Skip to main content Accessibility help

Trophic niche overlap among scavengers in Patagonia supports the condor-vulture competition hypothesis



Animals that share resources tend to use different foraging strategies in order to decrease potential competition. Scavenging birds using the same nutritional resources can segregate into different space and time scales. However, it has been suggested that when the species do not co-evolve to achieve such segregation competition may result. Our aim was to study the trophic niche overlap between three species of obligate scavengers, the Andean Condor Vultur gryphus, Turkey Vulture Cathartes aura and American Black Vulture Coragyps atratus, which are the main avian consumers of carcasses in north-western Patagonia. Black Vultures arrived in the area relatively recently, have expanded their distribution following human activities, and have been suggested to compete with the threatened condor. We collected pellets in communal roosts of the three species to determine their diet, and to estimate the diversity (Shannon Index) and diet similarity (Pianka overlap index). We found that the Turkey Vulture has greater niche breadth and, apart from domestic livestock, it incorporates smaller items such as fish, reptiles and a great number of birds, carnivores and mice. Although the Black Vulture diet includes arthropods, they feed primarily on introduced ungulates, overlapping more with condor diet when roosting far from urban centres. As these latter two species share the same food resource, human activities that positively affect the abundance of the Black Vulture could increase competition among them, with possible implications for the conservation of the Andean Condor.


Corresponding author

*Author for correspondence; email:


