THE GRIFFON VULTURE IN EXTREMADURA (2008)

The 2008 national Griffon Vulture (Gyps fulvus) census recorded 1570 breeding pairs in Extremadura, with a more realistic estimate of 1943 pairs spread out around 198 different sites: 156 colonies and 42 isolated pairs. Spain’s total Griffon population was reckoned to be about 25,000 pairs in 2008, with an educated guess of 30,000 pairs and a total population of 75,000 to 100,000 birds; this means that Extremadura ranks sixth among Spanish regions, accounting for about 6.3% of the total.

Broken down by provinces Cáceres weighs in with 1361-1743 pairs, nearly 90% of the region’s total and 5.5% of Spain’s. This makes it the 8th ranking province in terms of its Griffon population and 14th in density (8.8 pp/100 km2). Extremadura’s other province, Badajoz, is home to 199-200 pairs, 0.8% of Spain’s total, making it the 22nd province in terms of population and the 28th in terms of density (0.9 pp/100 km2). Pride of place in Cáceres goes to the River Tagus and the final runs of its tributaries Tiétar, Alagón, Almonte, Erjas, Salor and Aurela. Most important amongst the mountainous areas are Ibores-Villuercas in the south east and, some way behind, Las Hurdes and Gredos in the north, together with some sierras of the extreme southwest. In the province of Badajoz Griffons breed in three sectors: northwest (Alburquerque), centre and northeast (La Siberia and La Serena). By far the most important area of all is Monfragüe, boasting 650-800 pairs, 42% of Extremadura’s population, nearly all of them in the 18,000 hectares of the National Park.

Extremadura has only two of Spain’s 39 vulture colonies numbering over 90 pairs, both in Monfragüe: Salto del Corzo (127-170 pp) and Salto del Gitano (124-145). In Cáceres there are 17 colonies with over 25 pairs, 11 of them in Monfragüe (e.g. El Boquerón, 50-67; Portilla del Tiétar, 46; Portilla del Barbaón, 32-43) and the rest in Valencia de Alcántara (San Mamede, 59-73), Bajo Alagón (Canchos de Ramiro, 40-55; Las Bravas, 32-51), Valle del Jerte (Villavieja, 34-38) and Villuercas (Canchos de Vadillo, 23-30; Estrecho de la Peña, 26). Badajoz has another two vulture colonies with over 25 nests (Puerto Peña, 50; El Muro, Embalse de Cíjara, 29-30).

Alongside the census, breeding success was also monitored in 526 pairs, one third of the total population found, with an average of 4.2 visits. The results of this survey were: productivity 0.58 and breeding success rate 0.63; slightly lower than the figures for Spain as a whole, with a productivity of 0.62 and breeding success rate of 0.67. This figures are 12% down on 1999, although the average number of visits back then was only 2.3, so in all likelihood they were overestimated. Although the breeding success rate was nearly the same in both of Extremadura’s two provinces, productivity differed, with figures of 0.61 in Cáceres and 0.54 in Badajoz. One possible reason for this difference is the higher proportion of nonbreeding pairs detected in Badajoz (13%) in comparison to Cáceres (5%), as well as a higher number of visits in Badajoz (5 against 3.8 in Cáceres).

As for the population trend, this has always been steadily upwards since the very first national census in 1979. In this 30-year period the figure has quadrupled, with a 40% rise from 1999 to 2008, an increase of under 55% from 1979 to 1989 and 88% from 1989 to 1999. No real changes were appreciated in the breeding range from 1999 to 2008, although new colonies were occupied within and on the edge of the known range. The number of new sites occupied was 39 (up 24%), mainly small colonies and isolated pairs. The increase is therefore due above all to the growth of existing colonies. By way of comparison the increase in Spain as a whole was 58% from 1999 to 2008.

Reference:
Prieta, J. 2009. El buitre leonado en Extremadura. Pág. 122-124.
Traverso, J. M. 2009. El buitre leonado en Badajoz. Pág. 125-126.
Prieta, J. 2009. El buitre leonado en Cáceres. Pág. 127-130.
En, J. C. del Moral (Ed.). El buitre leonado en España. Población reproductora en 2008 y método de censo. SEO/BirdLife. Madrid.

