Project
© Adobe
© Gonzalo Pardo
Chloephaga rubidiceps
Chloephaga picta
Chloephaga poliocephala
Scope of the project
In the 1930s, they were declared a pest and the massive destruction of their nests was promoted, as well as the use of airplanes, poisoning, control hunting and sport hunting. These actions resulted in a drastic decrease in their populations. Currently, in the wintering areas, the geese are persecuted by some farmers and sport hunting continues to be practiced illegally. On the other hand, their breeding areas have been modified due to overgrazing by sheep and cows, and the introduction of exotic predators, such as the American mink, factors that have probably reduced the reproductive success of these species.
© Mariano Bertinat
© Pablo Díaz
© Adobe
© Santiago Cicotti
context
Geese are waterfowl similar to geese endemic to South America. Three of them, the Ruddy-headed Goose, the Ruddy-headed Goose and the Ruddy-headed Goose have migratory populations and are endemic to southern South America, in Argentine and Chilean Patagonia. All three are categorized as endangered at the national level, both in Argentina and Chile. In the 1930’s they were declared pests and the massive destruction of their nests was promoted, as well as the use of airplanes in wintering areas, poisoning, control hunting and sport hunting. These actions resulted in a drastic decrease in their populations. Currently, in the wintering areas, the geese continue to be persecuted by some rural producers, but also sport hunting continues to be practiced illegally. On the other hand, their breeding areas have been modified due to overgrazing by sheep and cows and the introduction of exotic predators, mainly on Tierra del Fuego Island, factors that have probably reduced the reproductive success of these species.
patagonia in action program
Technical Team
Completed
The objective of this particular project was to study aspects of the ecology of the three threatened species of migratory geese, the Ruddy-headed Goose, the Ruddy-headed Goose and the Ruddy-headed Goose, to generate recommendations for their conservation in the breeding area. The specific objectives of this line of research were to characterize the environment used by the three species in the breeding area at two scales, study the breeding biology of the Ruddy-headed Goose, study the impact of terrestrial predators on reproduction, and characterize the interactions between the geese and livestock.
The work was carried out in Santa Cruz and Tierra del Fuego. During the work we characterized the habitat used by the geese during the breeding season using the transect count method and linked it to different vegetation variables, presence of wetlands and other herbivores. To study the reproductive biology of the Common Goose we took into account the activity of the males (which defend the territory) and conducted a systematic search for possible nesting sites. Once these sites were found, we used camera traps to monitor the nesting activity of the Ruddy-headed Goose. To evaluate the presence and frequency of use of native and exotic predators, we conducted transects in search of feces and tracks. Among these native predators we can mention the Gray and Red Fox and the American Mink as the exotic predator. To choose the sites where the nests were placed, we took into account the previous record of Common Goose pairs and/or the presence of Ruddy-headed Goose in the area. To investigate interactions between geese and livestock, we recorded the number of sheep, cows and/or horses within 100 m of the group or pair. We also recorded the disposition of the livestock with respect to the groups of geese, i.e. if they were intermingled or on the periphery of the group, as well as the behavior of groups of geese through observations from vehicles. In addition, electric fences were created to exclude cattle from nesting sites.
