Counties: Marinette

Photos:

• Photo 1
• Photo 2
• Photo 3

Seagull Bar, 19 Aug. 2000. Emergent aquatic community (dominated by softstem bulrush) to open mud flats along Green Bay. Photograph, E.J. Judziewicz.

Site Description

This site includes the Seagull Bar State Natural Area.

Seagull Bar is a sand spit and accompanying embayment marsh at the mouth of the Menominee River on the margin of Green Bay, lying just east of the City of Marinette. The embayment is a large area of shallow water with emergent marsh vegetation that expands or recedes, depending on lake levels. In lower water years the bare mud substrate is exposed, and the lagoon is nearly enclosed by the sand bar. The eastern edge of Seagull Bar is a system of sand beach ridges and low dunes resulting from wave action and sand deposition.

During suitable water levels the margins of the lagoon support a broad emergent marsh dominated by softstem bulrush, and associates include other bulrush and rush species. On slightly drier ground the dominants shift to boneset, beggar-ticks, a wool grass species and the invasive purple loosestrife. Acreage of the emergent beds changes often due to the bay's seiches and long-term water level fluctuations. The dunes support a diverse and characteristic flora including marram grass, Canada rye, beach pea, and several rush species in low, wetter areas. The sand beach is currently broad and supports a representative flora of the community that includes at least one plant endemic to the Great Lakes coast.

When appropriate substrates are exposed during spring and fall migration periods, shorebirds by the thousands congregate here. The lagoon area is particularly attractive to waterfowl. Small passerines are trapped occasionally by suddenly unfavorable weather conditions and are then seen in large numbers searching for insects and seeds washed onto the shores. Several rare bird species have nested here historically.

This site is threatened by recreational overuse and the potential spread of invasive species.

Additional Comments

Seagull Bar is a small site within an urban setting but supports a dynamic, good quality marsh and provides habitat for large numbers of migratory water birds.