Wednesday 1 December 2010

NORTH-AFRICAN LONG-LEGGED BUZZARD IN EXTREMADURA: THE TIP OF THE ICEBERG?

North-African Long-Legged Buzzard (Buteo rufinus cirtensis), adult in captivity. September 2010, Plasencia, Cáceres (J. Prieta). Typical adult with rufous plumage, pale breast and darker thighs ("trousers") and unbarred reddish tail.

The Long-Legged Buzzard (Buteo rufinus) lives in North Africa (cirtensis subspecies) and in Eastern Europe (rufinus subspecies); it is hard to tell apart from the Common Buzzard (Buteo buteo). Check out specialist guides and internet sites (e.g., , here, here and here) to find out more about its complex identification features. As a general rule, however, any particularly pale or rufous buzzards in the field should be checked carefully. The Buzzard is a notoriously variable species but the birds in Extremadura, where it is abundant, are usually dark and fairly uniform.

The Long-Legged Buzzard is classed as a rare vagrant in Spain and observations have to be vetted by SEO's Rarities Committee. Taking only officially accepted records into account, it comes out as extremely rare in Extremadura, where there has only been one confirmed observation: an adult of unknown subspecies seen on 06/12/05 in Regina, Badajoz (J. J. Ramos Encalado, Ardeola 54:419). Possibly the same bird was seen in the same site on 25 and 26/12/05 and in January 2006 (Javier Salcedo et al). The tip of the supposed iceberg is therefore tiny. And to give a good idea of the identification difficulties, this particular bird was considered by some observers to be a Steppe Buzzard (Buteo buteo vulpinus).

Long-Legged Buzzard (Buteo rufinus) dark adult. 1-5-2009. Regina, Badajoz (drawing and fieldnotes by Juan José Ramos Encalado). The uniformly red tail tells us it's an adult.

There are now at least three other observations up before the Rarities Committee. One from 01/05/09 in Palomas, Badajoz (Antonio Matador): a 2nd-year bird, possibly of the cirtensis subspecies, casually photographed without the least idea it could be a Long-Legged Buzzard and then confirmed by several experts (Andrea Corso, Ernest García, Javier Elorriaga). Curiously enough, on the same day and only 35 km away an immature was recorded between Usagre and Hinojosa (Xurxo Piñeiro), but we don't know if this record has been sent in to the Rarities Committee.
Buzzard (Buteo sp.). Possible Long-Legged Buzzard (B. rufinus) immature. 1-5-2009. Palomas, Badajoz (Antonio Matador). It shows rufous plumage, pale breast and dark "trousers". The lightly barred tail tells us it's an immature.

Another two were recorded in 2010, once more 2nd-year cirtensis, near Trujillo, which might be two birds or the same bird seen twice: on 11/06/10 in Belén, to the east of Trujillo (Ernest García; ex member of the Rarities Committee) and on 22-23/06/10 in Los Cerralbos, to the west of Trujillo (Martin Kelsey). In this same zone there were other tentative observations in April and May that have not been sent up for acceptance.

Buzzard (Buteo sp.). Possible Long-Legged Buzzard (B. rufinus cirtensis) immature. 11-6-2010. Belén, Trujillo, Cáceres (Ernest García).

Further west there are other uncertain records, including one on 10/4/10 between Cáceres and Santa Marta de Magasca of another possible immature (Godfried Schreur and Jan van Schaik).
Buzzard (Buteo sp.). Possible Long-Legged Buzzard (B. rufinus), immature. 10-4-2010. Between Santa Marta de Magasca and Cáceres (Jan van Schalk).

On 18/4/10 a different bird was again seen in Santa Marta de Magasca: an immature female with some rufinus features. This bird was accompanied by a male Common Buzzard, both giving out the characteristic Buzzard mew and showing similar behaviour (John Muddeman and John Cramer).

