Sky High Raptors

What do the 2 two geese (above) have to do with raptors, or birds of prey? Well, if I hadn’t been paying attention to those two geese I would not have seen a bald eagle soaring over our wetlands last week.

As I approached a corner of our 750’ boardwalk near the Black Bear Exhibit, I noticed our two resident Canada geese below me in the water. As I peered over the rail, I realized both geese were staring skyward. I know from experience that when a bird, any bird, cocks its head to the side and concentrates its gaze skyward, there’s something up there of interest.

Pied-billed grebe keeping an eye on an osprey above.

Sometimes it’s a large, sky-high lone bird such as a migrating heron. Often, though, it’s a raptor, a hawk, eagle, or osprey. This time it was a bald eagle. A mere spec in a cloudless blue sky to me, these two geese had spotted it and were watching with care. Birds have excellent visual acuity and can see objects with much greater clarity and detail than we humans, even distant objects. It may be a matter of life and death for them.

It can be devilishly difficult for we humans to pick out high-flying birds in a clear blue sky. Clouds help out by adding contrast and reference points, but it can still be mighty tough to find birds which are near the vanishing point. To my eye, the eagle in question was very near that point, the distance beyond which an object of whatever size ceases being a dot and simply disappears from view. If it weren’t for the fact that it was an adult eagle with white head and tail, which shone in the bright sunlight, I may not have been able to see it. I certainly would not have seen it if not prompted by the geese.

This was not the first time here at the museum that I was alerted by other birds to the presence of hawks in the stratosphere, or at the limit of my personal vanishing point. The grebe above clued me in to an osprey soaring overhead. And, I spied a Cooper’s hawk above me while I was watching hooded mergansers swim around the wetlands.

The following are photos of three different species which were spotted with the help of another bird. There are two photos of each bird. The first photo is of the bird as seen through a 400mm camera lens. The second was enlarged on the computer. I only enlarged enough to help distinguish the species without completely destroying the image with grain and distortion.

Adult bald eagle photo’d with 400mm lens.
Enlarged. Cleary, this is a bald eagle.
A speck in the sky with 400mm lens.
Enlarged. The unmistakable shape of an osprey.
Cooper’s hawk against cloudy sky with 400MM lens.
Enlarged. Cooper’s hawk.

Even if you don’t have waterfowl at your disposal to help you locate distant birds, this is an excellent time of the year to be looking up. March and April are the premier months to watch for migrating eagles and ospreys, as well as other raptors. So, look up, you might see something interesting.

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