Avian Use of Purple Loosestrife Dominated Habitat Relative to Other Vegetation Types in a Lake Huron Wetland Complex

Purple loosestrife (Lythrum salicaria), a native of Eurasia, is an introduced
perennial plant in North American wetlands that displaces other wetland plants.
Although not well studied, purple loosestrife is widely believed to have little
value as habitat for birds. To examine the value of purple loosestrife as
avian breeding habitat, we conducted early, mid-, and late season bird surveys
during two years (1994 and 1995) at 258 18-m (0.1 ha) fixed-radius plots in
coastal wetlands of Saginaw Bay, Lake Huron. We found that
loosestrife-dominated habitats had higher avian densities, but lower avian
diversities than other vegetation types. The six most commonly observed bird
species in all habitats combined were Sedge Wren (Cistothorus platensis), Marsh
Wren (C. palustris), Yellow Warbler (Dendroica petechia), Common Yellowthroat
(Geothylpis trichas), Swamp Sparrow (Melospiza georgiana), and Red-winged
Blackbird (Agelaius phoeniceus). Swamp Sparrow densities were highest and Marsh
Wren densities were lowest in loosestrife dominated habitats. We observed ten
breeding species in loosestrife dominated habitats. We conclude that avian use
of loosestrife warrants further quantitative investigation because avian use
may be higher than is commonly believed. Received 27 May 1998, accepted 26 Aug.
1998.