GREYLAG GOOSE IN EXTREMADURA. JANUARY 2013

 
The 2012-2013 winter has come to an end and it is time to talk about  the wintering birds in Extremadura. There are many who are interested after waterfowl, crane and cormorant censuses. I think its a good idea to start with the wintering greylag goose (Anser anser). The census of January 2013 recorded 23,173 individuals in Extremadura, almost triple that of January 2012 (8,020 birds). The graph shows the official census figures for January in the last 23 years. The interpretation must be made with caution, because of the large difference in census coverage over the years (very low in 2011 or 2009, for example, and several years without information). Still, there is a very clear upward trend, as already stated in a previous post. However, the distribution of the species is restricted to a few locations, the same as contained in the censuses of the early 1990s, over two decades ago.

The most prominent location is again Vegas Altas (#1), which has primarily rice stubble and, to a lesser extent, corn and other crops. Within the wide area available each year, most are concentrated in the eastern part of the county, it being too complicated to count scattered foraging areas and roosts (although in some seasons, as in 2007, there were more than 8,000 geese in Sierra Brava reservoir). On 14 and 15 January 2013, there were estimated 18,800 greylag geese, mostly at Logrosán municipality (15,000), and the rest between Madrigalejo (3000), Navalvillar de Pela (600) and other localities (200). This is the highest known, thanks to the good condition of the flooded rice fields. Quite the opposite during the dry winter before, when in January 2012, just over 4,000 geese were counted. The previous high dating back to January 2006, when there were 13,800 Greylag Geese.

Valdecañas reservoir (#2) also reached a peak in January 2013 (2,950 birds), perhaps helped by the low level of the reservoir and the large area of shoreline available. The geese were divided into two zones of the reservoir, a thousand in Bohonal de Ibor and two thousand in El Gordo-Peraleda de la Mata. Rare geese observations suggest little movement between the two sectors. Also, at the end of January the water level rose and some of the geese moved to the nearby pastures of Lugar Nuevo, Peraleda de la Mata. The highest numbers of greylag at Valdecañas were known to be 2250 birds in January 2012 and 1,875 in January 2005.

The remaining traditional greylag locations for winter populations harbored more modest numbers and in no case exceeded previous highs. So, in the reservoir of El Borbollón (#3) 186  were counted compared to the 458 of 2005. In Gabriel y Galán reservoir (#4) there were only 156 birds, half the maximum of 300 in 2000. Portaje reservoir (#5) had 206 geese in 2013, and the maximum was 293 in 2006. In Salor reservoir (#6), and nearby wetlands, there were only 56 individuals. The geese wintering in Llanos de Cáceres may vary location according to the years, the last two being focused on Valdesalor, when before they were at the ebmalse de Guadiloba, with the most in the region (250 birds in 2006). Los Canchales reservoir (#7) was the third location in importance in 2013, with 377 individuals, still far from the 900 of January 2000. Meanwhile, the Torremejía lagoons (#8) had 206 birds, well below the 1,050 peak of January 1999. This subpopulation occupies both these lagoons as Alange reservoir depending on water levels. Finally, the Llerena-Arroyoconejos reservoir (#7) showed a figure of 120 geese, far below the 1,100 in 2002. Although in other locations there can be geese in winter, they are not regular wintering areas. So in the January 2013 census, there were19 sites, and in January 2012, 21 sites. Other censuses, show more than 80 places with a greylag presence, in some cases it could be semi-domestic geese.

