down by the swamp…

With apologies to Raffi’s lyrics for Down by the Bay 

“Down by the swamp, where the water lilies bloom
I take my camera and my big zoom.
I edge up close, the birds won’t stay —
Did you ever see a duck, stand in the muck?

mallards at snail lake park

Ducks standing in the muck

Did you ever see a heron that didn’t like sharin’?

great egrets-snail lake park

Great Egrets (herons that don’t like sharin’)

Did you ever see a bird that didn’t say a word?

least flycatcher

a little bird that didn’t say a word (least flycatcher chasing bugs in the swamp)

Did you ever see a Snapper looking so dapper?

alligator snapping turtle

A dapper snapper sporting a coat of algae

Down by the swamp.”

 

Great Egret at Snail Lake Park

The little ditty above was inspired by this Great Egret who croaked and threatened every other egret that attempted to come into his foraging territory.

Great Egret at Snail Lake Park

Neck stretched ready for the attack. How can it possibly see what is swimming around in that murky water?

Great Egret at Snail Lake Park

Stab and grab …

Great Egret at Snail Lake Park

Success! I watched this bird for 30-40 minutes and never saw it miss, judging by the swallowing that followed the stab and grab move.

Great Egret at Snail Lake Park

Now here’s a different strategy, lean the head and neck way over to one side for better viewing of the prey in the water?

Great Egret at Snail Lake Park

That beak is a powerful weapon for all sizes of prey.  Usually birds cannot move their eyes around in the orbit like humans can, so how does this bird see what is swimming around beneath it while its eyes are projecting forward?

I don’t know what these egrets were catching, but they caught a lot of them.  According to a study done by H. Mincey in Georgia, Great Egrets catch something with 70% of their strikes, which makes this wait and strike strategy highly efficient. However, I was surprised to learn that the average size of prey taken by these birds was only 4-6 cm (1.5-2.5 in).  They must have to consume a huge number of such small items to meet their daily energy needs.

Like some other avian species, herons and egrets gather split visual field information from each eye. The upper part of the field provides a lateral monocular view of the landscape around the bird (useful for scanning for prey as well as other encroaching herons — or photographers), and the lower part of the visual field provides a binocular field of view of what is directly beneath the bird.  It’s like having four eyes instead of two! In tilting its head and neck to the side, the bird is probably using monocular vision to fix the position of the prey in the water while reducing glare from the angle of the sun on the water.

3 thoughts on “down by the swamp…

  1. Great posting. I watched those egrets today and picked on one to watch … which kept the meals going down at the rate of one every few minutes — then took a rest, and came back to do it all over again. I may have a shot of the meal, and will send it. Either small frogs or fish. But there has to be allot of them in that slough — which is getting shallower now.

  2. I enjoyed your ditty and your photos too. Our egrets are still with us, but later in the fall they will depart for warmer places. They are indeed so much fun to watch. You captured the egret wonderfully, Sue. The bright white coloration can sometimes make exposures tricky.

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