The main results we obtained are presented in several scientific articles and in Natalia Cossa's doctoral thesis (2019). We managed to obtain information on the habitat use of migratory geese in their breeding area, where successive surveys show that there are mixed groups of individuals of the three species, of two of them, or, mostly, monospecific groups of Common Goose. The latter was present in almost all groups (98%) and was the most abundant in all surveys, followed by the Ruddy-headed Goose, and finally by the Ruddy-headed Goose. In turn, these groups were found mainly in the summer season and in sites with grass, meadows and coironales. All this is very interesting for the protection of the species, since it would indicate that the protection of the same in the cold months would be key to the conservation of the cauquenes that occupy the southernmost areas of the continent. We studied the breeding biology of the Ruddy-headed Goose in the northwest of Santa Cruz where we found nests mainly in meadows and in an environment of highly variable vegetation cover. In addition to this, we observed the presence of domestic cattle in these areas, which disturb the females during incubation, forcing them to abandon the nests. This observation allowed us to create an enclosure area with an electric fence, which was monitored through camera traps (inside and outside the enclosure). As a result, we obtained that inside the enclosure 67% of the nests were successful, but outside the enclosure, only 13%. These preliminary results indicate that electric fences are efficient in increasing the reproductive success of geese. This information is essential to advance in the implementation of management actions for the conservation of geese in different zones of the breeding area, with special emphasis on the most threatened species, the Ruddy-headed goose. The main predators of the nests in the areas studied were the Gray and Red Fox, and in the feces of American Mink we recorded the presence of adults and chicks of the Ruddy-headed Goose. The results of the study of interactions between cattle and geese show no evidence that the former provide a feeding benefit to the geese. This means that the presence of cattle affects the behavior and reproductive success of the geese.
© Matías Cabezas
© Matías Torreguitar
© Matías Torreguitar
© Patricia Mancilla
Gabriela Gabarain
Active
The Ruddy-headed Goose is categorized as critically endangered at the national level (in Argentina and Chile), and part of the problems we have detected is the low reproductive rate in its natural environments of Santa Cruz and Tierra del Fuego. In these cases, population reinforcement from captive-bred individuals is a conservation strategy to consider. Ex situ rearing involves the removal of the clutches and the subsequent incubation of the eggs and rearing of the chicks until they become independent. In birds with restocked clutches, this removal encourages a second clutch. There are successful experiences of ex situ rearing of these species, the result of which was the creation of an ex situ rearing protocol, which is available for replication. The Ruddy-headed Goose, a species that is very close to the Colorado Goose, is categorized as endangered in Argentina, but its populations are still abundant in some sectors of Patagonia. For this reason, the objective of this work was to adjust the protocol to be applied to cauquenes in Argentina, with the aim of reinforcing wild populations. Although we used the Ruddy-headed Goose as a model because of its lower degree of threat, the adjusted protocol will aim to reinforce mainly the populations of the Ruddy-headed Goose.
In November 2021 we collected eggs from the Common Goose at Estancia La Vizcaína, in northwestern Santa Cruz. We transferred them to the rearing facilities located at the "Juan Mazar Barnett" Biological Station, in a conservative with a stable heat source. Once at the center, we labeled them, weighed them and placed them in the incubator. We periodically weigh the eggs and carry out control candling. The last two days of incubation we transferred the eggs to a hatcher conditioned with recovered down, moved them to an indoor pen with a heat source (lamp) and fed them with balanced feed and herbaceous plants (mainly Trifolium sp). Feeding was ad libitum and water was also permanently available. After ten days, we moved them to an outdoor pen with a small artificial pond where they began to feed naturally. Periodically (~5 days) we weighed and measured the chicks to evaluate their growth.
- Will Costa - Wildfoul and Wetland Trust (UK).
- Centro de Rehabilitación de Aves Leñadura, Punta Arenas, Chile.
We collected a complete clutch of six Common Goose eggs, the transfer lasted approximately 2 hours and we incubated them artificially for 23 days. The 6 chicks hatched within 19 hours of each other. The development and growth of the individuals was as expected. At 68 days of life we released 5 fully fledged young near the collection site. In subsequent follow-ups we observed that the behavior of the released individuals did not differ from that of the free-living specimens. The successful release of 5 juveniles demonstrates that it is possible to reinforce wild populations from captive-bred individuals. The experience of working with the Ruddy-headed Goose suggests that it would be possible to replicate the process with the Ruddy-headed Goose given their similar breeding and living habits.
© Gonzalo Pardo
© Patricia Mancilla
© Patricia Mancilla
© Gonzalo Pardo
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