Over 300 bird species have been recorded in the park, which acts as a migratory stopover for thousands of warblers, thrushes, sparrows, and other passerines in Spring and Fall. It is also the nesting habitat for the endangered Prothonotary Warbler and King Rail. Rondeau Bay hosts tens of thousands of migrating waterfowl, including Tundra Swans, in the early Spring and in Fall.
Rondeau Park is internationally recognized IBA due to the significant geographical location for migration. It regularly attracts rare migrant and vagrant bird species in the spring and fall: recent species include Yellow-throated Warbler (Spring 2013), Blue Grosbeak (Spring 2011), Kirtland’s Warbler (Spring 2013), and Townsend’s Solitaire (Spring 2011).