two attempts there by a single pair UK occurred only occasionally during this time, failed. A pair bred at a third site in 2003. and the pairs that were successful in England, for example in the 1940s, did not develop into Wales an established population. No breeding occurred during the period of this By 1973, breeding was confined to Scotland. survey in Wales, although migrants or non- The population changed little during the fol- breeding single birds have been seen in ten years lowing years, but by the end of the 1970s the in the period under review in Gwynedd, where number of sites at which birds were reported birds winter off the coast. Migrants were also began to increase slowly. From 1982, however, seen in Clwyd and Gwent in 1994. there was a significant rise in the number of Ian Fisher 152. Black-necked Grebe Podiceps nigricollis with young chick, Northumberland,April 2006.

British Birds 100 • June 2007 • 368–378 375 A survey of breeding Black-necked Grebes in the UK localities recording Black-necked Grebes in the sistent cold and wet weather do affect breeding breeding season, particularly in England, and by success. At sites where nests are built on floating 1989 a maximum total of 34 pairs was recorded. vegetation such as Amphibious Bistort, cold It is clear that what was then happening in springs delay plant growth and breeding cannot Britain was part of a much wider increase in then begin until late June or even early July. northwest Europe, as a dramatic rise in the Finally, in the Cheshire and Greater Manchester breeding population was noted in The Nether- area, four birds are known to have been killed by lands during the 1980s (Hustings 1991). hitting overhead power lines in recent years. It is This improved showing continued into the not known if this presents a significant threat to 1990s (fig. 1). More waters in east, southeast and this nocturnal migrant. central England were visited during the breeding Although information is limited, two long- season, although breeding was only occasionally term studies provide interesting data on the confirmed, suggesting that most birds were breeding success of Black-necked Grebes. Leible either on passage or found the sites unsuitable. & Zach (1992) studied a large population of The same applied to southwest England, where Black-necked Grebes (up to 172 pairs) in north- breeding has occurred on only a few occasions, east Bavaria from 1972 to 1990. At one of the in Hampshire, Gloucestershire and Avon. main sites, they found that the average number Throughout this period, Black-necked Grebes of hatchlings was 1.92 per pair (n = 751 pairs), continued to breed on a number of lochs in while the average number of fledged young was south and mid Scotland, and the annual popula- only 0.74. Fiala (1991), in a similar study in the tion ranged from eight to 17 pairs. Czech Republic, reported that 85.1% of clutches By 1998, birds were reported at 15 sites, and 77.1% of eggs hatched successfully (mean which held 50 confirmed pairs, the highest clutch size from year to year varying from 2.80 breeding number ever recorded. Since then, to 3.44), although the average number of young there has been a levelling-off to 25 localities and fledged per breeding pair was only 1.01. It 43 confirmed pairs in 2004. A significant change seems that the number of young fledged in since the 1980s has been the shift of the popula- many parts of Europe, the UK included, is low. tion into northern England, with sites in Fiala (1991) reported the greatest losses occur- Cheshire and Northumberland now of major ring shortly after hatching and believed that importance for this species (fig. 2). A further site chilling, disease and the inability of the adults in Nottinghamshire held up to seven successful to meet the food requirements of the young are pairs, and another in the southeast of England the main causes. We can confirm the last factor has attracted a small but growing population. from many years of monitoring the large Pleasing though the overall increase is, 40% Cheshire colony. There, broods of three occur of the confirmed pairs in 2002 were at just one regularly, but in 20 years no pair has ever site. In addition, productivity at some sites fledged three young. At 10–14 days old, the (notably in Scotland) is low. The reasons for this brood is split between the adults, each of which are unclear. Respondents to a questionnaire sent generally copes successfully with the needs of by the North-west England Black-necked Grebe only one chick (B. Martin pers. obs.). Study Group to fieldworkers at current and Leible & Zach (1992) found that Black- former breeding waters blame mammalian necked Grebe colonies were always associated predators such as American Mink and Stoat M. with Black-headed Gulls. For observers familiar erminea, as well as Pike, for taking eggs and with breeding sites in the UK, there has long young in some years. Common Coots have been been an impression that the presence of Black- observed displaying aggressively to Black-necked headed Gulls is an important factor in nest-site Grebes, while at one Cheshire breeding colony selection by Black-necked Grebes. The Little Grebes have regularly attacked both adults responses to the questionnaire referred to above and young (B. Martin pers. obs.). Red-eared Ter- showed that, of the 14 regularly used sites, nine rapins Trachemys scripta have recently been (64.3%) had thriving Black-headed Gull reported at two sites in the north of England. colonies, ranging from as little as 50–100 pairs Whether or not predation is a serious problem is up to 14,000 pairs at one site in southern Scot- unclear, but it may well be important in some land (unpubl. data). Of the five sites where gulls years. There is no doubt that fluctuations in were absent, one reported past breeding nearby water levels, notably during incubation, and per- and a few pairs holding territory occasionally

