Archived 2011-2012 topics: Long-tailed Duck (Clangula hyemalis): uplist to Endangered?

Initial deadline for comments: 31 January 2012.

BirdLife species factsheet for Long-tailed Duck

Long-tailed Duck Clangula hyemalis is a widespread circumpolar species that breeds mainly in the Arctic tundra and winters generally to the south, mainly far offshore. It is currently listed as Least Concern because it was not thought to approach the thresholds for Vulnerable under any of the IUCN Red List criteria.

This species has an extremely large range (Extent of Occurrence [EOO] in breeding season estimated at c.9.55 million km2; wintering EOO >1.7 million km2), and hence does not approach the thresholds for Vulnerable under the range size criteria (B and D2: EOO of less than 20,000 km2, combined with a declining or fluctuating range size, habitat extent/quality or population size, and a small number of locations or severe fragmentation). The population size is also extremely large (c. 6.5 million individuals; Wetlands International 2006), and hence does not approach the thresholds for Vulnerable under the population size criteria (C and D1: fewer than 10,000 mature individuals with a continuing decline estimated to be at least 10% over ten years or three generations, or with a specified population structure).

Therefore, the only relevant criterion is A, which relates to reductions in population size. Until recently, the population was thought to be declining slowly, but not sufficiently rapidly to approach the threshold for listing as Vulnerable under criterion A (at least a 30% decline over ten years or three generations, whichever is longer).

However, a new publication, comparing the results of winter surveys in the Baltic Sea in 1992-1993 and 2007-2009, indicates that the species has declined significantly there (Skov et al. 2011). An estimated total of c.4,272,000 individuals was counted there in 1992-1993, falling to c.1,486,000 individuals in 2007-2009, which suggests that a decline of c.65% has occurred over a period of 16 years. This extrapolates to a decline of c.83% over the last three generations, estimated by BirdLife to be 27 years (based on a generation length of c.9 years). This decline appears to be on-going, with Swedish survey results from 2011 indicating a decline of c.80% since 1992-1993 (K. Larsson in litt. 2011).

The Baltic Sea is the most important wintering area for this species in the world, holding most of the northern European and western Siberian breeding populations. The c.4.3 million birds recorded there in 1993 represented c.66% of the latest (but obviously now outdated) global population estimate of c.6.5 million birds (Wetlands International 2006). The decline detected in the Baltic Sea therefore has global significance. The current trend of the small component of the European population that winters outside the Baltic (c.300,000 birds) is unknown, but there is some evidence that it may also be declining (e.g. in the UK: Holt et al. 2011, Musgrove et al. 2011).

North America holds the second largest population (c.1 million birds; Wetlands International 2006). The North American Waterfowl Breeding Population Survey (NAWBPS) traditional area survey suggests that an annual change of -5.3% occurred in the species’s population from 1973 to 1997 (Sea Duck Joint Venture 2003). The Mid-winter inventory (US Atlantic coast) shows a decline of -1.1% per year during 1976-1997. The Atlantic Coast Sea Duck Survey shows no statistically significant trend during 1991-1999, but the data do suggest a decline. In contrast, the Arctic Coastal Plain Survey indicates a relatively stable breeding population since 1986 and the Yukon-Kuskokwim Delta Coastal Zone Survey shows slowly increasing numbers since 1988. The Atlantic flyway Christmas Bird Count (CBC) data show no trend during 1973-1995 (Sea Duck Joint Venture 2003). Overall, however, CBC data indicate an annual population change of -1.9% between 1965 and 2005, across c.70% of the species’s range in North America (Butcher and Niven 2007), suggesting that a decline of c.54% has occurred over 40 years, or a c.40% decline over 27 years (three generations).

No trend data are available for the third largest population (c.500,000–1,000,000 birds), which breeds in eastern Siberia and winters off eastern Asia. The fourth and smallest population (c.100,000–150,000 birds), which breeds in Greenland and Iceland and winters in the north Atlantic, is poorly monitored and trends are uncertain, although it may have been stable until the 1990s (Wetlands International 2006).

