I wrote about white Great Blue Herons in 2007, and thanks to a recent comment there by David Ammerman alerting me to a whitish Great Blue Heron chick in a nest, I made the short trip to Bolton, MA yesterday (July 7, 2016). It was not hard to find the nest, and I was able to get some photos of the white nestling with its nest-mates and one parent.
This bird brought up several questions posed by my 2007 post on Great White Herons. In particular: is this bird distinguishable from the white morph (“Great White” Heron) of southern Florida, and it certainly is, having gray-brown flight feathers. It’s clearly a dilute plumage (partial albino) individual, simply lacking some melanin, and very similar to one photographed in Massachusetts in 2005 (scroll down to the bottom of my 2007 post for a photo).
This doesn’t help answer questions about the white nestlings that have been found in Texas, but it highlights the absence of fully white birds in the rest of the species’ range, and reaffirms the distinctiveness of the south Florida population.