Attraction of Little Terns to Artificial Roof-top Breeding Sites and Their Breeding Success

27 Mar Attraction of Little Terns to Artificial Roof-top Breeding Sites and Their Breeding Success

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Abstract

English Abstract

We found a roof-nesting colony of Little Terns Ster albifrons in Tokyo in 2001. The colony was found in a sewage disposal plant (35゜34’N, 139゜45’E), which was located on reclaimed land in Tokyo Bay. Breeding success in 2001 was only 2.1% because of the lack of gravel on the rooftop. We observed many eggs being rolled by strong wind. We proposed that gravel be spread on the rooftop. Many ture conservation citizens’ groups requested Tokyo Metropolitan Government and Ota Ward to maintain the rooftop. Consequently the sewage disposal plant and Ota Ward decided to spread the 2ha rooftop with small gravel. Many volunteers joined to help cover the rooftop. After treating the rooftop, we found Little Tern nesting on May 18 2002. We studied the number of adults, eggs and chicks from May 11 to August 11. We counted 1224 nests, 920 chicks and 606 fledglings. Breeding success was 22.7 %. We concluded that the attraction of Little Tern to the artificial rooftop breeding site had succeeded. This case is good example of a partnership between government and citizens.