The 2008 national Griffon Vulture (Gyps fulvus) census recorded 1570 breeding pairs in Extremadura, with a more realistic estimate of 1943 pairs spread out around 198 different sites: 156 colonies and 42 isolated pairs. Spain’s total Griffon population was reckoned to be about 25,000 pairs in 2008, with an educated guess of 30,000 pairs and a total population of 75,000 to 100,000 birds; this means that Extremadura ranks sixth among Spanish regions, accounting for about 6.3% of the total.

Broken down by provinces Cáceres weighs in with 1361-1743 pairs, nearly 90% of the region’s total and 5.5% of Spain’s. This makes it the 8th ranking province in terms of its Griffon population and 14th in density (8.8 pp/100 km2). Extremadura’s other province, Badajoz, is home to 199-200 pairs, 0.8% of Spain’s total, making it the 22nd province in terms of population and the 28th in terms of density (0.9 pp/100 km2). Pride of place in Cáceres goes to the River Tagus and the final runs of its tributaries Tiétar, Alagón, Almonte, Erjas, Salor and Aurela. Most important amongst the mountainous areas are Ibores-Villuercas in the south east and, some way behind, Las Hurdes and Gredos in the north, together with some sierras of the extreme southwest. In the province of Badajoz Griffons breed in three sectors: northwest (Alburquerque), centre and northeast (La Siberia and La Serena). By far the most important area of all is Monfragüe, boasting 650-800 pairs, 42% of Extremadura’s population, nearly all of them in the 18,000 hectares of the National Park.

Extremadura has only two of Spain’s 39 vulture colonies numbering over 90 pairs, both in Monfragüe: Salto del Corzo (127-170 pp) and Salto del Gitano (124-145). In Cáceres there are 17 colonies with over 25 pairs, 11 of them in Monfragüe (e.g. El Boquerón, 50-67; Portilla del Tiétar, 46; Portilla del Barbaón, 32-43) and the rest in Valencia de Alcántara (San Mamede, 59-73), Bajo Alagón (Canchos de Ramiro, 40-55; Las Bravas, 32-51), Valle del Jerte (Villavieja, 34-38) and Villuercas (Canchos de Vadillo, 23-30; Estrecho de la Peña, 26). Badajoz has another two vulture colonies with over 25 nests (Puerto Peña, 50; El Muro, Embalse de Cíjara, 29-30).

Alongside the census, breeding success was also monitored in 526 pairs, one third of the total population found, with an average of 4.2 visits. The results of this survey were: productivity 0.58 and breeding success rate 0.63; slightly lower than the figures for Spain as a whole, with a productivity of 0.62 and breeding success rate of 0.67. This figures are 12% down on 1999, although the average number of visits back then was only 2.3, so in all likelihood they were overestimated. Although the breeding success rate was nearly the same in both of Extremadura’s two provinces, productivity differed, with figures of 0.61 in Cáceres and 0.54 in Badajoz. One possible reason for this difference is the higher proportion of nonbreeding pairs detected in Badajoz (13%) in comparison to Cáceres (5%), as well as a higher number of visits in Badajoz (5 against 3.8 in Cáceres).

As for the population trend, this has always been steadily upwards since the very first national census in 1979. In this 30-year period the figure has quadrupled, with a 40% rise from 1999 to 2008, an increase of under 55% from 1979 to 1989 and 88% from 1989 to 1999. No real changes were appreciated in the breeding range from 1999 to 2008, although new colonies were occupied within and on the edge of the known range. The number of new sites occupied was 39 (up 24%), mainly small colonies and isolated pairs. The increase is therefore due above all to the growth of existing colonies. By way of comparison the increase in Spain as a whole was 58% from 1999 to 2008.

Reference:
Prieta, J. 2009. El buitre leonado en Extremadura. Pág. 122-124.
Traverso, J. M. 2009. El buitre leonado en Badajoz. Pág. 125-126.
Prieta, J. 2009. El buitre leonado en Cáceres. Pág. 127-130.
En, J. C. del Moral (Ed.). El buitre leonado en España. Población reproductora en 2008 y método de censo. SEO/BirdLife. Madrid.