First rule of thumb, always have your camera ready.  Just as I reached the brook I was head to head with a mink. It was a cold, but bright morning. The shot below was taken with a 10-Stop ND filter. ISO 400, 34mm, f/9.0, 30.0 sec. These last two shots were taken with a IR filter and converted to B&W. Both shots: ISO 250, 10mm, f/5.6, 10.0 sec.