WATERFOWL CENSUS IN SIERRA BRAVA AND LOCALITIES. JANUARY 2013

Shoveler (Anas clypeata). Detail of a typical raft in Sierra Brava Reservoir (Cáceres), on 12/1/2013. The shoveler was again the most numerous species in the wetlands of Vegas Altas (photo Eva Palacios)

As usual, during the month of January the wintering waterfowl census takes place in Extremadura. January 2013 was the second year  that the regional census was organized by SEO-Cáceres in collaboration with the Department of Environment of Extremadura.

The overall result of the region has yet to be finalised, as we are still waiting for some details, but here are the 2013 results from Sierra Brava reservoir and its surroundings. Also called Zona Centro de Extremadura and Vegas Altas, a term we prefer to call this complex of wetlands, the most important of Extremadura for waterfowl. Specifically eight wetlands have been the targets of the census: four reservoirs located north of the River Guadiana (Sierra Brava, Gargáligas, Cubilar y Ruecas), three ponds for livestock farming (Casas de Hitos, Moheda Alta y Majadas Altas) and a wide area of thousands of acres of irrigated crops, especially rice. During the waterfowl census there were also other small wetlands censused and stretches of the Guadiana river within the region of Vegas Altas, which however are not included in this analysis.

The following table shows counts of waterfowl, coot and grebes obtained in each of the eight wetlands cited. Compared to January 2012, when we used the same methodology and effort, it is seen that the total is very similar (one thousand birds more in 2013), but with a slightly different distribution. Sierra Brava Reservoir remains the most important, although decrease of 17,000 individuals. In contrast, the counts at the reservoirs of Cubilar and Gargáligas increase altogether 10,000 birds and 13,500 more in the ricefields, almost exclusively greylag goose. Majadas Altas ponds had reduced numbers down to a quarter, perhaps because during the previous weeks people have been hunting ducks here. The Casas de Hitos has lost almost all wildfowl after changing its use from agricultural to industrial (associated with a solar thermal plant). The comparison with the average of the 2002-2013 censuses is only indicative and should be treated with caution, since they were made with different teams and methods. Still, the 2013 figures are close to the average of the last 12 years.

The detected species and their abundance are given in another table. The most numerous were the shoveler and the greylag goose, with nearly 19,000. Next in importance the teal and pintail ducks, mallard and gadwall. All other species have less than a thousand individuals, their presence in some cases being anecdotal. Compared to January 2012, we see a sharp increase in the number of greylag geese, probably because of the major flooding of the rice fields. The pintail is maintained at levels, while other similar dabbling ducks decrease, in particular, gadwall,wigeon and coot. In 2013 there have been increasing of crested grebe and common pochard, the latter absent in 2012.

Considering exclusively Sierra Brava reservoir, the figures are lower by 17,000 ducks compared to 2012, affecting all species and most especially wigeon (seventh), Gadwall (fourth) and mallards (half). The only increase is the great crested grebe. However, we must bear in mind that the ducks use these dams as daytime resting sites, feeding at night in irrigated land by the day and returning to the same or different reservoir.

The method used was the same as in 2012. Reservoirs and ponds were surveyed in a coordinated system on January 12, 2012 by nine people divided into four teams. The irrigated areas were covered on 14 and 15 January by several teams with the main objective to census waders and cranes respectively, while obtaining information on other waterfowl, particularly on greylage geese. Except in Sierra Brava, in all places direct counts were made, although an estimate was made at Cubilar for the number of teal as to the difficulty of counting (5,000 birds). In the case of Sierra Brava, as in 2012, the method consisted of a mixture of direct census and photographic census. Certain reservoir areas and rare species were recorded in situ and numerous birds were counted after the photographs taken. Link here for more details of this method. Unfortunately, in 2013 the conditions for photography were much worse, due to wind and waves in the reservoir, which has become much more slow and laborious to carry out photographic counts.

As more than one has asked how to count in the pictures we have shown two cases. Above, marking various species by color (blue pintail, teal yellow, red shoveler). This system is very slow, so we preferred the picture below, which involves splitting the picture in sectors and making partial counts by species in each. In this particular example 1519 individuals have been counted, almost 1200 shovelers and the rest common teals and mallards. Photos by Eva Palacios.

Participants in the census of 2013 in Vegas Altas. Coordinador Javier Prieta.  12 January: Javier Prieta and Eva Palacios (Sierra Brava and Casas de Hitos); Marc Gálvez, José Guerra and César Clemente (Gargáligas, Ruecas and Cubilar); Sergio Mayordomo and Antonio Calvo (Majadas Altas and Sierra Brava); Óscar Llama and Javier Fernández (Moheda Alta and support at Sierra Brava). 14 January: Joaquín Fernández, Miguel Ángel Romo, Luis Lozano, Juan Pablo Prieto, Fernando Yuste, Ángel Sánchez, Domingo Rivera, Manuel Gómez Calzado, Ángel Luis Sánchez, Benigno Cienfuegos, Sergio Mayordomo, Marcelino Cardalliaguet, César Clemente, Javier Prieta and Emilio Jiménez. 15 January: José Antonio Román, Fernando Yuste, Marc Gálvez, José Guerra, Juan Pablo Prieto, Marcelino Cardalliaguet, Emilio Peña, José Luis Ciudad and Manuel Gomez Calzado.