Little Blue Heron - Egretta caerulea

The Little Blue Heron's range includes southern California (e.g San Diego), with the occasional vagrant to Northern California. They are more common in Florida, where we see them in both winter and spring and can follow the striking plumage changes that take place. In February 2014 we watched an adult foraging at Fred Howard Park, Tarpon Springs. The adult has a bicolored bill year round. In winter the bill is gray at the base, the iris straw colored, and the legs gray-green.

By April many adult Little Blues display changes known as "high breeding plumage". We watched this one almost every day on a visit to Tarpon Springs in April. A bright sky blue color now suffuses the bare skin around the eye and extends to the proximal bill, accompanied by darkening of the legs and iris. It has breeding plumes hanging from the crown, but lacks the profusion of aigrettes seen in the closely related Snowy Egret.

Same bird, but closer. I often had to back up as it approached, as it had become accustomed to seeing people here and took no notice of my presence.

A better view of the elongated breeding plumes is seen on this bird, Feb 20, 2012, same location in Tarpon Springs (Gulf Front Lagoon). The bare parts have yet to show any of the bright blue of high breeding plumage.

I've labored under the presumption that breeding plumage, and especially "high" breeding plumage, was restricted to adult birds. But in going through past images I rediscovered this one of a juvenile Little Blue Heron taken April 9 2012 at Corkscrew Swamp (southwest Florida). Viewers may recognize this as the "Lettuce Fields".

It struck me that the above bird, probably just shy of its first birthday, is exhibiting pretty dramatic breeding plumage, as evidenced by the sky blue color of the bare skin on the face and proximal bill, as well as the elongated plumes of the crest, back and lower neck. Leg color not easily seen here, but appears darker than normal winter plumage. Compare the plumes here to those on the adult above from February.

The Tricolored Heron displays similar high breeding plumage changes, and as with the Little Blue the bright bare parts are seen in both sexes.​ The Little Blue has been known to hybridize with both the Snowy Egret and the Tricolored Heron.​ 

Hybrid Little Blue Heron x Tricolored Heron, Hammonasset State Beach, CT, 7/28/2013.

Also of note, the Little Blue is the only member of the Heron Family (Ardeidae) where the first year plumage is white and the adult highly pigmented.  A number of species have a white morph (Great Blue Heron, Reddish Egret, etc.), sometimes classified as as subspecies.

Found it hard to research breeding plumage versus age, and particularly anything about "high breeding plumage", which is attributed to a hormonal surge  signaling a readiness for mating. Regarding the Little Blue's first alternate plumage (Alternate 1), Palmer writes, "…late first winter until age OVER A YEAR. At least new head, neck and mantle feathers…". Well, that explains the feather finery of the juvenile. And he continues, "REPRODUCTION  Age breeding begins not known exactly, but numerous references to breeding of white or pied birds suggests breeding at 1 year." ( Handbook of North American Birds Vol. 1 - Loons through Flamingos, Yale, 1962).

Many of the larger bird species don't breed until second year or later (some Albatross not until age 8!), so I was surprised about how early the herons can start. Well, it turns out that a number of heron and egret species are able to breed in their first spring, although I'd guess most of them don't. Maybe the white one above is precocious! Lot's to learn, and fun to share it.