Built by the Infante Henry the Navigator in about 1459, and in 1983, it was classified as a UNESCO World Heritage Site, and is the most important monument in Portugal. Situated by the sea, they had the problem of the seagulls that would land on the roof and nest. They- tried other systems- the last one was the ultrasonic devices, which only lasted for a month, and then the gulls would stay by the speakers, the last one was the ultrasonic devices. The droppings were damaging the monastery year after year, and a solution was urgently needed. Part of the roof was recently partially replaced, as you can see in one of the photos.
The trays were placed at a distance of 30 cm with about 40 g of ByeBirds. The higher amount of ByeBirds was due to the size of the gulls and their high population. After installation, for a few days, some gulls remained in some areas of the building, while most stayed away. As was done in spring, during the breeding season, the gulls made new nests elsewhere and did not return.
