While investigating the feeding interactions of the Andean condor (Vultur gryphus) in Peru, researcher Victor Gamarra-Toledo found something that concerned him — plastics featuring in the scavenger bird’s diet. And this was not an isolated finding. In almost all samples analyzed, pieces of plastic made up part of the food the condors had eaten..
“We were very surprised to find plastic in so many samples. When we finished our field work, we began looking at the birds’ pellets — regurgitated balls that are made up of undigested matter — and we were surprised to find an excessive amount of plastic,” says Gamarra-Toledo, a researcher in ornithology at the Natural History Museum of Peru’s National University of San Agustín de Arequipa.
Gamarra-Toledo also explains that such a high level of microplastics and plastics found in Andean condor populations is barely seen in any other condor group in South America.
Only one study, published in Chile, looked at the presence of plastic in the food of condors living near a garbage dump — but the populations studied by Gamarra-Toledo live in protected areas.
The study was conducted in the San Fernando National Reserve, in the Ica region on the Peruvian coast, and in the buffer zone of the Pampa Galeras Barbara D’Achille National Reserve, in the Andean region of Ayacucho. “The area between these two regions represents a biological corridor between the Andean mountains and the coast,” says the published study.
The Andean condor is an emblematic species of South America that inhabits an area stretching from Venezuela, Colombia and Ecuador down to southern Argentina and Chile. The International Union for Conservation of Nature (IUCN) has classified the species as vulnerable to extinction and as possibly extinct in Venezuela.
En este artículo, recientemente publicado, participaron investigadores de dos países Latinoamericanos: Pablo Plaza y Sergio Lambertucci, del Grupo de Investigaciones en Biología de la Conservación del Instituto de Investigaciones en Biodiversidad y Medioambiente (Inibioma-Conicet) y Universidad Nacional del Comahue, en Argentina; Yuri Peña, Gonzalo Cano, Santiago Barreto y Sandra Cáceres, del Museo de Historia Natural (MUSA), de la Universidad Nacional de San Agustín de Arequipa, en Perú; así como la guía de turismo peruana Pierina Bermejo y Juan López, de la Reserva Nacional Pampa Galeras Barbara D’Achille.
Excess plastic found in condors
“The results of the investigation are incredibly concerning,” Gamarra-Toledo says. “We found plastic in 100% of the samples analyzed from the coastal zone and 85% from the Andean zone.”
What worries him most is that these plastic-contaminated Andean condor populations live in protected natural areas, relatively far from human populations and, therefore, far from garbage dumps. “This worries us even more, because condors are at the top of the food chain. Finding evidence that they are contaminated with plastic means that the links below the condor are also contaminated,” Gamarra says.
Gamarra-Toledo has two theories about the source of these plastics. The first is related to transfer via the food chain. For condors living along the coast, it has been proven that the ocean is polluted with microplastics and that these are consumed by fish. Other animals that feed on these fish, such as birds, sea lions and other species, also ingest the microplastics. When these marine species die, scavenger birds, like the Andean condor, arrive and feed on the carcasses containing microplastics. “Something similar happens in the Andes,” Gamarra-Toledo says, “but with camelids such as vicuñas and alpacas, the condors’ main diet. In this case, the camelids feed on vegetation containing microplastics.”
“Discovering that condor populations contain plastics and microplastics is an indicator of habitat quality or ecosystem health status. If there is plastic in condors, their entire food chain is also contaminated,” he says.
The second theory, explains Gamarra-Toledo, “corresponds to a more direct contamination. Here, animal or meat remains wrapped in plastic are thrown away, and when the condors try to eat the contents, they end up consuming the material.”
“Cattle and camelids in the Andean region have been reported to have died from eating plastic. We have found plastic in the stomachs of animals consumed by the condor, including masks used during the pandemic, as well as disposable plates. This shows that the transfer of plastics can occur through direct consumption in the food chain,” Gamarra-Toledo says.
As part of the research, scientists reviewed previous publications on plastic presence in animals in the study areas that are part of the condors’ diet. For the marine-coastal zone of the San Fernando National Reserve and its surroundings, they found articles on the presence of plastic in species that condors eat regularly, such as the South American sea lion (Otaria flavescens) and the South American fur seal (Arctocephalus australis). These animals “are exposed to and contaminated with plastic waste of different sizes both internally (presence of plastic in scats) and externally (collars, hooks embedded in body),” says the study.
