[mirekrusin]

"...and a nose of a kingfisher" - except that the kingfisher dives on that video with open mouth. Something's not right here, what's the point of modelling closed one for "no splash"/no soundwave. It's also low pressure -> high pressure in case of the diving bird and high pressure -> low pressure in case of train leaving a tunnel.

[chrisbennet]

I think they enter the water with a closed mouth and then open it to grab the fish. I see them frequently when I’m kayaking but they are too fast for me to tell which way their mouths are for sure.