Belonging to the same order as plovers and gulls, 28cm in total length, about the size of a brown-eared bulbul. For most to hear the name “swallow” or “sparrow” a clear image of the bird should rise. Most who hear the name “little tern” would probably just shrug their shoulders. The little tern is a familiar bird to us. 

Japan is an island nation, rivers flow down from the mountains to the sea to encapsulate the beauty that is Japan. This natural beauty is an important ecosystem. Our water rich ecosystem has supported us through farming and fishing for centuries and the little tern has been living alongside us for all this time. 

The little tern is a migratory bird which migrates to Japan in order to breed and raise their young. They create breeding areas called colonies on river banks and ocean shorelines to shelter from the summer heat. Recognizable by their small white bodies flying in large flocks and their cry “kiri-kiri”, which could be referred to as the commencement of summer. In order for little terns to raise their young they require not only a suitable breeding and resting area but also a successful fishing area. This requirement of a healthy environment to flourish as a species, makes the little tern an indicator species of a habitable waterside environment. 

Every year the little tern population decreases possibly in result of a collapsing ecosystem. One day, this once familiar species may not be so easily recognizable. 


Current Situation of the Little Tern Environment

River shores/ islets and along sandy beaches are favorable environments for little terns to raise their young instead of areas with vegetation. Currently little terns breed in landfills because their natural breeding areas are being destroyed by upstream dams. Dams ultimately can change an entire ecosystem forcing little terns to use landfills as alternative breeding areas. It may seem contradictory to say the creation of dams to stop flooding is causing a problem, but the once rocky shores are now covered with vegetation causing the population to decline along with the environment. 

Furthermore, it is possible that the problem also involves the fish in which little terns require to feed their young. It is difficult enough trying to catch fish underwater but the problem may be that fish shoals are declining from around breeding sites. A possible cause for environmental change is global warming. Some believe that little terns should migrate to areas with an abundant source of food. In reality suitable breeding areas and large shoals of fish coexisting are declining from all over Japan.

Lastly, landfills and similar areas were not designed for use by little terns and though they are of use now the solution is only temporary. Also, in natural breeding areas, little tern populations are disturbed by fishermen, other leisurely visitors and dog walkers. If disrupted too often the little terns will fail in breeding and ultimately not be able to repopulate in accordance to the decline. If the decline falls below eye sight then conservation for the species becomes more difficult. Which is why protection of the species is most important now, before it’s too late.


To Protect the Little Tern

The little tern is distributed worldwide, and similar to Japan on the verge of extinction everywhere. Thus far JSPB and the Ministry of the Environment has conducted national little tern surveys, we have created networks to exchange information and developed protection guidelines for means of conserving the little tern. We are taking advantage of our know-how’s combined with a global perspective to protect the little tern which is a definitive barometer of a waterside environment.

This year we conducted field research on the Little Tern population in Lithuania. Click here for 2014, 2015, 2016 research results. 　In 2015, our team was successful in retrieving 2 geolocators whichi wore attached in 2013 and 1 geolocator which was attached in 　　2014 at Morigasaki breeding area in Tokyo. 　Starting in 2016, a research grant from Mitsui & Co., Ltd. Environmental Fund was awarded for three years. With grant we 　　attached GPS devices to little terns and released them in Fukuoka and the Kanto region.