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Baghino L.,Centro Ornitologico E Of Educazione Ambientale Of Case Vacca | Premuda G.,Oetlingerstrasse 171 | Giraudo L.,Parco Naturale Alpi Marittime
Avocetta | Year: 2012

The autumn migration of the short-toed eagle Circaetus gallicus was studied from 15th to 26th September, in 2005, 2006 and 2007, at three sites in NW Italy: Stura Valley (S Piedmont), Arenzano (W Liguria) and Apuane Alps (NW Tuscany). During this 3-year period, 746, 2085 and 2352 shorttoed eagles were respectively counted at these three sites: correlations in both time and migration volume were found between the Apuane Alps and Arenzano, but not with the Stura Valley, where the migrating populations are probably of different origins (N Italy, with some reports of birds moving SW already from sites in the NE regions of Italy). Interestingly, the significant counts at the Apuane Alps suggest that birds performing this circuitous migration may involve a rather wide area through Central and Southern Italy; moreover, occasional findings on the Adriatic side of Central Italy (birds heading NW) would seem to show that this circuitous migration may also have a degree of longitudinal extension. During the second half of September a fair proportion (<20% of the whole volume) of juveniles is regularly observed at both Apuane Alps and Arenzano sites, and their migration dates are very close to the main adult movement, in agreement with the strategy to follow the adults performed by a portion of the juveniles. © 2012 CISO. Source


Rughetti M.,Parco Naturale Alpi Marittime | Rughetti M.,Universite de Sherbrooke | Festa-Bianchet M.,Universite de Sherbrooke
Journal of Zoology | Year: 2011

In many polygynous mammals, sexual size dimorphism (SSD) is thought to have evolved through sexual selection, because larger males prevail in male-male combat and secure access to estrous females. SSD is often correlated with higher age-specific mortality of males than of females, possibly because males have higher nutritional requirements and riskier growth and reproductive tactics. In adult chamois Rupicapra rupicapra, sexual dimorphism in skeletal size was about 5%, but dimorphism in body mass was highly seasonal. Males were about 40% heavier than females in autumn but only 4% heavier in spring. For a given skeletal size, males were heavier than females only in autumn. Chamois sexual dimorphism appears mainly due to greater summer accumulation of fat and muscle mass by males than by females. Male mass declines rapidly during the rut. Limited dimorphism in skeletal size combined with substantial but seasonal dimorphism in mass has not been reported in other sexually dimorphic ungulates. Seasonal changes in mass allow males to achieve large size for the rut by accumulating body resources during summer. The use of these resources over the rut may reduce mortality associated with sustaining a large size over the winter. © 2011 The Authors. Journal of Zoology © 2011 The Zoological Society of London. Source


Rughetti M.,Parco Naturale Alpi Marittime | Rughetti M.,Universite de Sherbrooke | Toigo C.,Office National de la Chasse et de la Faune Sauvage | Von Hardenberg A.,Alpine Wildlife Research Center | And 2 more authors.
Acta Theriologica | Year: 2011

Although weather-induced mass mortalities of wild ungulates have been reported, no study has quantified how these episodes may affect the survival of prime-aged adults. Long-term studies of marked ungulates have instead consistently found very weak or no effects of weather on the survival of this age class, particularly for females. We report on the effects of the exceptionally snowy winter of 2008-2009 on three populations of chamois in the western Alps: two in Italy, one in France. In the Alpi Marittime Natural Park in Italy, mortality of prime-aged females (aged 2-9 years) was 43%, about five times higher than reported by previous studies of chamois. Just across the continental divide in the adjacent Mercantour National Park (PNM) in France, however, prime-aged female mortality was only 6%. Senescent females suffered very high mortality in both populations (100% and 56%). In the Gran Paradiso National Park in Italy and in the Alpi Marittime Natural Park, adult male mortality rate was respectively of 81% and 44%, whereas in the PNM, it was only 10%. A recent reduction in population density in the French population, or lower absolute snowfall than in Italy, may explain the difference in survival. Survival of males and prime-aged females can be affected by exceptional weather events, possibly in combination with high population density. Adult chamois of both sexes appeared to show elevated mortality in response to harsh winter conditions. Our results underline the importance of considering sex and age classes in evaluating the impacts of population density in wild ungulates. © 2011 Mammal Research Institute, Polish Academy of Sciences, Białowieża, Poland. Source


Rughetti M.,Parco Naturale Alpi Marittime | Rughetti M.,Universite de Sherbrooke | Festa-Bianchet M.,Universite de Sherbrooke
Journal of Animal Ecology | Year: 2011

+Summary: 1.Environmental conditions during early development can affect the growth patterns of vertebrates, influencing future survival and reproduction. In long-lived mammals, females that experience poor environmental conditions early in life may delay primiparity. In female bovids, annual horn growth increments may provide a record of age-specific reproduction and body growth. Horn length, however, may also be a criterion used by hunters in selecting animals to harvest, possibly leading to artificial selection. 2.We studied three populations of chamois (Rupicapra rupicapra) in the western Alps to explore the relationships between female horn length and early growth, age of primiparity and age-specific reproduction. We also compared the risk of harvest to reproductive status and horn length. 3.Early horn growth was positively correlated with body mass in pre-reproductive females and with reproduction in very young and senescent adults. Females with strong early horn growth attained primiparity at an earlier age than those with weak early growth. Horn length did not affect hunter selection, but we found a strong hunter preference for nonlactating females. 4.Our research highlights the persistent effects of early development on reproductive performance in mammals. Moderate sport harvests are unlikely to affect the evolution of phenotypic traits and reproductive strategies in female chamois. A policy of penalizing hunters that harvest lactating females, however, may increase the harvest of 2-year-old females, which have high reproductive potential. © 2010 The Authors. Journal compilation © 2010 British Ecological Society. Source

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