Great blue herons leave Maine to migrate south each October, but there are always a few stragglers.
“Every year during Christmas bird counts, people see them. Even into January and February, people will often see them,” said Danielle D’Auria, wildlife biologist with the Maine Department of Inland Fisheries and Wildlife.
“It’s always the young of the year,” she added, “the birds that really don’t know what they’re doing. They don’t know that they’re actually going to have to leave, that it’s only going to get colder and things are going to freeze up.”
Usually, these young herons will simply migrate later than the rest, but sometimes, there are reports of lingering herons that have died from starvation after their freshwater feeding grounds have iced over.
The vast majority of the great blue herons that have left Maine for the winter will return in the spring. Most colony sites are occupied repeatedly over many years. Existing nests are uninhabited and new nests are often added to make room for last year’s hatchlings.