Great Blue Heron

Ardea herodias

The great blue heron is a large wading bird in the heron family (Ardeidae), common near shores of open water and wetlands over most of North and Central America, as well as Northwestern South America, the Caribbean, and the Galápagos Islands. It is occasionally found in the Azores and is a rare vagrant to Europe. An all-white population found in South Florida, the Florida Keys, and the Caribbean islands, is known as the great white heron. Debate exists about whether these white birds are a color morph of the great blue heron, a subspecies of it, or an entirely separate species. Source

Where it is now

In the last 8 weeks this bird was recorded 73,911 times across 78 areas (each area is a 5 degree square).

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Movement and weather

Each season it is first heard regularly where daytime highs are around 19°C (typically 8 to 26°C, from 20 areas). That range is wide, so temperature alone does not explain when it turns up.

Over the weeks it was present in the past year, its centre in North America ranged from 21°N in March to 48°N in August, about 3,000 km apart.

Arrival dates

The week it was first heard regularly in each region, after at least six weeks away. Dates differ from south to north, so a region has a range.

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Figures are effort corrected and come from automatic sound identification, which makes mistakes. How this is measured and how it compares with human observers.