PURPLE HERON IN EXTREMADURA

The purple heron (Ardea purpurea) was one of the species covered by the national census in 2011 ardeids promoted by SEO/BirdLife (Garrido et al., 2012). The registered population in Extremadura was 105 pairs, representing only 2% of total the Spanish population (5379 pairs). The most important regions were Andalusia (70%, mostly in Doñana) and, to a lesser extent, Catalonia (13%, 10% in the Ebro Delta). The purple heron trend in Spain is positive, although subject to significant fluctuations depending on the water situation in Doñana. There was an increase between 1960 and 1997 to 2003 and stability further increased in 2011. In Extremadura the heron was found in 11 colonies in eight locations. Most are in mixed colonies (except Zújar River and three isolated pairs) and the nesting sites were in marsh vegetation (90% of pairs), although in several colonies nests are built in trees and shrubs.

Breeding of the purple heron is a recent development in Extremadura, known only from the 1990s. The first colony was reported as Arrocampo reservoir, occupied first in 1992 and an estimated 50 pairs in 1994. The second colony, on the river Zújar, was discovered in 1996, reporting two pairs in 1998. The third location was the dam of Montijo, occupied by six pairs in 1997. Valdecaballeros  has had perhaps some nesting pairs since 1998 (for sure since 2004) and the Guadiana River in Badajoz since 2000. The Alqueva dam reported seven breeding pairs in 2007 and the two remaining colonies (Orellana and Los Molinos) were recorded for the first time in the 2011 census. Apart from these places, there have been casual reports of  the purple heron breeding  at the reservoirs of Portaje and Valuengo and Guadiana river, but not confirmed. There was a failed breeding attempt at the pond of La Calera, Toril (two pairs in 2007)

When assessing the regional trend it must be taken into account that there has been no previous censuses of the species. In 1994 it were estimated there were about 50 pairs in the only colony in Arrocampo. In 2002 it was estimated 70-80 pairs in three colonies: Arrocampo 50-60, Montijo reservoir 15 and River Zújar 5 couples. In 2007 there was a survey of breeding waterbirds, counting 142 adults purple herons in 52 Extremadura wetlands (11% of those sampled), mostly feeding sites close to breeding colonies. Thus in Arrocampo and its surroundings they were at at 14 sites, in the Guadiana between Merida and Alqueva in 18 locations, in two at Zújar River, four on the river Guadalupejo and 14 at other scattered locations. In 2008 the first census was conducted specifically at Arrocampo, with a count of 40-45 pairs, 26 of them successful (Garcia and Prieta, 2011). The second census was collected here in 2011 with 46 pairs, in line with all previous numbers, suggesting a high stability in this colony since its formation. At the Guadiana basin, the trend is positive, with the progressive occupation of new locations and a sharp increase in the number of breeding pairs, peaking (10 colonies and 59 pairs) in 2011.

As for the winter period, the presence of the heron is anecdotal in Spain and Extremadura. In January 2011, only three were found in Spain (Salamanca, Huelva and Malaga). In winter there are some records Extremadura, both adult and immature, aat Vegas Altas and Arrocampo.

Sources:
- Garrido, J. R., Molina, B. y del Moral, J. C. (Eds.) 2012. Las garzas en España, población reproductora e invernante en 2010-2011 y método de censo. SEO/BirdLife. Madrid.  [download]
- García del Rey, M. y Prieta, J.. 2011. Censo de garza imperial (Ardea purpurea) en el Parque Ornitológico de Arrocampo. En, Prieta, J. y Mayordomo, S. 2011. Aves de Extremadura, vol. 4. 2004-2008. SEO-Cáceres. Plasencia. [download]
- Aves de Extremadura. Volúmenes 1, 2, 3 y 4. Años 1998-2008. [download]

Collaborators 2011 survey: Coordinators: Javier Prieta (Cáceres) y José María Traverso (Badajoz). Badajoz: Alfredo Mirat, Antonio García-Ortiz, Antonio Núñez Ossorio, Carmen Galán, Casimiro Corbacho, Emilio Costillo, Fernando Yuste, Jesús Morena, Jesús Solana, José Ángel Salas, José Antonio Fimia, José Elías Rodríguez Vázquez, José Gordillo, José María Traverso, Juan Antonio Barquero, Juan Carlos Paniagua, Luis Galán, María J. García-Baquero, Patricia Gordón, Toribio Álvarez y Xurxo Piñeiro. Cáceres: Agustín Morena, Carmelo Fernández Martínez, César Clemente, Emilio Costillo, Helios Dalmau, Javier Briz, Francisco Javier Caballero, Javier Mahíllo, Javier Prieta, Jerónimo Jaén, Jesús Montero, Juan Manuel Brías, Julián Panadero, Manuel García del Rey, María José Moreno, Martín Kelsey, Sergio Mayordomo y Vicente Risco.