Buzzard (Buteo sp.). Possible Long-Legged Buzzard (B. rufinus), immature. 18-4-2010. Santa Marta de Magasca, Cáceres (John Cramer).

The Long-Legged Buzzard may well be more common in Extremadura than it seems, especially if we include in our trawl observations that were never sent in for ratification for one reason or another (identification doubts, groups of tourists pushed for time, lack of interest, etc.). Since 2005 there has been a series of possible Long-Legged Buzzard sightings. With all due caveats when working with unratified records, SEO-Cáceres has compiled the following list:

* 2005. At least 6 birds in April-May 2005 in Trujillo (3), Llanos de Cáceres (2) and Vegas Altas (1). In Belén, Trujillo, three birds, two light and one dark, recorded by at least 14 different observers between 17/04 and 29/05/05. First record of a light bird and another dark bird on 17/04/05 (S. Villa, T. Driscoll and B. Driscoll); the light bird was seen on 19/04/05 and 20/04/05 (J. Muddeman); on 20/04/05 a dark bird was seen hard by in Torrecillas de la Tiesa (J. J. Saiz); a bird on 22/04/05 and on 23/04/05 (M. Kelsey); a bird on 1/05/05 (Á. Molina and A. López; J. Portillo and J. Portillo) and on 5/05/05 (S. Villa); a bird was seen on 8/05/05 (A. López and J. Diego Acevedo); the bird was still present on 29/05/05 (K. Parker, G. Dodd); in May two light birds were seen (J Muddeman) and one dark (S. Villa). In Cáceres-Santa Marta de Magasca, 25 km west of Belén: two putative birds of the cirtensis race in late April 2005 (S. Villa, J. Boyes and J. Boyes) and a dark bird in May (S. Villa). In Vegas Altas: one light bird in May 2005 (J. Muddeman).
* 2006 and 2007. No information.
* 2008. One putative juvenile in Belén, Trujillo, on 4/05/08 (S. Villa)

Buzzard (Buteo sp.). Possible Long-Legged Buzzard (B. rufinus). April 2004. Belén, Trujillo, Cáceres (Santi Villa).

Let's hope the picture becomes clearer in the future. At present we have little to go on but the supposed presence of 2nd-year cirtensis birds in Spring in steppeland areas could reflect the dispersal of immature Long-Legged Buzzards from North Africa to southwest Iberia. The species has been breeding in Andalusia at least since 2009 (Elorriaga & Román, 2010), and in 2010 there were cases there of hydridisation with Common Buzzard (J. Elorriaga, pers. comm.); precedents of such crosses are known from Italy. Given the close genetic similarity of both species the hybrids might well be fertile. And if these crosses are occurring unbeknown to us there might be hybrids from more than one generation at large in the field, exacerbating the identification difficulties even more. Moreover, the taxonomy has not yet been well defined, since the morphologically different buzzards from the Western Palearctic are genetically very similar. Some authorities consider them to be subspecies rather than full species; on the other hand other pundits separate "B. cirtensis" as a full species in its own right. To complicate matters even more, a recent study moots the validity of the Iberian subspecies B. buteo hispaniae, morphologically different from other European forms (Kruckenhauser, et al., 2004) and sometimes showing a reddish tail.

Acknowledgements: thanks to Javier Elorriaga for his help in identifying the photos and his input of information. To Sergio Mayordomo for compiling the previous records (2005-2008). To the colleagues of GOCE forum who have swapped observations and opinions.

Sources:
- Elorriaga, J. & Román, A. 2010. Primeros casos de reproducción e invernada del busardo moro en la península ibérica. Quercus, 293:32-34. [read more]. Results on 2010, Quercus 298:15.
- Kruckenhauser, L., Haring, E., Pinsker, W., Riesing, M. J., Winkler, H., Wink, M. & Gamauf, A. 2004. Genetic vs. morphological differentiation of Old World buzzards (genus Buteo, Accipitridae). Zoologica Scripta, 33:197-211. [PDF]