Okay, there's no picture. The robins wouldn't stand still long enough, close enough for a photograph and the mass of ?? ~1 pound!!! of earthworms was so disgusting that I deleted the picture. In retrospect probably a mistake. The rains seem to have ended and in dry periods earthworms mass together in large groups to conserve water. While I was blowing debris off the path I happened upon a mass maybe 18" long, 2" high, and a foot across, a LOT of earthworms! Unfortunately I had dispersed the pile and mixed in leaves, petals, dried catkins, etc.. It wasn't pretty....it wouldn't have been pretty anyway.
Every summer in Fern Valley we dreaded the "attack of the robins". Starting in late June or early July, the robins went berserk, uprooting leaves, mulch, soil. They littered trails as fast as we could rake or blow them. Smoothly mulched beds became areas of riotous disorder. Now I know what they were looking for. A giant mass of "aestivating earthworms". I can't imagine what it would be like finding that clot of writhing worms if I were a hungry robin, but wow! It's no wonder they persevere!