Bird physiology is conducive to flight : small size, hollow bones, and generally symmetrical feathers on the wings and tail. It seems like a no-brainer that bird evolution was optimized for flight, but a new study suggests that things aren’t as clear-cut as they appear. The conclusion of a recent study in Nature Communications sounds rather unintuitive: most bird wings don’t appear to be built for maximum flight efficiency and aren’t perfectly fine-tuned for the way birds fly. What’s more, the birds with the most optimized wing shapes in the study were hummingbirds and penguins—with the latter using their wings for proficient swimming, not flying through the air. The researchers analyzed 1,139 images of bird wings with a method that allowed them to test the relative performance of different wing shapes without presumptions on what constituted an “optimal” wing shape.…