(A) Captive ruby-throated hummingbirds (n = 3 or 4, mean ± SE) were presented with solutions of test stimuli and sucrose (333 mM), and the drinking bout lengths, time spent drinking, and number of long bouts (>1 s) were recorded (linear mixed-effect models for differences between stimuli and sucrose, ***P ≤ 0.001). Red bars indicate palatability similar to that of carbohydrates. (B) The taste preferences of wild Anna's hummingbirds were measured (mean bout lengths ± SE, sample sizes: , Kolmogorov-Smirnov tests for differences between stimuli and sucrose: *P ≤ 0.05, **P ≤ 0.01, ***P ≤ 0.001). Concentrations: white, 500 mM; gray, 1 M; black, indicated. Red bars indicate equal preference. [Photo credits: (A) M.W.B. and F. Peaudecerf, (B) M.W.B.]