This video has been making the rounds, so many of you have probably seen it: Swimming Eagle of Baton Rouge.
What I find particularly rewarding about this little clip is that the quantitative model I built over the last year to estimate water launch in pterosaurs also predicts that eagles (and some other birds) should be able to do this, as unusual it is. Always validating to see expectations met.
I will post more about water launch in pterosaurs later, but the basic gist is this: the folded wing pivot of a bird (wrist) or pterosaur (base of fourth finger) can produce quite a bit of flat plate drag in the water, if the wing is still mostly folded. Combined with the powerful flight muscles, this provides a mechanism for generating substantial forces in the water without compromising flight anatomy.