摘要: The highest populations of Night Heron (17,500 nests) and of Little Egret (6,700) of any European country breed on a 150 by 450 km area in Northern Italy, together with small numbers of Squacco, Grey and Purple Herons. Within this area, some characteristics of colony distribution and species composition are related to the availability of different feeding habitats within the foraging ranges of the colonies. The heronries are concentrated in the zone of widespread rice cultivation. From data on feeding ecology of the Night Heron and Little Egret on rice fields, it is estimated that 46% and 39% respectively of their populations in Italy are supported by the fields and the irrigation canals as feeding habitats. Land reclamation has reduced colony site availability to a minimum. Recently, one third of the heronries have been protected by setting up natural reserves.
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