MACKINAC CITY (WWJ) - Worried motorists reporting a massive oil slick in the Straits of Mackinac had a hard time believing authorities when it turned out to a dense, record-setting mass of floating ducks -- thousands and thousands of ducks.
The Straits Area Audubon Society said a Christmas Bird Count conducted by volunteers on Dec. 21 determined 7,000 redhead ducks -- a medium-sized diving duck -- were hanging out in the straits near the Mackinac Bridge, causing confusion among onlookers.
By Thursday (Dec. 29), the group had swelled to over 28,000 birds.
"Dense flocks at a distance are suggestive of an oil slick which is a description I have frequently used," Steve Baker from the society said in a social media post last week. "Not surprisingly, the bridge office fields many calls by worried motorists reporting an oil slick and often remain unconvinced when informed that it is really ducks, not oil."
The volunteers counted a number of other sightings in the area, reporting a total of 8,700 individuals of over 47 species, including a lone song sparrow, red-winged blackbirds, three different Swan species and more.
But none of the sightings were noted to be as remarkable as the floating clusters, or "rafts," of redhead ducks gathered in the Straits -- and it continues to grow by the day.
"An update on the Redhead numbers at the Mackinac Straits: they are building, big time," Steve Baker said on the society's Facebook page on Wednesday (Dec. 28). "Today I watched a steady flow of Redheads take flight from a huge raft and form a second massive flock a mile away. This stream of birds lasted about 2-3 minutes before settling in the new raft."
According to the society, the migrant ducks tend gather in winter, mainly on coastal bays and lagoons, but also on freshwater lakes inland. The Straits of Mackinac is a common stop-over for the species' early-winter migration to warmer climates.
While seeing the brown-and burgundy-headed ducks in large groups is common, 28,000 of them is definitely record-breaking for the society's Christmas Bird Count.
Volunteers observed that some of rafts of floating ducks stretched for longer than half a mile on the surface of the water.
Baker said via Mlive that the ducks may continue to swell in the coming days, but the flock will eventually take off once the water ices over, prompting the the Redheads to continue their migration toward their winter habitat along the coastal southern United States.