It's April. Hydroid's young friends still hide in the pools and slower water. Their sides now have dark bands or parr marks to camouflage them and to hide them from predators.
They dart into the stream to grab small insects that live among the stream's rocks. As they move into the stream, they are wide open for attack. Fry are the favorite food of trout and other large fish. Not everything that looks like a branch is a safe hiding place.
Some branches turn out to be the legs of great blue herons. Hydroid also warns the young chinook to beware of shapes darting out from trees. The shapes could be kingfishers. The bright blue birds are looking for young fish to feed their own young this time of year. The young chinook learn how to find food and avoid danger.
NEXT: Part 3