It is possible that the lower numbers recorded in the Baltic (and possibly also in North America) relate not to a population decline, but to changes in the species’s winter distribution (e.g. Zipkin et al. 2010). In recent decades, many waterfowl species have responded to global climate change by ‘short-stopping’, i.e. taking advantage of warmer conditions to winter closer to northern breeding areas than was previously possible. Long-tailed Duck may have been affected by this phenomenon, but there is currently no evidence to suggest that the c.2.8 million birds ‘missing’ from the south-central Baltic are now wintering further north, either in the northern Baltic (Skov et al. 2011) or in, for example, the White Sea or Barents Sea off north-western Russia.

There is, however, evidence that the species is struggling on its Arctic breeding grounds. The results of autumn migration monitoring at various Baltic sites show that juveniles now represent a very low proportion of the population (e.g. Hario et al. 2009, Ellermaa et al. 2010), indicating that insufficient young are being raised to compensate for adult mortality. The breeding success of this (and other) species seems to have declined since the mid-1990s, when the formerly distinctive 3-4 year cycle in the abundance of Arctic rodents collapsed, probably due to climate change. With fewer rodents around, Arctic predators now take a heavier toll on breeding birds every single year, instead of only once every 3-4 years.

In turn, these missing recruits may have increased the impacts of oil pollution, hunting, bycatch and other threats on adult Long-tailed Ducks in the Baltic (e.g. Larsson & Tydén 2005). As expressed by Hario et al. (2009): “In long-living species, such as seaduck, the population growth rate is much more sensitive to variations in adult survival than to variations in fecundity or immature survival. With a missing “floating” element of the population, there are not enough debut breeders entering the breeding stock to fill the gaps created by increased adult mortality. This may be the biggest difference between the current dynamics of the Long-tailed Duck compared to the situation in past, when winter mortality was heavy, but the lemming cycles on the breeding grounds still existed, which allowed the population to recover”.

Taking the 27-year decline rates calculated for the Baltic and North American populations, and assuming that the two other smaller populations have remained stable, the species’s global population may be declining at a rate of more than 50% over three generations, which would qualify the species for uplisting to Endangered under criterion A. To permit a more comprehensive assessment, further and more recent information on the size and trend of the species’s population is requested for all parts of its range, but particularly from eastern Asia, Greenland, Iceland and North America.

References:

Butcher, G. S. and Niven, D. K. (2007) Combining Data from the Christmas Bird Count and Breeding Bird Survey to Determine the Continental Status and Trends of North American Birds. Ivyland, PA: National Audubon Society.

Ellermaa, M., Pettay, T., & Könönen, J. (2010) [Autumn migration in Põõsaspea Cape in 2009.] Hirundo 23(1): 21-46. (in Estonian, with English summary) http://www.eoy.ee/hirundo/sisukorrad/2010_1/Ellermaa_etal_23_1.pdf

Hario, M., Rintala, J. & Nordenswan, G. (2009) [Dynamics of wintering long-tailed ducks in the Baltic Sea – the connection with lemming cycles, oil disasters, and hunting.] Suomen Riista 55: 83-96. (in Finnish, with English summary)

Holt, C. A., Austin, G. E., Calbrade, N. A., Mellan, H. J., Mitchell, C., Stroud, D. A., Wotton, S. R. and Musgrove, A. J. (2011) Waterbirds in the UK 2009/10: The Wetland Bird Survey. Thetford, UK: BTO/RSPB/JNCC.

Larsson, K. & Tydén, L. (2005) [Effects of oil spills on wintering Long-tailed Ducks Clangula hyemalis at Hoburgs bank in central Baltic Sea between 1996/97 and 2003/04.] Ornis Svecica 15: 161-171. [in Swedish, with English summary] http://www.nioz.nl/public/mee/birds/0483.pdf

Musgrove, A. J., Austin, G. E., Hearn, R. D., Holt, C. A., Stroud, D. A. and Wotton, S. R. (2011) Overwinter population estimates of British waterbirds. British Birds 104: 364-397.

