The big pond at Donnelley Wildlife Management Area is dotted with these little islands covered with clumps of marsh grasses. Maybe not quite technically hummocks, as I’m not sure the ground is in a mound or if the grass is just thriving in a clump.
It’s not uncommon to see Black-crowned Night-herons tucked into the grass, but on this cold day they were joined by a Great Egret and a Double-crested Cormorant was bobbing in the water. I couple other Night Herons came and went while I was watching.

Look closely and those little blurs are Swallows zipping through the air. By 11:30 AM it had warmed up enough for insects to be active at the water surface.

These Swallows are fast!

Talking pictures of swallovs is truly a challenge.
Yes it is, Hans, and their flight skills are amazing.