Collaborators. Emilio Peña, Adrián Chaves, Alberto Pacheco, Amado Franco, Andrés Maestre, Ángel Luis Sánchez, Ángel Sánchez, Antonio Calvo, Benigno Cienfuegos, Carlos Fernández, Casimiro Corbacho, César Clemente, Daniel Vicente, Dave Langlois, Diego Recio, Domingo Jiménez, Domingo Rivera, Emiliano Godoy, Emilio Costillo, Eva Palacios, Federico Hernández, Felipe Paniagua, Fernando Yuste, Francisco Bernáldez, Francisco Montaño, Godfried Schreur, Heliodoro Barquero, Inés García, Iván Castro, Iván Sánchez, Jasper Quak, Javier Briz, Javier Caballero, Javier Fernández, Javier Mahíllo, Javier Prieta, Jesús Montero, Jesús Porras, Jesús Solana, Joaquín Fernández, Joaquín Vázquez, John Muddeman, José Antonio Román, José Carlos López, José Fernández, José Luis Bautista, José Luis Caballero, José Manuel Rama, José María Guerrero, José Guerra, Juan Carlos Paniagua, Juan Fernández-Blanco, Juan Fernando Trejo, Juan José Blanco, Juan Pablo Prieto, Juan Rodríguez, Julián Panadero, Lorenzo Alcántara, Luis Lozano, Luis Salguero, Manuel Flores, Manuel García del Rey, Manuel Gómez Calzado, Manuel Rodríguez, Marc Gálvez, Marcelino Cardalliaguet, María José Moreno, Martin Kelsey, Miguel Ángel Romo, Óscar Llama, Paula Rodríguez, Rafael Alberto Rubio, Samuel Langlois, Santiago Cáceres, Sergio Mayordomo, Sergio Pérez y Vicente Risco. Coordinador: Javier Prieta.

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.

SIERRA BRAVA: DUCK COUNTS

Vast rafts of ducks on Sierra Brava Reservoir (Cáceres) on the morning of 14 January 2012.

No, it's not a swarm of mosquitoes or a negative of the Milky Way but several thousand ducks
resting up on part of the reservoir (click to see it larger). By Javier Prieta.

The celebration of World Wetlands Day is as good a time as any to look at one of Extremadura's most outstanding waterfowl sites. Sierra Brava Reservoir lies in the southeast of the province of Cáceres in the catchment area of the River Guadiana, the whole reservoir falling within the municipality of Zorita. It forms part of the irrigation scheme called Central Zone of Extremadura, comprising several reservoirs and a vast area of cropfields, mainly maize, rice and orchards. Built in 1994, Sierra Brava did not become half full until 1998. In January 2002 it was "discovered" by the birding world. In 1995 the traditional wintering wildfowl count fell into disuse in Extremadura so there is no information on the wintering wildfowl of its early years. In January 2002, the recently created GOCE group (Grupo Ornitológico Cacereño, today SEO-Cáceres) decided to re-establish the wildfowl count in Cáceres. Their findings were a huge surprise. No one imagined such a massive concentration of ducks on one reservoir, reckoned to be about 61,000. And Sierra Brava is not alone; other smaller and larger reservoirs of the Central Zone also have huge duck flocks.

Ten years later SEO-Cáceres repeated the wintering wildfowl count in January 2012, aiming to take in the whole of Extremadura. Obviously this time Sierra Brava wasn't to come as such a big surprise. On Saturday 14 six members of SEO-Cáceres set out to census the wetlands of the Central Zone, concentrating on Sierra Brava. Anyone who knows the reservoir will realise that it is impossible to count the birds in situ (see above photo). The chosen method, partially tried out in earlier years, was a mixture of photographic and direct counting. Weather forecasts predicted mist for that day and it even rained on the way there but the morning turned out to be splendid, sunny and windless. This enabled us to make a detailed telescoping scan of the famous rafts of ducks from a nearby high point. For four hours the least numerous species were counted (Greylag Goose, Shelduck, Wigeon and Gadwall), the shores and inlet waters were checked out while also sketching out the proportions of the most abundant species. The fieldwork thus came up with no final result.

The second part of the study came back at home, counting one by one the photographed birds and also indicating species. The working material amounted to 199 photographs and several pages crammed with notes. The photos with fewer ducks were counted on the computer screen, while the more complex photos were printed out in colour. The number of birds per photo ranged from three to 2093 (mean of 252), adding up to 50,187, which turned out to be 86% of the total (58,000). Ascertaining how many corresponded to each species was not as difficult as might be thought since the duck species do tend to flock together on the reservoir. Thus, thanks to 72 field observation points, counting 9703 individual birds (c.20% of the total), one of the great rafts was seen to be formed 99.9% by Shovelers. The figures obtained for this species are reckoned to be accurate. The other big raft was formed almost exclusively by Teal at one end and Pintail at the other, merging in the centre. In most of the photos it proved possible to identify the species, so estimates were made only in doubtful cases in certain parts of the reservoir. Now it remained only to tally these findings with the field counts of scarcer species and zones not visible in the photos (the Mallards occupy above all the outer zones and shores).

