An example of a birdie (often a antenna based single channel with high amplitudes) can be flagged easily with uvflag using line=chan,n,start,width,step:
#Birdies uvflag vis=$cfile "select=ant(1)" line=chan,1,32,1,1 flagval=flag uvflag vis=$cfile "select=ant(1)" line=chan,1,95,1,1 flagval=flag uvflag vis=$cfile "select=ant(1)" line=chan,1,158,1,1 flagval=flag uvflag vis=$cfile "select=ant(7)" line=chan,5,4,1,1 flagval=flag #End channels uvflag vis=$cfile line=chan,1,4,1,1 flagval=flag uvflag vis=$cfile line=chan,1,186,1,1 flagval=flag
After this you should recompute the wide band averages using uvwide, if you plan to use the wide band explicitly.