Birdfy Nest Duo brings dual-camera monitoring to backyard bird nesting boxes

Birdfy's Nest Duo is a smart nesting box equipped with two 1080p cameras—one inside and one outside the entry hole—plus a built-in thermometer and hygrometer. The reviewer used it to observe an entire chickadee nesting cycle, from excavation and egg-laying to hatching and fledging, streamed live to a smartphone. The device is part of a broader Birdfy lineup that includes single-camera and pole-mountable models.