Out in the flat prairies, marshes, and agricultural fields surrounding Pelican Lake, there are few structures from which a hunting bird can search for its prey. Power lines and poles are the most convenient perches, and narrow dirt roads lined with short, mowed grass make excellent hunting grounds.
Within a 1/2 mile stretch of one such dirt road, I saw a male Harrier (marsh hawk) making its huge sweeping forays across the fields, a huge (female?) Red-tailed Hawk perched atop a power pole, and an American Kestrel, and a Loggerhead (I think) Shrike perched on power lines. Of course, I scared all of them off with my exuberance in jumping out of the car to take some photos, but I spied a couple of them again on a return trip to the same dirt road when I returned a couple of hours later.
Loggerhead and Northern Shrikes are very similar in appearance, but Northern Shrikes spend the winter in MN and then migrate north to northern Canada and Alaska to breed. Loggerhead Shrikes spend the winter down south, and migrate to the northern U.S. and southern Canada to breed. Unfortunately for birders, the two species overlap during their migration through Minnesota in April, making it difficult to determine which species you’ve seen.
Both Kestrels and Shrikes are sit-and-wait predators, preferring to hunt from a high perch, looking down on their insect, amphibian, reptilian, or even small mammal prey. Birds of prey, like the kestrel, are known for their keen eyesight, which results from the high density packing of light sensitive rods and cones in their retinas. Kestrels, for example, are said to be able to see a 2 mm insect from the top of a 18 m (~50 foot) tree! I don’t know if anyone has measured eyesight in Shrikes, but they probably have excellent vision as well. An additional difference in predatory birds is the forward placement of their eyes, enabling binocular vision that gives them depth perception. Although Shrikes are technically songbirds and not raptors, they also appear to have more forward placement of the eyes to promote binocularity.
Hawk-eyed sounds better than Shrike-eyed, doesn’t it?