Sea Duck Joint Venture (2003) Species status report. http://www.seaduckjv.org/meetseaduck/species_status_summary.pdf

Skov, H., Heinänen, S., Žydelis, R, Bellebaum, J., Bzoma, S., Dagys, M., Durinck, J., Garthe, S., Grishanov, G., Hario, M., Kieckbusch, J. K., Kube, J., Kuresoo, A., Larsson, K., Luigujoe, L., Meissner, W., Nehls, H. W., Nilsson, L., Petersen, I. K., Roos, M. M., Pihl, S., Sonntag, N., Stock, A. and Stipniece, A. (2011) Waterbird Populations and Pressures in the Baltic Sea. TemaNord 2011: 550. Copenhagen, Denmark: Nordic Council of Ministers.

Wetlands International (2006) Waterbird population estimates. Fourth edition. Wageningen, The Netherlands: Wetlands International.

Zipkin, E. F., Gardner, B., Gilbert, A. T., O’Connell, A. F., Royle, J. A. and Silverman, E. D. (2010) Distribution patterns of wintering sea ducks in relation to the North Atlantic Oscillation and local environmental characteristics. Oecologia 163: 893-902.

The following input from Dr. Gennady Grishanov was forwarded to us on 30 January 2012: Clangula hyemalis Grishanov Jan12

The following letter was received on 31 January 2012; Clangula hyemalis Lehikoinen et al. Jan12

Long-tailed Duck revised global three-generation decline estimate – added 14/2/12 (see comment posted by Andy Symes on 14/2/12 for background)

Related posts:

  1. Archived 2011-2012 topics: Taxonomic changes in the genus Melanitta, part I: suggestion to list M. nigra as Vulnerable and request for information on M. americana
  2. Archived 2011-2012 topics: Ribbon-tailed Drongo (Dicrurus megarhynchus): uplist to Near Threatened?
  3. Archived 2011-2012 topics: Short-tailed Scimitar-babbler (Jabouilleia danjoui): downlist to Least Concern?
  4. Archived 2011-2012 topics: Semipalmated Sandpiper (Calidris pusilla): request for information
  5. Archived 2011-2012 topics: Green-tailed Bristlebill (Bleda eximius): eligible for downlisting?
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16 Responses to Archived 2011-2012 topics: Long-tailed Duck (Clangula hyemalis): uplist to Endangered?

  1. Leif Nilsson says:

    Within the SOWBAS Swedish waters were completely surveyed in 2009. The surveys continued with full intensity during 2010 and 2011 with the aim to establish a monitoring program for the species (and other offshore waterbirds). In contrast to 2009, 2010 and 2011 were very hard ice winters. in 2010 numbers in Swedish waters were somewhat higher than in 2009, but there was heavy ice in important areas in the eastern Baltic, The important areas (offshore banks) were covered to the same extent in 2011 but with lower totals than in 2010. With the very heavy ice conditions in the last too winters and most important ice-free areas covered in 2011 it may be probable that the numbers are even lower for the Baltic in total than presented in the report.
    There are no possibilities to find Long-tailed Ducks in the northern parts of the Baltic as was proposed as a possibility in line with the northern shifts of the distribution fiund in some other diving ducks. The areas further north are normally ice-covered and all potential offshore sites have been surveyed.
    The Swedish data are to be found on the webpage below with more detailed information of LTD and also other species. A more full analysis of the data on the LTD from Swedish waters from 1970s to this day is under way.
    http://www.zoo.ekol.lu.se/waterfowl/index_e.htm

  2. As for LTD in Asia, its migration throuigh the continental part of Central Asia seems to increase in the last decade of years. It may be induced with either some climatic changes, but may do not. So, before 2000s LTD was a rare winter guest at the waterbird wintering in the Angara River source at Lake Baikal, which is uncoverd by ice at winter. The LTD number was up to twenty individuals. But since early 2000s an increasing trend is going. In the last season 2010/11, c. 160 individuals LTD spent winter here. The species did somewhat increase a record frequency in the adjacent regions as well, for example in Mongolia, where it is as the extremely rare vagrant as before, however. But generally, the number of intracontinental migrants is insignificant in comparison to the main LTD population.

