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.

HERONS IN SPAIN AND EXTREMADURA. SURVEYS 2011.

SEO/BirdLife has published a monograph of the census results of breeding and wintering herons carried out in Spain in 2011 (Garrido et al. 2012). Although Extremadura is not renowned for its wetlands, rather the opposite, it ranks second after Andalusia, in terms of importance for wintering birds (32 900, 14% of Spain) and third in terms of breeding pairs (9,900 pairs, 15% of Spain, in 84 locations).

As a family, the herons are increasing and most of the studied species show increases in Spain. The night heron (Nycticorax Nycticorax) has risen from 1,300 in 1986 to 5,400 pairs in 2011. The squacco heron (Ardeolla ralloides) from 200 in 1980 to 2100 pairs in 2011. Grey heron (Ardea cinerea) from 168 in 1950 to 7,000 pairs in 2011. The purple heron (Ardea purpurea) from 2,000 in 1997-2003 to 5,400 pairs in 2011. The bittern (Botaurus stellaris) from 26 pairs in 1980 to 41 in 2011. And the great white egret (Egretta alba), which began breeding in 1997 in the Ebro Delta has gone to 53 pairs in 2011. By contrast decreases were detected in the little egret (Egretta garzetta), with a small drop in the last ten years, resulting in 2011 (9350 pairs) against 1990 figures (7,600 pairs) but lower than 2002 (10,400). The most abundant species is the only one who has suffered a significant decrease. We talked about the cattle egret (Bubulcus ibis), down from 70,000 pairs in 1989 to 40,000 in 2011. This is a species that has incresed during the twentieth century and whose population can fluctuate greatly depending on local conditions. Experts say that some species show strong expansions, then suffer a decline after which the population is consolidated and stabilized.

 

 

 

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.

BREEDING HERON COUNT IN CÁCERES: PRELIMINARY RESULTS

Colony of Grey Herons (Ardea cinerea), 9 nests, and White Stork (Ciconia ciconia), 3 nests. The photograph shows the whole colony, built in a single dead Maritime Pine. The 9 Grey Heron nests break down into 5 nests with chicks of varying ages, two nests with sitting adults and two empty ones. Toril, Cáceres. 19-05-2011 (Javier Prieta). Click on the photo to see it bigger.

Now that summer has come for real, the breeding heron count in Cáceres is pretty much over. With some last-minute information still to come in, with the consequent tweaks and corrections, we can give a foretaste here of the final results, mainly to reward the participants and thank them for their sterling efforts. These thanks are fully deserved because the censusing team achieved practically complete coverage of the whole province. Once all the final results are in, especially from the province of Badajoz, which has bigger populations than Cáceres for most heron species, this blog intends to give a complete account of this final result. To see other entries on herons in Extremadura, click here.

Breeding heron count in the province of Cáceres. Preliminary results, 2011.

- Grey Heron. At least 44 colonies found with about a thousand breeding pairs between them. It is the most widespread heron species in the province, with presence in all the heron colonies found. Sharp upward trend.

- Cattle Egret. Present in only 6 colonies with a total of about 1700 pairs. Although it is still the most numerous of Extremadura's heron species, this is the lowest known figure for the species in Cáceres, with an appreciable downward trend, both in the number of colonies and the number of pairs.

- Little Egret. About 60 pairs found in 5 colonies, all mixed colonies with Cattle Egret. It has always been a scarce species in Cáceres and the present result is similar to previous counts (stable trend).

- Night Heron. One known colony (Arrocampo Reservoir) with about 20 pairs. Slight increase.

- Purple Heron. Estimated 46 pairs in the province's only breeding site (Arrocampo). Stable trend.

- Squacco Heron. At least three pairs, also in Arrocampo Reservoir. Stable trend.

- Great White Heron. After breeding for the first time in Arrocampo in 2010, at least two pairs are now nesting in the same site this year.

- There is no information on two heron species that were not targeted by the count: Little Bittern (common breeder) and Bittern (occasional breeder).

- Interesting spinoff Spoonbill information was also obtained during the heron count, with 4 breeding sites found accounting for a total of about 40 breeding pairs. These are the highest provincial figures, both in terms of colonies and breeding pairs (see 2010 figures). Upward trend.

From here we pass on our thanks to all participants and wish all blog readers a good summer.