The goal of the project, which was carried out in 2020 with financing from the Lombardy Region, was to position three floating structures to encourage nest building for the common tern (Sterna hirundo), a species listed in Annex I of Directive 2009/147/EC. The project was designed to continue work that began in 2019, when the first two rafts were positioned.

In Italy, the common tern is in steep decline, especially due to the disappearance of breeding sites such as river islands. In the natural environment, this species builds its nests on pebbly riverbed islands with little vegetation. In contrast with other terns, however, it is able to adapt and also build its nests on artificial structures.

The rafts were positioned in protected areas of the Reserve far from visitor paths and entrances, within the basins in the Lame. The floating structures can only be seen through binoculars from the birdwatching tower.

Description of the structure:

This is a floating structure supported by specific modular elements to ensure it floats. The base consists of a 2 m x 2 m frame divided into four parts, with a grille bottom. A system consisting of the same grille runs around the edge to prevent the chicks from falling. Inside, there are river stones and pebbles to recreate the appropriate environment for the species, as well as small wooden shelters attached to the bottom for the chicks.

It was deemed advisable to include pebbles, twigs, or other elements to divide the area into different brooding areas. The raft was then anchored with a counterweight attached via chains to the base of the structure, and twigs were also anchored to the base to create a shelter for fish. The rafts were also enriched with wooden shapes made in collaboration with the Passirano primary school.