PRIMI DATI SULLA PRESENZA IN BRESCIA DI CORNACCHIA GRIGIA Corvus corone cornix

RIASSUNTO-In due aree della città di Brescia si è accertata la presenza non occasionale di Cornacchiegrigie.Queste aree sono localizzate a nord ed a ovest(dove è stata rilevata la presenza di un nido)del centro storico della città.La presenza delle Cornacchie è simile nelle due aree di studio e varia infunzione della stagione e della presenza umana.L’Autore discute il vantaggio adattativo di tale colonizza-zione,anche se il limite imposto dall’esiguo numero di soggetti per ora presenti impone cautela nell’inter-pretazione dei dati.First data on the presence of Hooded Crows Corvus corone cornix in Brescia(NorthernItaly).Two areas near the centre of the town of Brescia were kept under observation in the courseof the day and of the year to ascertain the non occasional presence of hooded crows.These areas arelocalized north and west from the centre of the town.The number of Hooded Crows is similar in bothareas but,throughout the year,it fluctuates with seasons and human presence.A nest presence hasbeen ascertained in the western area were the animals are more regularly present throughout the year.I argue the adaptive advantage of this colonization.

CORVI,Corvus frugilegus L.,SVERNANTI NELLA VALPADANA CENTRALE E CONSERVAZIONE DEL PAESAGGIO AGRARIO TRADIZIONALE

RIASSUNTO-Nel corso di tre inverni(1990-91,1991-92 e 1992-93)sono stati osservati,lungo differentipercorsi stradali della Valpadana centrale,10370 Corvi.Per ogni individuo sono stati rilevati tipo dicoltivazione sulla quale era posato,ampiezza del campo e presenza di filari/siepi.In anni singoli sonostati esaminati altri fattori(distanza da abitazioni,dalla strada e dai filari o loro uso come posatoio).Lungo un percorso di circa 70 km(Cremona-Pavia)è stata inoltre rilevata la posizione cartografica deiCorvi osservati.Dai dati raccolti si può dedurre che questa specie può svernare soltanto in aree consufficiente varietà colturale e paesaggio agrario tradizionale,e che modificazioni gestionali possono elimi-narne la presenza.Wintering Rooks,Corvus frugilegus L.,in the central Po Valley and conservation ofthe traditional agricultural landscape.During three winter seasons(1990-91,1991-92 and 1992-93)10370Rooks were observed,along roads of the central Po Valley.The kind of cultivation,the extension offield and the presence of tree rows/hedges was noted for every resting Rook.Other factors(distancefrom habitations,road and tree rows,and their use for resting)were examined during single years.Alonga 70 km road(Cremona-Pavia,Northern Italy)the geographic position of the observed Rooks was noted.According to the observations,it seems that Rooks can winter only in areas with sufficiently variouscultivations and a traditional agricultural landscape,and that variations in their management can elimina-te the presence of the species.

REAZIONI DI CORNACCHIE GRIGIE Corvus corone cornix A CONSPECIFICI MUMMIFICATI IN PARTICOLARI POSTURE E PRESENTATI IN CAMPAGNA

Reaction of wild Hooded Crows to conspecific mummified in particolar postures and exposedin the field.A method for preparing bird specimens to be used as stimulus-objects in the field was tested bymeasuring the response of wild Hooded Crows,Corvus corone cornix.In a first series of experiments,HoodedCrows specimens were tested for general responsiveness and posture discrimination by conspecific.Moreapproaches were consistently made to Bristle-head posture than to Sleeked posture.In a combination of bristle-head specimens of different subspecies and species,C.c.corone was approached more times than C.c.cornix,whereas C.frugilegus elicited intermediate interest.In a different combination of bristle-head specimens,C.c.corone was more attractive than C.c.cornix,whereas a hybrid C.c.corone x cornix was less attractive than eachpure form.The approaches were usually aggressive.Bristle-head posture was confirmed to be a self advertisingposture and the comparisons between subspecies provided suggestions about the mechanism againsthybridation.