This painting was donated to the Crow Wing County Historical Society by someone who thought it could be a Sarah Thorp Heald painting. When I first came across it in the Museum, having no knowledge of its history, I too suspected it to be one of Heald's works. After consulting with the Crow Wing County Historical Society Director, Hillary Swanson, we both believed it to be a painting by Heald.
The reasons for this are as follows:
Subject Matter: Sarah has two other paintings of birds in flight, as seen here and here. The colors of this painting also remind me of this painting of hers.
Technique: The way the background is done is similar to her other paintings. Heald also often paints in such a way that is suited towards watercolor, which I see here; Heald layers oil paint a lot without doing much blending of colors.
Medium: This painting is Oil, which was Heald's Primary Medium later in her life. This painting is also on panel, and on the "wrong" side of the panel. Most artists paint on the smooth side of these paintings, but not Heald, who preferred to paint on the rough side.