Tachikawa Wildlife Guide: Birdwatching, Fireflies and Tanuki Walks

Wildlife in Tachikawa: 77 bird names, 106 species on the Tama River, tanuki in the drains, fireflies in a park, and hawks whose nests stay secret.

日本語で読む（Japanese version）

Birds in Tachikawa? Pigeons and crows. Then the sparrows perched on the railings of the elevated deck in front of the station. That was about all the Tachikawa birds I knew. I assumed a busy town’s birds would be only the kind of birds that suit a busy town.

But when I opened the guide to Tachikawa’s wildlife that residents have built by pooling their photos, the bird index listed 77 names. There is the common kingfisher. There is the northern goshawk. There are seven photos of the Japanese sparrowhawk, the tsumi, a little hawk about the size of a pigeon. In the mammal section, the red fox and the Japanese marten. Foxes and martens, in Tachikawa.

And as I browsed the guide, I noticed something odd. Seven photos of the sparrowhawk, two of the goshawk. Not one of the hawk photos says where it was taken. Every one is “unspecified.” So where are the hawks? And why does nobody write down where they are? With that question in mind, I set out to visit Tachikawa’s wild creatures.

How many kinds of birds live in Tachikawa? 77 names in a residents’ guide

The guide is called the Tachikawa Ikimono (Living Things) Database. According to Tachikawa City’s Environment Book, it has been run jointly by a non-profit organisation and the city. From September 2016 it had a page where people could post photos of insects taken in the city, and by the end of March 2025 it held more than 10,000 entries. The table of the city’s environmental indicators gives the figure 11,298. The generous thing about this guide is that you can post a photo even if you don’t know what the creature is called.

According to the database’s own page, its operation as a city-commissioned project ended on 31 March 2025; since then it has been run by the citizens’ group “Mushi-mushi Tankentai Tachikawa” (the Tachikawa Bug Explorers) and accepts posts of wild plants and insects only. New photos of birds and mammals are no longer being added. Even so, the records collected up to then can still be browsed.

I read down the bird index. In Japanese order it begins with the Japanese green woodpecker, the grey heron, the black-faced bunting, the brown-headed thrush, the brambling. The Japanese grosbeak, the long-billed plover, the blue rock thrush. The Japanese bush warbler, the Eurasian bullfinch, the long-tailed tit, the northern goshawk, the Eurasian coot. The little grebe, the eastern spot-billed duck, the great cormorant, the common kingfisher, the green pheasant, Japan’s national bird. A pheasant! The Japanese pygmy woodpecker, the little egret, the black-crowned night heron. The striated heron, the Japanese tit, the Daurian redstart, the Japanese wagtail. The common kestrel, the Japanese sparrowhawk, the black kite, the eastern buzzard. Of birds of prey alone, the list runs to the goshawk, sparrowhawk, kestrel, kite and buzzard.

The entry that caught my eye most was one in the “ha” row. “Hybrid of Eurasian wigeon and American wigeon,” 4 photos, taken in Showa Kinen Park. A bird guide with an entry listing the names of two parents side by side. The people who built the guide must have been at a loss over how to file it. In the end they honestly wrote down both. That single line was enough to make me trust this database completely.

At the very end of the index, in the “ra/wa” row, there is just one species: the rose-ringed parakeet. It is a parakeet native to India and Sri Lanka, and in Japan it is a bird that escaped from being kept as a pet and went wild. According to Wikipedia, its first confirmed establishment in Japan was in 1969, in the south-west of Tokyo’s 23 wards. Now it has been photographed in Tachikawa, in the Nishisunacho and Ichibancho area and in the south of the city. The descendants of birds that escaped from Showa-era birdcages are flying in the skies of Reiwa-era Tachikawa.

These 77 names, however, are not all of Tachikawa’s birds. They are a register only of the birds that someone photographed and someone posted. Birds that are hard to find, or hard to photograph, are not here. So what happens when the national government counts in earnest? The stage for that was the river that flows along the south of town.