Detail of Sierra Brava Reservoir (Cáceres) on 14-01-2012. A total of 1019 ducks has been counted in this image, the immense majority being Teal (Anas crecca) with some Pintail (Anas acuta) in the foreground. By Eva Palacios.

As in other posts of this blog, the idea was to check the previous information published on Sierra Brava and the Central Zone. There is little to go on but we do have the official January counts of Extremadura passed on by SEO/BirdLife to the Environment Ministry. These figures are summed up in the tables below. Unfortunately there is no indication of the methods used, the authors of the count or the dates (some counts seem to have been conducted in February), so we decided to eschew any thorough check. The trend graph shows wild swings; this came as a surprise to us since the many visits paid to Sierra Brava over the last 10 years showed no such thing. It is also surprising to find that some counts give figures of zero Teal or only 140 Shoveler, figures that hardly tally with the real situation. The total Sierra Brava figures, ranging from 11,000 to 102,000 Anatidae, coots and grebes, have been quite controversial for various reasons. At least on two occasions there were simultaneous counts: in 2002 on the same day, throwing up estimates of 45,000 in one case and 73,000 in the other (66% difference; we decided to split this difference); in 2003 the two estimates were similar (about 100,000 birds) but with a very different species breakdown. Despite this, Sierra Brava's importance is unquestionable, accounting as it does for over half of Extremadura's wintering Anatidae on most occasions. If we consider the Central Zone as a whole the area ranks third in Spain for wintering wildfowl, coming behind only Doñana and Ebro Delta.

We don't know if photographic counts were employed on earlier occasions; judging from our 2012 experience, however, it is the method we recommend. Obviously there will be some error but we believe it to be simple and objective. The main limitation might be bad weather with bad light or especially, wind, so the right days do need to be carefully chosen. Coverage also needs to be improved on shores and some of the inlet waters to detect above all Mallards, which might well have been underestimated by this current count.

In case anyone is wondering, we also tried a computer count, using Photoshop, as well as the photographic count. The method works and it proved possible to determine the number of points per photo, but the figures came out 20-30% below the direct count since 2 or more adjacent birds might merge into a single point.

The 2012 count in the Central Zone of Extremadura forms part of the Extremadura Wintering Wildfowl Count brokered by SEO-Cáceres. The most meritworthy work in this endeavour was carried out by Eva Palacios, who patiently took the photos and even more painstakingly counted up the ducks on each one. Javier Prieta completed the fieldwork and came up with the final figures for Sierra Brava. Sergio Mayordomo, Marcelino Cardalliaguet, César Clemente and Javier Mahíllo censused the rest of the Central Zone. Independently, Miguel Ángel Romo and Javier Pérez Gordillo covered the ponds of Manzanares (Campo Lugar, Cáceres). Lastly, our thanks go to Raúl Guzmán for coming up with the alternate computer method and to Blas Molina (SEO/BirdLife) for the figures from the counts of earlier years.

RARE GEESE IN EXTREMADURA

Greylag Goose (Anser anser). The only frequently seen goose species in Extremadura. By Juan Pablo Resino.

Winter in Extremadura is the time of cranes ... and also of geese. The latter are relative newcomers to the region and their distribution is still patchy but there is always the potential thrill of finding a stowaway rare goose amongst the annual winterers. Sometimes you can luck into one easily but usually it takes of hours of patiently scanning the hundreds or thousands of Greylags. The site hosting the national Crane Festival on 4 December is the place where most of the rarer geese have been sighted in Extremadura, so it provides the ideal chance for a bit of a "wild goose chase".

Ten different species of geese have been seen in Extremadura to date. Apart from the Greylag (Anser anser) these include four "grey geese" of the Anser genus and five "black geese" of the Branta genus. The best sites are those that also host the biggest wintering Greylag flocks, especially Vegas Altas (up to 15,000 geese), but also in reservoirs like Valdecañas (up to 4000), Portaje, El Borbollón, Arroyoconejos or Los Canchales.

White Fronted Goose (Anser albifrons). First winter. Portaje Reservoir, January 2011.

By Sergio Mayordomo.

