Friday 20 August 2010

THE EGYPTIAN VULTURE IN EXTREMADURA (2008)

In 2008 SEO/BirdLife promoted the 3rd National Egyptian Vulture Census (Neophron percnopterus). A total of 179 pairs were found in Extremadura, although 12 are rated as only probable breeders. The shareout between Extremadura's two provinces is very uneven, Cáceres weighing in with 80% (143 pairs; 12 probable) and Badajoz with the remaining 20% (36 pairs). Although the coverage was good, the census probably understates the real population due to the difficulty of censusing the species (it is calculated that 3 visits per territory will detect only 75% of the population). These figures mean that the region ranks third in importance nationwide, behind Castilla y León and Aragón, accounting for 11.5% of the 1452-1556 pairs found in the nationwide census. Broken down by provinces, Cáceres boasts the country's biggest Egyptian Vulture population, ahead of Huesca and Navarre; while Badajoz ranks in a modest 18th place nationwide. The mean regional density was 0.42 pairs per 100 km2, well above the national mean density of 0.3). Cáceres recorded a much higher density (0.79) than Badajoz (0.16).

The Egyptian Vulture has an ample range throughout the province of Cáceres; it is missing only in flat areas (river plains of Alagón and Tiétar, Llanos de Brozas, Cáceres, Trujillo y Zorita) and some mountainous areas such as the Sierra de Gata. In the northern third of the province there are three small clusters: Las Hurdes (2 pairs), Alagón medio (3) and Gredos (7). The rest of the territory is occupied fairly evenly: centre-east, in the final half of Alcántara reservoir, including Canchos de Ramiro (19 pairs); Monfragüe (34); the area southwest of Monfragüe, between Cañaveral and the rivers Almonte and Tamuja (9); southwest of the province, taking in the Tajo Internacional, Sierra de San Mamede and the rivers Aurela and Salor (30); Sierra de San Pedro (12); Ibores and Villuercas (25) and three isolated pairs in Montánchez, Llanos de Cáceres and Trujillo. Particularly worthy of note is the high density recorded in Monfragüe, Tajo internacional and Canchos de Ramiro. The species is scarcer and more local in the province of Badajoz, where it breeds in La Siberia (10 pairs), La Serena (11), central sierras (6) and Alburquerque-Sierra de San Pedro (9). Broadly speaking the Egyptian Vulture is a rock nester on cliffs and crags in extensive livestock rearing areas. Curiously enough, however, this census unearthed one Cáceres pair of Egyptian Vulture breeding in a White Stork's nest in a Stone Pine (Pinus pinea). This was apparently the only tree nest in Spain in 2008, although there are past records of two pairs breeding on Holm Oak and Pyrenean Oak in 1990 in Salamanca.

There is little to go on in terms of breeding performance. In the province of Cáceres 81 pairs began incubation with a failure rate thereafter of 18% (15 pairs). Likewise, a sample of 34 nests with initiated breeding in Monfragüe and Tajo Internacional shows a breeding success rate of 1.03 young per pair that began breeding and a fledgling rate of 1.25. Both figures were the best recorded in Spain in 2008, well above the respective national means of 0.88 and 1.03. They should be taken with some caution, however, in default of any detailed information about the monitoring procedure.

The published figures suggest that the Egyptian Vulture in Extremadura is recording a steadily upward trend. Each census has always recorded higher figures than the previous one. The 50% increase recorded from 1987 (108 pairs) to 1992 (151 pairs) is due mainly to increased efficiency of the census. In the eight year period running from 1992 to 2000 the population increased by 13% up to 170 pairs; in the next eight year period, running from 2000 to 2008, the growth rate was 5%, increasing to 179 pairs. Given that it is impossible to ascertain how far this increase is due to a better knowledge of the species, the most prudent conclusion to draw is that the Egyptian Vulture is holding steady in Extremadura.
Between the censuses of 2000 and 2008, 42 territories were apparently abandoned while 61 new ones were taken up. These are very high figures that do not tally with the findings of other better studied areas; they could therefore be due to differences in criteria and quality from one census to another. At provincial level the situation seems to be better in Cáceres, where a certain growth is observed, than in Badajoz where the population seems to be stable. On a smaller scale, local differences are observed within the general scenario of ongoing stability, with a continuation of the abovementioned pre-2000 trend of abandoned territories in peripheral areas and new territories taken up in areas of lower density. Such are the cases of Monfragüe, Tajo Internacional and Villuercas, where real increases are recorded; conversely, declines have been observed in northern Cáceres or La Siberia in Badajoz. It should be pointed out here that cases of poisoning have been discovered in the latter district, and this may well be behind the specie's decline.

The 2008 Extremadura Egyptian-Vulture census was carried out by the Dirección General del Medio Natural (Environment Board) of the Junta de Extremadura (Regional Council of Extremadura), with subsequent addition of information from SEO-Cáceres.

Sources:
Prieta, J. 2009. El alimoche común en Extremadura. Pp. 106-109.
Prieta, J. 2009. El alimoche común en Badajoz. Pp. 109-111.
Prieta, J. 2009. El alimoche común en Cáceres. Pp. 111-114.
In:
Del Moral, J. C. (Ed). 2009. El alimoche común en España. Población reproductora en 2008 y método de censo. SEO/BirdLife. Madrid.