Archived 2020 topic: Junin Grebe (Podiceps taczanowskii): revise global status?

BirdLife species factsheet for Junin Grebe

Junin Grebe is endemic to Peru, where it is restricted to the Lake Junín in the wet-central highlands.  The species is found in open water near the centre of the lake, but keeps close to the margins of reed marshes in the breeding season (J. Fjeldså in litt. 2020). Junin Grebe used to be extremely abundant in the past, numbering over 1,000 individuals by the mid 20th century (Morrison 1939, O’Donnel and Fjeldsa 1997). Since then, the species has declined dramatically to about 200 individuals in 1995 (O’Donnell and Fjeldså 1997). The population has stabilised in recent years, when standardised population censuses counted between 217 and 304 individuals between 2001 and 2007, and between 238 and 468 individuals between 2014 and 2019 (A. Chamorro and R. Tito per Engblom 2016a, A. Chamorro per Engblom 2016b, Chamorro and Aucca 2017, Chamorro et al. 2018, Dinesen et al. 2019, A. Chamorro in litt. 2020).

The main threat to the species is the degradation of its habitat with deteriorating water quality due to pollution from mining activities and sewage (Valqui 1994, O’Donnell and Fjeldså 1997). Fluctuations in the water level to supply hydroelectric plants may cause nesting and feeding areas to dry out and breeding to fail (Valqui 1994). Furthermore, unstable climatic conditions linked to El Niño Southern Oscillation events may present a threat to the species (T. Valqui in litt. 1999), as does the increase in trout population in the lake, which may reduce food availability (A. Chamorro in litt. 2020).

Junin Grebe is currently listed as Critically Endangered under Criterion C2a(ii) (BirdLife International 2020). However, the recent stabilization of the population trend suggests that the species may warrant a change in Red List status. Therefore, it will be re-assessed against all criteria:

Criterion A – The species has undergone a dramatic population decline in the past. Recent counts however indicate that this decline is historical and that the species has been recovering since the early 2000s. While the species is thought to fluctuate in numbers and recruitment, no declines have been observed, and it appears that the species is overall stable. To account for high levels of uncertainty, we can however precautionarily suspect that the species is undergoing a slow decline over three generations (14.7 years; Bird et al. 2020)*, which does not approach the threshold for listing as threatened under Criterion A. Junin Grebe is hence listed as Least Concern under this criterion.

Criterion B – Both Extent of Occurrence (EOO) and maximum Area of Occupancy (AOO), calculated as a 4 km2 grid over the area of mapped range, are 140 km2. This meets the threshold for listing as Endangered under Criterion B1+2. However, in order to be listed as threatened under this criterion, a species needs to fulfil at least two further conditions.

The species is restricted to one lake and is therefore not severely fragmented sensu IUCN (IUCN Standards and Petitions Committee 2019). The most severe threats to the species are changes in water level, pollution. These threats can potentially impact a relatively large area and consequently a relatively large part of the population at once, with potentially drastic consequences on the population size within one generation length (4.9 years). The number of locations** of occurrence is therefore placed in the band 2-5, and condition a is met at the level of Endangered. Habitat quality is declining throughout the range, and hence condition b(iii) is met. The species does show some fluctuations in population size, however they do not involve tenfold increases or decreases, and hence are not considered ‘extreme fluctuations’ (see IUCN 2001, 2012), and condition c is not met. Junin Grebe consequently qualifies for listing as Endangered under Criterion B1ab(iii)+2ab(iii).

Criterion C – Based on population counts carried out between 2014 and 2019, the population is roughly estimated to number 150-320 mature individuals. This meets the threshold for listing as threatened under Criterion C, however to do so requires further conditions to be met.

All individuals belong to the same subpopulation. Precautionarily, the population is suspected to undergo a slow decline due to the degradation of its habitat. A suspected decline however precludes a listing as threatened under Criterion C. Junin Grebe is therefore considered Near Threatened, approaching the threshold for listing as threatened under Criterion C2a(ii).

Criterion D – The population is estimated to number 140-320 mature individuals. Assuming that the true population size is closer to the lower end of the estimate, Junin Grebe qualifies for listing as Endangered under Criterion D.

Criterion E – To the best of our knowledge no quantitative analysis of extinction risk has been conducted for this species. Therefore, it cannot be assessed against this criterion.

Therefore, it is suggested that Junin Grebe (Podiceps taczanowskii) be listed as Endangered under Criteria B1ab(iii)+2ab(iii); D. We welcome any comments on the proposed listing.

Please note that this topic is not designed to be a general discussion about the ecology of the species, rather a discussion of its Red List status. Therefore, please make sure your comments are relevant to the discussion outlined in the topic. By submitting a comment, you confirm that you agree to the Comment Policy.

