Looks a bit different in max zoom, and clarity. . . (of course ~ pixelated image goes comes with it!)There are over 200 bird species recorded as observed on or over Svalbard. These include larger birds like buzzards, geese, herons and egrets.
The silhouetted shape in the Mirror photo looks like a larger bird flying horizontally and photographed at the extreme "down-stroke" of its wings. The shape is asymmetrical horizontally, with a thinner extension to the left and a fatter extension to the right. There is no visible gap to suggest the downward extension represents multiple things (e.g., legs).
The claim that this shape represents something hovering comes exclusively from the photographer's separate description of the scene.