Otter

Shot yesterday. I was shooting Ring-necked ducks at nearby Wildlife Refuge and something spooked them out and they all disappeared.
First I thought it was eagle, falcon or hawk that scared them, but it was passing by otter. I have seen them there from time to time, but they are so hard to spot since they swim so fast and spend most time under the water when on the move.
I saw trail of bubbles and I knew exactly were this otter is heading.
There is a canal winding around and there are few land bridges with a huge pipes under connecting to the canal. I sprint to the first bridge and I missed it, otter was already heading for next one.
I sprinted to next one.
This time I got there just in time to get few shots of this rascal

1D4, SIGMA 500mm f/4.5 EX DG HSM + 1.4X TC
1/640, ISO-1600, f/8, handheld.

Please click on the image for uncompressed view, thank you.