*Bird generation lengths are estimated using the methodology of Bird et al. (2020), as applied to parameter values updated for use in each IUCN Red List for birds reassessment cycle. Values used for the current assessment are available on request. We encourage people to contact us with additional or improved values for the following parameters; adult survival (true survival accounting for dispersal derived from an apparently stable population); mean age at first breeding; and maximum longevity (i.e. the biological maximum, hence values from captive individuals are acceptable).

**The term ‘location’ refers to a distinct area in which a single threatening event can rapidly affect all individuals of the taxon present, with the size of the location depending on the area covered by the threatening event. Where a taxon is affected by more than one threatening event, location should be defined by considering the most serious plausible threat (IUCN 2001, 2012).

An information booklet on the Red List Categories and Criteria can be downloaded here and the Red List Criteria Summary Sheet can be downloaded here. Detailed guidance on IUCN Red List terms and definitions and the application of the Red List Categories and Criteria can be downloaded here.


Bird, J. P.; Martin, R.; Akçakaya, H. R.; Gilroy, J.; Burfield, I. J.; Garnett, S.; Symes, A.; Taylor, J.; Šekercioğlu, Ç.; Butchart, S. H. M. (2020). Generation lengths of the world’s birds and their implications for extinction risk. Conservation Biology online first view.

BirdLife International. 2020. Species factsheet: Podiceps taczanowskii. (Accessed 16 April 2020).

Chamorro, A.; Aucca, C. 2017. Final report strategic conservation plan for the Junin Grebe (Podiceps taczanowskii) at Lake Junin, Peru. ECOAN.

Chamorro, A.; Salcedo, D.; Guere, S.; Aucca, C.; Palacio, W. 2018. Evaluación poblacional del Podiceps taczanowskii y las aves acuáticas que ocurren en el lago Junín. Asociación Ecosistemas Andinos

Dinesen, L.; Chamorro, A.; Fjeldsa, J.; Aucca, C. 2019. Long-term declines in waterbirds abundance at Lake Juníi, Andean Peru. Bird Conservation International 29(1): 83-99.

Engblom, G. 2016. Nest success of Critically Threatened Junin Grebe. (Accessed 22 January 2018).

Engblom, G. 2016. The Junin Grebe may go extinct and we did not even notice. (Accessed 22 January 2018).

IUCN. 2001. IUCN Red List Categories and Criteria: Version 3.1. IUCN Species Survival Commission. IUCN, Gland, Switzerland and Cambridge, U.K.

IUCN. 2012. IUCN Red List Categories and Criteria: Version 3.1. Second edition. IUCN Species Survival Commission. IUCN, Gland, Switzerland and Cambridge, U.K.

IUCN Standards and Petitions Committee. 2019. Guidelines for using the IUCN Red List Categories and Criteria. Version 14.

Morrison, A. 1939. Notes on the birds of Lake Junín, Central Peru. Ibis: 643-653.

O’Donnell, C.; Fjeldsa, J. 1997. Grebes: A global action plan for their conservation.

Valqui, T. 1994. The extinction of the Junín Flightless Grebe? Cotinga: 42-44.

This entry was posted in Americas, Archive, South America and tagged , . Bookmark the permalink.

