Birding Italy Net - Tunisia, a sparrow's puzzle.

Birding Italy Net

Tunisia, a sparrow's puzzle.

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Luca Boscain, a young Italian birdwatcher, during a recent trip in Tunisia was able to observe and photograph a wide range of variability among breeding sparrows of the genus Passer (apart from Desert Sparrow, Passer simplex, breeding in S Tunisia). Finally he was able to realize a plate showing this variability associated to the Tunisia map, pointing particularly to the shape and size of the black bib extending to upper breast and eventual streaks extending down flanks. According to Beaman & Madge’s Handbook of Bird Identificaion (1998) Tunisia hosts both House Sparrow and Spanish Sparrow; however, birds resembling Italian Sparrows may occur outside Italy as a result of hybridization between these two closely related species. Indeed, none of the sparrows found in Tunisia by Luca Boscain were showing the typical grey forehead/crown of the House Sparrow, all having a head similar to Italian Sparrows with brown forehead/crown. The only birds showing the features of the Spanish Sparrow (Passer hispaniolensis) were present close the Chateau Boire Bou at Cap Bon, N Tunisia, even the voice of them was indistinguishable from to the call of Italian Sparrow (that is very similar to the voice of House Sparrow). Probable hybrids P. hispaniolensis x domesticus with streakes extending down flanks were found at Hammamet and Mahares. Along the desert borders birds were losing features of the Spanish Sparrow, with very few streakes down bib and no streaks at all at Douz, the last oasis before the Great Tunisian Erg, where birds appeared indistinguishable from a pure Italian Sparrow. As about the voice, none of the Tunisian sparrows were calling as Spanish Sparrow (e.g. those breeding in the Po Delta, NE Italy, coming from the Balkans). According Cramp et al.'s Handbook (1994) the form Passer domesticus tingitanus of N Africa is closely related to P. d. italiae of Italy (the former being a subspecies of the latter according Stephan 1986); however populations in Tunisia show extreme individual variation, from pure P. domesticus to pure P. hispaniolensis and all forms between. Isolated Sahara populations are more stabilized and usually nearer P. domesticus tingitanus (which is itself variable, probably due to introgression of P. hispaniolensis characters even in its pure form), those of coastal Tunisia are nearer P. hispaniolensis. However during his trip, Luca Boscain was unable to find neither P. hispaniolensis nor P. domesticus tingitanus pure forms.

Last minute. G. Olioso suggests to check this paper out:

Stephan B. (1999). [Taxonomy of Mediterranean sparrows, genus Passer – further problems in hybridisation, italiae, tingitanus.] [in German, summary in English] Mitt. Mus. Nat. kd. Berl. Zool. Reihe 75: 3-9.