A cadre of caddis flies swarm this Esplanade light pole as the flies patrol the region and help maintain the ecological balance of the Columbia River.

A cadre of caddis flies swarm this Esplanade light pole as the flies patrol the region and help maintain the ecological balance of the Columbia River.

On the night shift

A cadre of caddis flies swarm this Esplanade light pole as the flies patrol the Greater Trail region.