8 Responses to Archived 2020 topic: Junin Grebe (Podiceps taczanowskii): revise global status?

  1. JUNIN GREBE. Podiceps taczanowskii
    To have an efficient team for our projects ECOAN invest a lot in our areas, on the beginning we prepare our monitoring team with better equipment, training for many years with lots of exchanging experiences, a solid work with local stake holders such RNJ- SERNANP, and at the same time implementing Conservation Strategies with local communities, at the moment we are sure that we have a serious research and conservation team.
    The data obtained by ECOAN’s team and technical team from the National Service of Protected Natural Areas (SERNANP) of the Junín National Reserve (RNJ), was a serious and honest monitoring where was reported the total population seen after of all the conservation activities done by ECOAN, SERNANP, ABC and BirdLife International to provide a better quality of water that goes to the lake, after many years this produce a high production of fishes (Orestias) and this of course helps a lot to increase the population with new individuals; but this information we recommended to take with care because as we saw a fast recovery, this could descent drastically mainly due to unknown natural variability. The different changes in the local natural scene due to the permanent threats and pressures (Walsh Perú SA 2002, Chamorro & Aucca 2017, Chamorro & Aucca 2019) and their consequences on species such as those from the Rallidae and Anatidae family (Dinesen et al 2017, Dinesen et al 2018, Chamorro et al 2018), and other taxa such as amphibians of the genus Telmatobius, show us an adverse reality for all fauna. On the last two years appeared another threat that is killing not only Silvered Greebe and other water species produced by local fishers who are spending nets to capture trouts, those reports appears at the media twice in a year.
    Criterion A:
    Been me Constantino Aucca a Guardian Species for the Junin Grebe, my petition is to use with care the Criterion A about the Critical Endangered species, because our experience doing conservation of threatened species for more than 20 years is: the populations responds surprisingly on ground after some special conditions that will not going to be the same all the time. The changes at the population of this specie since 2007 when we started to work on this area, were so unstable.
    We had this same problem before with Royal Cinclodes, White bellied Cinclodes and others.
    Criterion B:
    The main discrepancy lies in the extent of occurrence (EOO) and the area of occupation (AOO); The total Census carried out by ECOAN and SERNANP throughout Lake Junín, using 1 km2 grids, show that the Junín diver population has an EOO of 80 – 95 km2 and an AOO of 25 – 48 km2 of a total of 148 km2 mirror of the lake, plus 33 km2 of lake associated with a large number of reed islands (occurrence extension less than 100 km2); This preference, focused on some parts of the lake, has been described by Fjeldsa (1981) and Walsh PERU S.A. (2001), the reduction of the area has been evidenced in the different census carried out in 2016, 2017, 2018 and 2019 (Chamorro in litt 2020), the main responsibility being contamination (by heavy metals and organic matter) and the artificial management of the Agua del Lago (Walsh Perú SA 2002, Dinesen et al 2017, Dinesen et al 2018, Chamorro et al 2018, Chamorro & Aucca 2019). Criterion c does not apply since no extreme fluctuations have been observed.
    As described, criterion B1ab (i) + (iii) of Critically Endangered (CR) will be met.
    Criterion C:
    We agree, there is a lack of information to argue that the population is decreasing, but as explained in criterion A, from a precautionary position and by the information provided in criterion B, the present and / or future panorama of the population decrease is the most likely scenario. In this sense, criterion C2aii would be met. We don’t have a strong position from the government to stop and manage the mining tailings that enter to the lake annually, plus no funds to run a sustainable conservation program for those threatened species.
    Criterion D:
    Criterion E:
    That is correct, perhaps they could help us in providing tools for the assessment of the risk of extinction.
    Therefore, I recommend that the Junín Diver remain Critically Endangered according to criteria B1ab (i) + (iii)

  2. Fernando Angulo says:

    I have been researching on this sentence ” Junin Grebe used to be extremely abundant in the past, numbering over 1,000 individuals by the mid 20th century (Morrison 1939, O’Donnel and Fjeldsa 1997)”. Morrison (1939) says “Extremely abundant on the lake, though rarely seen close to the shore.”. From Morrison notes, seems like he hasn’t been into the lake itself but only on the shores. The same adjective (abundant) has been used in the same paper for Vanellus resplendens (very abundant), Calidris bairdii (most abundant), Lessonia oreas (abundant) and Fulica ardesiaca. Later, O’Donnell & Fjeldsa (1997) say “There were probably well over 1000 Junin flightless grebes in 1961 (F. Gill, R:W: Storer pers. comm.)”.

    I believe that the fact that Junin grebe “used to be extremely abundant in the past”, is not totally reliable and, in this context, to state that “the species has undergone a dramatic population decline in the past” has to reviewed or reconsidered.

  3. alan freddy chamorro cuestas says:

    The Podiceps taczanowskii censuses at Junin lake, show a reduction of the Extent of Occurrence (EOO) and Area of Occupancy (AOO). The results obtained from the last four years describe the EOO between the values of 85 to 38 Km2 against the 108 to 107 Km2 from 2012 and 2007 respectively. The Potential area of distribution of the Junin grebe is 181 Km2, but different studies accomplished by ECOAN since 2008 to 2019, show that grebe uses less than 50% from the area, because of the preference and habitat quality.
    Further more, there are new elements in the ecosystem which impact in the Grebe population or in its hábitat is unknown. One example is the use of nets to fishing trout (invasive specie) that accidentaly catches birds, causing on them drowning death. There are records of birds death as: Silvery grebe, andean coot and diverse ducks, but its unknown if it is causing Junin grebe death.
    Diverse papers and documents mentioned by Contantino Aucca, show a deteriory in the ecosystem quality that is afecting birds and amphibians, because of that we suggest to take the population apparent stabilityof the Junin grebe with caution.
    Therefore, we suggest that the Junin grebe stay in Critical Endangered, below the B1ab(i) + (iii) standard as Constantino Aucca suggests, due to a EOO less than 100 Km2, it happens in one location and with a continuous decrease of EOO and habitat quality.

