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Ecoacoustic techniques using multiple acoustic sensors and two metrics of the acoustic community – the acoustic complexity index (ACI) and the chorus ratio (CR) – were successfully used to describe and characterize the morning acoustic activity of birds according to three equal temporal intervals during spring 2013: Dawn Chorus, Post Chorus 1, and Post Chorus 2.The metrics were applied across five Italian Mediterranean locations (Valenza, Madonna dei Colli, Monte Curto, Virolo, Croce di Tergagliana) that differed by land-cover typologies. Results from the ACI metrics showed a peak during the Dawn Chorus and a visible lull close to sunrise between Dawn Chorus and Post Chorus 1.The lull was evident in all localities except Valenza, where singing activity was relatively constant across the successive morning intervals. Temperature and vegetation structure were confirmed as important factors associated with morning acoustic activities. Vegetation evenness and temperature across the season was negatively correlated with ACI, whereas CR was positively correlated with temperature and vegetation diversity. Of the 33 species of birds identified during the maximum dawn chorus activity, Blackcap, Blackbird, European Robin, and Great Tit were acoustically dominant and their activity was significantly higher before sunrise except for Blackcap, whose acoustic activity showed no significant differences across time intervals. The dawn chorus is one of the most conspicuous behaviours of birds, engendering much speculation but no definitive, univocal explanations. The ecoacoustic approach opens a new perspective for investigating this complex phenomenon.

The Red-billed Leiothrix (Leiothrix lutea) is an invasive species which has recently been found to be locally abundant in eastern Liguria (Italy). The song production of this bird was recorded over the course of an entire year (2011) and evaluated using both aural information and applying innovative automatic processing metrics. Our findings revealed that the Red-billed Leiothrix has loud vocalizations that are heard for most of the year, including in July and August when other birds are silent. Its song production has been estimated to amount to 37% of the sounds uttered by the entire bird community. The next most vocal species are the European Robin (36%), the Common Blackbird (18%), the Subalpine Warbler (5%) and the Sardinian Warbler (1%). The Red-billed Leiothrix can be seen as a new acoustically dominant species and, consequently, a potential modifier of the soundscape patterns of the indigenous bird community. The modification of acoustic traits in the repertoire of both indigenous species and the Red-billed Leiothrix is to be expected according to a co-evolution hypothesis.

In territorial songbirds, duets between mates represent one of the best-known examples of communal display, with the main function being the defence of joint resources. In this study, we found evidence of a coordinated choral display performed by neighbouring heterospecific songbirds. In such choruses, most of the participating species perform a deliberate temporal overlap of songs, thus suggesting agonistic behaviour. However, they then utilize a complex form of behaviour to avoid signal jamming, making the aggressive purpose unlikely. We define these displays as “coordinated interspecific choruses”. We recorded dusk choruses of songbirds living in a mixed turkey oak wood in central Italy, and then carried out a niche overlap analysis using null models that were intended for investigations of concurrent emissions of songs, finding that species tend to sing concurrently instead of using the refractory period of another species. Among the species singing concurrently, about half used the same frequency range, but instead of finding considerable spectral overlap between their vocalizations, the number of real spectral overlaps was lower than would be expected by chance. We propose a tentative explanation for this, where such choruses are the expression of the existence of a neighbourhood of different species that has evolved a communal signal that is similar to that used by mates in a pair, i.e. coordinated vocalizations. As coordination requires experience of each other's songs, we propose that evolution has selected individuals that are more skilled at learning heterospecific songs.

Islands and mainland coastal ranges are fragile systems rich in biological endemisms and ecological peculiarities. In these environments, the cultural heritage that represents an important component of the overall ecological complexity is under attack from human pressures (urban sprawl, logistics, fish farming and mass tourism).

Landscape Ecology and the General Theory of Resources: Comparing Two ParadigmsThis paper is an attempt to connect the General Theory of Resources (GTR) with the principles that guide the Landscape Ecology Principles (LEP). The recent GTR is based on the assumption that resources are the common requirement for individual species, populations, communities and ecosystems. We therefore describe the main characteristics of resources, while the biosemiotic mechanisms with which to track them are also discussed.Moreover, and with a view to their reinterpretation, we have confronted the issues of patch shape, heterogeneity, corridors, ecotones and fragmentation with these GTR principles. According to the thesis presented in this paper, resources can be tracked using the specific spatial configuration carrier of meaning (the eco-field), while the major features of landscapes, such as size, shape and the distribution of patches, are used by organisms (animals) as a semiotic cue with which to identify eco-fields and associated resources.

Bird community structure and dynamics were studied in seven habitats of northern Italy during three periods. Respectively 87 and 70 species were detected in 1984 and 1985 (a total of 98 species for 1984 + 1985). Of these, 45% belonged to permanent resident species. This category was dominant in abandoned mountain farmland, shrublands, young wood and abandoned chestnut orchard.The tree cover was negatively correlated with bird diversity. The permanent resident and transient migrant species had the highest interseason turnover. Abandoned chestnut orchard showed the highest value of specific dominance (322). The species with the widest habitat breadth (> 0.80) were: blackcap (Sylvia atricapilla), blackbird (Turdus merula), great tit (Parus major) and greenfinch (Carduelis choris).Based on the relative abundance of single species abandoned chestnut orchards, shrubland and young wood were the habitats with the most similar bird community. Seven species had an acoustic repertoire breadth > 0.60. The permanent residents and summer migrants were the least acoustically varied species. Transient migrant birds were attracted to open fields and shrubland habitats. Woodland habitats had a more evenly distributed bird assemblage.The availability and concentration of food in patchy habitats were probably most responsible for habitat choice during the period studied. Permanent residents and winter migrants showed the broadest habitat preferences. The spatial heterogeneity of birds decreased during spring according to a more diffuse distribution of resources.The interpretation of the specific acoustic repertoire could be helpful in distinguishing intraspecific populations.

Sixty-two species have been recorded in autumn-winter in 11 selected habitats of Northern Tuscany (Italy). Riparian woodland and olive orchard supported the highest number of bird species. The interhabitat similarity is higher in woody habitats than in open habitats. The specific inter-monthly stability and the habitat breadth are positively correlated (p < .001). In woodlands the residents are dominant whereas in farmlands the partial and transalpine migrants are dominant. The patchy structure of habitats and the abundance of resources are probable factors responsible for the low intercategory overlap.