Crowned Eagle – Argentina

Crowned Eagle – Argentina

Reconstitution of rescued specimens of Crowned Eagle and study of habitat use. 

Crowned eagle (Harpyhaliaetus coronatus) is one of the most endangered birds of prey of the Neotropical region.

The result of Telenax transmitters have favored us during fieldwork, we have found the tagged animals in less time thanks to its directionality and clean signal despite the difficult terrain. Marked birds showed a high tolerance to the transmitter.

Background:

Crowned eagle (Harpyhaliaetus coronatus) is one of the most endangered birds of prey of the Neotropical region. Its distribution includes Bolivia, southern Brazil, Paraguay, Uruguay and Argentina, mostly inhabiting open areas and semi-arid forests with physiognomy of savanna. The species is included in the lists of threatened fauna in Brazil and Argentina and is considered as locally extinct in Uruguay (BirdLife International 2004).

During the past decades the crowned eagle was considered a vulnerable species worldwide (Collar et al. 1992) but its status has been recently reviewed and has been included in the category of endangered species, with an estimated world population of less than 1000 individuals for 2001 (BirdLife International 2004). However, the influential factors on the current status of conservation of this predator have not yet been clearly determined. Some authors suggest that a major cause of population decline of the species is habitat loss (Collar et al. 1992), although for others direct prosecution by man would have the most threatening factor (Sarasola & Maceda 2006 Sarasola et al. 2006). Uncertainty as to the factors influencing the survival of this predator are mainly due to widespread ignorance of the ecology and biology of H. coronatus (Sarasola et al, 2006).

Studies on the use of habitat of a specie is particularly important when framing efficient conservation strategies (Newton 2004). There are currently very few works published for the specie, based mainly on anecdotal descriptions given the difficulty of finding individuals with whom to make methodical studies. Bellocq et al. (1998) presents results on habitat use based on surveys of residents and survey of the area where individuals were recorded. This work is the only study to date focused on habitat use of H. coronatus. Moreover in recent years there have been studies and descriptions of the environment in the nesting site (Bragagnolo et al. 2006) at landscape level (Paulini 2009), reviews and technical reports on the species (Bellocq et al. 2002 Maceda 2007 Chebez 2008, Fandino et al. 2008).

Although several studies on reproductive biology and diet of the species (Maceda 2007) are available, the information is still scarce, as are studies of habitat use and dispersal. According to different authors and specialized institutions, this information is considered essential for the conservation of the crowned eagle (Bertonatti & Aprile 1998, Newton 2004, Maceda 2007 Chebez et al. 2008 GNCAC in prep.). There are currently studies being performed on the biology and ecology of crowned eagle in two provinces of Argentina, representing the region of Desierto del Monte (Mendoza) and the Espinal-Monte (La Pampa). Studies about dispersal and movement of crowned eagles using satellite technology have started in the province of La Pampa (Sarasola et al. Unpublished data).

Studies on the use of top predators for education and local awareness of the biology, ecology and behavior have proved a useful tool for conservation for the species under study and the environment that they use (Cuesta et al. 2000, Peregrine Fund 2006, Sergio et al. 2006). Research should be complemented by extension work to enable residents and the general public to increase their knowledge on these species, thereby creating a sense of belonging so they can collaborate with their conservation (Maceda 2007). In Argentina, research projects on H. coronatus have gradually incorporated a component of education and outreach to local communities and mass media. These educational extension tasks include among others, the screening of educational videos and distribution of graphic material developed by government institutions and NGOs dedicated to conservation (Sarasola et al. Unpublished data). However, the species is still unknown at different points of distribution,
making it necessary to continue and reinforce the work already in place. Some measures of ex – situ conservation, such as strengthening population recovered from animals in rehabilitation centers have successfully fulfilled the purpose of supplementing and enhancing wild populations at a stress of financial and human resources far less than that would imply a captive breeding program (Negro et al. 2007).