  3. I agree with Leif Nilsson that there could not be significat relocation of wintering Long-tailed Ducks from Baltic to outside the Baltic Sea neither within Baltic.

  4. Unpublished data on age ratio of gillnet victims in the Southern Baltic (which is likely to be a representative sample) suggest a decline in breeding success by app. 75% from prior to 1990 until c. 2000. Such a change might explain most of the observed decline in numbers in the Baltic. The current low levels of breeding success may also impair the population’s ability to compensate (adult) mortality due to gillnet bycatch, oil pollution, hunting, etc.
    As already stated, we cannot identify alternative wintering areas for the birds missing in the Baltic. In Northern waters, if ice-free, the species might have difficulties to meet its food demands during very short daylight periods.

  5. Our investigation in East-European tundra of Russia (Nenets autonomous district of Arkhangelskaya region) since 1973 shows great declining of Long Tailed Duck number – 15 individuals per square km in 1973 and 1,6 individuals per square km in 2011. We think this great declining is connected with several reasons: natural cycles of the species, pollution from oil and gas extractions, pollution from landfill of nuclear and chemical waste in northern seas. As an example in 2006-2007 on the Hatpudirskaya bay coast (Barents Sea) there were several thousand of dead Long Tailed Ducks ejected to the beach.

  6. Jari Kontiokorpi says:

    In Vyborg NW-Russia close to border of Finland Finnish ornithologists were observing spring migration of arctic waterfowl in 1988-2008. Observation was irregular; best observed springs were 1992-2002, with more than 100 observing hours/spring. Most in spring 1993, total of 300 observation hours (Kontiokorpi & Parviainen 1995). Total observation time was 2486 hours. Almost all observation was carried out 6.5.-1.6. and it was quite uniform from sunrise to sunset. There was only a small dip in the afternoon hours.
    Vyborg Bay is one of the world’s best arctic migrations route in spring. It has known as good bottle-neck for arctic migration for years, like Hynén wrote in 1908 (Kontiokorpi 2000). In 1988-2008 we counted total of 10 million ducks, 2,8 millions geese, 160 000 divers and waders and 2500 skuas.

    Long-tailed Duck was the most numerous duck in Vyborg in 1990´s. Best spring was 1993, when counted 700 000 LtD´s, in one day 207 000 (13.5.). Migration peak for LtD, Common and Velvet Scoter has been in the evening, between 19 and 22 at local time.
    Because of irregular observation in 1988-2008, it was splitted in to three periods in Long-tailed Duck migration time (6.-24.5.): 1988-1994 (total 762 observed hours), 1995-1999 (1061) and 2000-2008 (628). In number of LtD there is clear decreasing trend: in 1988-94 we counted in average 2051 ind./observed hour, in 1995-99 1306 and 2000-2008 888 ind. (N=3,5 million).

    Hynén, O. 1904: Birds in the Vyborg Bay in spring time. – Luonnon Ystävä 8, pp. 80-84.
    Kontiokorpi, J. 2000: Vyborg, Russia – The Arctic Migration. – Alula 6(1): 8-15.
    Kontiokorpi, J. & Parviainen, A. 1995: Spring migration of arctic waterfowl from Vyborg and Repino (Russia) in spring 1993. – IWRB Seaduck Research Group Bulletin 5: 25-29.

