Monday, 23 August 2010


In 2008 SEO/BirdLife promoted the 2nd National Golden Eagle Census (Aquila chrysaetos). A total of 123 pairs were found in Extremadura, although 14 of these are only probable. The shareout between Extremadura's 2 provinces is pretty even, with 65 pairs (6 probable) in Cáceres and 58 (8 probable) in Badajoz. Although the coverage was good, the census may well understate the actual Golden Eagle population. These figures mean that the region has middling importance on a national scale, ranking fifth with 7% of the total census of 1553-1769 pairs. Broken down by provinces, Cáceres and Badajoz come 8th and 13th, respectively, with densities similar to the national mean of 0.35 pairs per 100 km2 (density of 0.3 pairs per 100 km2 in Extremadura, 0.33 in Cáceres and 0.27 in Badajoz).

The Golden Eagle occupies much of Extremadura's territory; it is missing only from the plains of the rivers Guadiana, Alagón and Tiétar and almost the whole of southwest Badajoz. In Cáceres it breeds in the districts of Gata-Hurdes (3 pairs), Gredos (7), SPA Canchos de Ramiro (2), southwest of the province from Tajo internacional to Sierra de San Pedro (15), Monfragüe and the surrounding area (18, six in Monfragüe itself), Ibores-Villuercas (17) and Montáchez-Trujillo (3). In Badajoz it breeds in the Sierra de San Pedro (4 pairs), La Siberia (11), La Serena (14), Campiña Sur (9), central sierras (10), Sierra Morena-Tentudía (10) and the south western corner (one isolated pair).
Although most pairs are rock nesters, 24% did nest in trees in 2008, using the following tree species: Holm Oak (13 pairs), Cork Oak (9), Maritime Pine (4) and Eucalyptus (2). At least one Gall-Oak nest is known from previous years. The proportion of tree nests is higher in Badajoz (27%) than in Cáceres (18%), with a similar breakdown of tree species. The sectors with most tree nesters were the area between Monfragüe and Llanos de Cáceres (9 pairs), Tentudía (7) and Campiña sur (5); there were also tree nests in Sierra de San Pedro (3), La Siberia (2), Villuercas (1) and Trujillo (1).

No detailed breeding information is to hand, although it is known that at least 73 pairs laid eggs and 58 pairs bred successfully (79%). Figures from 2020 point to a productivity of 0.83 young per breeding pair, similar to the national mean in 2008 of 0.8.

The published figures indicate a steady upward trend with an observed growth rate of 35% in 20 years. The trend is similar in Spain as a whole, with an observed growth rate of 40% and estimated growth rate of 20%. Broken down by periods, from 1988 to 1994 the observed increase in Extremadura was 16%; the period 1994 to 2002 clocked up a similar 17% growth rate, although 10% came in only two years (2000 to 2002); lastly, numbers apparently held steady from 2002 to 2008. Part of the increase can almost certainly be put down to better surveying than a real increase in the bird's population. This supposition is borne out by two factors: firstly, the fact that the sharpest increase came in a period of only two years and, secondly, the higher proportion in recent years of tree nesters (trees nests are harder to find and were probably overlooked in earlier counts). In general many of the traditional nest sites repeat from one census to another, though there are known cases of abandoned territories and occupation of new ones, some in flat almost treeless areas. Given that the objective and subjective factors of this apparent increase cannot really be disentangled, the most prudent conclusion is to assume that the Golden Eagle is holding steady in Extremadura.

The 2008 Extremadura Golden Eagle Census was carried out by the Dirección General del Medio Natural (Environment Board) of the Junta de Extremadura (Regional Council of Extremadura) with subsequent grafting on of information from SEO-Cáceres.

Prieta, J. 2009. El águila real en Extremadura. Pp. 107-110.
Prieta, J. 2009. El águila real en Badajoz. Pp. 111-112.
Prieta, J. 2009. El águila real en Cáceres. Pp. 112-114.
In: Del Moral, J. C. (Ed). 2009. El águila real en España. Población reproductora en 2008 y método de censo. SEO/BirdLife. Madrid