An important flyway for raptors in Europe: 13 years of monitoring in the North East of Italy

Mezzavilla F., Gargioni A., Girardello M., Bellintani S., Martignago G., Pasqua A., silveri G., Piccolo F.

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Abstract:

There has been an increase of interest in the study of raptor migration in Italy during the last two decades. We present the results of a long-term program aimed at monitoring post-breeding migrating raptors at two sites in North-eastern Italy. The sites are 107 km apart from each other, one being at Colle S Giorgio (430 sml) in the Asolani Hills (Province of Treviso E 11.56 N 45.49), and the other at Ponti sul Mincio, a few kilometers south of Lake Garda (Province of Mantova E 10.37 N 45.28). Monitoring at Colle San Giorgio has been underway since 1994. Monitoring at Ponti sul Mincio started in 2002. Both sites showed a constant increase in the number of birds observed with the highest peak of 11421 individuals recorded at Colle San Giorgio in 2004, and 15581 recorded at Ponti sul Mincio in 2003. The mean angle of the flying direction of the birds was 243°. A comparison of daily counts showed a similarity in the daily number of individuals counted at both sites, suggesting that the two sites count many of the same birds. Flying height was also estimate or recorded, using a telemeter. Flying height was generally above 1500 m, suggesting that a large proportion of migrating raptors were not counted. Honey Buzzard was the most commonly observed species making up between 97.3 % and 99.9 % of total number of birds observed. In conclusion, in comparison with the results reported by Zalles and Bildstein (2000) this new flyway is amongst the most important sites in Europe for the number of Honey Buzzard recorded in recent years.