Hummingbird — Smithsonian hover tunnel · 182

The shoulder allows a nearly horizontal figure-eight. Lift on the upstroke as well as the downstroke pays the hover bill that a typical avian stroke cannot. Do hummingbirds live on sugar water alone? No. Nectar is fuel. Arthropods supply protein, especially for chicks. Feeders that omit insects do not replace a territory.

How does a 3-gram bird cross the Gulf of Mexico? Ruby-throated hummingbirds fatten, then fly 800+ km nonstop. Tailwinds and a high mass-specific power output make the crossing possible, not a rest on ships. A controlled drop in body temperature and metabolic rate overnight. Without it, many species would exhaust nectar stores before sunrise.

Diversity peaks in the Andes. Anna’s hummingbirds now winter in Vancouver gardens; ruby-throated breed to southern Canada. Who first illustrated hummingbirds for Europe? John Gould’s 19th-century monographs and skins made trochilids a Victorian craze — with a collecting cost that modern field work still cites.