Archived 2010-2011 topics: Flightless Cormorant (Phalacrocorax harrisi): downlist to Vulnerable?

Link to BirdLife species factsheet for Flightless Cormorant

Flightless Cormorant Phalacrocorax harrisi is endemic to Fernandina and Isabela in the Galápagos Islands, Ecuador, and is currently classified as Endangered under criteria B1a+c(iv) and B2a+c(iv) because it has a very small breeding range and a population which has been estimated to have undergone severe fluctuations in the number of mature individuals.

However, according to IUCN guidelines “for the ‘extreme fluctuations’ subcriterion to be invoked, populations would normally need to fluctuate by at least 10-fold (i.e., an order of magnitude difference between population minima and maxima)” – although this species has undoubtedly undergone significant population fluctuations there appears to be no evidence that they meet the IUCN definition of extreme fluctuations. In addition, recent data suggests the population of this species may be stabilising at a new high (Jiménez-Uzcátegui et al. 2006).

It is therefore proposed to reclassify the Flightless Cormorant as Vulnerable under criterion D2, because it has a very restricted area of occupancy and occurs at only two locations such that it is prone to the effects of human activities (such as oil spills) or stochastic events within a very short time period in an uncertain future, and is thus capable of becoming Critically Endangered or even Extinct in a very short time period. Comments on this proposal and any up to date information on population trends and current threats to this species are welcomed.

Jiménez-Uzcátegui, G., Hernán Vargas, F., Larrea, C., Milstead, B. and Llerena, W. (2006) Galapagos Penguin and Flightless Cormorant survey. Report for the Charles Darwin Foundation, The Galapagos National Park and the Seaworld & Busch Gardens Conservation Fund.

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4 Responses to Archived 2010-2011 topics: Flightless Cormorant (Phalacrocorax harrisi): downlist to Vulnerable?

  1. Juan Freile says:

    Not sure. We all know it has a tiny global population and geographic distribution, along with very limited habitat preferences, introduced (or potentially introduced) predators, parasites or diseases, and the potential effects of unpredictable climatic phenomena (ENSO, global climate change). It might ‘easily’ vanish if some of these factors match up, even under the total-protection scenario it currently faces. No protected area will prevent eventual catastrophic effects of climate change for a species completely confined to a extremely narrow ‘altitudinal belt’ (a few cm above sea level!!).
    Even though my experience with Galapagos birds is very limited, I strongly suggest to keep current category for this endemic.

  2. Gustavo Jimenez-Uzcategui says:

    It’s true that the Cormorant population census in 2006 had a high number and the 2007 was the highest from 1977. However, in the next years until 2009 the number of the population fluctuates (down and up). The problem with this data, show the annual tendency (one time per year). Then, in 2010 I changed the methodology (I can compare the old with the new data); however the study is to long term. Meantime, I could say that the number of the population in 2010 was the third highest number record. However, we need to know the problems of this population: 1. principally is the climate change, like says Vargas 2006 and how the census data show that the population down drastically when the ENSO (El Niño) is present. The problem is the El Niño’s frequency and if the cormorant has the time to recover. 2. The number of the population, could be the highest, but the adults populations is less that 2500 according the IUCN-C-criteria. 3. The small colonies (space where the cormorants have a nest) that we recorded on past years, we didn’t find in 2009-2010, but in older and bigger colonies we found more individuals; this, could affect them faster, specially with the introduce species or infectious agents. 4. The artesanal fisheries and tourism, like says Larrea 2007, could affect the species, because these groups share the same space. For this reasons the species have to continue classified as Endangered.

    Jiménez-Uzcátegui, G. 2010. Monitoreo del pingüino de Galápagos y cormorán no volador 2010. Informe para la Fundación Charles Darwin y Parque Nacional Galápagos. Puerto Ayora, Ecuador, 18 pp.
    Larrea, C. 2007. Movimiento, dispersion y exito reproductivo del cormorant no volador Phalacrocorax harrisi en las islas Galapagos. Tesis sometida para la obtencion del titulo de Licenciatura en Ciencias Biologicas. Universidad Catolica del Ecuador.
    Vargas, F. H. 2006. The ecology of small populations of birds in changing climate. A thesis submitted for the degree of Doctor of Philosophy. Lady Margaret Hall, University of Oxoford.

  3. Although the Flightless Cormorant population has done very well in recent years, the population is still quite small, and the species’s range is VERY small, even less than it appears because of the narrowness of its habitat and the very small number of possible breeding sites. It also faces very significant threats, that could quickly wipe out the species. These are not all man-made: a single large eruption of the volcanoes on Fernandina or Isabela could wipe out most of the population. This is not a hypothetical: it apparently almost occurred in February 1825 ( The Flightless Cormorant population may have taken most of the rest of the 19th Century to recover.
    In addition, of course, the population faces man-made threats from introduced rats, cats, and dogs on Isabela, fishing, and significantly from global warming. Increased intensity of ENSO events could quickly wipe out the small population.
    Because of the small population size and very restricted range, this species should not de downlisted to VU.

  4. Andy Symes says:

    The Red List criterion of Vulnerable D2 is designed to capture the threat risk to those species with a currently stable population within a very restricted range where there are plausible future threats that could drive the species to CR or even EX in a short space of time (see p58 of the Red List Guidelines

    This seems to fit perfectly with the situation as currently known for this species, which cannot continue to qualify as EN under B1a+c(iv) and B2a+c(iv) as there is no evidence for extreme (i.e. order of magnitude) fluctuations in the population.

    We do however appreciate the concerns around this species, the status of which is undoubtedly of high concern, and which should remain a conservation priority. Is there any evidence for a continuing decline in the area, extent and/or quality of the habitat of this species?

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