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 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 Guadiana River in Badajoz
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
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]
- Aves de Extremadura. Volúmenes 1, 2, 3 y 4. Años 1998-2008. [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
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