The weight of birds

Have you ever had a songbird in your hand? They are wildly lightweight, yet the little strong feet are memories of reptiles. These metal versions, found at the exceedingly cute Cog & Pearl, are modeled on passerine – song bird – bird feet, with one toe in the back to wrap around a branch. This is a perching bird, not a swimming, tree climbing, snow-walking, marsh wading, dirt-scratching bird, all of whom have different feet. This arrangement is called anisodactyl, and the rear toe is the hallux; it's actually the first digit. There are at least four other toe patterns among the birds. Passeriformes, the song birds, are the largest order of birds, with some 5700 species. The crow and raven, not known for their melliferousness, are the largest of these; the winter wren is one of the smallest:

Think of the wren
and how little flesh is needed to make a song.
-- Galway Kinnell