ACTIVITY REPORT – UPDATE OF THE POPULATIONAL CENSUS OF Mergus octosetaceus
UPDATE OF THE POPULATIONAL CENSUS OF Mergus octosetaceus
Jalapão State Park and ESEC boundary of Serra Geral of Tocantins
Períodos: 02 a 06/07/2018 e 23 a 27/07/2018
From: 02nd – 06th of July, 2018 and 23th – 27th July, 2018.
Team: M.Sc. Marcelo Barbosa, Master student Aline Vilarinho (Naturatins) and Alexandre Resende (Veterinarian Zooparque / Blue Stone)
Collaborative institutions: Instituto Natureza do Tocantins – Naturatins and Blue Stone Metals – Piracicaba/SP.
UC’s: APA from Jalapão, Jalapão State Park and ESEC boundary of Serra Geral of Tocantins
During the period from July 2nd to the 6th, 2018, technicians from Naturatins (Marcelo and Aline) traveled to Jalapão to visit land areas of the Rio Novo of the APA and PE of Jalapão with nests / nesting records in the past years, with the purpose of verifying their reuse in this reproductive age and also of establishing strategies for the expedition that would be carried out in the week of July 23rd to 27th, 2018.
We visited the sites of 03 nests of the species in the Rio Novo used in 2015 (10°34’21,10″S/46°45’22,20″W) and 2017 (2 nests – 10°27’26,40″S/46°51’6,30″W and 10°37’50,50″S/46°45’13,10″W). In only one of the nests there was a more detailed verification, with inspection of the interior of the cavity, which was empty, being this the nest used in 2017. In the other two nests it was possible only an external verification of the site and observation of the presence or not of the wandering male close to the nest (Picture 1). In this case, no individual was seen in the vicinity of the other nests. On July 4, we detected a male (Picture 10) in the Rio Novo (10º33’47,87’’S/46º45’38,10’’W) near the bridge over the TO-255.
Probably the male belongs to Pair 1 known for inhabiting the stretch above the bridge, according to Barbosa et al. (2011, 2015) and Barbosa (2018).
From May 23 to 27, 2018 we carried out the expedition along the stretches of the Rio Novo and Rio Preto rivers using inflatable kayaks donated by Blue Stone. The travel to the site was through land on July 23th, using a 4×4 vehicle. The fuel and the daily presence of technicians was provided by Naturatins as a counterpart. In this vehicle, which was driven by Luiz Wanderley from Naturatins, were also present biologist Marcelo Barbosa and veterinarian Alexandre Armando Netto, both members of the advisory group of PAN of the of the Brazilian Merganser.
The expedition also counted with the participation of a team from EPTV Campinas, an affiliate of Rede Globo, of the Terra da Gente program, which traveled by their own vehicle for the audio / visual documentation of the works. A expedição contou ainda com a participação de equipe da EPTV
The entire team was lodged in the facilities of the Posto das Dunas, which also had the support and logistics of the team from Jalapão State Park – PEJ.
On July 24, 2018 we made the shift to make the descent with inflatable boats along a stretch of Rio Novo River On July 24, 2018, we made a shift to to inflatable boats along a section of the Rio Novo, near the bar with Rio Preto, ESEC Serra Geral do Tocantins limit.
On July 24, 2018 we made to make descent with inflatable boats along a stretch of the Rio Novo, near the bar with the Rio Preto, limit of the ESEC Serra Geral of Tocantins. A stretch of about 18 km was followed with a route followed to the bridge over the Rio Novo river in TO-255 (Picture 2).
In this section two groups were detected: a pair and a couple with 04 ducklings with about 15 days of development, according to a visual evaluation performed in the place. In this section it was also possible to verify, by means of a more detailed inspection of the interior of the cavity, that there was a reuse of a used nest in 2015, which could not be verified in the week of 02 to 06 of July/2018 when the nest was revisited by land. There were feathers, egg shells and two rotten eggs in the nest, which were collected for analysis with genetic studies (SISBio License 26006-11). This nest reuse is the first fact verified for the Jalapão region, which can be verified in other areas of occurrence of the species.
On July 25th we made a descent along another section of the Rio Novo, which corresponds to the tour downstream of the bridge over the TO-255 to Fazenda Progresso area, making a total of 25.5 km. In this section were also detected two groups, being a couple with 06 ducklings with approximately one week of life and a pair displayed at the end of the route. It was notorious to verify the difference in size of the ducklings compared to the family group detected in the previous day and section, being these smaller and newer. In this section, we also revisited two other known nests and none of them had been reused (Picture 3).
