(A–D) Bin-size distribution of raw classifications for Common Redstart Phoenicurus phoenicurus at Britz (BRITZ01) (A, B) and Melbgarten (MGB01) (C, D) in spring 2022 (1 March to 30 June). X-axis: confidence level with a resolution of 0.02 (2 % steps), y-axis: number of classifications. Top (A, C): Bin-size distribution when the entire confidence interval is considered (≤ 0.02 to 1.0). Total number of classifications ‒ BRITZ01, n = 1,639,352; MGB01, n = 1,671,813. Bottom (B, D): Zoom-in on bins with confidence levels ≥ 0.2.