Two interesting Pantanal raptor sightings

Two interesting raptor sightings from Brazil's Pantanal - Snail Kite and White-tailed Hawk. The former species is locally common, while the latter I'd call uncommon. Both geographically widespread species, neither are likely near the top of the list for birders visiting the Pantanal.

But I found these two particular sightings pretty interesting.

First, we witnessed an obvious Snail Kite migration event. Mid-morning on Oct 26, as we were cruising at 30mph down the Paraguay River (an area of the Pantanal that is off the beaten path and not often birded), we spotted directly overhead two tight migrating flocks of Snail Kites - 155 and 110 birds each, a few miles apart from one another. They were each headed S/SSW in classic kettle-glide-kettle fashion. I was a bit distracted by my task of guiding, so was unable to consistently watch the skies as we were ripping down the river, but I wonder how many we would have turned up if we could have set up a hawk watch right then and there.

migrating Snail Kites

I knew nothing about Snail Kite migration/movements, and from the bit I've been able to read, folks really haven't known much until recently. Alex Jahn via Smithsonian is currently working on satellite tracking them in this region; I plan on emailing him about this. I wonder if flocks like this are routinely seen or not.

Second...another bonus for looking up...a dark morph adult-like White-tailed Hawk. I had not seen a dark morph before. Dark birds seem to only occur in southern populations of the species, but I am unsure how frequently they are seen. Judging from online images, possibly not very often...though perhaps they are more regular in the Pantanal?

dark morph adult White-tailed Hawk

 - NB