If some of the birds are eating something that is on the ground.
return birds ;return ground ;return something on #2 ;return #1 that are eating #3 ;return number of  #1 ;return number of  #4 ;return difference of #5 and #6 ;return if  #6 is at least one ;return if  #7 is at least one ;return if  both  #8 and #9 are true
['select', 'select', 'project', 'filter', 'aggregate', 'aggregate', 'arithmetic', 'boolean', 'boolean', 'boolean']