Whether it is Schipper Mfg, Tonka Manufacturing or Darel Schipper of Wayzata Minnesota, you are talking about the same company. Just at different times.

Schipper Manufacturing emerged from the Minnetonka "tonka" Bait Company. Started in 1944 that was produced good working decoys. Decoys have signatures sometimes "D. Schipper" or a stamp as shown in the picture below.

photo courtesy of Dan Flanagan-www.silvertopgraphics.com

Photos courtesy of eBay ID jennken1970

Unknown provider

1951 Schipper Paten