A strange common kestrel,変なチョウゲンボウ

This year is likely to become the year's least number of migrating birds.

Whenever I every time see a common kestrel, it reminds me of things somewhat strange colored one that has taken Nov.2016.No matter how you look at it, it has white-colored feathers partly. As I am not a specialist of wild bird, asked Yamashina Institute for Ornithology located in this city where I live in.

The reply is as follows:

In the photo, the face is bluish-gray from the head, the back and rain cover are brown with black spots, and the tail is gray with a thick black belt at the tip.The underside of the wing has black spots on a white background and looks a little whitish, so it is considered to be a male Kestrel. Besides, white feathers are thought to be partial whitening, which is an abnormality in feather color.

                                      A common kestrel(normal)