  4. Red List Team (BirdLife International) says:

    Many thanks to everyone who has contributed to this discussion. We greatly appreciate the time and effort invested by so many people in commenting. The window for consultation is now closed. We will analyse and interpret the new information and post a preliminary decision on this species’s Red List status on this page in early July.

    Thank you once again,
    BirdLife Red List Team

  5. Red List Team (BirdLife International) says:

    Preliminary proposal

    In informing the following decision, it is important to first consider the methodology behind an Extent of Occurrence (EOO). The IUCN Standards and Petitions Committee (2019) defines EOO as the measure of the spatial spread of areas occupied by a species, not the actual area it occupies. Thus, it is assumed that the spatial spread of the species, as measured by a Minimum Convex Polygon (MCP), is likely to be greater than 100 sqkm. Whilst 50% of the area may be used due to preference and habitat quality (A. F. C. Cuestas in litt. 2020), a viable Area of Occupancy (AOO; defined as the area of suitable habitat currently occupied by the taxon) is also unlikely to fall below the required threshold of 10 sqkm. Thus, it is untenable to list the species under a Critically Endangered status in this instance.

    Based on available information and consensus of ongoing threats therefore, our preliminary proposal for the 2020 Red List would be to adopt the proposed classifications outlined in the initial forum discussion and list the Junin Grebe as Endangered under Criterion B1ab(iii)+2ab(iii); D.

    There is now a period for further comments until the final deadline in mid-July, after which the recommended categorisations will be put forward to IUCN.

    Please note that we will then only post final recommended categorisations on forum discussions where these differ from the initial proposal.

    The final 2020 Red List categories will be published on the BirdLife and IUCN websites in December 2020/January 2021 (information on the IUCN Red List update process can be found here), following further checking of information relevant to the assessments by both BirdLife and IUCN.

  6. Fernando Angulo says:

    on BCI. I have trying to find the literature cited in the comments (well, the mentions, since there is no compelte cites) but failed. I was only capable to locate Dinesen et al. 2019, published on BCI. There, the number given is 335-468.

    On Dinesen et al. (2019) (sic, page 93):
    50–304 birds was estimated between 1985 and 2007 (ECOAN 2010)
    304 in 2001 (ECOAN 2010)
    249 in 2002 (ECOAN 2010)
    217 in 2007 (ECOAN 2010)
    between 11 and 335 counted and 232 to 335 estimated between 2007 and 2013 (Chamorro and Aucca 2015).
    a total of 468 individuals in October 2016 (Chamorro and Aucca 2017)

    What I see here are stable numbers and even an increase by 2016 (335-468).

    I am happy to see that the species is recovering!

  7. I appreciate the effort of the total count, but I really feel there are too many variables in order to compare one year to the other. The effort varies, the conditions vary, etc, the experience of the observers, shaky boats, skittish birds that does not allow for getting close enough for certain ID, and the similarity of Junin Grebe and Silvery Grebe. Adults are usually not a great problem ID:ing, but young birds of Junin Grebe can be tricky.

    The main thing that the total censuses are telling us, is that the bird is still there, but it shall be very complicated to read any trends into this.

    To catch any population trends there needs to be a continuous survey of reproductive success. We have daily population data of counts from two points at the reed edge carried out by Cesar Zevallos that needs analyzing. I think it is vital that these point counts continue.

    As Alan Chamorro points out, the trout fishing is a completely new threat, which has not been taken into account on previous assessments. The danger of fishing with fine nylon gill nets is well documented, and the main reason of the temporary demise of Titicaca Grebe around the year 2000. There is less fishing with gill nets in the Titicaca Lake today, because of the many trout farms within the lake (not a good thing, but stopped the threat) that simply don’t allow any fishermen close to their trout pools. Hence, the grebes can fish in the vicinity without danger.

    With the present COVID outbreak and the strained economy, the fishing for trout with gill nets in the lake have increased.

    Furthermore, the trout will compete for the Orestias fish that the Titicaca grebes eat and are a threat to the young.

    Cesar Zevallos in personal communication with me tells me that they have caught very large trout in the lake. The trout was not there say 5 years ago or so, and there was no fishing activity with nets in the lake. I repeat, this is a completely new threat, and it needs to be addressed urgently.

  8. Red List Team (BirdLife International) says:

    Recommended categorisation to be put forward to IUCN

    Following further review, the recommended categorisation for this species has changed. Junin Grebe is recommended to be listed as Endangered under Criteria B1ab(i,ii,iii)+2ab(i,ii,iii); D.

    Many thanks for everyone who contributed to the 2020 GTB Forum process. The final 2020 Red List categories will be published on the BirdLife and IUCN websites in December 2020/January 2021, following further checking of information relevant to the assessments by both BirdLife and IUCN.

Comments are closed.