376 British Birds 100 • June 2007 • 368–378 A survey of breeding Black-necked Grebes in the UK on site. Those findings suggest that the presence south (Rocamora & Yeatman-Berthelot 1999), of Black-headed Gulls may not be an essential though ringing recoveries suggest that win- prerequisite for Black-necked Grebes but it is tering birds in France principally come from interesting that, of the five sites without The Netherlands, Denmark and central and breeding gulls, only one had a high level of eastern Europe (Dubois et al. 2000). It is pos- chick survival. Fiala (1991) related the case of a sible that some British birds move to France, Black-necked Grebe colony in central Europe although there is no evidence to confirm this. which failed completely after attacks by Hooded Crows Corvus cornix and Magpies Pica pica Hope for the future during a year when Black-headed Gulls did not One of the most positive developments in recent breed at the site. years has been the formation, under the auspices Interestingly, concerns about poor breeding of the RSPB, of two specialist Black-necked success have also been raised for Scotland’s Grebe Study Groups, one in Scotland, the other Slavonian Grebe population and the reasons for in northwest England. Now, previously isolated this species’ poor productivity are unclear too. fieldworkers are exchanging information, while Much research has been carried out into the studies have been set up that will hopefully reasons for nest failure of Slavonian Grebes in increase knowledge of, for example, habitat Scotland, including day-and-night camera sur- requirements, aquatic invertebrate populations, veillance over two seasons. Otter, Pine Marten predation levels and water chemistry, about Martes martes, European Wildcat Felis silvestris, which little is known at most sites. The data Badger Meles meles, American Mink, Stoat, obtained should prove helpful in the manage- Brown Rat Rattus norvegicus and domestic cat ment of existing Black-necked Grebe breeding and dog were the mammals recorded visiting sites, while encouraging the development of new nests, but wave action, flooding and accidental sites to attract this fine grebe. displacement of eggs by the birds themselves Although many breeding sites in the UK also led to clutch loss. The presence of crows and experience low productivity, there are a few Pike was found to be circumstantially important where breeding success is consistently high. in clutch and chick survival respectively. The There is scope for a study into the reasons for numbers and distribution of small fish, them- this. Consideration also needs to be given, at a selves dependent on midge (Chironomidae and national level, to the control of alien predators. Ceratopogonidae) abundance, may also be The British Black-necked Grebe breeding important and may affect the choice of breeding population has in the past decade reached its loch: it is unclear why some apparently suitable highest known level, but the species remains a lochs are ignored. Human disturbance, particu- rare breeding bird. Since birds prefer to nest on larly by bank- and boat-fishing, is an important undisturbed waters, it is likely to remain scarce, factor, as it is with Black-necked Grebe. Good but there is no reason why further increases weather conditions in the first two weeks after should not continue if disturbance is kept to a hatching is also helpful, so that chicks do not die minimum and new, carefully managed, sites of hypothermia; stable water levels throughout become available. The Black-necked Grebe is the breeding cycle were also shown to be impor- protected under Schedule 1 of the Wildlife and tant (Benn 2003; Summers et al. in prep.). Countryside Act 1981, and the majority of Much remains unknown about Britain’s breeding waters are Sites of Special Scientific summer population of Black-necked Grebes. Interest. Even so, some are known to be vulner- For example, where do they winter? A small able to development or recreational pressures. population has wintered for many years in har- Black-necked Grebe is more numerous as a bours and estuaries on the south coast, but the breeding species in other parts of Europe, and numbers there would not account for all of since no British sites support numbers even Britain’s breeding birds. It may well be that approaching 1% of the European total, none many winter further south, perhaps in the would qualify for the higher level of Special Pro- Mediterranean. During the 1970s and early tection Area status. 1980s, up to 3,900 Black-necked Grebes win- Acknowledgments tered on saline lagoons at Formentera (Balearic First and foremost, we wish to thank all the County Islands) (Mayol 1984), while in the late 1990s Recorders and other observers who have contributed over 15,000 wintered in France, mainly in the records to the Rare Breeding Birds Panel over the years.

