We present the importance of flooded area size for avifauna feeding in a temporary wetland formed by the spring flooding of a brook. There was a significant difference in the number of recorded species when over 90% of the area was flooded, compared to the species number at 30% flooded area. While changes occurred in the size of the flooded area, there were no significant changes concerning the water level. Regarding the use of the floodplain for feeding by species belonging to various orders, the only significant difference between the two flooding periods was found in the case of the Charadriiformes. Significant differences between the number of individuals belonging to the two duck species in the two flooding periods were found only in the case of Anas querquedula. The existence of un-regularized flowing water sections that allow natural flooding is a necessary condition for the maintenance of such wetlands which are compulsory for the feeding of passage birds.