We recorded the diurnal behaviors of the endangered Black-faced Spoonbill (Platalea minor) for 16 days during the wintering season in Jeju Province, Korea to find an appropriate and effective sampling technique for behavioral study. Two main techniques were used and compared: focal sampling with continuous recording and scan sampling with instantaneous recording at various time intervals. As a result, recording the behavior of a focal bird for more than 20 min per h was the best technique with high accuracy and precision. However, to select less time- and labor-intensive techniques we concluded that scan samplings with less than 10 min intervals or focal samplings with more than 15 min durations are appropriate measurements of the spoonbill’s behaviors. Considering sampling sizes, scan sampling with 5 min recording intervals can be an effective technique but additional methods are also required to obtain significant information for infrequent or occasional behaviors. We suggest that each sampling technique should be validated by preliminary or supplementary surveys to estimate the endangered animal’s behaviors and this can be an important part of the groundwork for conservational efforts on the Black-faced Spoonbill.