Hide All
Arjo, W. M. and Pletscher, D. H. (1999) Behavioral responses of coyotes to wolf recolonization in northwestern Montana. Can. J. Zool. 1927: 19191927.
Ballejo, F. and De Santis, L. J. M. (2013) Dieta estacional del jote cabeza negra (Coragyps atratus) en un área rural y una urbana. Hornero 28: 714.
Barbar, F., Werenkraut, V., Morales, J. M. and Lambertucci, S. A. (2015) Emerging ecosystems change the spatial distribution of top carnivores even in poorly populated areas. PLoS One 10: 112.
Barton, P. S., Cunningham, S. A, Lindenmayer, D. B. and Manning, A. D. (2013) The role of carrion in maintaining biodiversity and ecological processes in terrestrial ecosystems. Oecologia 171: 761–72.
Bellati, J. (2000) Comportamiento y abundancia relativa de rapaces de la Patagonia Extrandina Argentina. Ornitol. Neotrop. 11: 207222.
Blázquez, M., Sánchez-Zapata, J. A., Botella, F., Carrete, M. and Eguía, S. (2009) Spatio-temporal segregation of facultative avian scavengers at ungulate carcasses. Acta Oecologica 35: 645650.
Buckley, N. J. (1996) Food finding and the influence of information, local enhancement, and communal roosting on foraging success of North American vultures. Auk 113: 473488.
Buckley, N. J. (1997) Experimental tests of the information-center hypothesis with black vultures (Coragyps atratus) and turkey vultures (Cathartes aura). Behav. Ecol. Sociobiol. 41: 267279.
Campbell, M. O. N. (2014) The impact of urbanization and agricultural development on vultures in El Salvador. Vulture News 66: 1628.
Carey, M. P., Sanderson, B. L., Barnas, K. A and Olden, J. D. (2012) Native invaders – challenges for science, management, policy, and society. Front. Ecol. Environ. 10: 373381.
Carrete, M., Lambertucci, S. A., Speziale, K., Ceballos, O., Travaini, A., Delibes, M., Hiraldo, F. and Donázar, J. A. (2010) Winners and losers in human-made habitats: interspecific competition outcomes in two Neotropical vultures. Anim. Conserv. 13: 390398.
Chehébar, C. and Martín, S. (1989) Guía para el reconocimiento microscópico de los pelos de los mamíferos de la Patagonia. Acta Vertebr. 16: 247291.
Coleman, J. S. and Fraser, J. D. (1989) Habitat use and home ranges of black and turkey vultures. J. Wildl. Manage. 53: 782792.
Cortés-Avizanda, A. (2010) Efectos ecológicos de la heterogeneidad espacial y predecibilidad en la distribución de los recursos: carroñas y gremios de carroñeros. Madrid, Spain: Universidad Autónoma de Madrid.
Cortés-Avizanda, A., Jovani, R., Carrete, M. and Donázar, J. A. (2012) Resource unpredictability promotes species diversity and coexistence in an avian scavenger guild: A field experiment. Ecology 93: 25702579.
Darwin, C. (1839) Narrative of the surveying voyages of His Majesty’s ships Adventurer and Beagle, between the years 1826 and 1836. London, UK: Coribun.
De Marinis, A. M. and Asprea, A. (2006) Hair identification key of wild and domestic ungulates from southern Europe. Wildlife Biol. 12: 305320.
Del Hoyo, J., Elliott, A. and Sargatal, J. (1994) Handbook of the birds of the world. New World Vultures to Guineafowl, Lymx Editions, Barcelona.
Donázar, J. A., Cortés-Avizanda, A. and Carrete, M. (2010) Dietary shifts in two vultures after the demise of supplementary feeding stations: consequences of the EU sanitary legislation. Eur. J. Wildl. Res. 56: 613621.
Giraudoux, P. and Giraudoux, M. P. (2015) Package ‘pgirmess’. See
Grayson, D. K. (1978) Minimum numbers and sample size in vertebrate faunal analysis. Am. Antiq. 43: 5365.
Gutiérrez, G. (1998) Estrategias de forrajeo. Pp. 359–381 in Ardila, R., López, W., Pérez, A. M., Quiñones, R. and Reyes, F, eds. Manual de análisis experimental del comportamiento. Madrid, Spain: Librería Nueva.
Hertel, F. (1994) Diversity in body size and feeding morphology within past and present vulture assemblages. Ecology 75: 10741084.
Hiraldo, F., Blanco, J. C. and Bustamante, J. (1991a) Unspecialized exploitation of small carcasses by birds. Bird Study. 38: 200207.
Hiraldo, F., Delibes, M., Bustamante, J. and Estrella, R. R. (1991b) Overlap in the diets of diurnal raptors breeding at the Michilia Biosphere Reserve, Durango, Mexico. J. Raptor Res. 25: 2529.
Hiraldo, F., Delibes, M. and Donazar, J. A. (1991c) Comparison of diets of Turkey Vultures in three regions of Northern Mexico. J. Field Ornithol. 62: 319324.
Houston, D. C. (1985) Evolutionary ecology of Afrotropical and neotropical vultures in forests. In Buckley, P., Foster, M., Morton, E., Ridgley, R. and Buckley, F., eds. Neotropical ornithology, American Ornithologists Union. Washington D.C. pp. 6864.
Houston, D. C. (1988) Competition for food between Neotropical vultures in forest. Ibis 130: 402417.
Iñigo Elías, E. E. (1987) Feeding habits and ingestion of synthetic products in a black vulture population from Chiapas, Mexico. Acta Zool. Mex. 22: 115.
Kendall, C. O. K., Virani, M. Z., Kirui, P., Thomsett, S. and Githiru, M. (2012) Mechanisms of Coexistence in Vultures: Understanding the Patterns of Vulture Abundance at Carcasses in Masai Mara National Reserve, Kenya. Condor 114: 523531.
Kristan, W. B. and Boarman, W. I. (2007) Effects of anthropogenic developments on common Raven nesting biology in the west Mojave Desert. Ecol. Appl. 17: 17031713.
Kruuk, H. (1967) Competition for food between vultures in East Africa. Ardea 55: 171193.
Lambertucci, S. A. (2007) Biología y conservación del Cóndor Andino. Hornero 22: 149158.
Lambertucci, S. A. (2010) Size and spatio-temporal variations of the Andean condor Vultur gryphus population in north-west Patagonia, Argentina: communal roosts and conservation. Oryx 44: 441447.
