Brazilian Merganser (Mergus octosetaceus)

Mohamed bin Zayed Species project number 232531982

Overcoming Breeding Bootlenecks of the Northern Brazilian Merganser Population

The project primary objetive is to detect the current contraints affecting this Brazilian Merganser population's breeding success. To achieve this goal the breeding monitoring activities coverage will increase with a larger field crew and longer field expeditions, closely following Brazilian Merganser´s active nests during the 2024 breeding season, as well as the families after hatching. As a cavity-nesting species, before the nesting season we will improve their nesting sites availability artificially opening entrances of suitable-sized tree cavities when too small for the species' use. And artificially shortening tree hollow entrances much larger than the species demands. Both managements had been already successfully tested in two nests in 2021 and 2022 in the Novo River, both with Brazilian Merganser breeding activities following the nest hollow entrance managements. Artificial nests also will be tested hoping to increase the nest sites availability for the species. After hatching, the first two weeks have been proved challenging for the newborns. Most of the ducklings´ losses occur within this period and few field observations are available to establish the major causes of such mortality. Besides the nesting activity monitoring, the crew will conduct regular censuses using an inflatable boat and oars in the whole 145km section of the Novo River inhabitated by this Brazilian Merganser population. The mergansers will be counted and thei key river sectors used after the brood left the nest will be mapped. Another important aim is to add hands-on training for at least one young researcher. The preferrence will be for those from Tocantins (where this population lives) or nearby states hoping to improve the number of local people involved in the species study and conservation.