Archived 2012-2013 topics: Macaroni Penguin (Eudyptes chrysolophus): correctly listed as Vulnerable?

This discussion was first published as part of the 2012 Red List update, but remains open for comment to enable reassessment in 2013. BirdLife species factsheet for Macaroni Penguin Macaroni Penguin Eudyptes chrysolophus breeds in at least 216 colonies at 50 sites in the higher latitudes of the southern hemisphere (Woehler 1993, Woehler and Croxall 1999). The total population is estimated by BirdLife to be c.9 million pairs, although it is argued that this is likely to be an underestimate because of potential underestimates in the South Georgia Island region (USFWS 2008). The species is listed as Vulnerable under criteria A2b,c; A3b,c; A4b,c, on the basis that the global population appears to have declined rapidly, by 30-49% over the preceding three generations, estimated to be c.34 years, and it is projected to decline by 30-49% over the next three generations. As noted in the assessment, however, the current classification is heavily reliant on the extrapolation of small-scale data, thus large-scale surveys are needed to confirm this categorisation. The current trend estimate is based on recorded local declines. Populations on South Georgia and Bouvet Islands probably increased substantially in the 1960s and 1970s, but have subsequently decreased. Study populations on South Georgia declined by 65% from 1986 to 1998 (J. P. Croxall unpublished data), and the overall South Georgia population probably halved between c.1978 and 1998 (Trathan et al. 1998). Study populations on Marion Island decreased by 50% between 1979 and 1998. In contrast, populations on Kerguelen increased by c.1% per year between 1962 and 1985, and subsequent data from 1998 indicated that the colonies were stable or increasing (H. Weimerskirch per T. Micol in litt. 1999). Populations in South America may be stable, but data are scant. The validity of the current assessment for this species has been brought into question by a review by the US Fish and Wildlife Service (USFWS 2008). Criticism was levelled at the use of trends at small study colonies to estimate the overall trend for the Prince Edward Islands. Likewise, the conclusion that overall numbers on South Georgia declined by 50% in the last two decades of the 20th century was criticised because it has not been empirically verified in the literature. Although the species is thought to have undergone a recent decline on Bouvet Island, there are apparently no current estimates for the population there. Significant recorded declines in colonies on Marion Island have also been questioned due to changes in survey methodology, and an overall decline of 18% in the island’s estimated total population between 1994-1995 and 2002-2003 is not considered significant by the USFWS (2008) in the context of small fluctuations in the three subsequent three breeding seasons. It has also been asserted that the decline noted on Prince Edward Island between 1976-1977 and 2001-2002, in which the estimated population fell from c.17,000 pairs to c.9,000 pairs (Crawford et al. 2003) was overestimated, and that the overall decline on Marion and Prince Edward Islands combined (c.3.4% of the species’s global population) was 32% between 1979 and 2003 (USFWS 2008). These criticisms, combined with suggestions that some populations are stable or increasing, or have unknown trends, suggest that the overall estimated rate of decline should be reduced for this species. Comments on the current listing and further information on the species are requested. References: Crawford, R. J. M., Cooper, J., Dyer, B. M., Greyling, M., Klages, N. T. W., Ryan, P. G., Petersen, S., Underhill, L. G., Upfold, L., Wilkinson, W., de Villiers, M., du Plessis, S., du Toit, M., Leshoro, T. M. et al. (2003) Populations of surface nesting seabirds at Marion Island, 1994/95-2002/03. Afr. J. Mar. Sci. 25: 427-440. Trathan, P. N., Croxall, J. P., Murphy, E. J. and Everson, I. (1998) Use of at-sea distribution data to derive potential foraging ranges of macaroni penguins during the breeding season. Mar. Ecol. Prog. Ser. 169: 263-275. USFWS (2008) Endangered and Threatened Wildlife and Plants; 12-Month Finding on a Petition To List Four Penguin Species as Threatened or Endangered Under the Endangered Species Act and Proposed Rule To List the Southern Rockhopper Penguin in the Campbell Plateau Portion of Its Range. Federal Register, Vol. 73: No. 244. Woehler, E. J. (1993) The distribution and abundance of Antarctic and Subantarctic penguins. Cambridge, U.K.: Scientific Commission on Antarctic Research. Woehler, E. J. and Croxall, J. P. (1999) The status and trends of Antarctic and subantarctic seabirds. Mar. Ornithol. 25: 43-66. Regional Red List assessment for Eudyptes chrysolophus in South Africa: Eudyptes chrysolophus – South Africa RL – Dyer and Crawford