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Malcolm Ogilvie, the former Secretary to the Rare Breeding Dubois, P.J., le Marechal, P., Olioso, G., & Yésou,P.2000. Birds Panel, kindly supplied essential datasets for 1973 to Inventaire des Oiseaux de France: avifaune de la France 2000 and Mark Holling, the Panel’s present Secretary, supplied metropolitaine. Fernand Nathan, Lyon. the rest. In addition, we are grateful to many people with past Fiala,V. 1991. Zweiter Beitrag zur Brutbiologie des and current knowledge of Black-necked Grebe breeding sites Schwartzhalstauchers. Folia Zool. 40 (3): 241–260. who gave much help with the clarification of population levels Gibbons, D.W., Reid, J. B., & Chapman, R. A. 1993. The New in the early years of the period under review, and Ken Shaw Atlas of Breeding Birds in Britain and Ireland: 1988–1991. in particular, who provided invaluable data for several Scottish Poyser, London. sites. Others in Scotland who gave freely of their knowledge Guest, J. P., Elphick, D., Hunter,A., & Norman, D. 1992. The included Peter Gordon, Alan Leitch and Andrew Wight, whilst Breeding Bird Atlas of Cheshire and Wirral. Cheshire & the late W. T. Appleyard, Keith Brockie, Sandra Hacker and Wirral Ornithological Society. Mike Ramage contributed much in monitoring Black-necked Hagemeijer, E. J. M., & Blair, M. J. (eds.) 1997. The EBCC Atlas Grebe populations in Scotland. Ian Armstrong, Mark Dennis of European Breeding Birds: their distribution and and Graham White readily shared their knowledge of Black- abundance. Poyser, London. necked Grebes from three important breeding sites, and we Hustings, F. 1991. Explosiev toename van broedende are also grateful to Bill Curtis, Geoff Dobbs, Gary Geoorde Futen Podiceps nigricollis in 1983–1989 in Nuechterlein of the University of North Dakota, and the Nederlands. Limosa 64: 17–24. BTO Nest Record Scheme. Thanks are also due to Prof. Kalela, O. 1949. Changes in the geographic ranges of the David Norman and members of the Scottish Black-necked avifauna of northern and central Europe in relation to Grebe Study Group for reading initial drafts of this paper and recent changes in climate. Bird Banding 20: 77–103. suggesting improvements and corrections. The Cheshire & Leible, F., & Zach, P.1992. Migration, population size and Wirral Ornithological Society kindly supplied financial breeding biology of Black-necked Grebes in the assistance towards Brian Martin’s research at the Edward Oberfalz. Vogelwelt 113 (1): 35–47. Grey Institute, where Linda Birch was particularly helpful. Mather, J. R. 1986. The Birds of Yorkshire. Croom Helm, London. Endnote Mayol, J. 1984. Concentration of Black-necked Grebes in saline lagoons at Formentera, Balearics. Bull. de Since the completion of this Estraction Central de Ecologica 13, No. 25. Madrid. paper, the Rare Breeding Musgrove, A. J., Pollitt,W., Hall, C., Hearn, R., Holloway, S., Birds Panel has adopted the Marshall, P., Robinson, J., & Cranswick, P.2001. The Black-necked Grebe as its Wetland Bird Survey 1999–2000: wildfowl and wader new logo; a fitting tribute to counts. BTO/WWT/RSPB/JNCC, Slimbridge. this charismatic bird. Pennant,T. 1771. A Tour in Scotland. Privately published, Chester. References Rocamora, G., & Yeatman-Berthelot, D. 1999. Oiseaux Adamian, M. S., & Klem, D. 1999. Handbook of the Birds of Menaces et a Surveiller en France: listes rouges et Armenia. American University of Armenia. recherches de priorites. Populations, tendances, menaces, Banks, A., Collier, M., Austin, G., Hearn, R., & Musgrove, A. conservation. SEOF/LPO. 2006. Waterbirds in the UK 2004/05: the Wetland Bird Sharrock, J.T. R. 1976. The Atlas of Breeding Birds in Britain Survey. BTO/WWT/RSPB/JNCC, Slimbridge. and Ireland. Poyser, Berkhamsted. Benn, S. 2003. Conserving Scotland’s Slavonian Grebes, Summers, R.W., Mavor, R. A., & Hancock, M. H. In prep. Podiceps auritus. Brit.Wildlife 15 (1): 25–30. Determinants of breeding success of Slavonian Grebes Boe, J. S. 1992.Wetland selection by Eared Grebes, Podiceps auritus in Scotland. Podiceps nigricollis, in Minnesota. The Canadian Field- Temperley, G.W. 1951. A History of the Birds of Durham. Naturalist 106: 480–487. Natural History Society of Northumberland, Durham Brown, A., & Grice, P.2005. Birds in England. Poyser, London. and Newcastle upon Tyne, Newcastle. Brian Martin, 45 Albert Road, Grappenhall, Warrington WA4 2PF Judith Smith, 12 Edge Green Street, Ashton-in-Makerfield, Wigan WN4 8SL /Birdwatch Steve Young Steve 153. Black-necked Grebes Podiceps nigricollis,Warrington, Cheshire & Wirral,April 2006.

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