Friday 2 December 2011

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).