american redstart setophaga ruticilla perched in a tree during migration through colorado

adaptation alpestris american animal anthropogenic avian biology bird birding birds birdwatching black carbon change climate climatic closeup colorado conservation conservatism distribution ecology environment eremophila extinction gases global greenhouse habitat indicator microevolution migration natural nature niche orange ornithology outside perched redstart richness ruticilla science setophaga species temperatures threatened tourism tree warmdwelling warming wild wildlife