I received a notice from the e-Bird verifier that the White-winged Scoter
should be an Illinois bird.  I have read similar things in the past for
other birder's reports dealing with the Melvin Price Dam.  I am a retired
Air Force Navigator and a professional MLS librarian, and understand maps.
 All of the maps I have dealing with the Missouri / Illinois state line show
the state line running down the middle of the river, and the middle of the
dam. "Google Maps" and the "Missouri Conservation Atlas" reflect the middle
of the river and the middle of the dam as the dividing line (even my AAA
road maps reflect the middle of the river as the dividing line).  If I plot
the position of this bird on e-Bird maps, it shows St Charles County,
Missouri.  Please inform me what maps we are using to make 10 feet northeast
of the rip-rap wall to be in Illinois.

I understand changes in river course to create different state or county
lines, i.e., Kaskaskia Island is in Randolph County Illinois, but physically
on the Missouri side.  Or, Howell Island is St Charles County, but sits
pretty much on the St. Louis County side.

Will an expert please educate me about where the state line falls in this
situation, and inform me what reference map is used.

Thank you sincerely,
   David & Mary Anne Marjamaa
   Manchester, MO

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