Red-wing Blackbirds Riding on Red-tailed Hawk?

The pictures below were taken by a photographer in Minnesota. They show Red-Winged Blackbirds hitching a ride on the back of a Red-Tailed Hawk. He claims this is not terribly uncommon, as red-winged blackbirds are extremely protective of their nests. They will dive-bomb humans, and he claims it is reasonable that they were harass a hawk. The birds apparently only stay for a matter of seconds.

So are the pictures real or Photoshopped? You decide: