Evidence of High Consumption of Waste by the Andean Condor (Vultur Gryphus) in an Anthropized Environment of Chile

Abstract

· Anthropogenic food subsidies and waste disposals have become a new food resource for wildlife, including the Andean Condor (Vultur gryphus), a situation that implies benefits and health risks. To increase understanding of Andean Condor feeding habits in the most anthropized area in Chile, we analyzed 280 pellets collected during 2016 from one roost in the Metropolitan Region, central Chile. We identified the main diagnostic elements microscopically and expressed them as percentage of occurrence (percentage of each item in relation to all pellets). We found 12 prey categories (including mammals, birds, and plant material) and 9 waste categories. Condors fed mainly on mammals (99%); livestock was their main feeding source (52%), followed by native (22%) and exotic wild species (19%). Birds were detected less frequently (8%). We found a high occurrence of waste (31%), of which plastic remains were the main item (27%). According to our results, landfills serve as a complementary food source for condors, probably a low-quality but easily accessible, and which exposes them to a variety of health and mortality risks. Despite the fact that Andean Condors can reach distant places in foraging flights to find food resources, a high proportion of the population is attracted to rubbish dumps and landfills. Despite the spatio-temporal limitations of our results, this is the first record that describes and quantifies a high presence of waste as a component of the Andean Condor diet. We recommend a more comprehensive study to assess their feeding habits and habitat preferences in a broader spatio-temporal context, and to determine the possible impact of the use of waste disposals on Andean Condor populations.Resumen · Evidencia de alto consumo de basura por el Cóndor Andino (Vultur gryphus) en un ambiente antropizado de Chile Los subsidios antropogénicos y sitios de disposición de basura se han convertido en una nueva fuente de alimentación para la fauna, incluido el Cóndor Andino (Vultur gryphus), lo que implica beneficios y riesgos. Con el fin de estudiar los hábitos alimenticios del cóndor andino en un área altamente antropizada, analizamos 280 egagrópilas colectadas durante 2016 en un dormidero de la Región Metropolitana, en Chile central. Identificamos microscópicamente los principales elementos diagnósticos y los expresamos como porcentaje de ocurrencia (porcentaje de cada ítem respecto del total de pellet). Encontramos 12 ítems dietarios (incluyendo mamíferos, aves y materia vegetal) y 9 ítems de basura. Los cóndores se alimentaron principalmente de mamíferos (99%); el ganado fue la principal fuente de alimento (52%), seguido por especies silvestres nativas (22%) y exóticas (19%), mientras que las aves estuvieron escasamente representadas (8%). Encontramos una alta ocurrencia de basura (31%), de la cual los restos de plástico fueron el principal ítem (27%). De acuerdo a nuestros resultados, los basurales sirven como una fuente complementaria de alimentación para los cóndores, probablemente de baja calidad, pero de fácil acceso, y que los expone a una variedad de riesgos de mortalidad y para su salud. Aunque el Cóndor Andino puede alcanzar lugares distantes en sus vuelos de forrajeo, una alta proporción de su población es atraída a vertederos y rellenos sanitarios. A pesar de las limitaciones espaciotemporales de nuestros resultados, este es el primer registro que describe y cuantifica la alta presencia de basura como componente de la dieta del Cóndor Andino. Recomendamos ampliar el estudio para evaluar sus hábitos alimentarios y preferencias de hábitat en un contexto espacial y temporal amplio y poder determinar el posible impacto del uso de basurales en poblaciones de Cóndor Andino.

Landfill Use by Andean Condors in Central Chile

“…The poisoning events and the consumption of plastic bags that we observed in our study illustrate this problem. The regular consumption of plastic bags that we observed at the landfill may be accompanied by the consumption of other potentially dangerous items as confirmed by pellets collected at a communal roost 4 km south of the landfill (Pavez et al 2019). Anthropogenic objects, such as glass fragments, can be a major cause of nestling mortality of California Condors ( Gymnogyps californianus ) and vultures of the genus Gyps (Ferro 2000, Mee et al 2007, Rideout et al 2012).…”

“…Regular presence of condors eating a large number of rabbits killed by myxomatosis in the Andean foothills of the Metropolitan Region has been reported since 2016 (Pavez 2020b). Indeed, rabbits and hares ( Lepus europaeus ) are important in the diet of condors (Lambertucci et al 2009, Perrig et al 2016, Ballejo et al 2017, Pavez et al 2019, Duclos et al 2020). Thus, during the period from 2013 to 2019, the abundance of dead livestock and rabbits away from the landfill resulted in high food supply for condors and the sharp decline of their numbers at the landfill.…”

“…Today, many avian scavengers including the Andean Condor ( Vultur gryphus ) feed mainly on carrion from domestic and wild exotic species (Lambertucci et al 2009, 2011, Pavez et al 2019), which represent ephemeral, unpredictable resources, heterogeneously distributed over space. However, during the past century, because of the rapidly changing agro-grazing economies, domestic carrion available in Chile, especially in central Chile, has been reduced (Jaksic et al 2001, Pavez 2012).…”

“…In this context, waste products associated with human populations have become a new and predictable food source for Andean Condors in central Chile (Pavez and Tala 1995, Pavez 2012). In fact, waste occurs with high frequency in regurgitated pellets of condors in the Metropolitan Region of central Chile (Pavez et al 2019, Duclos et al 2020).…”

Perceptions of the Andean condor in the urban population of Ecuador

“…About the Andean condor's diet, a generalized knowledge was registered as a scavenger species, as it has typically been described (Donázar et al, 1999;Perrig, Donadio, Middleton, Pauli, 2017;Lambertucci et al, 2018;Pavez et al, 2019). These observations were answered mostly by people (employees, students and independent) who carry out outdoor activities.…”