an immature calliope hummingbird selasphorus calliope drinks sugar from the bottom of a feeder during bird migration

adaptation alpestris animal avian biology bird birding birds birdwatching bottom calliope carbon change climate climatic closeup colorado conservation distribution drinking drinks ecology environment eremophila extinction feeder gases global greenhouse habitat hummingbird immature indicator juvenile microevolution migration modeling natural nature niche ornithology outside perched richness science selasphorus species sugar temperatures threatened warmdwelling warming wild wildlife