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Range DescriptionPodiceps gallardoi breeds on a few basaltic lakes in the interior of Santa Cruz, extreme south-west Argentina; the only known wintering grounds are the río Coyle, río Gallegos and río Chico estuaries on the Atlantic coast of Santa Cruz (Johnson and Serret 1994, Imberti et al. 2004, Roesler et al. 2011b). It is apparently accidental in Magallanes, south Chile (Roesler et al. 2011b). The total population was estimated at 3,000-5,000 individuals in 1997 with half of these on Meseta de Strobel (O'Donnell and Fjeldså 1997). Counts on the wintering grounds suggested a decline of 40% over a seven year period (S. Imberti in litt. (2006), and surveys conducted in December 2006 and January 2009 that revisited key known breeding sites surveyed in 1987 (Lagunas del Sello, del Islote and Tolderia Grande) and 1998 (Encadenadas) also found sharp declines; numbers fell from 452 to 51 at Laguna del Sello, from 700 to 0 at Laguna del Islote, from 90 to 0 at Tolderia Grande (H. Casañas in litt. 2009) and from 198 to 0 at Lagunas Encadenadas (Konter 2008). During the 2010-2011 breeding season 535 individuals were counted, indicating a population decline of more than 80% over the last 26 years (Roesler et al. 2011b). In 2013, greater resources allowed a simultaneous count across all plateaus known to have ever held grebes and visiting virtually every lake with historic records of the species, resulting in a count of 691 adults and 144 chicks in 12 colonies (Casañas et al. 2013). While there is speculation that numbers fluctuate dramatically at breeding sites from year to year driven by movements rather than actual population fluctuations (Fjeldså 1986), overall declines detected on the wintering and breeding grounds appear to be real and rapid (Roesler et al. 2011b). Examination of photographs from the 1980s suggests that P. gallardoi was formerly the commonest waterbird on its core breeding grounds, the Buenos Aires, Strobel and San Martin plateaus; the 2009 surveys visited two of these areas and recorded the declines above as well as noting that a number of former breeding sites were completely dry.