Volume 40 - N. 2
Measuring bird abundance: a comparison of methodologies between capture/recapture and audio-visual surveys
Basile M., Balestrieri R., Posillico M., Mancinelli A., Altea T., Matteucci G.Abstract Read Article Download30 66
Research on species-habitat relationship implies that a specific parameter related to the species, such as abundance, has to be measured and compared to environmental features. Different methods have been implemented in the collection of abundance data on birds and different statistical techniques have been developed to deal with the great diversity of data collection. The aim of this study is to compare different sampling methods and statistical techniques currently used to estimate abundance, employing them in a dense forest environment: capture-mark-recapture vs. point counts. Short-toed treecreepers Certhia brachydactyla were captured through mist-netting and surveyed through song count. Capture data were analysed using a classical approach and a spatially-explicit approach (SECR), while count data were analysed with N-mixture models. Results show that classical capture analyses yield a lower abundance, while SECR and N-mixture models give similar and higher estimates. An optimization of the sampling design for studies regarding birds` abundance and species-habitat relationship should consider the use of point counts for song/visual detection of individual birds while fitting N-mixture models for abundance estimation.
Breeding habitat selection of the Black Woodpecker Dryocopus martius L. in Mediterranean forests
De Rosa D., Andriuzzi W.S., Di Febbraro M.Abstract Read Article Download34 102
The Black Woodpecker has a wide northern Palearctic range, but in much of western Europe it has a highly fragmented distribution. As these isolated populations are vulnerable to land cover change, a better understanding of the factors driving their presence is needed in the perspective of conservation. To shed light on the habitat preferences of the Black Woodpecker in the southern part of its range, we carried out a research in a large protected area, the Cilento and Vallo di Diano National Park (the first investigation on this species anywhere in southern Italy). We used a playback technique to detect occurrence of Black Woodpeckers, as well as sympatric woodpecker species, and recorded environmental characteristics that might explain the bird’s occurrence, such as tree species and stand age. The “extent of occurrence” of the Black Woodpecker was calculated, and its habitat preferences investigated. Occurrence of the species was clearly dependent on beech dominance, in contrast with the other woodpecker species, with an estimated total population for National Park 18.56 (± 6.19) pairs in beech-dominated woods. Habitat preferences were narrower compared to northern European populations, highlighting the dependence of this species on beech forests in southern Europe. Since beech forests in the Mediterranean region are predicted to recede due to climate change, our findings highlight the vulnerability of southern Black Woodpecker populations.
First breeding colony of Audouin’s gull Larus audouinnii in Sicily, characteristics and its origin
Ientile R., Linares A., Brogna F.Abstract Read Article Download21 51
The Audouin’s Gull Larus audouinii Payraudeau, 1826 has never been recorded breeding in Sicily: the authors are here reporting the discovery of a breeding colony on the island of Vendicari, province of Siracusa, off the south-east coast of Sicily. An estimated 50 60 pairs have bred there in 2010 and 2011 and 100 to 130 pairs in the period 2012-2016. All the basic information on breeding attempts and success, egg-laying dates, number of eggs laid, number of chicks fledged, and characteristics of each nest was collected. During the breeding season of 2012-2016 a total of 19 ringed adults were observed at the colony: 11 of these originated from the same colony (Vendicari) while 8 came from other colonies, of which 6 from Italy and 2 from the Ebro delta in Spain. Those gulls ringed as chicks from the Vendicari colony have so far shown that they spend the winter months in Sicily and North Africa, while in the spring and summer months, these birds have been observed in Sicily, Calabria, Apulia and Campania. The data presented here demonstrate the ability of this species in occupying new territories, sometimes on the periphery, and a tendency of population increase in a very short period of time, presumably through recruitment of individuals originating from other colonies. The data collected confirm a strong nest-site tenacity and also show that a significant part of the individuals present in the colony consisted of birds in their third year of life.
How to get by in a floodplain forest: the reaction to forestry as evidence by the Tawny owl Strix aluco
Czocherová I., Baláz M., Turcoková L.Abstract Read Article Download18 69
To establish a management plan that does not contribute to species loss, it is essential to fully understand the response by organisms to human impacts. Forests on floodplain of rivers face several threats. One of them is intensive forestry. Along the Danube River, forests are changing rapidly, which affects the composition of species. Due to short rotation logging, cavity-nesting birds are restricted by the lack of old trees. Thus, in our study we intended to identify the habitat preferences of the Tawny Owl, in areas with populous plantations and fragments of natural softwood forest. We measured 28 environmental parameters (type of forest, age, perimeter of trees, height and coverage of herbaceous layer, shrub and trees in proper categories) in Tawny owl territories as well as outside these territories. By using discriminant analysis with forward stepwise method we found significant difference in overall vegetation structure inside and outside the territories. The Tawny owl remains close to the oldest (older than 26 years) and largest trees (with perimeter greater than 161 cm), which are common for patches of natural forest. However, the owl seems to avoid monocultures with small trees and larger cover of tall grass and shrubs. Hence we concluded that the natural forests should be maintained as a fundamental element in the floodplain areas. Furthermore, based on our results, the priority of managing the populous plantations should be in a way that at least few old trees would remain in logging units.
New colony of Little Egrets Egretta garzetta at Trapani saltpans
Colonization of Eurasian Jay Garrulus glandarius and Holm Oaks Quercus ilex: the establishment of ecological interactions in urban areas
La Mantia T., da Silveira Bueno R.
Expansion of the breeding range and probable high-altitude nesting of the European Nightjar Caprimulgus europaeus in the Carnic Alps (North-eastern Italy)
- Italian review of Doctoral Theses in Ornithology (second edition)
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