1,720,991 research outputs found
Micromys minutus (Mammalia, Rodentia, Muridae) nel comprensorio dei laghi di Chiusi e di Montepulciano (Toscana - Umbria) [Micromys minutus (Mammalia, Rodentia, Muridae) from the lakes of Chiusi and Montepulciano (Tuscany - Umbria)]
No full textA survey of micromammals living around the lakes of Chiusi and Montepulciano revealed Micromys minutus in three sites. This area is the second in Tuscany, after the Padule di Fucecchio, where the species is recorded
Holocene Adelie penguin diet in Victoria Land, Antarctica.
No full textOrnithogenic soils (N = 97) dated up to 7000
Before Present (BP) were sampled in 16 relict and modern
breeding colonies of Ade ́lie penguin along the Victoria
Land coast (Ross Sea, Antarctica). Taxonomic identification
of fish otoliths (N = 677) recovered in these soils
allowed to identify the Antarctic silverfish as the most
eaten prey (90.1%) throughout the investigated period. A
morphometric analysis of the otoliths revealed that the
Ade ́lie penguin primarily selected prey averaging
67.23 ± 23 mm of standard length. Temporal distribution
of Pleuragramma antarcticum showed a peak between
2,000 and 4,000 years BP, a period corresponding to the
maximum spread of Ade ́lie penguin in the Victoria Land.
Possible explanations of the variations of the abundance of
the fish prey in the diet are discussed in the context of the
paleoclimatic events and as possible consequences of dietary
shifts due to the temporal variation of prey availability
in the Ross Sea ecosyste
Nonlinear effects of winter sea ice on the survival probabilities of Adelie penguins
No full textThe population dynamics of Antarctic seabirds are influenced by variations in winter sea ice extent and persistence; however, the type of relationship differs according to the region and the demographic parameter considered. We used annual presence/absence data obtained from 1,138 individually marked birds to study the influence of environmental and individual characteristics on the survival of Adélie penguins Pygoscelis adeliae at Edmonson Point (Ross Sea, Antarctica) between 1994 and 2005. About 25% of 600 birds marked as chicks were reobserved at the natal colony. The capture and survival rates of Adélie penguins at this colony increased with the age of individuals, and five age classes were identified for both parameters. Mean adult survival was 0.85 (SE = 0.01), and no effect of sex on survival was evident. Breeding propensity, as measured by adult capture rates, was close to one, indicating a constant breeding effort through time. Temporal variations in survival were best explained by a quadratic relationship with winter sea ice extent anomalies in the Ross Sea, suggesting that for this region optimal conditions are intermediate between too much and too little winter sea ice. This is likely the result of a balance between suitable wintering habitat and food availability. Survival rates were not correlated with the Southern Oscillation Index. Low adult survival after a season characterized by severe environmental conditions at breeding but favorable conditions during winter suggested an additional mortality mediated by the reproductive effort. Adélie penguins are sensitive indicators of environmental changes in the Antarctic, and the results from this study provide insights into regional responses of this species to variability in winter sea ice habitat. © Springer-Verlag 2009
Factors affecting thwe breeding success of the South Polar skua Catharacta mackormicki at Edmonson Point, Victoria Land, Antarctica
No full textA south polar skua (Catharacta maccormicki) population was studied at Edmonson Point (74°20′S-165°08′E), Victoria Land, Antarctica, in 1998/1999. The local population consisted of 101 pairs, 89 of which were located within a large, loose colony associated with a rookery of about 2,000 pairs of Adélie penguin (Pygoscelis adeliae). Skua nests were clumped around penguin subcolonies. Mean skua Nearest Neighbour Distance (NND) was 21 ± 15 m (n = 89). NND was positively correlated with the distance from the nearest penguin subcolony. Mean laying date was 24 ± 6 December (n = 89). Mean clutch size was 1.9 ± 0.2 eggs (n = 89). Hatching success was 77% (n = 174 eggs laid), and 20.2% of the breeding pairs successfully raised chicks to fledging. Mean number of fledged young was 0.2 ± 0.4 per breeding pair (n = 89), and 1 per successful pair (n = 18). Main causes of breeding failure were intraspecific predation and sibling aggression. Breeding success was negatively related to distance from the nearest penguin nest and to laying date. Because of the extensive and persistent sea-ice cover, penguins represented an important source of food for the skua population
Distribution of nocturnal birds (Strigiformes and Caprimulgidae)in relation to land-use types, extent and configuration in agricultural landscapes of Central Italy
No full textGone fishing: Adélie penguin site-specific foraging tactics and breeding performance
