One summer day three years ago, Agustino Alonzo and his partner Valentina Barreto heard from a friend about a wild animal that was showing up on his nearby farm in the Lavalleja hills of east-central Uruguay. Their friend couldn’t get a good enough look to identify the creature, so Alonzo and Barreto bought a camera trap—at US$50, one of the cheapest at the time—and installed it on the friend’s farm. Soon they had successfully “hunted” their first cat.

The animal turned out to be a Geoffroy’s cat (Leopardus geoffroyi), a small species of wild feline found in South and Central America. “Then we bought a better camera, and another and another,” Alonzo recalled during a recent interview at his home in Solís de Mataojo, a town of 3,000 residents located 80 kilometers (50 miles) from Montevideo.

Neither Alonzo nor Barreto is a scientist. In fact, Alonzo is an industrial mechanic who works in a slaughterhouse, and Valentina is an English teacher. Still, they quickly learned how to find areas of wild-animal traffic by locating the animals’ tracks. After setting up their cameras in those locations, the couple in a matter of months had become familiar with the routines of margays (Leopardus wiedii)—small wild cats that are rarely seen in Uruguay, which is the southern end of their range. Says Alonzo: “Every 15 days they pass through the same place.”

The pattern they discerned, let alone the sightings, were news to trained Uruguayan wildlife scientists interested in the presence of margays. The couple created an Instagram account, @uruguay_fototrampeo, when they had gathered video and stills of margays and of numerous other animals. These included the crab-eating fox (Cerdocyon thous), capybara (Hydrochoerus hydrochaeris), South American racoon (Procyon cancrivorus) and brown brocket deer (Mazama gouazoubira).

Scientists took note. “It is incredible what they are achieving,” says Nadia Bou, a biologist at Uruguay’s University of the Republic who contacted the couple to learn from their fieldwork.

Enabling such learnings are camera traps, the increasingly affordable and widely used devices that serve as the eyes, and sometimes ears, of trained and amateur scientists in remote woodlands, mountains and plains. Night and day and in most all weather conditions, camera traps awaken to the motion or body heat of an approaching animal, then begin capturing images without producing noise, movement or scent that might give a camera-toting human away. The devices have significantly bolstered conservation research, as well as environmental education and outreach to communities interested in learning more about local, hard-to-see fauna, according to scientists EcoAméricas interviewed for this article in Argentina, Chile, Colombia, Paraguay and Uruguay.

Among those on the forefront of the trend is Diego Valencia, chief of monitoring and information for a nationwide Chilean camera trap network. That network, called the National System of Photo-monitoring and Nature, is operated by Chile’s forest service, the National Forestry Corporation (Conaf). It currently runs 1,045 cameras in all 28 of the national protected areas under its jurisdiction.

Networks like Conaf’s are relatively recent. Camera traps have come into ever-wider use over the past 10 years, but only in the past two or three years have they been organized by environmental agencies to surveille multiple locations. The accumulation of images and other information from such systems has spurred ever-deeper analysis of the data they gather, helping wildlife experts gain new insights. For instance, until they deployed camera traps, Colombian scientists did not know that the jaguar (Panthera onca) and spectacled bear (Tremarctos ornatus) often used the same paths in shared habitat. Camera trap images also revealed that the colorful, pheasant-like hoatzin (Opisthocomus hoazin) sometimes descends from the trees to eat on the ground. And in Uruguay, scientists using camera traps learned that male nine-banded armadillos (Dasypus novemcinctus) fight violently during mating season.

Camera traps have also helped document how cattle displace the endangered Patagonian huemul, or south Andean deer (Hippocamelus bisulcus), out-competing them for land and forage. Valencia says this last example in particular serves the interests of conservation, since “showing it to the community helps get neighboring people to control their cattle.”

