Friday, January 20, 2017

Little Blue Heron hunting posture

I was looking unsuccessfully in late December for a rare Tricolored Heron at the Tijuana Slough National Wildlife Refuge in Imperial Beach. The tide was unusually high and a group of Little Blue Herons were actively feeding up close to the road. There was one white immature and three adults--all at close range. Only the rainy weather kept me from getting even more photos.

There was also a white Snowy Egret feeding nearby. And I noticed that there was something different in the way these similar-sized birds hunted....

The Snowy Egret was quite active, high-stepping and taking short runs and frequent stabs at whatever was driven up out of the flooded estuary. Not as animated, certainly, as a Reddish Egret, but active nonetheless. Typically when hunting the neck was looped tightly with the head near the body.

The Little Blue Herons often held the same kinked-neck pose, but also did something different when hunting. For one thing, the Little Blue Herons were more slow and deliberate in stalking their prey.

A typical and apparently unique pose of the Little Blue Heron is to extend the neck fully, nearly horizontal to the ground. Then, keeping its head in the same position over the ground, it walks slowly forward until the rest of the body catches up with the head. The neck is now kinked and ready to strike.

This horizontal hunting posture may be a good identification mark for quickly finding immature Little Blue Herons among all the other white egrets in the marshes.

Little Blue Heron hunting posture
This particular pose is typical for a hunting Little Blue Heron.
Immature Little Blue Heron
The pale-based bill is a give-way that this is NOT a Snowy Egret.
Immature Little Blue Heron
Immature Little Blue Heron.
Little Blue Heron
Ready to strike.
Little Blue Heron
Looking for its next snack.
Little Blue Heron
Taking a moment to rest and look around.
Little Blue Heron hunting posture
This horizontal hunting pose may be an identification mark whether blue adult or white immature.
Nature Journal Little Blue Heron hunting posture
Nature Journal page based on photos, graphite and colored pencils. Greg Gillson.