No full textThe ecological drivers underlying breeding performance are expected to differ across the geographical range of seabird species, but few studies have compared trade-offs between colonies with different local conditions. During chick-rearing (2000–01), we compared the foraging trips, diet and breeding parameters of two Adélie penguin colonies in the Ross Sea, at Edmonson Point (EdPo; ~2000 breeding pairs) and Inexpressible Island (InIs; ~24 000 breeding pairs). Penguins from InIs travelled farther and performed longer feeding trips. The quantity of food brought to the nest was the same for the two colonies, but penguins from InIs brought more fish and less krill. Eggs hatched earlier at EdPo. Breeding success did not differ, but chick weight during hatching–fledging was greater at InIs. Despite worse weather conditions at InIs, the larger proportion of high-energy food brought by penguins from InIs (i.e. fish) may explain their offspring‘s better performance. In addition, the persistence of fast ice at EdPo may have led to greater energy expenditure of breeding individuals, possibly reducing chick growth. The greater intraspecific competition expected at InIs may have been reduced by longer foraging trips and/or counteracted by the more nutritious diet. Our findings reveal complex trade-offs between foraging effort and environmental constraints in determining the breeding performance of Adélie penguins
Going out to mate: excursion behaviour of female roe deer
No full textAmong mammals, female searching behaviour for a mate has been poorly investigated in behavioural studies on sexual selection. The social organization of roe deer and its physiological constraints suggest the existence of searching strategies by females. Using radiotracking and direct observation we studied the spatial behaviour and intersexual interactions of 32 roe does during the rut in two areas of Tuscany, central Italy. Respectively, 55% and 33% of females performed excursions outside their usual home ranges during the peak of the rut (15 Jul.-15 Aug.). Excursions ranged from 0.6 to 3.0 km, if measured in a straight line, and lasted 30-52 h. During excursions, females (1) moved quickly in one direction; (2) met and were courted by a male; (3) copulated with a male and (4) returned to their home ranges after mating. Before starting an excursion, roaming females were observed to approach unsuccessfully males already courting other females. Most likely excursions represent a condition dependent mating tactic adopted by a variable proportion of females and involving active searching behaviour. © 2008 The Authors
The first five years of the Italian? Australian joint programme on the Adelie Penguin: an overview
No full textAbout 2000 breeding pairs of Adelie penguin (Pygoscelis adeliae) nest in Edmonson Point (Wood Bay, 74 degrees 21' S, 165 degrees 10' E). The penguin colony is located on a raised terrace, divided into 13 discrete small units or colonies separated by unoccupied areas, where South polar skua (Catharacta maccormicki) nest. Colony layout, breeding chronology, breeding success, diet, and foraging areas were studied for five consecutive austral summers. Satellite transmitters, time-depth recorders, and electronic tagging were used for monitoring feeding behaviour and nest attendance. An Automated Penguin Monitoring System was installed which records weight, identity, and direction of penguins as they move between the sea and their breeding colony. So far, the results of this study are documentation on colony trends, breeding biology, and differences in foraging strategies at different study seasons
Attività di ricerca e monitoraggio degli uccelli marini nell'ambito del programma Nazionale di Ricerche in Antartide
No full textAnnual variation in reproductive parameters of Adélie penguins at Edmonson Point, Victoria Land, Antarctica
No full textAnnual egg and chick production and breeding success at the Adélie penguin (Pygoscelis adeliae) colony Edmonson Point (74°21′S- 165°10′E), Victoria Land, is presented for eight breeding seasons between 1995 and 2005. During this period the colony consisted of 10-13 subcolonies and averaged 2098 ± 278 breeding pairs. A sample of over 100 nests (114-150), belonging to two subcolonies, was monitored each year. Some breeding parameters remained constant while others showed substantial annual variation. Laying date showed little variation, and laying was highly synchronous: 82.5% of clutches were initiated in a 10-day period, 9-18 November. In contrast, clutch size (1.77-1.97) and incubation period (34.4 ± 2.5) varied significantly. Variation among years was also recorded in hatching success (from 58 to 86%) and breeding success. This last parameter, measured as number of chicks reared to crèche per nest with eggs, varied between 0.34 and 0.97. © 2007 Springer-Verlag
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