  7. On Kolguev island in the Barentz Sea LTD is quite common during breeding period in 2006-2011, with density of 1-2 pairs/sq.km in June, but then the density of broods is almost 10 times less. Same figures for June breeding density (1-2 pairs/sq.km) was mentioned here in mid-90-ies as well (with no estimations of brood densities.
    The main reason for low number of broods seems to be likely connected mainly with skipped breeding, rather than with increased predation pressure. The are no any rodents on the island (neither lemmings, nor voles), but still quite many foxes. So, the ceased lemming fluctuation after mid 90-es as an explanation for more stable predation pressure could be hardly implemented here – it was always stable. Also, though in June Velvet Scoter pairs are 5-10 more scarce than LTD pairs, it is just vice-versa during brood-rearing period, when Scoter broods are up to 2-3 time more common on the routes than LTD broods, so the great proportion of Scoter pairs breed successfully in the same conditions. Velvet Scoters are late (so – more income) breeders on Kolguev, while LTD usually start nesting soon after arrival, and it looks like that many LTD females just skip breeding attempt, as they persist staying on the lakes in pairs for the whole June with seemingly no breeding attempt. For me it seems that the clue for decreased breeding propensity of LTD is more linked to worsened female body conditions, than to increased predation pressure.

  8. Joe Taylor says:

    The following comments by Dr. Sergei P. Kharitonov were forwarded to us on 30 January 2012:

    Two extensive tundra areas were monitored in the western half of Taimyr: 1) in 2004, 2007, 2010 at the central Taimyr we surveyed near 400 km of the Agapa River streams, from the southernmost Red-breasted Goose colony (70.11N, 86.15E) up to the river mouth (71.26N., 89.13E); 2) in 2000-2007 at the northern Taimyr, Medusa Bay area we monitored 380 sq. km area near the Willem Barents Station (73.23N, 80.32E), including lower streams of the Lemberova, Maximovka and Efremova Rivers and part of the Kara Sea coast.

    1) In the north-west Taimyr, Medusa Bay area only Long-tailed Duck is common staging and breeding bird. Numbers are fluctuating with slight trend to decrease. Years of very low numbers – 2003 and 2007 (flock of several staging birds), usual numbers are – flocks of 10-20 staging birds
    Black Scoter – occasional bird, usually singles very rare can be observed, one time in 2001 flocks of 10 birds was recorded
    Velvet Scoter – occasional bird, singles. In 2003 surprisingly was registered 100 birds, then does not seen in 2004-2007.

    2) Agapa River area – all four duck species are present. Long-tailed duck breeding, it is the most common duck in that area, however numbers ids not high – first hundreds bird per the 400 km river stream.
    Great scoup – numbers is low, several tens of birds per 400 km river stream
    Black Scoter – rear duck, decreasing in numbers over 2004-2010
    Velvet Scoter – rear duck – several tens per 400 km of the Agapa river streams, numbers trend is unclear.

  9. Since 1973-2011 area over than 200 000 square km of the East-European tundra of Russia from Kanin peninsula to the Baidaratskaya bay were monitored. Methods of study: aircraft routs (over than 65 000 km), boating routs (7300 km, down the rivers, in bays of the Barents Sea), pedestrian routes (7700 km).
    The list of main publications:
    1. Mineev Y. N. Waterfowl of the Bolshezemelskaya tundra. Fauna and ecology // Leningrad, publishers: Nauka, 1987. 110 p. (in Russian)
    2. Mineev Y. N. Waterfowl of the Yugorskij peninsula // Syktyvkar, 1994. 103 p. (In Russian)
    3. Mineev Y. N., Mineev O. Y. Waterfowl of Pechora River delta and Ruskij Zavorot peninsula // OMPO Newsletter No 20, September 1999, p.5-10
    4. Mineev Y. N. Anseriformes of the East-European tundra // Publishers Ekaterinburg: Ural Dep. of RAS, 2003, 225 p. (in Russian)
    5. Mineev O. Y. Waterfowl of the Malozemelskaya tundra and Pechora River Delta // Publishers Ekaterinburg: Ural Dep. of RAS, 2005, 161 p. (in Russian)
    6. Mineev Y. N., Mineev O. Y. Birds of the Malozemelskaya tundra and Pechora River Delta // Saint-Petersburg, publishers: Nauka, 2009. 263 p. (in Russian)

  10. Here are comments for the 2012 IUCN Red List update proposal from the Finnish expert group on birds, which did the evaluation for the last national Red List (2010). Our comments concern four duck species: the Scaup Aythya marila, Long-tailed duck Clangula hyemalis, Velvet scoter Melanitta fusca and Common scoter Melanitta nigra. We have used Finnish breeding censuses (nest counts and breeding atlas) and migration counts as sources of conclusions. We must point out that the migration count analyses are quite harsh, since there was not enough time for detailed analyses. Nevertheless, we believe that the trends that they show indicate real changes in the population sizes, but we should not put too much weight on the exact magnitude of change especially in the uncommon Scaup and Velvet scoter.

