Justification of Red List Category
This species qualifies as Endangered as it occupies a small range that is restricted to Lake Junín, with a small number of individuals remaining. Counts over recent years indicate some fluctuations in numbers and recruitment but no overall decline and thus assumes stability, albeit there is a high level of uncertainty. The population is therefore thought to be undergoing a slower, suspected decline precautionarily. Potential new threats due to invasive species and fishing activities may however cause further, more significant reductions. If the population continues to show that it is remaining stable or increasing however, the species may warrant further change in status in the future.
Different survey methods and identification challenges (such as similarities between Junin and Silvery Grebes; G. Engblom in litt. 2020) 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, Chamorro and Aucca 2018, Chamorro et al. 2018, Dinesen et al. 2019). The latest censuses estimates the population at 373 individuals (Chamorro et al. 2018), with 294 and 359 individuals in 2018 and 2019 respectively (A. Chamorro in litt. 2019). Combined censuses from 2010 to 2018 indicated that the population thus generally fluctuated between 300-400 individuals (Chamorro and Aucca 2019). However, due to high levels of uncertainty, assuming that the population may well go below 300 individuals in certain years, tentatively using a population size of 217-468 individuals, the population is thought to number 145-312 mature individuals, placed in the band of 140-320 mature individuals.
The population had undergone rapid declines of c. 80% in the past, leaving around 50 birds by 1993 (Chamorro and Aucca 2019). Trends for this species are unclear due to difficulties in carrying out reliable surveys. It is however now considered that the population had remained stable from the 1970's, through to the 1990's at c. 250-300 individuals (Chamorro and Aucca 2019). It is therefore likely that the species recovered in the early 2000's, and whilst the population has seen subsequent fluctuations (at c. 300-400 individuals between 2010 and 2018; Chamorro and Aucca 2019) and remained small, overall it is likely to have remained stable. However, due to high levels of uncertainty and natural variability of the species (C. A. Chutas in litt. 2020), it is suspected to be undergoing a slow decline over a three generation period (14.7 years; Bird et al. 2020) due to ongoing and potential future threats.
Podiceps taczanowskii is a flightless waterbird confined to Lake Junín in the highlands of Junín, west-central Peru. It is thought to use only less than 50% of the lake on account of preference and habitat quality (A. Chamorro in litt. 2020). 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 had 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). It has now however been considered that following a major decline, the population had remained stable from the 1970s, through to the 1990s at c. 250-300 individuals (Chamorro and Aucca 2019). 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 335-468 individuals (Chamorro and Aucca 2017, Dinesen et al. 2019). Following a period of drier climate, the latest censuses estimates the population at 373 individuals (Chamorro et al. 2018), with 294 and 359 individuals in 2018 and 2019 respectively (A. Chamorro in litt. 2019). Combined censuses from 2010 to 2018 shows that the population has generally fluctuated between 300-400 individuals (Chamorro and Aucca 2019).
Lake Junín is fairly shallow and bordered by extensive reed marshes at 4,088 m. The grebe forages in open water, near the margins of the reed marshes in the (wet) breeding season (November-March), and in the centre of the lake in the dry austral winter. Spatial distributions have shown that the species concentrates mainly in the centre and further north of the lake, usually occurring in groups of over 50 individuals (Chamorro et al. 2018). It is likely that the species therefore only occupies around 50% of the lake due to preference and habitat quality (A. Chamorro in litt. 2020). 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), and breeding may fail completely in certain years (J. Fjeldså in litt. 2020). Adults will usually use the deepest parts of the lake for courtship, whilst areas with high densities of vegetation (such as Southern Bulrush [Schoenoplectus californicus] and Baltic Rush [Juncus balticus]) for nesting and rearing (Chamorro and Aucca 2019).
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). Sewage from nearby towns also considerably increased when the Upamayo dam was built, as well as increasing the susceptibility to droughts and floods downstream (Chamorro and Aucca 2019). 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). Burning of nearby bulrush grass may cause destruction of nests and breeding habitat (Chamorro and Aucca 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). Non-native species such as Rainbow Trout (Oncorhynchus mykiss) may also compete for nesting sites and food with juveniles further threatening the species's population (Chamorro and Aucca 2019, A. Chamorro in litt. 2019). Nets used by fisherman in order to catch invasive trout have also lead to the death of some individuals creating a new threat towards the species (A. Chamorro in litt. 2019, G. Engblom in litt. 2020). Hunting has been prohibited and is thought to no longer be a major problem (Chamorro and Aucca 2019).
Conservation Actions Underway
Lake Junín has been declared a national reserve. It was also a designated Ramsar Site in 1996 and an Important Bird Area in 2008. Hunting and fishing are regulated but little was previously done to interfere with the management of the water level, which is controlled by hydro-energy companies that provide energy to the country; it is estimated that 20% of Peruvian energy is supply by dams on Lake Junín (O'Donnell and Fjeldså 1997, A. Chamorro in litt. 2020). Hunting is now however considered to be prohibited, albeit may bilaterally be affected by hunting of other species within the area (Chamorro and Aucca 2019). 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). Servicio Nacional de Áreas Naturales Protegidas (SERNANP, formerly INRENA: National Service of Natural Protected Areas) commissioned a species recovery plan in 2000 (Chamorro and Aucca 2019). 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). Areas of water are now 'cleaned' with less contaminated water (Chamorro and Aucca 2019). 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). In 2014, the Mohamed bin Zayed Species Conservation Fund implemented further conservation actions on Lake Junín (Chamorro and Aucca 2018). ECOAN has been undertaking conservation actions including a range of education and training activities with local communities and students, and research and monitoring of the species's population size and threats (ECOAN 2016, Chamorro and Aucca 2018, Chamorro and Aucca 2019). SERNAP, together with the Pedro Silvestre Atoc Family Group and the District Municipality of Carhuamayo have also endeavored to implement garbage collection in the northern sector of the lake (recovering 4 hectares of contaminated area) and providing fencing and natural trash bins to prevent further garbage disposal (Chamorro and Aucca 2018).
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). Ensure continual of yearly surveys to overcome uncertainty in population trends (G. Engblom in litt. 2020). 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 viable captive-breeding population as captive-bred populations may not always succeed due to difficulty of rearing the species in captivity (J. Fjeldså in litt. 2020). Develop ecotourism in the area including building a lookout platform for the lake to aid population monitoring (Hirschfeld 2008). Implement regional tools to treat pollutants, and enforce laws for those who are responsible for their release (Chamorro and Aucca 2019). Investigate the potential of competition from Rainbow Trout and subsequent fishing activities in becoming significant future threats (G. Engblom in litt. 2020).
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
Wheatley, H., Fernando, E.
Angulo Pratolongo, F., Ashpole, J, Aucca Chutas, C., Benstead, P., Bird, J., Calvert, R., Chamorro, A., Clay, R.P., Engblom, G., Fjeldså, J., Hennessey, A.B., Pilgrim, J., Sharpe, C.J., Symes, A. & Valqui, T.
BirdLife International (2021) Species factsheet: Podiceps taczanowskii. Downloaded from http://www.birdlife.org on 21/09/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 21/09/2021.