Distribution

Hooded Grebe is a near endemic species in Argentina with a local distribution in Santa Cruz province, southern Patagonia, where it is a breeding endemic. Records from southern Chubut province (Harris 2008) are not confirmed. There are very few records in Chile, including some sights from the Torres del Paine National Park area to the south, XII Región and some photographic evidence (R. Matus pers. comm.) and sight records (St. Pierre and Davies 1998) from Monumento Natural Laguna de los Cisnes in Tierra del Fuego.

During the breeding season its distribution extends over an area of high plateaus (the main ones are Buenos Aires, Asador, Strobel, Siberia, Cardiel Chico, Basáltica and Vizcachas) from 47° to 51° S at elevations varying between 500 and 1500 meters a.s.l., well to the east of the Andean range (Johnson 1997).

The main known wintering sites are on the estuaries of the Atlantic coast (Johnson and Serret 1994, Imberti et al. 2004), especially the Coyle and Gallegos estuaries which hold the greatest numbers (Imberti et al. 2004),  with occasional records at Santa Cruz River and San Julián Bay (Johnson and Serret 1994). These areas hold less than 20% of the estimated population; the whereabouts of the rest of the population is only speculated upon. It has been suggested that they might use the Chilean fiords during this season (Fjeldså 1986, Johnson and Serret 1994) but a good search of the area yielded no results (Imberti 2005 and several pers. comm.). It is likely that most of the grebes are largely sedentary using the bigger lakes (Strobel, Quiroga, Sello, Islote among others) that do not freeze over during the winter. However, it also has been suggested that although they migrate to the coast, not all of the grebes enter the estuaries with the tides, but instead remain well offshore where they can not be accounted for (J. Fjeldså pers. comm.).

Little is known about the grebe's migration, as there are only a handful of records from intermediate areas. Grebes migrate down to the coast in April and remain there until August (Imberti et al. 2004). They are known to use a number of small lagoons as stopover (Johnson and Serret 1994, SI pers. obs.), where the numbers observed are regularly fewer than 20 individuals.

Endemic to the Americas.

Perhaps the first reference to the existence of Hooded Grebe went largely unnoticed for almost 100 years (Rumboll pers. com.). In 1902 H. Hesket Prichard, while traveling in Patagonia, wrote: “Here we camped and found yet another deep and rocky lagoon, on which were many divers which I could not identify”.

Hooded Grebe was only discovered for science as late as 1974 (Rumboll 1974) when a group of 150 birds was found at Escarchados Lagoon. The receding numbers of that population provoked more extensive searches by researchers from Fundación Vida Silvestre Argentina. The discovery of another group further north hinted at the fact that the Escarchados population was not a relict one and changed the search priorities. The need for establishing an estimate of the size of the population of the species was realized and field trips where organized during 1979 – 1987. The core of the population was established in the 1980’s, largely due to the efforts of the late Andrés Johnson and others (Bremer and Bremer 1984, Beltrán et al. 1992, Johnson 1985, 1986, 1997, Johnson and Serret 1994). Having established the breeding grounds, the question of the wintering grounds remained until part of the population was found wintering in the Atlantic coast (Johnson and Serret 1994). Further investigations were not carried out until the period 1999 - 2005, when Imberti et al. (2000, 2003, 2004, 2005) set out to survey a large portion of the coast of Santa Cruz province and the Chilean Fiords searching for other possible wintering sites.