In the northern Great Plains, cattails (Typha spp.) have overgrown man
y wetlands, contributing to a decline in numbers of Black Terns (Chlid
onias niger). Since 1991, wildlife agencies have applied glyphosate-ba
sed herbicide to cattail-dominated wetlands with the objectives of inc
reasing duck (Anatinae) abundance and reducing crop-depredating blackb
ird (Icterinae) populations. In 1990 and 1991, we serially applied gly
phosate-based herbicide to cattail-dominated wetlands in North Dakota
to assess the influence of habitat changes on birds. Numbers of Black
Terns and selected ducks species were positively correlated with open
water and dead cattails (r(17) range: 0.77-0.46); whereas, blackbird n
umbers were positively related with live cattails (r(17) range: 0.52-0
.48). Black Tern numbers were positively related (r(17) range: 0.76-0.
49) to numbers of Mallards (Anas platyrhynchos), Blue-winged Teal (A.
discolor), Redheads (Anthya americana), and Yellow-headed Blackbirds (
Xanthocephalus xanthocephalus), suggesting some common habitat require
ments among these species. Cattail management programs designed specif
ically to enhance duck use and decrease Red-winged Blackbird (Agelaius
phoeniceus) numbers probably benefit Black Terns.