Mergansers and Warblers on the Au Gres
Chris Izworski's daily Michigan birding report looks at Arenac County this morning, where the past two weeks have delivered steady October movement across the northern Lower Peninsula. The dominant story is waterfowl, particularly Common Mergansers: 200 individuals were documented at Singing Bridge Park as recently as October 11, a substantial concentration for this county. Canada Geese and Ring-billed Gulls are also present in solid numbers along the Au Gres drainage, with 25 geese and 20 gulls recorded at the 2768 E Booth Rd location in Au Gres within the past four days.
The warbler activity, while modest by fall standards, remains worth tracking. Yellow-rumped Warblers number five sightings at the same Au Gres hotspot as of October 14. This is typical late-October fare for Arenac County; the bulk of warbler movement has already passed through. Swamp Sparrows and Pine Siskins round out the transient songbirds, each with five reports from mid-month, suggesting ongoing but not exceptional passage.
Sandhill Cranes are present, six individuals seen at Au Gres on October 14. This is worth noting as a regular but always compelling species for this region. Eastern Bluebirds, six counted at the same location, indicate lingering late migrants or early winterers. Red-winged Blackbirds, American Robins, and Dark-eyed Juncos are all present and building toward winter populations.
Weather and Timing Today
Today breaks clear and calm: 57 degrees, sunny, with westerly winds only 5 to 15 mph. This is a stable weather window with essentially zero rain chance. Tomorrow strengthens the wind to 15 to 20 mph from the southwest, which may push a bit more movement if anything is still passing through, but October 17 is late in the season for dramatic warbler waves in the northern Lower Peninsula.
Sunrise is 7:50 AM with the dawn chorus window running from 7:20 to 9:20 AM. Day length has contracted to just under 11 hours, so field time is limited and concentrated. The clear, calm conditions favor stable bird behavior over active movement.
Where to Bird Today
The Au Gres River Mouth and the immediate Au Gres area around 2768 E Booth Rd have been the productive focal point for the past two weeks. Both locations sit within the broader Au Gres drainage complex, which has generated 61 observations of 61 species in the past 14 days according to eBird; that is thin activity overall, reflecting the post-peak migration period. The Au Gres River Mouth carries a lifetime total of 207 species, making it the strongest hotspot in the county. Focus on waterfowl concentrations, particularly the Common Merganser flocks at Singing Bridge Park.
Santiago Rd. boardwalk and the Wigwam Bay SWA units offer alternative access to the marsh and wetland habitat that characterizes Arenac County birding. These have produced 197 and 196 all-time species respectively. Waterfowl and late warblers would be the target on both fronts today, though the eBird data suggest recent activity has centered on the Au Gres focal areas.
October Mid-Month Expectations
This is not a banner time in Arenac County. September produced the peak warbler passage; October mid-month is the cleanup phase. Late Yellow-rumped Warblers, lingering sparrows, and the occasional kinglet or creeper are the remaining song migrants. Waterfowl, by contrast, are ramping up in earnest. Mergansers, goldeneye, and diving ducks will become increasingly prominent over the next four weeks as Great Lakes staging birds move into and through the region. The 200 Common Mergansers already present are a leading indicator of that trend.
No notable or rare sightings have been flagged in the past two weeks. This reflects the ordinary October composition of the county's avifauna at this point in the season.
Check the live map and full county data at https://birding.chrisizworski.com.