Holiday Beach / Big Creek CA (ON034)
Altitude 174 - 180m
Description du site
Holiday Beach and Big Creek Marsh Conservation Area are located near the western end of Lake Erie, just east of where the Detroit River empties into Lake Erie. Geographically, this site is located at the bottom-end of the migratory funnel created by the lower Great Lakes (Lake Huron, Lake Ontario, Lake Erie and Lake St. Clair). Birds migrating along the northern shore of Lake Erie have only a short flight across the Detroit River before they are then able to fan out in a broader southern movement. In addition, to acting as concentration site for raptors and other species, the site also includes a large shallow marsh with mostly open water that is interspersed by stands of cattails. It is the largest wetland in the immediate area, and has areas of swamp forest and thicket communities. Several islands and parts of the shoreline support moisture-tolerant forests and vegetation. The adjacent Holiday Beach Conservation Area (formerly a provincial park) contains drier Hackberry and oak dominated forest.
Casual observers have noted hawks at this site since the 1950s, with more systematic counts beginning in the 1970s. Since 1974, volunteer observers have worked towards full coverage during daylight hours throughout the fall migration period. Peak daily counts and highest ever annual totals for the more commonly observed hawks include: Turkey Vulture (daily 3,200, annual 19,645); Sharp-shinned Hawk (daily 2,130, annual 18,604); Broad-winged Hawk (daily 95,499, annual 110,221); and American Kestrel (daily 1,105, annual 5,747).
Each fall observers tally between 600,000 and 750,000 migrant birds of which 300,000 may be Blue Jays. Peak daily counts for Blue Jays exceed 50,000, with a peak day in September 1994 of 65,400. Other daily peaks include Ruby-throated Hummingbird (200), Eastern Bluebird (825) and Great Egret (195). Annual totals are quite high for some species, such as American Goldfinch (25,000). During the breeding season of 2000, three to five pairs of Prothonotary Warblers (nationally endangered) were recorded at this site, up from the usual one pair.
Big Creek Marsh, and the adjacent waters of Lake Erie, occasionally support large numbers of staging waterfowl: Canvasback (850 October 1996); Redhead (1,275 October 1996), and Red-breasted Merganser (an astounding estimate of 195,000 in November 1992). Such large numbers of mergansers do not concentrate at this site on a regular basis.
Enjeux de conservation
In general, there are no significant threats affecting the raptors that migrate through this site. However, the magnitude of this migratory movement does need to be recognized and land uses, such as the establishment of transmission or telecommunication towers, or airplane flight corridors, need to be avoided.
Holiday Beach and Big Creek Conservation Areas are run and owned by the Essex Region Conservation Authority. Much of the remaining marsh is a privately owned U.S. hunt club. Runoff entering the marsh from the adjacent agricultural areas is enriched with nutrients and possibly contaminated with pesticides and herbicides. This enrichment leads to increased phytoplankton growth, and this along with bottom-feeding Carp that stir up the mud, result in very turbid water conditions that limit light penetration and growth of macrophytes that sustain staging waterfowl.
Menaces Potencielles ou Existantes
Status de Protection