Raiders of the Lost Eagle
-The Longest Trip-
Yesterday I returned from one of the most exhausting trips I made during my time in Santa Rosa, we drove 1400 km in two days to recover the GPS-tracker of a dead eagle in the surroundings of Sierra Grande (Fig. 1). In this case, it was not a crowned eagle (Buteogallus coronatus) but a Black-buzzard eagle (Geranoaetus melanoleucos).
The black-buzzard eagle (Fig. 2) is medium sized raptor widely distributed in South America, it can be found from Colombia to Tierra de Fuego (the southern province of Argentina), in both sides of the Andean Mountains. The adults of this species have a very characteristic plumage, with a dark grey colouration in the head and back, and a contrasting white chest. On the other side, during the first three or four years of life they exhibit browner colourations.
Figure 1: Main places visited during our trip. The red point represents the village of Arrollo de la Ventana
This species usually inhabits mountainous areas with low and scattered vegetation. Still, black-buzzard eagles can also be found in forests and other kind of habitats in certain parts of South America. The main item of their diet are rodents, like for example the yellow-toothed cavy (Galea musteloides; Fig. 2), but they also prey on other species like birds or insects. Regarding the conservation status, the black-buzzard eagle is categorized as “Least Concern” by the UICN.
Figure 2: Left: a juvenile black-buzzard eagle (Geranoaetus melanoleucos). Right: A yellow-toothed cavy (Galea musteloides).
According to the GPS coordinates, the dead eagle was located 70 km away from a village named Sierra Grande in the Province of Rio Negro. This 7500-inhabitant village, was traditionally devoted to mining until the year 2017, when according to Wikipedia the last mine closed. The landscapes of this area are quite different from those that can be found in La Pampa (Fig. 3). During the 70 km ride in a dirt road from Sierra Grande to the point where the eagle was, we realized that this was a hillier and more mountainous place with significantly fewer trees than in the typical places we visit when looking for crowned eagles
Figure 3: Some of the landscapes found during our trip.
We employed 8 hours to travel the 700 km between Santa Rosa and Arroyo de la Ventana, a small town near to the point where the eagle was. After a quick lunch and some more driving we arrived to a farm where the road ended. We walked the last 5 km enjoying the views and the temperature, in spite of the rocks that made our walking rather difficult (Fig 4).
Figure 4: More landscapes
We found the eagle after an hour and a half walk, with some unexpected things in the surroundings. In addition to the eagle we also found four young foxes dead. I am not sure whether they were grey foxes (Lycalopex griseus) or culpeos (Lycalopex culpaeus), the two fox species that can be found in this area. Finding these dead animals was a really sad situation specially because the most probable cause of their dead was poisoning, as we also found a dead sheep probably used as a bait (Fig. 5). The use of poison if far more common than one can expect, as farmers use it to kill the cougars (Puma concolor) that are present in the area. However, most of the times other animals like foxes, eagles or even Andean condors (Vultur gryphus) die poisoned by these baits (Link).
Figure 5: Our unfortunate finding. 4 dead foxes and the black-buzzard eagle with the sheep potentially used by as a bait
After covering the sheep and the foxes with some stones, we headed back to the car and left the area. We slept in a camping close to the Colorado River, arriving in Santa Rosa the following day. In spite of the distance we traveled in less than 48 hours and the sad situation when we recovered the dead eagle, this was a funny trip. I was able to discover some isolated places of Argentina not easily accessible as a tourist and see some new bird species (Fig. 6).
Figure 6:: Some of the animals I saw during this trip. From left to right: Austral negrito (Lessonia rufa) male and female, hornero (Furnarius rufus), female Crested-black tyrant (Knipolegus aterrinus) and a Darwin's gecko (Homonota darwinii)
David López-Idiáquez 24-February-2019