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2 Responses to Archived 2012-2013 topics: Macaroni Penguin (Eudyptes chrysolophus): correctly listed as Vulnerable?

  1. RJM Crawford says:

    Thank you for copying me into the discussion.

    Trends in Macaroni Penguins at South Africa’s Marion Island were updated in 2009 by Crawford, R.J.M., Whittington, P.A., Upfold, L., Ryan, P.G., Petersen, S.L., Dyer, B.M., Cooper, J. 2009. Recent trends in four species of penguin at the Prince Edward Islands. African Journal of Marine Science 31: 419–426. Please advise if you wish to have a reprint of this paper.

    Between 1994/1995 and 2008/2009, numbers of macaroni penguins at South Africa’s Marion Island decreased by about 30% from some 430 000 pairs to about 290 000 pairs. Most birds (ca. 80%) breed in two large colonies (Bullard, Kildalkey), where after 1994/95 there have been decreases in numbers of birds breeding and decreases in the densities of nests. At each of these two colonies large decreases in numbers breeding followed outbreaks of disease (Cooper, J., Crawford, R.J.M., de Villiers, M.S., Dyer, B.M., Hofmeyr, G.J.G., Jonker, A. 2009. Disease outbreaks among penguins at sub-Antarctic Marion Island: a conservation concern. Marine Ornithology 37: 193–196). Between 1994/1995 and 2008/2009, there was also a large decrease (ca. 50%) in numbers counted at the smaller colonies at Marion Island. Between 2001/02 and 2008/09 there was a probable small decrease in numbers of macaroni penguins breeding at Prince Edward Island, the smaller of the two islands in the Prince Edward Island group of islands (Crawford et al. 2009).

    It is incorrect that at Marion Island the observed decreases were based only on counts/estimates at small colonies. In each breeding season from 1994/95 onwards, estimates of the whole island population have been obtained in a consistent manner. These estimates are available in the Crawford et al. 2003 and 2009 papers.

    It is correct that the Crawford et al. 2003 paper additionally reported counts at three of the smaller colonies at Marion Island that dated back to the 1979/80 breeding season and that indicated a substantial decrease at those colonies from 1979/80 to 2002/03. The same paper indicated that the Bullard and Kildalkey colonies were more or less stable from 1983/84 to 1994/95 and then decreased.

  2. Joe Taylor says:

    A regional Red List assessment for the species in South Africa has been shared by Rob Crawford, Bruce Dyer and Martin Taylor. A PDF of the assessment can be viewed and downloaded via the link below the forum topic. Extracts are posted here:

    Justification
    Conservation status was assessed from the rate of decrease in estimates of numbers of Macaroni Penguins Eudyptes chrysolophus breeding at Marion Island against the IUCN criterion A2, because the decrease may not have ceased, the causes of decrease are not fully understood and they may not be reversible (Birdlife International 2000). The metric used was the percentage decline in three generations or 10 years (whichever is greater). The average generation for Macaroni Penguins is 11.4 years (M Taylor, BirdLife South Africa, in litt.). The estimates of numbers of Macaroni Penguins breeding at Marion Island decreased by 41% between 1976/77 and 2012/13 (see below), equivalent to a decrease of 38% in three generations, which merits a classification of Vulnerable. The modelled decrease in numbers breeding between 1994/95 and 2012/13 was 33% in 18 years (see below), which is equivalent to 63% in three generations. This suggests that the rate of decrease increased since the mid 1990s to a level that would justify a rating of Endangered. However, the decrease since the mid 1970s, a period equivalent to about three generations, has been used to assign the Red List status.

