MBM-AK protocol for calculating bird abundance indices from WBPHS_AK data includes doubling the number of observed lone birds (i.e., Obs_Type field = “single”) and <5 flocked drake ducks (i.e., Obs_Type field = “flkdrake” and Num field < 5) for certain species. WBPHS_Indicated_Birds.csv provides information on which species get these observations doubled and which species do not.