In Colombia, camera traps have aided experts in demonstrating “the important role of national parks,” says Angélica Díaz, an investigator at the Alexander von Humboldt Biological Resources Research Institute, a nonprofit biodiversity-research center associated with Colombia’s Ministry of Environment and Sustainable Development. Says Díaz: “We have captured images in national parks of endangered, endemic species breeding. We see jaguar and tapir cubs, which are not observed in [human]-impacted areas, allowing us to say that conservation works.”

Díaz says systematic use of camera traps has led Colombian conservation authorities to wiser technical decisions. The Humboldt Institute began using camera traps in 2013, then significantly expanded their role in 2020 with the purchase and installation of 600 cameras. Analysis of 315,000 images captured in the country’s Mid-Magdalena and Orinoco regions yielded 20,000 useful images, she says. From 2013 to 2019, Colombia’s 585 camera trap sites yielded images of 172 different bird, mammal and reptile species. Following the purchase of 600 more cameras, images of 232 species were recorded in 2020 alone. “With these results it will be possible to develop, for the first time, biomodels of species distribution at a regional scale, which will inform connectivity and cost-effectiveness analyses to optimize conservation investments,” Díaz says. The data also will shed light on “how human intervention affects biodiversity and biodiversity-loss thresholds,” she adds.

Experts say camera-trap images have proven immediately effective in easing unfounded public fears about wild animals. Notes Díaz: “Large felines are perceived as a threat, but once the camera shows them in their environment, that perception immediately changes in local communities.” Although the Humboldt Institute’s camera-trap program was designed mainly to aid wildlife-protection planning, the informal use of it in community education has become the project’s “most influential aspect,” she says.

In Argentina, a nonprofit called the ProYungas Foundation has used camera traps for 10 years to monitor wildlife in both natural and agricultural areas. The latter effort, called Protected Productive Landscapes (PPP), has involved the installation of camera traps for an average of 40 days at sites in the northern provinces of Formosa, Jujuy, Salta and Tucumán. “The information has helped improve distribution maps for various species [and] confirm the presence of certain species that were thought to be extinct in certain places,” says Alejandro Brown, the foundation’s director. Brown adds the camera traps also reveal that the daily patterns of activity of many species at different times of the year, leading to improvements such as “emergency stairs” that animals can use to extract themselves from irrigation canals.

The ProYungas project’s objective is to get landowners to take on the responsibility of protecting species that camera traps have shown are living on their land. With the help of US$780,000 from the European Union, the ProYungas Foundation has expanded monitoring in the Chaco region, particularly on agricultural and natural lands near the Pilcomayo River and its wetlands. Over the next three years, the foundation plans to expand its efforts in northern Argentina to promote the improvement of farming practices with wildlife protection in mind. Brown points out that this region, home to a thousand indigenous communities of 20 different ethnicities, is where 90% of Argentine agricultural expansion is occurring, along with its associated deforestation and ecological destruction.

In Lavalleja, Uruguay, the forest until very recently was seen by locals as little more than a source of firewood. Thanks to the use of camera traps in the area, community members are now more aware of the dozens of animal species that inhabit nearby woodlands. “The teacher of the local school has known us from the beginning [early 2021] and has been showing the videos to kids in the class,” says Agustino Alonzo, whose camera-trap work in the area with Valentina Barreto caught the attention of Uruguayan scientists. “Through the window they see hills where we have cameras, and on video recordings they see animals that live there but at first glance are not visible. Academics lack what we have in abundance: knowledge of and access to habitat where we’ve lived all our lives.”

After biologist Nadia Bou saw Alonzo and Barreto’s monitoring work and contacted the pair, they agreed to set their cameras to provide contextual information including the time of sightings, the outdoor temperature and the moon phase. Data of this sort would help scientists fine-tune wildlife protections for specific areas, she says.

From a research standpoint, the ability of scientists to observe wildlife at close range—for instance watching females interact with their offspring—dramatically improves their understanding of species that are difficult to observe. Bou, whose area of research is wild cats, says Alonzo and Barreto’s videos and stills offer richer information on margays than all other data and images from previous Uruguayan sightings of the cat. Says Bou: “We have very little information on this nice, striking and little-known species.”

