Tennessee Warblers
Tennessee Warblers The ranges of certain migratory birds are impressively wondrous. Some passerines – the perching birds – are tiny dynamos. The Tennessee warbler, for example, weighs an average of 10 grams (0.35 ounces). While this diminutive stature might make flight easy, the metabolic rates of birds are astronomically high. Somehow, a creature that weighs a …