The least rare of the nine is the White Fronted Goose (Anser albifrons), recorded 20 times in Extremadura since 1998 between the months of November and February in the reservoirs of Portaje Alange, Valdecañas, Sierra Brava, Arrocampo and Los Canchales and, above all, in the crop fields of Vegas Altas. In all, the sightings add up to nearly 50 birds, the biggest group being five. In November 2011 it has already been spotted several times in Moheda Alta, Navalvillar de Pela, including a possible sighting of two birds of the Greenland flavirostris race, classed as a rare vagrant in Spain. Also in 2011, but back in January and February of last winter, it was seen in Sierra Brava, Portaje, Peraleda de la Mata (near Valdecañas) and in Moheda Alta.

White Fronted Goose (Anser albifrons). Two birds with a very heavily barred breast, a typical feature of the Greenland subspecies (flavirostris). Moheda Alta, November 2011. By Samuel Langlois.

The Bean Goose (Anser fabalis) was the most numerous goose in the northern meseta until the mid nineteenth century. But the huge contraction of its wintering range has turned it into an official rarity since 2006. In Extremadura there have been only five records (11 birds) in the years 1998-99, 2002, 2005, 2007 (accepted by the rarities committee) and January 2011 (pending acceptance). It has been seen between November and February and only in Vegas Altas (Sierra Brava and Navalvillar de Pela) and Los Canchales, with records of both subspecies, the Tundra Bean Goose (beak nearly all black) and Taiga Bean Goose.

Pink Footed Goose (Anser brachyrhynchus). Casas de Hitos, Navalvillar de Pela. 27 November 2010.
By José María Salazar.

The Pink Footed Goose (Anser brachyrhynchus) was for a long time considered to be a subspecies of the similar Bean Goose so you need a keen eye to spot this rarity. Only two birds have ever been recorded in Extremadura, a single bird each time in Vegas Altas: Sierra Brava (Cáceres) on 12/01/2002 (J. Muddeman; accepted) and Casas de Hitos (Badajoz) on 27/11/2010 (J. M. Salazar et al; pending acceptance).

The fourth rare goose, the Bar-Headed Goose (Anser indicus) is in fact a feral bird that originally escaped from European wildfowl collections. There have been four records in Extremadura, always a single bird, in Valdecañas (January 1987), Arroyoconejos (February 1996), Saucedilla (March 2003) and Portaje (with ring, July to October 2009).

Barnacle Goose (Branta leucopsis). Portaje Reservoir, November 2011. By Sergio Mayordomo.

Moving onto the "black" geese, we find that the commonest one is the Barnacle Goose (Branta leucopsis), recorded 20 times in the region since 1993 between the months of November and February, with a one-off seen in April-May 2011. The best spots, with more than 5 records each one, are Valdecañas reservoir and its hinterland and Vegas Altas (Sierra Brava, Madrigalejo and Navalvillar de Pela). It has also been seen in the reservoirs of Portaje, Ayuela, Borbollón, La Anguila (Serrejón) and Arroyoconejos. In all they account for 26 sightings, the biggest group being five. In November 2011 three birds have already been seen in Moheda Alta and one bird in Portaje Reservoir. In 2010 there were sightings in Valdecañas, Casas de Hitos and Moheda Alta.

Brent Goose (Branta bernicla). Pale-Bellied bird, a typical plumage feature of the American hrota subspecies. Guadiloba Reservoir, April 2008. By Martin McGill.

The rest of the black geese are really rare in the region. The Red-Breasted Goose (Branta ruficollis), a species "Endangered" on a world level, has been seen only once in the region: a juvenile on 12/01/2002 in Sierra Brava Reservoir (in a flock with six species of geese and a hybrid) and on the next day in a Madrigalejo ricefield (J. Muddeman). The Canada Goose (Branta canadensis) is originally from America but now has many feral populations in Europe. The four Extremadura records (seven birds) are very scattered in time: two in Valdecañas in 1977 and 1999 and two recent in Sierra Brava and Moheda Alta in December 2009 and 2010. The Brent Goose (Branta bernicla) accounts four records, in November 1993 (Arroyo de la Luz), November 1996 (Los Canchales) and April 2008 (reservoirs of Guadiloba and Charco Salado, maybe the same bird, reckoned to be the American hrota subspecies).

Cackling Goose (Branta hutchinsii). Casas de Hitos, Navalvillar de Pela. 2 January 2010. By Antonio Ceballos.