In Chile, Conaf’s Valencia says continuous, systematic monitoring with camera traps allows researchers to gauge the quantity of wild animals in a certain area and to learn how they interact with others of their species and with the environment. The expansion of projects to include hundreds of cameras has sometimes involved a deliberately random broadening of coverage in hopes of capturing more variety.

Valencia says that when Chilean forest agency personnel set up the agency’s first camera traps in 2014, they played it safe, positioning them at watering holes. In the Llanos de Challe National Park, located in northern Chile’s arid Atacama region, the cameras captured images of pumas (Puma concolor) and Pampas cats (Leopardus colocolo). As the monitoring system was built out to cover more of the park, more puma sightings occurred. This, Valencia says, “gave a picture of the animal’s spatial distribution and its use of the habitat.”

Says Héctor Soto, director of Conaf’s Atacama region: “The puma, as a meat-eater and top predator, is one of the key groups needed to ensure that natural ecosystems function properly, since it keeps natural populations of prey in balance. In the case of the smallest felines, such as the Pampas cat, their presence indicates that the ecosystem is reasonably well conserved.”

Preventing abuse
By revealing the presence of certain species, however, a camera trap could endanger the animals by tipping off illegal hunters to their location. To reduce the chances of this, Chile uses a system of large quadrants for monitoring purposes and only reports in which of these quadrants a given sighting occurs, withholding the specific location within the quadrant.

“Information has to be public, but the sensitivity of the information that is released has to be taken into account as well to avoid [unfortunate] consequences,” says Valencia. “This issue is very sensitive in other parts of the world, especially in the case of gorillas.”

In Paraguay, the Association for the San Rafael Mountain Chain (Pro Cosara), a conservation nonprofit, has used cameras for several years to monitor San Rafael National Park—home to one of the country’s few remaining contiguous swaths of Atlantic Forest. This tropical forest biome once covered two million square kilometers (770,000 sq. miles), stretching from inland portions of present-day Paraguay and Argentina northward along the Atlantic coast of what is now Brazil. Today less than 15% of it remains, and much of that is highly fragmented. Pro Cosara frequently changes camera locations to gain a variety of perspectives. The Paraguayan habitat and biodiversity it monitors have been under severe pressure from forest fires, poaching and illegal land clearing for agriculture.

Once cameras are installed in the field, their functionality is not necessarily ensured. Camera trap operators interviewed for this article report setbacks that include a cow toppling one camera trap, a spider spinning a web over another, and a fox urinating on a third. Sometimes humans who come across camera traps steal the equipment. And if left for long periods, cameras can reach their recording capacity or use up their battery power. That’s why cameras that are close enough to check on regularly are often used to capture video, but those in more remote locations typically take still pictures.

Higher tech
The technology is advancing rapidly, however, with cameras becoming increasingly autonomous, sturdy and capable of recording images over ever-longer periods—and with ever-greater clarity. And it is becoming more feasible to transmit images directly. Indeed, with the use of camera traps growing, a key challenge has been to filter the rising tide of images they produce. Colombia’s Humboldt Institute plans to speed the process by using artificial intelligence to identify species captured on video, says Angélica Díaz.

Valencia says Chile is taking advantage of new technology, too. “We are heading toward a form of image recognition that comes from security technology in order to identify species,” he says. The result, he explains, will be “data that can be applied to science and management for use in decision-making.”

Experiments are also underway with autonomous devices that capture audio, an approach that is already used in bat research and could bolster work ranging from species identification to environmental enforcement. Says Valencia: “It can detect gunshots or the sound of a chainsaw, so we are going to explore this world of audio sensors.”

Meanwhile, though, the current, less elaborate camera-trap technology has been a boon. Says Díaz: “There were hardly any records of native felines in [Colombia’s] natural history museums,” she notes. “The abundance of images we have now of mammals in general is surprising and extremely useful.”