Green Heron

Most tool use in birds is seen in ostensibly more intelligent species such as parrots and crows, but there’s a common bird right here in New Hampshire that’s also part of the club: the Green Heron. Our smallest heron (not counting the rare Least Bittern) will drop small objects into the water as bait to attract fish closer to the surface. They will even move these objects back closer to their hunting perch if they start to drift away. Many different items have been recorded as bait, including small leaves, feathers, insects, and pieces of bread. A closely related species in Japan has even been recorded making tools by breaking sticks into smaller pieces for use in baiting.

Green Herons fish – with bait or otherwise – in highly vegetated ponds and marshes throughout most of New Hampshire. Because they are small, secretive, and generally solitary they are not seen as often as their larger or showier cousins, but they are probably more common than we think. Their secrecy makes it hard to assess population size or trend, but available data from most of the species’ range show a decline starting around 1980. Unfortunately, the Green Heron has not been the subject of many detailed studies, so causes for decline are largely speculative. Habitat loss is likely a contributing factor, even though these herons regularly use small and man-made wetlands. Studies on environmental contaminants have documented lower levels compared to other herons and no consistent impacts on reproduction. The good news is that Green Herons remain common across their wide range, even if they are rarely seen.