cliff swallow petrochelidon pyrrhonota perched on a barbed wire fence on the plains

adaptation alpestris animal anthropogenic avian barbed biology bird birding birds birdwatching carbon change cliff climate climatic closeup colorado conservation conservatism distribution ecology environment eremophila extinction fence gases global greenhouse habitat indicator microevolution migration natural nature niche ornithology outside perched petrochelidon plains pyrrhonota richness science species swallow temperatures threatened tourism warmdwelling warming wild wildlife wire