The caddisfly larva has the interesting practice of covering itself with an intricate protective case made from found materials—each casing being slightly different. It can look rather like a tiny twig or a bit of bark. By such a camouflage, it seeks to avoid predators.
Dippers find the larvae tasty and have an effective way of extracting them from the casing, as was illustrated in an earlier posting: dipper shake. But, which bit of debris in the water is a larva, and which is merely a twig? It seems that the camouflage can confuse a dipper into picking the wrong thing.
A dipper scans for interesting titbits.
Spotting something, the dipper reaches underwater to grab it.
At this stage, neither the dipper nor I can tell if it’s a larva.
The dipper soon assesses it as a twig and doesn’t try to open it.
Maybe hunting from another log will prove more successful.