To wind up, mention must also be made of the Cackling Goose (Branta hutchinsii), seen for the first time on the Iberian Peninsula in Casas de Hitos on 02/01/2010 (A. Ceballos) and again on 24 and 28 January and 1 February (SEO-Cáceres, including on a group excursion of this forum). Breeding in the American Arctic, it has only recently been separated from the Canada Goose and does even yet have an official name in Spanish. Although haling from such distant climes, ringed birds have proven that it does turn up in Europe naturally.

This brief overview shows that all the geese species recorded in Spain can, with luck, be found in Extremadura. All of them? No. There is one species that has yet to show up: the Lesser White Fronted Goose (Anser erythropus). Recently there was an exciting near miss, however. The above photo shows a tiny goose that seemed at first to be a juvenile Lesser White Front (size, wing length, beak colour), but was finally identified at as first-winter White Fronted Goose (Moheda Alta, Navalvilar de Pela, 13/11/2011; by M. Gálvez, J. Guerra, M. J. Valencia, X. Piñeiro, E. Palacios and S. Mayordomo; photo by Eva Palacios). Recently, however, a project in Sweden to reintroduce this internationally threatened species was dropped because the introduced birds were proven to have genes of the White Fronted Goose. Maybe the "half and half" bird of the photograph has something to do with this project... but this is pure speculation.

Sources:
- Anuarios ornitológicos of Extremadura (1998 to 2008).
- Monthly summaries of this blog (May 2010 to November 2011).
- Base de datos de Aves de Extremadura. Sergio Mayordomo (2009 and 2010, unpublished).

WINTERING GREYLAG GEESE IN EXTREMADURA

Flock of Greylag Geese (Anser anser). Casas de Hitos lake, Navalvillar de Pela, Badajoz. 22-01-2011. Juan Pablo Prieto.

The traditional wintering areas for Greylag Geese (Anser anser) in Spain are in the northern plains of Spain, the "meseta norte" (Zamora and Palencia) and in the saltmarshes of the River Guadalquivir in the south. Until a few years ago these two areas accounted for almost the whole Iberian population. Extremadura lies between these two spots and all geese heading for Doñana must overfly it. For decades they did just that, flew straight over without hardly stopping. This stands to reason given the dearth of natural wetlands in Extremadura. The figures are telling: the January counts from 1978 to 1989 throw up the paltry mean figure of 59 Greylags wintering in the area. But two factors brought about a change in this situation; firstly the construction of more reservoirs and irrigated farming land and secondly the increase in the European Greylag population. From 1991 to 1995 the mean number of wintering Greylags in Extremadura soared to 2700, increasing almost fifty-fold, with peaks of 3750. The standout site is Valdecañas Reservoir in northeast Cáceres, with 33-65% of the total. The rest are spread around large and medium-sized reservoirs, each of which holds at most a few hundred birds. During the next seven winters no January counts were made in Extremadura but the general impression was of a continuing upward trend. At the turn of the century the number of wintering Greylags perhaps topped 5000 for the first time. The January count of 2002 came out as 4500 in the province of Cáceres alone and an estimate of 8000 for the whole of Extremadura. The renewed regional counts as from January 2003 bear this out, with figures that were undreamt of only a few years back. The 2006 count was 19,043 Greylags and 10,380 in 2007. Numbers seem to have been quite similar in 2010 and 2011. Nonetheless, a detailed look at the figures shows that in most places, mainly reservoirs, the numbers have held pretty steady since the 1990s. Barring one district: the Vegas Altas of Guadiana, where the massive takeup of irrigated farming created the conditions for a new and sizeable wintering area for Greylags. This district now boasts 14,000 birds, sometimes up to 90% of Extremadura's wintering Greylags, most of them feeding in maize and rice stubble. This poses a stiff and thrilling challenge for birdwatchers for these huge flocks often have a few stowaways of the rarer and much sought-after geese species.

Greylag (Anser anser) in Extremadura. The red bars show the figures recorded in the official January counts (DGMN, GIC-UEX, SEO/BirdLife). The blue bars show estimates for years without a count or not yet published (2010). Some official counts (e.g.2008) are partial, given that the main aim was to count the wildfowl in wetlands and many of Extremadura's wintering Greylags live and feed in cropland that does not come into the wildfowl count. Another factor that hinders counts is that geese do not usually form winter roosts in Extremadura.