    Best wishes,

    Antti Below, Finnish Forest and Park Service, Metsähallitus
    Martti Hario, Finnish Game and Fisheries Institute
    Aleksi Lehikoinen, Finnish Museum of Natural History
    Esa Lehikoinen, University of Turku
    Markku Mikkola-Roos, Finnish Environment Institute
    Jorma Pessa, Centre for Economic Development, Transport and the Environment, Oulu
    Ari Rajasärkkä, Finnish Forest and Park Service, Metsähallitus
    Teemu Lehtiniemi, BirdLife Finland
    Juha Tiainen, Finnish Game and Fisheries Institute
    Jari Valkama, Finnish Museum of Natural History

    Clangula hyemalis (IUCN recommendation EN)
    The Finnish breeding population is small (1500-2000 pairs in northernmost Lapland) and poorly monitored. Despite the small reduction amount of occupied grids between the 1970s–1980s’ and the 2000s’ atlases (197 and 147 grids, respectively) the Finnish breeding population was classified as LC in 2010.
    However, migration numbers along the main migration flyway in the Gulf of Finland have dropped dramatically. Migration numbers from the Söderskär station were already published (Hario et al. 2009), and they show an initial increase from the 1970s till the early 1990s, and a rapid collapse in numbers after that.
    Migrant numbers in the eastern Gulf of Finland (Vyborg) dropped about 57 % during last two decades. Finnish ornithologists have annually monitored migration in Vyborg during spring migration in 1988–2008 (between 5 May and 1 June, altogether 2486 hours; Jari Kontiokorpi, unpublished). In 1988–1994 the density was 2051 individuals/observation hour (n = 762 hours), in 1995–1999 1308 ind./hour (n = 1061 hours), and in 2000–2008 888 ind./hour (n = 628 hours, total n = 3 500 000 birds).
    In the western Gulf of Finland, the Hanko Bird Observatory, migration numbers of both spring and autumn have been counted since 1979 using standardized observation methods (e.g. Vähätalo et al. 2004, Journal of Avian Biology). The mean densities during spring in Hanko in five years periods are showed below (main spring migration season 29.2.–20.5.)
    1979-1985 96 ind./observation day (n = 334 days)
    1986-1990 150 ind./obs. day (n = 162 days)
    1991-1995 190 ind./obs. day (n = 217 days)
    1996-2000 158 ind./obs. day (n = 357 days)
    2001-2005 46 ind./obs. day (n = 415 days)
    2006-2010 18 ind./obs. day (n = 416 days)
    The mean densities during autumn in Hanko in five years periods are showed below (main autumn migration season 29.9.–20.11.).

    1979-1985 804 ind./observation day (n = 284 days)
    1986-1990 700 ind./obs. day (n = 217 days)
    1991-1995 509 ind./obs. day (n = 245 days)
    1996-2000 580 ind./obs. day (n = 263 days)
    2001-2005 152 ind./obs. day (n = 265 days)
    2006-2010 431 ind./obs. day (n = 265 days)

    All three Finnish-Russian migration data sets from the Gulf of Finland support the recent rapid decline and recommended EN classification.
    Hario, M., Rintala, J. & Nordenswan, G. 2009: Dynamics of wintering long-tailed ducks in the Baltic Sea – the connection with lemming cycles, oil disasters, and hunting. Suomen Riista 55:83–96. (In Finnish with English summary).
    Vähätalo, A.V., Rainio, K., Lehikoinen, A., Lehikoinen, E. 2004: Spring arrival of birds depends on the North Atlantic Oscillation. J Avian Biol 35:210–216
    Valkama, J., Vepsäläinen, V. & Lehikoinen, A. 2011: The Third Finnish Breeding Bird Atlas. – Finnish Museum of Natural History and Ministry of Environment. http://atlas3.lintuatlas.fi/results/species/long-tailed%20duck

  11. Joe Taylor says:

    The following comments by Dr. Vitaly V. Bianki and Irina A. Kharitonova were forwarded on 30 January 2012:

    Study area: Kandalaksha State Nature Reserve, head of Kandalaksha Bay, the White Sea.

