Monday, 9 September 2013


The Squacco Heron (Ardeola ralloides) was one of the species covered by the national heron census 2011, promoted by SEO/BirdLife (Garrido et al., 2012). The population in Extremadura totalled only 11 pairs, representing a tiny 0.5% of the total Spanish population (2,075 pairs). The most important regions were Catalonia (50%, especially the Ebro Delta), Valencia (32% at the Albufera de Valencia) and Anaadluycia (15%, Coto Doñana). The population trend in Spain is positive, with a strong increase since 1960, slowing down in the period 1990 – 2002. In Extremadura, the Squacco Heron occurred in six colonies in five localities. Most of the population was of isolated pairs within mixed colonies dominated by Cattle Egrets, the main site being the Arrocampo reservoir with four pairs. The substrate most used was marshy vegetation, although in several colonies the nests were built in trees or shrubs.

Breeding Squacco Herons is a new development in Extremadura, only established since 2000 in two localities simultaneously: the reservoirs of Arrocampo and Montijo. Breeding at Arrocampo has been regular since 2000, with annual records of between one and five pairs, with two or three being the most frequent (in 2012 there were two and in 2013 only one pair). At the Montijo reservoir, it is similar with regular nesting since 2000, although with fewer birds: one breeding pair from 2000 to 2006 and 1-3 pairs from 2007 to 2013. Information about other localities is very scarce. In the less often-watched Alqueva reservoir three nests were found in two zones in 2011, with irregular breeding in earlier and later years, owing to the fluctuating water levels (there was no breeding in 2013). At the Azud de Badajoz, there have been sightings since 1990, but with no breeding suspected for a decade afterwards. In 2011, one nest was confirmed, although others may have been present, and it was the same in 2012 and 2013. Finally, at the Orellana reservoir, information is only available from 2011 (one nest), but one has to take into account that this heronry, situated on islands, does not assemble each year, because of variations of water level and is also very difficult to survey.

To understand the regional trend, one needs to take into account that there are no previous censuses. In 2000, there had been at least five pairs in the two known colonies and in 2011, this rose to eleven pairs in six sites. The geographical expansion is evident, as in the slight population increase, but presently three of the colonies are only of irregular occupation and the figures there fluctuate greatly, possibly in relation to the situation of colonies in Andalucía.

Although traditionally Squacco Herons are considered as summer visitors in Europe, in Extremadura they are possible to find throughout the year, indeed the wintering population (of 15-25 birds) is similar or even larger than the breeding population. In winter the species is more dispersed, is not present at roosts and has rather secretive habits, so it is likely that the actual figures are even greater. In the map the presence of the species in January 2011 is shown in violet. Four of these sites are regular wintering areas, two in breeding sites (Arrocampo, Guadiana in Badajoz) and two in rice-growing areas (Vegas Altas and Alagón). The largest group in winter was nine birds on the Guadiana River in Badajoz in December 2011.

At other seasons, the species can be found in wetlands throughout almost the whole region, with the largest numbers at the end of summer and start of autumn, when individuals are dispersing from other areas, probably mainly from Doñana. However, there are no records of ringed birds to substantiate this. The largest group ever recorded was 19 (Guadiana river in Badajoz, September 2012).

- 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]
- Aves de Extremadura. Volúmenes 1, 2, 3 y 4. Años 1998-2008. [download]

Participants in the 2011 census: Coordinadores: Javier Prieta (Cáceres) and 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 and 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 and Vicente Risco