Are female red-winged blackbirds territorial?

Spacing behaviour of female red-winged blackbirds (Agelaius phoeniceus) was observed to determine whether resident females within a herem divide their mate's territory into sub-territories. Some results accorded with defence of sub-territories: (1) females were more aggressive (towards decoys and mounts) close to their own nests than further away; and (2) there was little overlap in the use of space betwee residents on a male's territory. Other results did not accord with defence of sub-territories: (1) when the nest site was eliminated from the analysis, spatial overlaps were large; (2) areas defended through aggression by different females overlapped greatly; and (3) areas defended through advertisement by different females overlapped greatly. I conclude that the spacing behaviour of female red-winged blackbirds does not meet a strict difinition of territoriality.