Mass Heron Deaths in Toyama Possibly Caused by Cutting Nesting Trees, Officials Say  

The Yomiuri Shimbun

17:40 JST, July 29, 2025

The cause of the large number of deaths of herons at Toyama Joshi Park, Toyama City, which has been observed since last month, is likely the cutting of pine trees where the birds make their nest, a city official said on Tuesday.

It is speculated that these trees were cut down while the young herons were not yet capable of living on their own. Consequently, the young herons were unable to find their food, fend off predators, possibly leading to their deaths. It is also believed that territorial quarrels, heat exhaustion, as well as hypothermia when they fell into the water, are potential factors.

More than 100 herons have been found dead at the park since late last month. Environmental ministry and Toyama city government have launched investigations into the causes.

Japan City Apologizes After Herons Found Dead after Trees Cut Down; Officials Believe Birds Lost Their Nests Before Independence

More Than 100 Herons Die in Toyama Park, Japan; Causes of Deaths Are Unknown