Justification of Red List Category
This species qualifies as Critically Endangered as it has undergone significant population declines, such that an extremely small number of adults remain. Counts over recent years do not indicate an overall decline, but the trend is precautionarily retained as declining due to the high level of uncertainty. If population counts continue to show that the population is remaining stable or increasing, the species may be downlisted to a lower category of threat in the future.
Different survey methods and identification challenges have made population estimates difficult. However, surveys between 2007 and 2016 indicate a population of between 217 and 468 individuals (ECOAN 2009, Engblom 2016a, b, Chamorro and Aucca 2017, Dinesen et al. 2019), roughly equating to 145 - 312 mature individuals, rounded here to 140 - 320 mature individuals.
Trends for this species are unclear due to difficulties in carrying out reliable surveys and an apparently fluctuating population size. Counts over recent years do not indicate an overall decline, but the trend is precautionarily retained as declining due to the high level of uncertainty.
Podiceps taczanowskii is a flightless waterbird confined to Lake Junín in the highlands of Junín, west-central Peru. It was extremely abundant in 1938 (Morrison 1939), and the population was probably well over 1,000 birds in 1961 (O’Donnel and Fjeldsa 1997), but has undergone a severe decline since then (Dinesen et al. 2019). In the early and mid-1980s there were c. 250 birds, but only 100 were counted in 1992, falling to around 50 in 1993 (Valqui 1994). New extrapolations in early 1995, using a different methodology, estimated 205 individuals (O'Donnell and Fjeldså 1997). In August 1998, over 250 Podiceps sp. were found in 4 km2 of the lake (suggesting a total of 350-400 birds) and all those identified (over 20) were P. taczanowskii (T. Valqui in litt. 1999). Counts in 2001, 2002 and 2007 using standardised survey methods estimated the population at 304, 249 and 217 individuals respectively (ECOAN 2009). Censuses in August 2014 and 2015 counted 315 and 238 birds, respectively (A. Chamorro and R. Tito per Engblom 2016a, A. Chamorro per Engblom 2016b). In 2016, the population size was estimated at 468 individuals (Chamorro and Aucca 2017, Dinesen et al. 2019).
Lake Junín is fairly shallow and bordered by extensive reed marshes at 4,080 m. The grebe forages in open water, near the shore in the (wet) breeding season (November-March), and in the centre of the lake in the dry austral winter. It feeds mainly on small Orestias fish (which become scarce when the reedbeds dry out [O'Donnell and Fjeldså 1997]), and invertebrate larvae and adults. Nests are built in flooded reedbeds; clutch size is two eggs (O'Donnell and Fjeldså 1997). It is probably long-lived, and invests little in recruitment per season (O'Donnell and Fjeldså 1997).
Declines followed a deterioration in water quality owing to mining activities, and extreme water-level fluctuations (Valqui 1994). Water-level regulation for a hydroelectric plant supplying nearby mines causes nesting and foraging areas to dry out, and breeding to fail. Mining activities also pollute the lake, with the north-western part rendered lifeless by iron-oxide sedimentation (O'Donnell and Fjeldså 1997, ECOAN 2009). The lake is also polluted by sewage from nearby towns, which causes eutrophication and oxygen depletion and may lead to a reduction in the amount of fish available for the grebe to feed on (Dinesen et al. 2019). Relatively unstable climatic conditions, linked to El Niño Southern Oscillation events, may have contributed to large population fluctuations, with a recovery in years with high water levels (e.g. 1997-1998) (T. Valqui in litt. 1999), and previous poor breeding successes. Although the population has shown major fluctuations, its ability to recover were it to experience a series of poor years is in doubt. Many individuals died during extreme cold conditions in 1982; similar conditions in June 2007 gave cause for concern (G. Engblom in litt. 2007).
Conservation Actions Underway
Lake Junín has been declared a national reserve. Hunting and fishing are regulated but little has been done to interfere with the management of the water level, which is controlled by mining companies (O'Donnell and Fjeldså 1997). An attempt was made to translocate grebes to a lake north of Junín; capture and transfer were feasible, but the chosen lake (and others) was unsuitable because gill-nets are used to fish rainbow trout (O'Donnell and Fjeldså 1997). In 2002, the Peruvian government passed an emergency law to protect the lake which makes provisions for its cleaning and places greater restrictions on the extraction of water (Valqui 1994). In 2009 the species was adopted as a symbol of wetland conservation in the high Andes by groups including BirdLife International, American Bird Conservancy, ECOAN and INRENA, who have called for an independent environmental audit and continuous environmental monitoring of the lake (BirdLife International 2009). ECOAN has been undertaking conservation actions including a range of education and training activities with local communities, and research and monitoring of the species's population size and threats (ECOAN 2016).
Conservation Actions Proposed
Monitor the population and reproductive success (O'Donnell and Fjeldså 1997, T. Valqui in litt. 1999, Anon. 2007). Research the species's requirements throughout its life-cycle (O'Donnell and Fjeldså 1997). Protect clean watercourses flowing into Lake Junin and improve legislation and enforcement to prevent pollution (Dinesen et al. 2019). Identify and reduce sources of pollution in dialogue with local stakeholders (Dinesen et al. 2019). Reduce fluctuations in water-levels as a result of discharges from the hydropower dam (O'Donnell and Fjeldså 1997, Dinesen et al. 2019) with the agreement and participation of the local mining company (Anon. 2007). Identify a lake for potential translocation of individuals (O'Donnell and Fjeldså 1997) and consider establishing a captive-breeding population. Develop ecotourism in the area including building a lookout platform for the lake to aid population monitoring (Hirschfeld 2008).
35 cm. Slim, long-necked grebe with pointed-head appearance. Grey frontal area and auricular. Blackish hind crown, continuing down upperside of neck. Completely dark upperparts. White throat to crissum, mottled dusky on sides of breast and belly. Slender, mostly grey bill. Red iris and buffy tarsus. Immature is greyer on flanks. Similar spp. Race juninensis of Silvery Grebe P. occipitalis is smaller, shorter necked, and has shorter, mostly blackish bill. Voice Melodic whistles dooi'th and wit reported.
Text account compilers
Pilgrim, J., Bird, J., Sharpe, C.J., Symes, A., Wheatley, H., Benstead, P., Calvert, R., Clay, R.P., Ashpole, J
Angulo Pratolongo, F., Engblom, G., Fjeldså, J., Hennessey, A.B. & Valqui, T.
BirdLife International (2020) Species factsheet: Podiceps taczanowskii. Downloaded from http://www.birdlife.org on 23/01/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 23/01/2020.