Catania, Italy
Catania, Italy

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Amato M.,Studio Natura Mediterraneo | Ossino A.,Studio Natura Mediterraneo | Brogna A.,Osservatorio Natura | Cipriano M.,University of Siena | And 5 more authors.
Acta Ornithologica | Year: 2014

Site quality may influence breeding performance especially in raptors showing strong territory fidelity as predicted by the site-dependent population regulation hypothesis. Thus, the occupancy of nest-sites is non-random, indicating a preference of certain territories, apparently of higher quality. During four breeding seasons (2003-2006), we recorded the occupancy rate and the number of young fledged from Lanner Falcon Falco biarmicus feldeggii nest-sites in eastern Sicily, Italy. Breeding sites with different occupancy rates showed significant differences in environmental attributes, mainly altitude. A generalised linear model revealed a significant effect of the slope of the nest-site on mean fledgling number per successful pair. In addition, the mean slope of the nest territory and the slope of the nest-site are the main predictors for differentiating the cliff selection by Lanners and by much more competitive Peregrine Falcons Falco peregrinus. Finally, our results suggest a crucial role of the high quality sites for the population viability. Occupancy rates were positively related to the mean number of young fledged per territorial pair and during the four years of the study period six high quality nest-sites raised 58% of young produced in the whole study area. We suggest that the annual production of young of the high quality territories should be preserved and that evaluation of the effective contribution of the low quality sites for the persistence of a viable population in Sicily should be performed.


Leonardi G.,Osservatorio Natura | Amato M.,Studio Natura Mediterraneo | Brogna A.,Osservatorio Natura | Cipriano M.,University of Siena | And 5 more authors.
Journal of Ornithology | Year: 2013

Detailed information is still lacking on structure and duration of calls of diurnal birds of prey as well on their vocal repertoire. The Lanner Falcon (Falco biarmicus) is considered a shy less-vociferous species but no quantitative data exist. Field evidence demonstrates that in the last decades this falcon did not improve its threatened status in Italy. We investigated call frequencies and their durations to ascertain the effectiveness of these signals, especially during the breeding season. In particular, if calls are honest signals about the genetic quality of males. We carried out this study during two breeding seasons in eastern Sicily where we monitored 25 nesting attempts at 19 breeding sites. During 114 observational sessions, we recorded (1) which sex uttered calls, (2) type of vocalisation (wailing and creaking calls) and (3) bird positions (flying or perched). In addition, we recorded duration of each vocal event because it seems to be significantly correlated with male quality. We checked nests annually to ascertain the number, age and gender of nestlings. Lanner mates employ calls mainly in crucial reproductive stages (courtship, incubation, the first week after hatching and when young are fledging) optimising their efforts. In addition, males performing shorter vocal events produce broods significantly smaller in size and with a sex ratio biased towards females. In addition, they seem to desert the breeding site in the subsequent year. We suppose that in Italian fragmented breeding populations of Lanners, call structure and rates can predict population viability. © 2012 Dt. Ornithologen-Gesellschaft e.V.

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