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Humpback whales undertake seasonal migration between productive high-latitude areas where they feed in summer and low-latitude tropical waters where mating and calving occur during winter. In the eastern south Pacific, the species breeds off Colombia and Ecuador, and feeds primarily in the western Antarctic Peninsula and in the waters of the Strait of Magellan (SM), recently described as a new feeding ground for humpback whales. Comparison of fluke photographs of 62 individuals from the SM obtained during the austral summer from 1999 to 2005 and 1,042 individuals from Colombia, provided conclusive matches for six individuals, with an overall interchange index of 0.093. Eight migratory trips between summer and winter grounds were registered for four whales during a complete migratory round-trip in consecutive years. The minimum distance traveled in a one-way trip ranged from 6,650 to 7,000 km. The duration of the two fastest trips between these migratory destinations was 88 and 99 days, with a mean speed of migration of 76 and 67 km day -1 respectively. Five of the whales present in both areas were males and three mitochondrial DNA haplotypes were identified: EM-1 for three individuals, EM-2 for two and EM-3 for the last one, all of which have been previously described for humpback whales from Colombia. All six individuals were seen several days in each season in the SM (as many as 39 days in one case), with an average stay of 72 ± 40 days (n = 20) per year, ranging from 3 to 125 days. On average, each of the six individuals was seen in the SM during 71 ± 18 % of the seven monitored summers. Three individuals were re-sighted in the SM six out of the seven surveyed years, during four to six consecutive years. These results provide the first direct evidence to include humpback whales that feed in the Strait of Magellan as part of the eastern south Pacific population of whales that feed off Colombian waters.Key words: Colombia, humpback whales, migration, photo-identification, Strait of Magellan. RESUMENLa ballena jorobada migra estacionalmente entre latitudes altas donde se alimenta en verano y latitudes bajas donde cría y se aparea en invierno. En el Pacífico sureste, la especie se reproduce en Colombia y Ecuador y se alimenta principalmente al oeste de la península Antártica, y en el estrecho de Magallanes (EM) recientemente descrito como nueva área de alimentación. Al comparar las fotografías de las colas de 62 ballenas individualizadas en el EM durante el verano austral entre 1999 y 2005 con 1.042 individuos de Colombia, se encontró a seis individuos comunes, lo que representa un Indice de Intercambio migratorio de 0,093. Se registraron ocho migraciones para cuatro de estas ballenas entre el EM y Colombia en el ciclo migratorio de años consecutivos. La distancia mínima recorrida en una sola dirección varió entre 6.650 y 7.000 km. La duración de los dos viajes más rápidos registrados entre estos dos destinos fue de 88 y 99 días, con una velocidad promedio de migración de 76 y 67 km día -1 respectivamente...

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SummaryRed-legged Cormorant Phalacrocorax gaimardi, considered Near Threatened, is one of the most conspicuous seabirds on the south Pacific coast, although its current status is unknown. During spring and summer of 1998, 1999 and 2000 we surveyed Red-legged Cormorants along the Chilean coast. Survey portions of the coast were chosen based on published information, and discussions with local people. Nesting sites were distributed from Arica (18°30′ S) to the Peninsula de Taitao (46°25′ S). We found 40 breeding areas with at least 54 colonies, ranging from two to 964 nests. Colony size (as number of breeding birds) was larger in the south than in the north. Isolated pairs or small colonies were found in the northern and central part of Chile. The southern coast (X th Region) held most colonies, including the largest one with approximately 1,000 breeding pairs, suggesting it is a critical area for the species. We estimated the Red-legged Cormorant population in Chile to be between 5,018 and 5,218 breeding pairs. The X th Region holds approximately 80% of the whole Chilean population. Factors affecting the breeding distribution of this bird in Chile include coastal development, nesting habitat availability and the occurrence of El Niño (ENSO) events. Human consumption may be important locally, mainly in the south. Chile holds more than 70% of the world breeding population, estimated at fewer than 15,000 individuals. The Peruvian population has declined during recent decades, and the Argentinean population seems to be small and stable. Thus the Chilean coast, particularly the X th Region, is a critical area for the conservation of this species.

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Ecología trófi ca de RESUMENSe analizó la dieta del pequén (Athene cunicularia) en cuatro islas del norte de Chile, mostrando que existe un fuerte predominio de artrópodos (89,1%) en comparación con los vertebrados (10,1%) respecto al número de presas consumidas.De estos taxa destacan los tenebriónidos (42,2%) y curculiónidos (31,2%) como los principales grupos consumidos, sin embargo, la presencia de mamíferos (3,6%) y de aves (6%) en la dieta es también relevante, ya que a pesar de representar menos del 10% del número total de presas, el aporte energético de estos vertebrados constituyó cerca del 80% de la biomasa total ingerida. Se registró evidencias de depredación sobre el yunco (Pelecanoides garnotii); presa destacada con un 71% dentro del ítem aves y 40% del total de vertebrados consumidos, así también destaca el consumo de la llaca (Thylamys elegans) con en un 21% del total de vertebrados. Se encontraron tres individuos de piuchén o vampiro (Desmodus rotundus) especie no descrita con anterioridad en la dieta del pequén en el norte de Chile. Se discute respecto a las posibles respuestas funcional y numérica del pequén en isla Choros, asociadas a los registros de distintas densidades de yunco. Se analizó además, la variabilidad de la dieta por isla, el patrón de tamaño de las presas consumidas y la distribución espacial de nidos del pequén.PALABRAS CLAVE: desierto de Atacama, ecología trófi ca, islas, yunco, pequén, respuesta del depredador. ABSTRACTThe diet of Burrowing owl (Athene cunicularia) was analyzed in four islands in the North of Chile, showing that a strong predominance of arthropods (89.1%) exists compared to vertebrates (10.1%) regard to the number of consumed preys. Tenebrionids (42.2%) and curculionids (31.2%) stand out because they are the main consumed groups. However, the presence of mammals (3.6%) and birds (6%) in the diet is relevant too, because despite representing less than 10% of the total number of prey, the energy contribution of vertebrates constituted about 80% of the total biomass ingested. Evidence of predation on Peruvian diving petrel (Pelecanoides garnotii) was found, this prey stands out with 71% from the birds group, while regarding the total consumed vertebrates it reaches a 40%. It is also worth mentioning the mouse-opossum (Thylamys elegans) consumption reaching 21% of the total vertebrates. Three individuals of Piuchen or vampire bat (Desmodus rotundus) were observed, this species have not been previously described in the Burrowing owl diet in the North of Chile. We discuss possibles functional and numerical responses of Burrowing owl in Choros Island, where different densities of Peruvian diving petrel were found. Besides, the diet variability per island, pattern size of preys consumed and spatial distribution of Burrowing owl nests were analyzed.