    Clangula hiemalis. Occasional visitor. No trend can be found.

  12. Tim Bowman says:

    Tim Bowman (Sea Duck Joint Venture Coordinator, U.S. Fish and Wildlife Service) has provided the following information:

    The North America population is roughly estimated at about one million birds. Indices of long-tailed duck abundance obtained during the North American Breeding Waterfowl Survey (mainly strata from Alaska and Yukon) indicate a steady long-term downward trend between the 1970s and early 1990s, and a stable population since. However, this species is especially poorly monitored because its breeding distribution is largely outside the area covered by breeding waterfowl surveys, and because of its offshore distribution during winter and the lack of comprehensive winter surveys. Regional surveys in Alaska (Larned et al. 2010) indicate stable populations over the most recent 10-15 years. No reliable long term, large scale, winter surveys of sea ducks have been conducted on either the Pacific or Atlantic coasts, that allow analysis of trends for wintering populations. However, large increases in long-tailed ducks have been documented at the lower Great Lakes during winter following the introduction of zebra mussels in the late 1980s (Petrie and Schummer 2002).
    Christmas Bird Count data for long-tailed ducks are probably unreliable because these species occur largely offshore where a large proportion may not be seen by shore-based observers, so those data should be viewed with caution.
    Because the North American population of long-tailed duck is widespread and abundant, and does not meet the criteria for Critically Endangered, Endangered, Vulnerable, or Near Threatened, we recommend this species be listed as Least Concern.

  13. Andy Symes says:

    The recent (6 Feb) posting by Tim Bowman provides important information about the status and trend of this species’ population in North America, and suggests that it has probably remained roughly stable there for the best part of two decades. This contradicts the information that was available when the forum topic was developed, and implies that assumptions of a c. 40% decline in the North American population are probably unjustified. It is therefore necessary to update the global trend calculations that were presented in the original topic and used as the basis for proposing uplisting to Endangered.

    The spreadsheet now added to the bottom of the original forum topic presents the results of two new calculations, based on the flyway population size maximum estimates presented in WPE4 (Wetlands International 2006). The first assumes that all populations (apart from that wintering in the Baltic) have remained stable. The second assumes that all populations (apart from that wintering in the Baltic) have increased by 20%. There is no evidence for any such increase in the North American, East Asian or Iceland/Greenland populations, so this serves only as an illustration for the purposes of this simple ‘sensitivity analysis’.

    These two calculations suggest an overall global decline of c. 41% and c. 35% respectively. On this basis, it seems clear that the global population of this species has declined by more than 30% over the last three generations, and that it should therefore be uplisted from Least Concern to Vulnerable on the 2012 IUCN Red List.

    Ian Burfield and Andy Symes

  14. Andy Symes says:

    Diana Solovyeva provided the following comment:

    Comment to up-listing of Long-tailed duck
    Our surveys in breeding grounds in Chaun delta, Chukotka, Russia, confirm high nest density in 6.25 nests per sq. km in 2011 (Solovyeva 2012, unpublished report). There was a decline from 10-11 nests/sq. km in 1974-76 to 3 nests/sq.km in 1984 and 1988 in Chaun delta (Kondratiev 1988). Continuation of nest density monitoring is planned in Chaun delta in 2012-15 and it is proposed for Kolyma delta for 2013-16. At the moment I couldn’t confirm decline of Long-tailed duck in Asian breeding grounds, and up-listing of the species to Endangered seems to be premature.

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