Photo/Illutration A brown-eared bulbul seen at Koishikawa Botanical Garden in Tokyo’s Bunkyo Ward (Provided by Kota Matsumoto)

Glance around the grounds and listen to discover that not only devout followers and tourists congregate at shrines and temples in central Tokyo.

Shrines, temples and historic parks have a richer diversity of bird species than municipal urban parks, according to a new study.

The research was led by Mayura Takada, a professor of conservation ecology at Chuo University, which examined green spaces in Tokyo’s Bunkyo Ward.

The researchers believe that the abundance of underbrush and the proliferation of evergreen trees are related to the thriving bird populations and diversity.

The research was conducted at 12 shrines and temples, three historical parks, and nine urban parks.

Shrines and temples included Gokokuji temple, Kichijoji temple and Nezu shrine.

Historical parks included Koishikawa Botanical Garden, which traces its origin to the residences of feudal lords in the Edo Period, and Sudo Park.

Urban parks included Edogawa Park along the Kandagawa river.

In fiscal 2022, the researchers surveyed each of these parks three times during the breeding season (from May to July) and wintering season (from December to February) to determine what kinds of birds were present.

Vegetation such as tree thickness and green cover were also examined to see if there was a relationship with the occurrence of birds.

In all, 2,186 individuals of 29 bird species were observed.

Statistical analysis showed that the number of birds spending the breeding season in forests tended to be higher in shrines and temples and historical parks than in urban parks.

During the wintering season, the number of bird species also tended to be higher in shrines and temples than in urban parks.

Seven of the 29 bird species were listed on the Tokyo metropolitan government’s “red list” of threatened species in the capital’s wards.

But in urban parks, four of these seven bird species, such as the little egret, were not spotted.

When combined with the vegetation survey, the researchers found that the more vegetation in the underbrush up to 1.5 meters from the ground or the higher percentage of evergreen trees, the higher the population of birds that spent time in the forest during the breeding season.

There was also a tendency for the bird species seen at shrines and temples during the breeding season to differ from place to place.

It is possible that their range of behavior is narrowed because they have more access to food than during the wintering season, the researchers said.

Kota Matsumoto, a graduate student at the University of Tokyo, who was in charge of the field survey, said sacred sites should be preserved as local assets. 

“Shrines, temples and historical parks in urban areas that have a lot of greenery are vulnerable to the wave of urbanization," he said. "But they are important not only for their cultural and religious value, but also for their biodiversity."

The research was published in the journal Urban Forestry and Urban Greening. The article can be seen at:
(https://doi.org/10.1016/j.ufug.2024.128550)

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