    Reasons for inclusion in the assessment
    The species was listed as Near Threatened in the 2000 regional Red List assessment (Barnes 2000), and is regarded as globally Vulnerable (BirdLife 2013).

    Population justification
    In 2012/13, it was estimated that 266 971 pairs of Macaroni Penguins bred at Marion Island compared to 433 723 pairs in 1994/95 (Crawford et al. 2003, 2009, Department of Environmental Affairs, unpublished information). The decrease was best fitted by a linear regression, which suggested that the population in 2012/13 was 278 000 pairs (see below). An estimated 12 000 pairs bred at Prince Edward Island in 2008/09 (Crawford et al. 2009). Therefore, the overall population at the Prince Edward Islands is of the order of 279 000–290 000 pairs.

    Trend justification
    From counts of small colonies and at two large colonies (Bullard Beach and Kildalkey Bay) measurements of areas occupied and densities of nests, or in 1974–1977 counts of birds moulting made on aerial photographs, it was estimated that there were 449 892 pairs of Macaroni Penguins at Marion Island in 1974–1977 (Siegfried et al. 1978), 405 084 pairs in the 1983/84 breeding season (Watkins 1987) and 433 723 pairs in 1994/95 (Crawford et al. 2003). It was then estimated that by 2008/09 numbers breeding had decreased by 32% (Crawford et al. 2009). By 2008/09, there were significant decreases in numbers breeding at the small colonies and at both of the large colonies, where densities of nests also decreased significantly (Crawford et al. 2009). In 2012/13, 266 971 pairs bred at Marion Island (see above). Therefore, between 1976/77 and 2012/13, a period of 36 years, estimates of the numbers breeding decreased by 41%. Numbers breeding at Marion Island were available for each season between 1994/95 and 2012/13 (Crawford et al. 2003, 2009, Department of Environmental Affairs, unpublished information). In this period, the overall decrease was best modelled by linear regression (n = 19, r = 0.861, p < 0.001), which estimated the population in 1994/95 to be 416 000 pairs and that in 2012/13 to be 278 000 pairs, a decrease of 33% in 19 years.

    Threats
    Inadequate breeding success has been a factor in the decrease of Macaroni Penguins at Marion Island (Crawford et al. 2003). Overwintering conditions are thought to influence the proportions of Macaroni Penguins skipping breeding and breeding success; feeding conditions during breeding also may influence breeding success (Crawford et al. 2006). Global change may have altered the availability of prey to Macaroni Penguins (Crawford et al. 2003). In winter, Macaroni Penguins from Marion Island forage mostly to the south of the island, sometimes approaching the edge of the sea ice (J-B Thiebot et al., unpublished information). No fisheries target the main prey of Macaroni Penguins at the Prince Edward Islands, but should they be introduced they could decrease prey availability (BirdLife International 2013). Long-line fisheries at winter feeding grounds have inflicted limited incidental mortality on Macaroni Penguins (BMD, unpublished information). Recoveries of fur seals Arctocephalus spp. at the Prince Edward Islands (Hofmeyr et al. 2006, Bester et al. 2009) could increase competition for prey and lead to increased predation of penguins by seals. Increasing seal herds also could block access to breeding sites thereby inhibiting colony growth, as happened at Bouvet Island (Isaksen et al. 1997). Giant petrels Macronectes spp. and Subantarctic Skuas Catharacta antarctica and Lesser Sheathbills Chionis minor also inflict mortality (BMD, pers. obs.). In 1992, 1993 and 2004 disease, including avian cholera Pasteurella multocida, killed substantial numbers of Macaroni Penguins at Marion Island (Cooper et al. 2009). Oil spills could kill large numbers of Macaroni Penguins.

    Further web sources: http://www.birdlife.org/datazone/species and http://www.adu.org.za.
    Assessor: Bruce Dyer and Robert Crawford
    Reviewers: Peter Ryan, Martin Taylor and Ross Wanless

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