The spreading of invasive species in new continents can vary from slow and limited diffusion to fast colonisations over vast new areas. We studied the sacred ibis Threskiornis aethiopicus along a 31-year period, from 1989 to 2019, with particular attention to the first area of release in NW Italy. We collected data on species distribution through observations by citizen science projects, population density by transects with distance method, breeding censuses at colonies, and post breeding censuses at roosts. The birds counted at winter roosts in NW Italy increased from a few tens up to 10,880 individuals in 2019. Sacred ibises started breeding in 1989, with a single nest in north-western Italy. The number of breeders remained very low until 2006, when both overwintering and breeding sacred ibises started to increase exponentially and expand their range throughout northern Italy with isolated breeding cases in central Italy. In 2019, the number of nests had increased to 1249 nests in 31 colonies. In NW Italy, the density of foraging birds averaged 3.9 ind./km2 in winter and 1.5 ind./km2 in the breeding period, with a mean size of the foraging groups of 8.9 and 2.1 birds respectively. Direct field observations and species distribution models (SDM) showed that foraging habitats were mainly rice fields and wetlands. A SDM applied to the whole Italian peninsula plus Sardinia and Sicily showed that the variables best related to the SDM were land class (rice fields and wetlands), altitude, and the temperature seasonality. The areas favourable for species expansion encompass all the plains of Northern Italy, and several areas of Tuscany, Latium, Sardinia, and Apulia.
[The breeding of the Red-crested pochard in Piedmont is known since 2006, when it was first described in a pond near the town of Asti. Data were collected from specific databases and from field observations performed in 3 sites located in the Asti province and 2 sites in the Cuneo province, all of them placed along the Tanaro riversides. A further site is located in the province of Alessandria near the Po river along the border of Lombardy. On the whole, in the time span 2006-2019 the number of breeding pairs increased from 2 to a maximum of 7 per year. A total of 64 females with 326 chicks were recorded (average 5.1/female), June being the most favorable month for reproduction. Results point to the occurrence of a seemingly stable small breeding population. The lack of any kind of legal site protection, the anthropogenic disturbance (hunting, fishing, abandoning wastes), and the loss of the ideal habitat for reproduction are among the critical threats for the maintenance of a vital breeding population. There was a probable case of nest parasitism by Mallard duck, which is seldom observed since the opposite situation seems to be more common.]
[Article in Italian]
[In an Ardea purpurea colony regularly monitored from 2004 to 2018, some predatory events of Vulpes vulpes have been observed since 2010. This was followed by a reduction in the reproductive success and in the number of breeding pairs. Some herons likely abandoned their nests in the reed bed and moved to nesting on trees. The Authors discuss the possibility that these events were a consequence of the predatory activity of the red fox.]
[Article in Italian]
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