The Critically Endangered pied tamarin Saguinus bicolor (family Callitrichidae) lives in the forests of Central Amazonia, Brazil. It has twice been listed as one of the 25 most threatened primates globally. It is threatened by the loss and fragmentation of its habitat and by loss of range to the congeneric species Saguinus midas. Following the implementation of the National Action Plan for the Conservation of the Pied Tamarin, conservation action has included the creation of a Wildlife Refuge. However, much remains unknown about the species’ distribution limits, occurrence in remote areas and its populations in protected areas.

Camera traps in the treetops, autonomous recorders and, more recently, drones with thermal cameras have revolutionized the way researchers search for arboreal animals, especially in difficult-to-access terrain. Thermal cameras allow visualization of the temperature difference between animals and the forest, facilitating detection.

In Central Amazonia, we have been using camera traps and autonomous recorders for several years to monitor S. bicolor, with good results. The use of drones with thermal cameras has been possible thanks to a partnership with the companies Ambientare and TNE Transnorte Energia S.A., within a wildlife conservation programme of IBAMA (the Brazilian Institute of Environment and Renewable Natural Resources). Despite the low expectation of their effectiveness in detecting a primate with a body weight of only 500 g, in a region of high background temperatures, we made the first record of a group of at least four pied tamarins in March 2025, in a forest with trees 15–25 m tall, with four subsequent records during the rainy season (12 November 2025, 25 and 27 January 2026 and 1 February 2026) in the same vicinity, confirming that drones with thermal cameras are a promising tool to complement other techniques being used to detect pied tamarins.

There are still many challenges to be addressed in optimizing this new technique, such as the limited availability of suitable forest openings for safe takeoff; poor signal reception caused by dense, tall vegetation on relatively flat terrain; high local temperatures within just a few hours after sunrise, which reduce the temperature contrast between animals and their forest surroundings; and frequent heavy rains that make flights impossible. Nevertheless, we expect that with creativity, practice and the addition of accessories such as external antennas, efficiency will be increased and protocols will be developed, and drones with thermal cameras may soon become an excellent tool for S. bicolor research and conservation.

The first group of pied tamarins Saguinus bicolor detected by a thermal camera on a drone; on the left, thermal image with at least three individuals; on the right, RGB colour image from the digital zoom ×56.