On July 26th, we made a descent along a tour of about 18 km of Rio Preto, bounded by ESEC Serra Geral of Tocantins and APA of Jalapão (Picture 4). The tour began in a area of the river next to the Administrative Headquarters of Jalapão – PEJ (10º35’48,70’’S/46º30’31,35’’W) and it was previously evaluated as being the section with the highest potential of occurrence of the species for presenting tour with rapids. This same area was covered in 2010 by Barbosa et al. (2015) and in the same matter no individual has been detected.
The tour presents potential characteristics, although there is a noticeable difference from the characteristics presented by the Rio Novo. The Rio Preto river is narrower and varies from shallow stretches with translucent water, to deeper stretches and with impaired visibility of the bottom, mainly due to humid compounds and aquatic macrophytes of the bottom and surface (aguapés). It was possible to verify some potential cavities for the installation of nests (10º37’21’’S/46º34’39’’W e 10º38’22’’S/46º37’17’’W). The cavities were in areas with good visibility of the water column and in shallower stretches of the river, with a verified bottom showing a sandy-rock stratum similar to what we found in the Rio Novo.
On the same July 26th, a Naturatins team that accompanied volunteers in the Rio Novo area, near Cachoeira da Velha, viewed and registered a couple with 05 ducklings (Picture 5). During the observations, the family group was seen foraging very close to the waterfall, which is about 10 to 12 m high. It was possible to verify that two of the ducklings moved away of the group and was taken by the waterfall, while the couple and other ducklings followed upstream. It is very likely that these two ducklings have not been able to regroup to the rest of the group and can be counted as a natural loss. To what is known there was no interference and human disturbance at that moment that could be associated with the fact. This demonstrates the ducklings’ fragility in these early days of development and the need of control activities along the rivers that could further compromise the survival of this endangered species. On July 27th, we returned to Palmas.
Barbosa, M. O, Pinheiro, R. T & Carvalho, V. F. 2011. Descrição de ninhos do pato-mergulhão (Mergus octosetaceus) em cavidade arbórea na região do Jalapão, Tocantins, Brasil. Cotinga 33: 71-75.
Barbosa, M. O, Pinheiro, R. T & Barbosa, K. V. C. 2015. Population estimate of Mergus octosetaceus in the Jalapão region, Tocantins, Brazil. Rev. Bras. Orn. 23: 417-427.
Barbosa, M. O. 2018. Novos registros de ninhos do peto-mergulhão Mergus octosetaceus na região do Jalapão, Tocantins, Brasil. Cotinga 40: 104-108.
Picture 1 – Visited and known nests in Rio Novo
Picture 2 – 18 km way from Rio Novo river, traveled on July 24, 2018.
Picture 3 – 25,5 km way from Rio Novo river, traveled on July 25th, 2018.
Picture 4 – 18 km way from Rio Preto river, traveled on July 26th, 2018.
Picture 5 – General map of the expeditions of July 2018 held in the region of Jalapão – Tocantins showing the stretches traveled, groups detected and nests known and visited.
Picture 6 – Blue Stone Team, Naturatins and Terra da Gente
Picture 7 – inflatable kayak donated by Blue Stone and used in the expedition
Picture 7 – Naturatins team traveling the Rio Novo
Picture 8 – Potential cavity identified in Rio Preto (closed view)
Picture 8 – Potential cavity identified in Rio Preto (open view 1)
Picture 8 – Potential cavity identified in Rio Preto (open view 2)
Picture 9 – Potential cavity identified in Rio Preto (open view)
Picture 9 – Potential cavity identified in Rio Preto (closed view)
Picture 10 – Adult male viewed on July 4th, 2018 near the bridge over the Novo Rio river on the TO-255.
Picture 11 – Pictured by Alexandre Resende. A couple with 04 ducklings in the Rio Novo river, stretch about 18 km with route followed to the bridge over the Novo Rio river in the TO-255 (Figure 2)
Picture 12 – Pictured by Alexandre Resende. A couple with 06 young ducklings Rio Novo, stretch down the bridge on the TO-255 to Fazenda Progresso area.
Picture 13 – Pictured by Alexandre Resende. Ducks donated by Blue Stone Metals to Naturatins and researcher Marcelo Barbosa.
ACKNOWLEDGMENTS TO THE INVOLVED ONES IN THE EXPEDITION