Passeriformes (2) Birds (2) oiseau (1) vallée (1) espèce (1) méthode (1) Colombie (1) The Valley (1) Dynamics (1) Methods (1) Description and travel (1) Rates (1) Variations (1) Ci (Chinese poetry) (1) Tarsus (1) Survival (1) Success (1) Storms (1) Species (1) Nutrition--Evaluation (1) Mechanics (1) Mass (1) Life (1) Hypothesis (1) Human behavior (1) Gray (1) Grasslands (1) Gifts (1) Flight (1) Feathers (1)