My friend Tami V. is the Communications Director of the Wildlife Rehabilitation Center of Minnesota. She and her colleagues recently released Great Blue Heron chicks rescued from a colony destroyed by last May's tornado, which damaged many parts of north Minneapolis. I asked Tami to take photos for me. The bird above is a Green Heron, a close up of its pectinate toe is below. I believe this structure is even more fully developed on adults.
Tami went a step further and photographed the pectinate toe on one of their other patients, a Common Nighthawk. Aside from other nightjars, as far as I know, the only other birds with such toes are Barn Owls. I do not know why more birds possess pectinate toes.
I appreciate the assistance of the Wildlife Rehabilitation Center of Minnesota and Tami's enthusiasm for pursuing my request for photographs. Both Tami and the Center are busy without odd requests from ornithologist bloggers.