Justification of Red List Category
This flightless grebe is listed as Endangered because it has suffered from very rapid population reductions. The population is small enough that, if declines continue, this species may need uplisting to Critically Endangered.
Based on counts on Lake Titicaca in 2003 (Martinez et al. 2006) and adults counted elsewhere in the Titicaca watershed (Engblom et al. 2001), the population was estimated at around 1,600 mature individuals. On Lake Titicaca itself, 2,583 individuals of all ages were counted; combined with smaller numbers elsewhere in the watershed, this represents a higher population than previously assumed. In 2007, 1,254 individuals were counted in the wet season (H. Aranibar-Rojas in litt. 2007). The species is however thought to decline at 50-60% over three generations; thus the population may number c. 600 mature individuals in 2020. To account for uncertainty, the population size is here placed in the band 250-999 mature individuals.
Surveys in the 1970s and 1980s led to population estimates of between 2,000-10,000 individuals, with at least 1,147 on Lake Umayo alone in 1986 (Engblom et al. 2001). Surveys in 2001 found just four individuals on Lake Umayo, and 156 adults on Lake Arapa, whereas 215 adults and 45 young were recorded from 16 lakes in the Peruvian range (Engblom et al. 2001). Counts during 1997 in Bolivia found a total of 100 individuals (Engblom et al. 2001). Further declines were indicated during a brief follow-up survey in 2003 (G. Engblom in litt. 2003), but surveys of Lake Titicaca in 2003 found a total of 2,583 individuals, which was thought likely to be an underestimate of the total population on the lake. In 2007 preliminary census data found 1,254 individuals in the wet season (H. Aranibar-Rojas in litt. 2007). A census on a small section of the Río Laka Jahuira (at Paso Julian) in 2004 found 138 mature individuals, and further surveys are needed along the entire eastern section of the river to confirm the size of this subpopulation (Konter 2006). In 2006, the total population was estimated at 1,600 mature individuals (Martinez et al. 2006). Estimates suggest that the species declined by 15% between 2003 and 2005 (Asociación Armonia 2007). This equates to a decline of 50-60% over three generations. The greatest current threat to the species, bycatch in fishermen's gill-nets, is continuing.
Rollandia microptera is endemic to open, freshwater lakes on the altiplano of Peru and Bolivia. It occurs from lakes Arapa and Umayo in south-eastern Peru, through Lake Titicaca into adjacent Bolivia, and along the Desaguadero River to Lakes Uru-uru and Poopó (O'Donnell and Fjeldså 1997). Temporary populations occur on smaller adjacent lakes in years when Lake Titicaca floods (O'Donnell and Fjeldså 1997).
It is a social species, but usually solitary when feeding (O'Donnell and Fjeldså 1997). It breeds in wide reed-marshes composed primarily of tule-rushes (Schoenoplectus tatora) in places with easy access to open water, or in open view in floating water weeds (O'Donnell and Fjeldså 1997). Fish of the genus Orestias comprise up to 94% of prey as measured by biomass (Martinez et al. 2006). The species is an opportunistic breeder and reproduction occurs throughout the year (Martinez et al. 2006).
Since at least the early 1990s, there has been unregulated use of 80-100 m long monofilament gill-nets in lakes throughout its range. Confirmation that birds are drowned in these gill-nets comes from local fishermen and direct observations - one study found 100% of Aymara fishermen questioned had found grebes drowned as bycatch in their nets (Martinez et al. 2006), 45% of the fishermen finding such birds on a weekly basis. A rapid evaluation with two fishermen in 2005 found one dead grebe per net/fisherman/day (B. Hennessey in litt. 2005) and studies in 2006-2007 found 2.7 individuals per fisherman/month. Local, natural fluctuations in water levels seriously impact breeding success (Engblom et al. 2001). Lakes Poopó and Uru Uru are threatened by chemical contamination from the heavy metal mining industry (Konter 2006). Lake ecosystems in the area are being affected negatively by the introduction of exotic fish such as Basilicthys bonariensis and Oncorhynchus mykiss (J. Fjeldså in litt. 2003, Martinez et al. 2006). Uro communities have recently started hunting birds, including Titicaca Grebes, on a commercial basis to sell at market (Martinez et al. 2006), and eggs may be harvested for food. Harvesting of tule-beds has taken place for centuries but human population growth and market demand for cattle may be changing harvesting patterns and posing a threat to the grebes' breeding habitat (Martinez et al. 2006). In particular, burning of tule-rushes during the grebes' peak breeding period may be affecting reproduction (B. Hennessey in litt. 2005). Tourism on Lake Titicaca has increased rapidly over the past decade, and disturbance by boats may be a threat to reproductive success (H. Aranibar-Rojas in litt. 2007). Alteration of the rio Desaguadero watercourse for extensive farming may affect the aquatic ecosystems of Lakes Poopó and Uru Uru in the future (H. Aranibar-Rojas in litt. 2007). Organic and inorganic waste from cities such as Alto is dumped in large quantities in some parts of Lake Titicaca (H. Aranibar-Rojas in litt. 2007).
Conservation Actions Underway
Although some areas are protected, there is currently no action being taken to protect the species or to mitigate the threats it faces.
28-45 cm. A distinctive flightless grebe. Upperparts blackish-brown. Chin, throat and foreneck white. Nape and lower foreneck reddish-brown. Bill yellow. Non-breeding adult is pale, duller and lacks crest. Juveniles are greyer, with striped heads and the white on the foreneck extending onto the breast.
Text account compilers
Aranibar-Rojas, H., Benstead, P., Engblom, G., Fjeldså, J., Hennessey, A.B., Pilgrim, J., Sharpe, C.J., Symes, A. & Wege, D.
BirdLife International (2021) Species factsheet: Rollandia microptera. Downloaded from http://www.birdlife.org on 22/01/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 22/01/2021.