These female common mergansers were moving fast as they flew toward the second dam at Loch Raven Reservoir, Maryland.
The blurred lines in the center and lower right of the image are twigs from a tree limb. The way the birds are illuminated by the sunlight made me decide to call the out-of-focus twigs an “artistic effect” and post the image despite the blemish.
A note on the identification, female red-breasted mergansers can be difficult to distinguish from female common mergansers. I’m going with common merganser as the identification based on the white chin patch.