The Tama River: 106 species counted by the state, and the birds that came back

The Keihin River Office of the Ministry of Land, Infrastructure, Transport and Tourism regularly surveys the wildlife of the Tama River as part of the National Census on River Environments, carried out on rivers all over Japan. In the 2004 bird survey, 106 species of birds in 33 families and 14 orders were confirmed at survey points on the Tama River and its tributary, the Asakawa. The fish survey of 2016 found 74 species, and the survey of land insects and other groups in 2009 found 1,268. For a river flowing through the suburbs of a capital city, the Tama is remarkably busy.

The bird list includes the common kingfisher and the long-billed plover. The common sandpiper, the great cormorant, the black-crowned night heron and the striated heron are there too. Read the columns and you find that in the Tokyo Metropolitan Red List the survey referred to, the kingfisher was listed as Near Threatened in the Kitatama area, and the long-billed plover as Vulnerable.

In the Tachikawa Ikimono Database the kingfisher, with 11 photos, is also among the most-photographed birds. Along with the grey heron, it is the star. Of those 11 photos, 10 have their location “unspecified.”

Besides birds, the Tama River has creatures that travel up and down it. The database has one photo of ayu (sweetfish) and two of the Japanese mitten crab taken on the Tama River. The mitten crab grows up in rivers and goes down to the sea to breed between autumn and winter. According to Wikipedia, its larvae can only grow in salty sea water. The crabs found on Tachikawa’s riverbank, too, will presumably one day go down the Tama River and raise their young in the sea. The crabs make that long journey to the sea and back on their legs alone. Far more diligent than the humans who commute by train.

Then and now: Tama River wildlife

The Showa-era Tama River was a very different river. According to “Tachikawa Monogatari,” the newsletter of the city’s history compilation project, from the Meiji era to the early Showa era the Tama River was the classic summer outing, busy with bathers and anglers. Watching cormorant fishing for ayu from a yakatabune (a roofed pleasure boat) and eating the freshly caught fish was a luxurious way to spend a day off. The Japanese Wikipedia article on the Tama River, citing the book “Tamagawa no Yacho” (Wild Birds of the Tama River), says that until around 1960 there were 44 nesting colonies of the little tern along the middle reaches, but they were later wiped out. In the high-growth era of the 1960s, the population of the river basin rose so fast that sewage treatment could not keep up, wastewater poured into the river, and its wildlife was at one point driven almost to extinction.

• Then (early Showa): pleasure boats and cormorant fishing. Summer day-trippers came to eat the Tama River’s sweetfish.
• Then (late 1950s to early 1970s): the little terns’ nesting sites vanished, and the river suffered under wastewater.
• Now: 106 species of birds and 74 of fish in the state’s surveys. In the residents’ guide, Tama River sweetfish, mitten crabs and long-billed plovers.

The same article says that sewerage in the middle reaches was mostly completed in the 1980s. From around 2003, little terns were seen trying to breed there again. The river where Showa-era day-trippers bathed is being chosen once more by the birds of the Reiwa era.

The Tama River’s tributaries also run as narrow waterways through the middle of Tachikawa. Peer into one of them, the Zanbori River, and you find the names of some unexpected little fish.

Little fish in the Zanbori River, and a “captive-bred” medaka

Tachikawa City surveys the water of the Zanbori River jointly with Musashimurayama City and Mizuho Town, which share its basin. According to the city’s Environment Book 2025, the 2024 survey of aquatic life in the lower reaches found 11 kinds of fish: common carp, pale chub, dark chub, Amur minnow, stone moroko, mugitsuku, tamoroko, the eastern striped loach, smallmouth bass, the Musashino juzukake-haze goby. And at the end of the list: “Oryzias (medaka), captive-bred variety.”

