Which bird thermals the best?

In article
,
Scott Alexander wrote:

So in a recent conversation with a greatly experienced soaring pilot,
I was told that Buzzard's have terrible thermaling skills. I tend to
agree with this as it sure seems Buzzards don't get into the core and
stay there. The lesson learned was don't let Turkey Buzzard show you
where the core is, just let them lead you to the thermal.

I thought it would be interesting to ask you good people if anyone has
any knowledge on these issues. Does anyone know which broad winged
birds have better or worse centering techniques that you can use to
your advantage?

SA

Others have mentioned swifts. Here in the eastern U.S. they seem to me
to be the best tell-tale of a superior thermal.

One bird that has not been mentioned, but is a great indicator of a good
thermal, is the Anhinga. They are also known as the snake bird or water
turkey. In flight, they look like an arrow with high aspect ratio wings
attached. They are a water bird so are usually around the low, wet
places we sailplane pilots dread. I have only found them thermalling in
good lift. Look for them the next time a sadistic CD puts your course
line right down a river valley or across a swamp or lake.