It usually starts with a quiet morning walk, a child’s curious shriek, or a pet tugging insistently at a bush in the backyard. There it is—tiny, fragile, and utterly helpless-looking: a baby bird, ...

Catching sight of birds just out of the nest is a bit like meeting someone’s new kid. The debate is instant: Does the babe most resemble mom’s family or dad’s? In the bird world, fledglings almost ...