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The increase in the average air temperature due to global warming has produced an early onset of the reproduction in many migratory birds of the Paleartic region. According to the ‘mismatch hypothesis’ this response can lead to a decrease in the breeding output when the conditions that trigger the departure from the wintering areas do not match the availability of food resources in the breeding ground. We used 653 brooding events registered during the period 1991-2013 to investigate the link between climatic variables and individual breeding performance of a partially migratory passerine, the Rock Sparrow Petronia petronia, breeding at the altitude limit of its distribution. The laying date of the earliest first clutch was associated with local spring (minimum) temperatures but did not show a significant trend during the period considered. The laying date of the latest first clutch had a positive and statistically significant trend, unrelated to local covariates and resulting in a longer breeding season (∼1.5 day per year). A longer breeding season allowed birds to produce more second clutches, which proportion increased from 0.14 to 0.25. The average breeding success was also positively correlated with the average temperature in July and with the duration of the breeding season. Contrary to expectations, the most important climate-dependent effect was a stretch of the breeding season due to a significant increase of the laying date of the latest first-clutches rather than an earlier breeding onset. We show how climate changes act on bird populations through multiple paths and stress the need to assess the link between climatic variables and several aspects of the breeding cycle.

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-First verified nesting of the Song thrush Turdus philomelos in the Aspromonte National Park, Italy.In Calabria, the Song thrush Turdus philomelos breeds only in the central and northern sectors of the Region (i.e. Pollino, Orsomarso and Sila areas) while in the province of Reggio Calabria small feeding and roosting aggregations are mainly observed during migration. During two successive breeding seasons (2015)(2016), using both distance sampling with line transects and point count methods for estimating relative bird abundance in woody habitats of Aspromonte National Park (PNA), we detected a total of N=16 breeding individuals of T. philomelos within different altitudinal bands (min 630 m, max 1,838 m a.s.l.) and predominantly in mesophilic deciduous forests. Whit this work we verified nesting of T. philomelos for the first time for both, PNA and province of Reggio Calabria, but extending future investigations to a wider area, we could more accurately quantify the number of nesting pairs and their distribution on a regional scale.Key words: Song thrush, Turdus philomelos, Aspromonte National Park, Calabria, Italy, first nesting Riassunto -In Calabria, il Tordo bottaccio Turdus philomelos si riproduce solo nei settori settentrionali e centrali della Regione (i.e. Pollino, Orsomarso e Sila), mentre in provincia di Reggio Calabria la nidificazione non è mai stata accertata e le osservazioni risultano scarse e concentrate esclusivamente nei periodi migratori. Durante due successive stagioni riproduttive (2015)(2016), abbiamo osservato N=16 individui di T. philomelos a differenti altitudini (min 630 m, max 1,838 m a.s.l.) prevalentemente nei boschi di latifoglie decidue mesofile. Sono stati utilizzati la modalità del "distance sampling" eseguendo un transetto a piedi ed altre 3 diverse tecniche di campionamento "point-count" per stimare la presenza della specie nel Parco Nazionale dell'Aspromonte. Con questo lavoro, abbiamo accertato per la prima volta la nidificazione del T. philomelos nel Parco Nazionale dell'Aspromonte e nella provincia di Reggio Calabria. In futuro, con l'incremento dell'area di investigazione, si potrà quantificare in modo più accurato il numero di coppie nidificanti e la loro distribuzione su scala regionale.Parole chiave: Tordo bottaccio, Turdus philomelos, Parco Nazionale dell'Aspromonte, Calabria, prima nidificazione.Il Tordo bottaccio Turdus philomelos è una specie politipica a distribuzione eurosibirica (Brichetti & Fracasso, 2008). In Europa la popolazione viene stimata tra 20 e 36 mln di coppie riproduttive e classificata con lo status Least concern (LC) nella European Red List (BirdLifeInternational, 2015). In Italia, con una stima popolazionistica di 200.000-400.000 coppie (BirdLife-International, 2016) e trend stabile (Rondinini et al., 2013), la specie nidifica, tra i 400 e i 2.000 m di quota, in boschi montani o collinari di conifere pure o miste a latifoglie, prediligendo boschi freschi e folti, ricchi di sottobosco e radure erbose. Più abbondante sull'arco alpino, la sua...