Once again, migrating ducks have caused meteorologists in northeast Minnesota to sit up and take notice.
Earlier this month, traveling ducks caused boffins at the National Weather Service to fear some sort of wildfire had started southwest of Duluth.
It turned out that the ducks were just heading south, with about 600,000 of them stopping off for sustenance at the Rice Lake National Wildlife Refuge.
On Thursday, they were at it again, except in much larger numbers.
The NWS-Duluth tweeted radar video showing the effect the ducks caused as they made their way to the refuge.
As it says above, an estimated 900,000 ring-necked ducks made a stop at the refuge Thursday morning.
That's not far off the Minnesota state record for the most waterfowl observed in one location, which saw more than one million observed there in October 1994.