The Conservation and Rehabilitation Project Raptor (PCRAR) of the Zoo of Buenos Aires, has fulfilled this function rescuing nine individuals of the species and relocating, to date, six of them: one in San Luis (Capdevielle et al. 2005, 2006 a, b, c), two in Mendoza (Rodríguez pers com. 2006, Capdevielle et al. 2008 a, b) and in the provinces of Catamarca, San Juan and La Pampa. Thus, rescue, rehabilitation and release into the wild of seized or convalescent in the natural environment animals is
presented as a valid form of conservation for the crowned eagle (Sarasola et al. Unpublished data). Additionally, the PCRAR conducted educational campaigns in those areas were specimens were reconstituted, contributing to the knowledge of it locally. During the first year of release, with the collaboration of governmental institutions in the province of San Luis, an educational video was made that complements extension work of various projects working with the species and is also available to the general public via Internet . In 2008 it was possible to access the mass media for the first time, which represented a major achievement in the diffusion level, thereby increasing popular knowledge of the species and its conservation problems. In 2009 a thematic calendar was produced on the species and distributed at the XIII RAO and in different areas and institutions involved in conservation. The extension work carried out hase shown a great acceptance by the recipients of information and media.

Therefore, it is particularly important to continue with these tasks to contribute to the conservation of H. coronatus.

Objectives:
Strengthen wild populations through the release of rescued specimens. Contribute to the knowledge of the biology and ecology of Harpyhaliaetus coronatus by studying the habitat use, analyzing and estimating dispersal movements, habitat preference and use in areas of release through terrestrial transmitters and satellite technology,

Methodology:
For monitoring of the specimens we have used VHF transmitters, and satellite transmitters (in one case). A crucial consideration when choosing a transmitter is how the weight, size and attachment can affect the animal. Selection of transmitters is made based on recommendations and proved techniques, considering the mass ratio of the transmitter and the consequent increase in energy expenditure that the bird should use for locomotion (Meyburg & Fuller 2007). For monitoring, in the particular case of the satellite transmitter, we selected a pack of 90 gr. The satellite transmitter allows obtaining data without field personnel, and a variety of records and identification of environments at large-scale (Steenhof 2005, Fernández 2009). Besides we have used a VHF transmitter Telenax TXE-203G of 8 gr, with a duration of 7 to 8 months to monitor the specimen in the field during the critical period of the first stage of liberation. (Coleman & Fraser 1989, Meyburg & Fuller 2007, Sanchez 2009). This transmitter allows us to locate the specimen and record its activities to supplement the data needed to analyze the distribution and habitat use.

The remaining individuals carry a transmitter Telenax TXE-315BF.
Expected results:
With the results of the monitoring of individuals of H. coronatus we hope to get more precise information about the use of their environment, and thus a better understanding of their biology and ecology. Finally, it is expected that the results of these studies generate local awareness of the problem of conservation of the Crowned Eagle, creating a sense of belonging that favors the preservation of the environment.

Telenax transmitters results:
The result of Telenax transmitters have favored us during fieldwork, we have found the tagged animals in less time thanks to its directionality and clean signal despite the difficult terrain.

Marked birds showed a high tolerance to the transmitter. Compared with other transmitters from other brands, we believe that the length of the antenna (just 15 cm) has influenced to this. Another advantage is that the transmitter’s body is long (in the case of the model used), so if the eagle pulls the antenna it will not turn upwards tightening the harness (which could kill the bird).

The greatest detection distance obtained was 14 km but the signal was good even at that distance. It is thought that it could have been much further away and could have been found. The transmitter is specified to have a range of 25 kilometers without obstacles.

Article submitted by Andrés Capdevielle, director of the Conservation of Raptors Proyect at the Buenos Aires Zoo.

Telenax wishes to thank Andrés Capdevielle, Zoo of Buenos Aires and PCRAR for sharing this article.

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