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Andean Condors (Vultur gryphus) are endangered in the northern portion of their South American range, but populations are larger further south. However, throughout their range, little is known about current population sizes and dynamics. Andean Condors use cliffs with shelves as communal roosts and, from 1999 to 2001, we surveyed three of these roosts in northwestern Patagonia, Argentina, to estimate population sizes and trends. The minimum population of Andean Condors in our study area was 196, one of the highest populations recorded for this species. The maximum number of condors observed increased during our 3‐yr study. However, there was a strong seasonal pattern in roost use and use also varied among roosts, possibly due to differences in their environmental characteristics, size, and room available for roosting, as well as proximity to nest sites and stage of the breeding season. In 1999 and 2000, more adults were observed than juveniles, but proportions were similar in 2001. Because we observed differential use of roosts among age classes, spatial segregation seems probable. We conclude that intensive censuses of communal roosts can provide useful information about the size, status, and dynamics of local populations. However, the large aggregations we observed may represent a potential risk for the conservation of the species because a single threat could affect multiple individuals. We suggest that a suitable conservation strategy for condors must involve the design and protection of a network of communal roosts.

The Andean condor Vultur gryphus is the largest bird in the world with flight capacity. For thousands of years the Andean condor has been honoured as a sacred link between space and humans by indigenous communities. In the last 100 years, the range of this emblematic species contracted rapidly and the Andean condor was pronounced extinct at both ends of its endemic South American range, in Venezuela and on the Atlantic coast of Patagonia. The Andean condor appears in Appendix I of the Convention on International Trade in Endangered Species of Wild Fauna and Flora and is listed as in ‘Danger of Extinction’ by the United States Fish and Wildlife Service. In addition, according to the International Union for Conservation of Nature, this species is classified as Near Threatened. In 1991, the Andean Condor Conservation Program (PCCA: Programa Conservación Cóndor Andino) was founded in Argentina. The PCCA started by performing genetic analyses and documenting the condor population in zoological institutions in a Latin American regional studbook. The PCCA then developed artificial‐incubation programmes and techniques for hand rearing birds without human contact, and worked to rescue and rehabilitate wild condors. The PCCA has succeeded in rearing 57 chicks and rescuing 197 wild condors. This paper describes the strategy used by the PCCA to reintroduce 160 condors throughout South America.

We characterized DNA sequence variation in the mitochondrial control region and 12S ribosomal subunit for a sample of Andean Condors (Vultur gryphus) representing populations distributed throughout the species' extensive geographic range (Colombia to central Argentina and Chile). Domains II and III of the control region along with part of the 12S gene were sequenced from 38 individuals (956 base pairs in 30 individuals and 430–824 base pairs for an additional 8 individuals sampled from museum specimens), and Domain I was sequenced from five of these birds (400 base pairs). We identified a total of five haplotypes based on four variable sites distributed over Domains II and III of the control region and the 12S gene. An additional variable site was identified in Domain I. All changes were transitions and no more than three sites differed between any two individuals. Variation in the control region of condors was lower than for most other birds analyzed for these loci. Although low genetic variability is often associated with endangered megafauna, the condor example is notable because the species still maintains a substantial geographic range. Thus, low genetic variability may occur even in megafauna whose ranges have not been severely reduced over recent centuries. Our results therefore suggest that genetic data from geographically widespread megafauna provide important baseline data for assessing the relationship between genetic variability and its causes in other endangered species. Baja Variabilidad Genética en Poblaciones de Vultur gryphus con Amplia Distribución Geográfica Resumen. Caracterizamos la variación de la secuencia de ADN en la región de control mitocondrial y la subunidad ribosomal 12S en una muestra de Vultur gryphus representativa de poblaciones distribuidas a lo largo del extenso rango geográfico de la especie (Colombia, hasta el centro de Argentina y Chile). Los dominios II y III de la región de control, junto con parte del gen 12S, fueron secuenciados en 38 individuos (956 pares de base en 30 individuos y 430–824 pares de base para una muestra adicional de 8 especímenes de museo), y el dominio I fue secuenciado en 5 de estas aves (400 pares de base). Identificamos un total de cinco haplotipos basados en cuatro sitios variables en los dominios II y III de la región de control y el gen 12S. Un sitio variable adicional fue identificado en el dominio I. Todos los cambios fueron transiciones y entre dos individuos cualesquiera no variaron más de 3 sitios. La variación en la región de control de los cóndores fue más baja que para la mayoría de las aves analizadas para estos mismos loci. Aunque la baja variabilidad genética es a menudo asociada con megafauna en peligro de extinción, el ejemplo del cóndor es notable porque la especie aún mantiene un rango geográfico substancial. Así, la baja variabilidad genética se puede dar incluso en la megafauna cuya dispersión no haya sido sujeta a severas reducciones en los ultimos siglos. Por lo tanto, nuestros resultados sugieren que los datos genéticos de rapaces con amplia distribución geográfica y de otra megafauna proveen de importante información de base para evaluar la relación existente entre la variabilidad genética y sus causas en otra megafauna en peligro.