Tree swallow nests across Pennsylvania are being collected for an investigation into the patterns that the common, fast-flying, cavity-nesting birds might incorporate into their nest construction.

Each Canada goose that you see flying around in formation around Lancaster County these days has between 20,000 and 25,000 feathers, most hidden from sight. A typical songbird at your backyard feeder ...

For sunbirds, all that shimmers is piping hot. The birds’ flashy, iridescent feathers heat up more than other types of feathers, possibly making it harder to stay cool in hot, sunny conditions. If so, ...