Lambertucci, S. A., Alarcón, P., Hiraldo, F., Sanchez-Zapata, J. A., Blanco, G., Donázar, J. A. (2014) Apex scavenger movements call for transboundary conservation policies. Biol. Conserv. 170: 145150.
Lambertucci, S. A., Donazar, J. A., Huertas, A. D., Jiménez, B., Sáez, M., Sanchez-Zapata, J. A. and Hiraldo, F. (2011) Widening the problem of lead poisoning to a South-American top scavenger: Lead concentrations in feathers of wild Andean condors. Biol. Conserv. 144: 14641471.
Lambertucci, S. A., Speziale, K. L., Rogers, T. E. and Morales, J. M. (2009a) How do roads affect the habitat use of an assemblage of scavenging raptors? Biodivers. Conserv. 18: 20632074.
Lambertucci, S. A., Trejo, A., Di Martino, S., Sánchez-Zapata, J. A., Donázar, J. A. and Hiraldo, F. (2009b) Spatial and temporal patterns in the diet of the Andean condor: ecological replacement of native fauna by exotic species. Anim. Conserv. 12: 338345.
Monsarrat, S., Benhamou, S., Sarrazin, F., Bessa-Gomes, C., Bouten, W. and Duriez, O. (2013) How predictability of feeding patches affects home range and foraging habitat selection in avian social scavengers? PLoS One 8: 111.
Moreno-Opo, R., Trujillano, A. and Margalida, A. (2016) Behavioural coexistence and feeding efficiency drive niche partitioning at carcasses within the guild of European avian scavengers. Behavioral Ecology 27: 10411052.
Moreno-Opo, R., Trujillano, A., Arredondo, A., González, L. M. and Margalida, A. (2015) Manipulating size, amount and appearance of food inputs to optimize supplementary feeding programs for European vultures. Biol. Conserv. 181: 2735.
Novaes, W. G. and Cintra, R. (2013) Factors influencing the selection of communal roost sites by the black vulture Coragyps atratus (Aves: Cathartidae) in an urban area in central amazon. Zoologia 30: 607614.
Novillo, A. and Ojeda, R. A. (2008) The exotic mammals of Argentina. Biol. Invasions 10: 13331344.
Oro, D., Genovart, M., Taveccia, G., Fowler, M. S. and Martínez Abraín, A. (2013) Ecological and evolutionary implications of food subsidies from humans. Ecol. Lett. 16: 15011514.
Oro, D., Margalida, A., Carrete, M., Heredia, R. and Donázar, J. A. (2008) Testing the goodness of supplementary feeding to enhance population viability in an endangered vulture. PLoS One 3: e4084.
Paruelo, J. M., Beltran, A., Jobbagy, E., Sala, O. E. and Golluscio, R. A. (1998) The climate of Patagonia: General patterns and controls on biotic processes. Ecol. Austral 8: 85101.
Pianka, E. R. (1973) The structure of lizard communities. Annu. Rev. Ecol. Systemat. 4: 5374.
Pianka, E. R. (1985) Ecología evolutiva. Barcelona, Spain: Omega.
Plaza, P. I. and Lambertucci, S. A. (2017) How are garbage dumps impacting vertebrate demography, heath, and conservation? Global Ecology and Conservation 12: 920.
Prior, K. A. and Weatherhead, P. J. (2004) Turkey vultures foraging at experimental food patches: a test of information transfer at communal roosts. Behav. Ecol. Sociobiol. 28: 385390.
Real, J. (1996) Biases in diet study methods in the Bonelli´s Eagle. J. Wildl. Manage. 60: 632638.
Sánchez, R., Margalida, A., González, L. M. and Oria, J. (2008) Biases in diet sampling methods in the Spanish Imperial Eagle Aquila adalberti. Ornis Fennica 85: 8289.
Sazima, I. (2007) Unexpected cleaners: Black Vultures (Coragyps atratus) remove debris, ticks, and peck at sores of capybaras (Hydrochoerus hydrochaeris), with an overview of tick-removing birds in Brazil. Rev. Bras. Ornitol. 15: 417426.
Selva, N. and Fortuna, M. a (2007) The nested structure of a scavenger community. Proc. Biol. Sci. 274: 11011108.
Shepard, E. L. C. and Lambertucci, S. A. (2013) From daily movements to population distributions: weather affects competitive ability in a guild of soaring birds. J. R. Soc. Interface 10: 20130612.
Speziale, K. L., Lambertucci, S. A., Carrete, M. and Tella, J. L. (2012) Dealing with non-native species: what makes the difference in South America? Biol. Invasions 14: 16091621.
Speziale, K. L., Lambertucci, S. A. and Olsson, O. (2008) Disturbance from roads negatively affects Andean condor habitat use. Biol. Conserv. 141: 17651772.
Steigerwald, E. C., Igual, J.-M., Payo-Payo, A. and Tavecchia, G. (2015) Effects of decreased anthropogenic food availability on an opportunistic gull: evidence for a size-mediated response in breeding females. Ibis 157: 439448.
Stolen, E. D. (1996) Black and turkey vulture interactions with bald eagles in florida. Florida Field Nat. 24: 4345.
Stolen, E. D. (2000) Foraging behavior of vultures in central Florida. Florida Field Nat. 28: 173181.
Thomaides, C., Valdez, R., Reid, W. H. and Raitt, R. J. (1989) Food habits of turkey vultures in West Texas. J. Raptor Res. 23: 4244.
Tonni, E. P. and Noriega, J. I. (1988) Los cóndores (Ciconiiformes, Vulturidae) de la Región Pampeana de la Argentina durante el cenozoico tardío: distribución, interacciones y extinciones. Ameghiniana 35: 141150.
Wallace, M. P. and Temple, S. A. (1987) Competitive interactions within and between species in a guild of avian scavengers. Auk 104: 290295.
Wilmers, C. C., Stahler, D. R., Crabtree, R. L., Smith, D. W. and Getz, W. M. (2003) Resource dispersion and consumer dominance: scavenging at wolf- and hunter-killed carcasses in Greater Yellowstone, USA. Ecol. Lett. 6: 9961003.
Wilson, E. E. and Wolkovich, E. M. (2011) Scavenging: how carnivores and carrion structure communities. Trends Ecol. Evol. 26: 129135.

Related content

Powered by UNSILO

Trophic niche overlap among scavengers in Patagonia supports the condor-vulture competition hypothesis



Altmetric attention score

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed.