Showing posts with label bittern. Show all posts
Showing posts with label bittern. Show all posts

Wednesday, 20 February 2013

THE BITTERN IN EXTREMADURA

Bittern (Botaurus stellaris). Steve Fletcher.

If anything distinguishes the Bittern (Botaurus stellaris) from other large birds it is the difficulty for observation. Much of the reason lies with their nocturnal habits, their ability to camouflage and also scarcity, quite a challenge for any fan of birds. In Extremadura there have not published bittern sightings until the late 1980s: one was hit near Moraleja (Agustin Iglesias). The next record shad to wait until September 1997, when a male was heard in the Laguna Grande de La Albuera (Gragera Francisco). Since 1998 sightings were reported from Arrocampo reservoir, the only regular presence in Extremadura. Against all odds, the first confirmed case of breeding in Extremadura took place at Casa Zafra Reservoir, Cáceres. In 2007 a male was heard rePeatedly calling and finally, on 08.05.2007, two juveniles were observed. At Casa Zafra a male was heard again in the spring of 2008, but this time breeding could not be confirmed (Jerónimo Jaén). We had to wait until 2012 to see the long suspected breeding bittern in Arrocampo reservoir. Specifically, an adult and two juveniles were observed on 07.07.2012 (Sergio Mayordomo). Therefore, the eight species of Iberian heron were all breeding, for the first time in Extremadura, in this unique reservoir.


The maps shows the locations where it is aware of the presence of bittern inExtremadura until 2012 . In such areas for breeding Arrocampo and Casa Zafra, join Montijo reservoir (one in fall 2001), Talaván rservoir (a bird on 22.11.2003, 12.03.2006 and 30.12.1007) and Santa Amalia ricefields (one on 01.11.2011). In January 2012 it was discovered a bittern in Valdefuentes gravel pit, Galisteo (S. Mayordomo) and shortly after they were found two individuals present (Javier Prieta), observed one of them until 12.03.2012. The presence of two individuals in a wetland so small suggests that the number of wintering bitternsExtremadura could be much higher than observed. In 2011-2012 there were at least five bittern in Extremadura : three at Arrocampo and two at Galisteo. In December 2012 have seen three Arrocampo from an observatory and may be more in other areas of the reservoir. In December 2012 was seen a bittern in Galisteo ricefields, an inauspicious area, and in January 2013 has again seen one in the nearby gravel pit of Valdefuentes.


The graphs show the temporal distribution of bittern in Extremadura with records up to 2012. In the red figures is Arrocampo Reservoir, a place that has 75% of the observations. For months, a pattern typically seen in winter (December to February shows the maximum), with the minimum being between June and August, when only one breeding pair remains. Regarding the annual trend highlights of 2012 when both Arrocampo as well as Galisteo became popular and were visited by numerous observers. Although the graph is proportionately very large in 2012, actually it is because of many observations of a few birds (half a dozen or so). This annual chart is not representative of the spread of the species, as the amount of effort depends heavily on information collection, dissemination, and largely by chance when locating bitterns.

Observers: Javier Briz, Francisco Lavado, Enrique Fernández Larreta, Saturnino Casasola, Vicente Risco, Dave Langlois, Samuel Langlois, A. Hernández, Fundación Global Nature, Monfragüe Vivo, Francisco Rámirez, Joaquín García, Miguel Ángel Muñoz, Fernando Yuste, Juan Pablo Prieto, J. Traín, S. Wood, Daniel López Velasco, Carlos González, Marta Zamora, Martin Kelsey, C. Delgado, Óscar González, Manuel García del Rey, Antonio Ceballos, Unai Fuentes, César Clemente, Javier Mahíllo, etc, etc, etc.

Monday, 26 November 2012

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.