The name Musashino juzukake-haze contains “Musashino,” the name of the plateau western Tokyo stands on. A little goby carrying the name of this very land lives in a river flowing through the middle of town. And beside it, the “captive-bred variety.” A medaka, the tiny Japanese rice fish, that had been swimming in somebody’s garden water bowl or a school aquarium was, for some reason, found in the river. The survey sheet distinguished it from wild medaka and honestly wrote “captive-bred variety.” Tachikawa’s surveyors are scrupulously honest, about hybrid ducks and about medaka that once had an owner.

In the Yagawa stream in the south-east of the city, the city surveys the fish once a year, and the Japanese eight-barbel loach (hotoke-dojo), an endangered species that lives in clean water, has been confirmed there. The springs and wetland of the Yagawa are covered in detail in another article in this series.

After little fish, I want to talk about little lights. There are two places in Tachikawa where fireflies have come back.

Fireflies on the Tamagawa Aqueduct and in Tachikawa Park

The first is the Tamagawa Aqueduct, the 17th-century canal that runs through the north of the city. The city’s Environment Book includes reports from two citizens’ groups. One is the “Association for Thinking about Nature Conservation on the Tamagawa Aqueduct,” which began its work in 1989 (Heisei 1). It works to protect the nature of the aqueduct’s upper section, the 12 kilometres from the intake at Hamura to the monitoring station at Kodaira, and its activities range from protecting wild plants, wild birds and butterflies, to reviving and protecting fireflies, cleaning the green path, and checking and putting up nest boxes. According to its 2024 report, about 80 fireflies, now breeding there naturally, flew along the section from Konpira Bridge to Seiganin Bridge. Japanese tits and other small birds raised their young in the nest boxes, and rare wild plants such as the orchids kinran and ginran (golden and silver Cephalanthera) were protected.

The other is the “Tachikawa Fireflies and Singing Insects Society,” which started in 2006 (Heisei 18). Besides reviving and protecting the Genji fireflies of the Tamagawa Aqueduct, it helps with environmental education at the city’s primary schools using Heike fireflies as teaching material, and holds a “Firefly Evening” in June. In June, the society says, it counts and records the number of Genji fireflies emerging every day along the section of the aqueduct from Konpira Bridge to Seiganin Bridge. Counting fireflies every night. Some people count sheep when they can’t sleep, but there can’t be many towns where people spend their nights counting fireflies.

The second place was somewhere I didn’t expect. According to the same society’s report, in 2021 it released Genji firefly larvae into the channel behind the “Ganigara rice paddy” in Tachikawa Park, and they have since established themselves there. The society writes that it hopes to protect these fireflies from now on in cooperation with the citizens’ group that works the paddy.

The city explains the name of Ganigara Plaza by saying that the area used to be called “ganigara” because there were once lots of crabs (kani) here. And it goes on: there are no crabs now, but you can find a great variety of plants and animals. The crabs have gone. But behind the paddy named after them, fireflies have started to glow.

The society is also a society for singing insects. In autumn it holds “Listening to Singing Insects” evenings; its report says that in 2024 one was held for members at the management building in Sunagawa Park, while the public session at Mikagebashi Park was cancelled because of rain. There was also an evening for listening to the insects members had raised at home. On autumn nights there are people who gather simply to listen to insects. Tachikawa’s nights have much better ears than I thought.

Tachikawa’s wildlife in numbers

• 77: names in the bird index of the Tachikawa Ikimono Database. One of them is a hybrid.
• 106: species of birds confirmed on the Tama and Asakawa rivers in the state’s 2004 survey.
• 11: kinds of fish found in the lower Zanbori River in the 2024 survey. One of them a “captive-bred variety.”
• About 80: fireflies that flew in 2024 along the Tamagawa Aqueduct between Konpira Bridge and Seiganin Bridge.
• 7: photos of the Japanese sparrowhawk in the database. Every location “unspecified.”
• 9: photos each of the tanuki and the raccoon in the database. Native and alien, tied at the same score.

After fireflies and insect song, the story turns to creatures a little bigger and a little closer to human life. They walk Tachikawa’s night streets better than we do.