Search results for "birds"
showing 10 items of 291 documents
Aggiornamento della check list degli uccelli della Riserva Naturale Orientata “Isole Dello Stagnone” (Sicilia)
2017
17 years after the publication of LO VALVO & MASSA (1999) the Check List of birds of the “Stagnone Islands” has been updated. The latest observations highlight the importance of the Nature Reserve as Important Birds Area (IBA).
Le zone ornitologiche della Sicilia: un metodo per l'individuazione oggettiva di ecoregioni.
2012
Gli autori presentano una zonizzazione ecologica della Sicilia costruita in maniera oggettiva su base ornitologica con i dati sulla distribuzione delle specie nidificanti raccolti nei periodi 1979-1984, 1985-1992 e 1993-2006. Le maglie quadrate 10x10 km in cui erano riportati i dati originali sono state raggruppate con una cluster analysis sulla base della somiglianza della comunità ornitica nidifican- te, utilizzando le specie indicatrici per individuare il livello ottimale di raggruppamento che caratte- rizza ciascun gruppo e, insieme alle categorie di uso del suolo, fitoclimatiche e geologiche prevalen- ti al loro interno, i caratteri ecologici principali di ciascun gruppo. Sono state in…
Factors affecting the diet of Peregrine Falcon in Italy
2016
The diet of top predators can provide useful information on phenology and abundance of their prey. The cosmopolitan and specialist Peregrine Falcon (Falco peregrinus) is an ideal model to assess whether food changes have occurred in the long-term. In this contribution, we reviewed all available literature on Peregrine Falcon diet in Italy which contained 11 detailed datasets useful for our review, and also included analysis of pellets, collected at three breeding sites of Sicily during 2014 and 2015. These data allowed us to shed light on the Peregrine Falcon’s diet over the last forty years (1978-2015). We calculated the numerical and biomass percentage of the resident and not-resident pre…
Limited potential for bird migration to disperse plants to cooler latitudes
2021
Climate change is forcing the redistribution of life on Earth at an unprecedented velocity1,2. Migratory birds are thought to help plants to track climate change through long-distance seed dispersal3,4. However, seeds may be consistently dispersed towards cooler or warmer latitudes depending on whether the fruiting period of a plant species coincides with northward or southward migrations. Here we assess the potential of plant communities to keep pace with climate change through long-distance seed dispersal by migratory birds. To do so, we combine phenological and migration information with data on 949 seed-dispersal interactions between 46 bird and 81 plant species from 13 woodland communi…
Year-round variation in the isotopic niche of Scopoli's shearwater (Calonectris diomedea) breeding in contrasting sea regions of the Mediterranean Sea
2022
Top marine predators are key components of marine food webs. Among them, long-distance migratory seabirds, which travel across different marine ecosystems over the year, may experience important year-round changes in terms of oceanographic conditions and availability of trophic resources. We tested whether this was the case in the Scopoli’s shearwater (Calonectris diomedea), a trans-equatorial migrant and top predator, by sampling birds breeding in three environmentally different regions of the Mediterranean Sea. The analysis of positional data and stable isotopes (δ13 C and δ15N) of target feathers revealed that birds from the three regions were spatially segregated during the breeding per…
THE EFFECT OF ALTERNATIVE PREY ON THE DYNAMICS OF IMPERFECT BATESIAN AND MÜLLERIAN MIMICRIES
2004
Both Batesian and Müllerian mimicries are considered classical evidence of natural selection where predation pressure has, at times, created a striking similarity between unrelated prey species. Batesian mimicry, in which palatable mimics resemble unpalatable aposematic species, is parasitic and only beneficial to the mimics. By contrast, in classical Müllerian mimicry the cost of predators' avoidance learning is shared between similar unpalatable co-mimics, and therefore mimicry benefits all parties. Recent studies using mathematical modeling have questioned the dynamics of Müllerian mimicry, suggesting that fitness benefits should be calculated in a way similar to Batesian mimicry; that i…
Comment on "Ecological importance of the thermal emissivity of avian eggshells".
2012
Eggshell emissivity must be known to determine accurately the cooling rate of avian eggs when the parent, after heating by conduction during the incubation, is temporarily absent. We estimate possible values of eggshell emissivities from in-situ measurements and spectral libraries. Emissivity is near to 1 (probably higher than 0.95) and therefore its effect on cooling rate may be negligible, with differences between the temperature of the egg assuming a value of e=0.95 and that of a blackbody (e=1) below 0.2 °C.
Characterization of poultry egg-white avidins and their potential as a tool in pretargeting cancer treatment.
2003
Chicken avidin and bacterial streptavidin are proteins used in a wide variety of applications in the life sciences due to their strong affinity for biotin. A new and promising use for them is in medical pretargeting cancer treatments. However, their pharmacokinetics and immunological properties are not always optimal, thereby limiting their use in these applications. To search for potentially beneficial new candidates, we screened egg white from four different poultry species for avidin. Avidin proteins, isolated from the duck, goose, ostrich and turkey, showed a similar tetrameric structure, similar glycosylation and stability against both temperature and proteolytic activity of proteinase…
The component helminth community in six sympatric species of Ardeidae.
2005
We studied the helminth communities in 6 sympatric species of Ardeidae (Ixobrychus minutus (Linnaeus, 1766), Nycticorax nycticorax (Linnaeus, 1758), Bubulcus ibis (Linnaeus, 1758), Egretta garzetta (Linnaeus, 1766), Ardea cinerea (Linnaeus, 1758), and Ardea purpurea (Linnaeus, 1766)) from "La Albufera de Valencia," Spain. The survey revealed 13 species of helminth parasites: 5 digeneans, 2 cestodes, and 6 nematodes. The component helminth communities of the Ardeidae examined are depauperate and conform to the pattern typically found in isolationist communities, probably because of their high trophic dependence on a few prey species. Evenness was positively correlated with richness and abund…
Heterospecific female mimicry in Ficedula flycatchers
2014
Mimicry is a widespread phenomenon. Vertebrate visual mimicry often operates in an intraspecific sexual context, with some males resembling conspecific females. Pied flycatcher (Ficedula hypoleuca) dorsal plumage varies from the ancestral black to female-like brown. Experimental studies have shown that conspecific and heterospecific (collared flycatcher, F. albicollis) individuals of both sexes respond, at least initially, to brown individuals as if they were female. We quantified the perceptual and biochemical differences between brown feathers and found that brown pied flycatcher males are indistinguishable from heterospecific, but not from conspecific, females in both aspects. To our kno…