Threatened seabird successfully breeds in artificial nests for first time

The declining Japanese Murrelet has bred for the first time in specially made concrete nest boxes, a promising start to its conservation efforts from BirdLife.

Japanese Murrelet is a small seabird with an equally small range to match, as it is only found in warm waters close to Japan. The birds' breeding range is smaller still, concentrated mainly on the ground of rock reefs or isolated islands from Kanto region and to the west, where they make their nests in the cracks of rocks. For the chicks, the stay on these uninhabited islands is brief: two days after hatching, the chick abandons the nest for the sea and is fed by its parents off the coast.

Little is known about the species' ecology because the bird lives at sea almost all year round. What we do know is that the population is decreasing rapidly, and as a result of these declines it has been designated as a Vulnerable species both by the Ministry of Environment of Japan and by BirdLife International, who have assessed the species' conservation status on behalf of the IUCN Red List.

The main causes of the decline been shown to be deterioration of the breeding sites, disturbance by people and predation of the adult birds, chicks and eggs by rats and crows. When people first came ashore, rats followed, and when sport fishermen left baits and garbage behind, crows were attracted by the waste. In response to these declines, the Wild Bird Society of Japan (WBSJ, the country's BirdLife Partner) has been working for conservation of Japanese Murrelet, with one of their main aims being to designate a protected area of breeding sites and improve the environment of the sites.

Japanese Murrelet (Photo: BirdLife International)

In an attempt to improve conditions at the breeding sites, the WBSJ has been developing prototypes of artificial U-shape concrete block nests since 2010. As the Japanese Murrelet had never been known to use artificial nests before, there was no prior knowledge of how to construct an artificial breeding site that would meet Japanese Murrelet's requirements, so WBSJ had to experiment with different designs.

After six years of trial and error, Japanese Murrelet chicks fledged from three artificial nests in 2016. This successful achievement is a promising beginning in our ambition to increase the bird's population by both creating artificial breeding sites, and improving the environment of the breeding sites.

WBSJ's manager of the Preservation Project, Hironobu Tajiri, said: "If we improve more artificial nests and standardise them, we could install them on islets where the bird population is decreasing or the bird can't be seen. It could be possible to have breeding birds there again."