For condors in the Andean region of the Pampa Galeras National Reserve buffer zone in Ayacucho, the researchers conducted interviews with farmers and park rangers to find out if they had seen cattle ingesting plastic or if they had found it in the animals’ internal organs after slaughter. All of those interviewed reported they had witnessed one or both of these scenarios.
The scientists also analyzed dimensions of the plastics found in approximately 570 pellets, or condor regurgitates. According to the published article, in the marine-coastal zone, most of the remains were microplastics, while in the Andean zone, they found plastic of all sizes. Most were plastic bags, but they also found sheets, fibers, hard fragments and synthetic foams. Pieces of paper, cloth and wool also appeared in some samples.
“We classified the plastics into four groups based on size — microplastics smaller than 5 millimeters [0.2 inches] and megaplastics larger than 10 centimeters [3.9 inches]. The amount and type of plastic in the condors is wide-ranging and highly concerning,” Gamarra-Toledo says.
Gamarra-Toledo adds that although they did not find any dead condors to include in the study, scientists in Arequipa, in southwestern Peru, found a dead specimen. A necropsy went on to reveal plastic remains in its stomach. “The condor’s stomach contained pieces of disposable plastic plates,” he says.
A new threat to condors
“Plastic is a pollutant and impacts the health of those who consume it. It can create endocrine disruption and is capable of mimicking hormones, generating alterations in body behavior, among other things,” says Sergio Lambertucci, director of a conservation biology research group at INIBIOMA-CONICET, part of the Biodiversity and Environment Research Institute at theNational University of Comahue in Argentina.
Lambertucci explains that although no studies have, as yet, looked at the effects plastics can have on condors, we do know what happens to other species very close to the Andean condor, such as the black vulture (Coragyps atratus), with studies showing that plastic disrupts their hormonal system. “If it happens to them, it is very likely it happens to condors as well,” says Lambertucci.
For this reason, Lambertucci says it is important to begin observing whether there are changes in condor population reproduction, because this could indicate whether plastic is a factor. “We know that plastic causes health issues, but we don’t yet know what these problems are for the condor,” he says.
Research suggests that this scientific study is the first to report the presence of microplastics in Andean condors’ regurgitate pellets. “We emphasize that the high level of plastic contamination we found has not been reported before in any terrestrial bird species in Peru or, to our knowledge, in any Andean region of the Neotropics,” the study’s authors write.
According to Lambertucci, up to now, nobody has paid much attention to plastic as a possible threat to condors. This is because the majority of threats usually concern poisoning, direct persecution, the hunting of animals consumed by the condors using lead bullets or collisions with infrastructure, such as power lines. “Here in Peru, this is something new that we have to start paying attention to. The most worrying thing is that even in places where species protection management is already taking place, such as within protected areas, some threats, like this one, slip through the net,” he says. “We’re talking about the presence of a product that we didn’t think about before but that is very much there, on the periphery or perhaps even entering protected areas.”
Lambertucci says the areas of focus for the study, such as San Fernando, do not typically contain garbage. However, he explains that some marine animals carry the plastic they have eaten to the coast, where condors then eat them. These condors end up taking these plastics to the mountains where, through regurgitated pellets, they again become part of the environment.
“Another very novel aspect of the study is that it suggests how plastic moves between different environments. Plastic that was in the sea can move tens or hundreds of kilometers, be consumed by species that are then carrion and serve as food for the condor. But part of what it consumes returns to the environment when the bird regurgitates its food,” Lambertucci says.
“This is how what we know as ‘plastic islands’ are formed. They are produced in very remote places where human impact is usually very low,” Lambertucci says. “The results of studying these birds confirm the high level of plastic contamination in southern Peru, which could have a negative impact on the biodiversity of the Andes and the coast — two of the country’s most important ecosystems.”
Gamarra-Toledo, V., Plaza, P. I., Peña, Y. A., Bermejo, P. A., López, J., Cano, G. L., … & Lambertucci, S. A. (2023). High incidence of plastic debris in Andean condors from remote areas: Evidence for marine-terrestrial trophic transfer. Environmental Pollution, 317, 120742.
This article by Yvette Sierra Praeli was first published by Mongabay.com on 27 February 2023 | Translated by Hayley Smith. Lead Image: Andean condor in the San Fernando National Reserve. Image by Víctor Gamarra-Toledo.
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