by , Ranger
Greg Dodge is a professional naturalist as well as a writer, videographer and producer of natural history DVDs. His images have been used in various TV productions, museum displays, and corporate videos. Above all, he has a fascination and passion for all things natural.
Stop by and say hello Tuesday thru Saturday in Explore the Wild, Catch the Wind, or on the Dino Trail.

Cooper’s Hawk or What!

May 20th, 2013

Cooper’s Hawk in immature plumage? (5/10/13)

I was very excited when I first spotted the bird in the above photo. I was making the final run of the day, driving from Explore the Wild into Catch the Wind. Glancing over at the swamp between those two areas of the outdoor exhibits I saw the hawk perched about twenty some feet above the floor of the swamp on my left.

Why the excitement over a Cooper’s Hawk? I see them fairly often here at the Museum throughout the year. Cooper’s Hawks have nested here every year since I arrived at the Museum, over five years ago, and probably longer. This year, I’d heard them calling and have seen them flying around the pines on the north side of the campus for several months. They’ve traditionally nested in those pines. When I spotted this particular Cooper’s Hawk I immediately thought, “Alright, they’ve done it again,” thinking this one of their offspring.

This was a reasonable assumption, the bird was in immature plumage, it was sitting in a tree close to the path and didn’t seem at all concerned with me in the Club Car clicking away on the camera, young birds often have to learn what and when to fear something. I thought that this bird must be a youngster fresh off the nest.

After I got back to the office, downloaded the photos and thought about this for a while, I realized, it’s too early for any Cooper’s Hawks to have fledged! Cooper’s Hawks hatched this year won’t be off the nest for a month or more. This bird was either one of the adults nesting back up in the pines or one of the offspring from last year’s nest. This was not a bird hatched this year.

Sure, the bird was in immature plumage, but look at the tips of the feathers, the tail feathers, they’re all worn, ragged. These are not the feathers of a newly hatched or fledged bird. The feathers of a recently fledged bird would be crisp and new.

It takes two or more years for these hawks to acquire full adult plumage which is basically blue-gray on the back and white with reddish barring on the front. This bird was/is still in its first plumage, its first immature plumage. It takes two years for a Cooper’s Hawk to reach sexual maturity. This bird has no blue or gray feathers on its back and no barring at all in the front. If this bird were old enough to nest it would probably have at least a few adult feathers. I see none.

There are no gray or blueish feathers on the back of this bird and the tail looks worn (5/10/13).

It seems to me that this bird is less than one year old and may be one of last year’s brood.

Am I seeing things?

But wait, there’s one thing that I noticed on the bird’s belly, one, maybe two feathers that have reddish barring (barring is horizontal, streaking or stripes are longitudinal). Look at the picture to the right and see if you notice it too. I suppose though, that one little feather (if that’s what it is) does not an adult bird make.

And then it hit me, this wasn’t a Cooper’s Hawk at all! This bird was a Red-shouldered Hawk!!

The tail is much too short to be a Cooper’s Hawk and the barring on the tail is wrong for Cooper’s Hawk. The wings on the bird, if it were a Cooper’s Hawk with a proportionally longer tail, would not extend so far down the tail as it does on the bird in the photo. And, the dark and light colored barring on a Cooper’s Hawk tail are of equal width, the light colored bars are about the same width as the dark bars. The dark bars on the bird in the photo are wider than the light colored bars which is consistent with Red-shouldered Hawk.

The eye color would be more yellow too, if it were a Cooper’s Hawk.

Oh, almost forgot, both species have reddish barring on the breast and belly in adult plumage, so the adult feather that’s coming in on the belly of the bird works with red-shouldered.

I guess what struck me initially about the bird, what made me jump right to Cooper’s Hawk when I first saw it perched there on that branch quietly surveying the swamp below, was its slimness, it looked very lean to me. Long and lean fits more with Cooper’s Hawk, than with Red-shouldered Hawk. And, I was secretly hoping that they (Cooper’s Hawks) were nesting here again and were successful.

So what does all of this matter? It doesn’t matter much at all in the grand scheme, I’m simply trying to work out this little mystery for myself and inviting you to listen in. I’ll stop now. But it goes to show you that things aren’t always what they seem, sometimes you have to take a closer look.

If there’s anyone out there that sees something in the photos, or in my reasoning, that I may have missed please let me know.

Enjoy!

Join the conversation:

  1. I came across your blog just now because I was trolling for information concerning sexual maturity in Cooper’s Hawks. Today, May 21, 2013, I observed a Cooper’s Hawk in immature plumage sitting (apparently incubating) on a nest. I spotted the nest and could see there was a bird on it. The tail looked like a Cooper’s Hawk, but I could also see the bird’s head and I could see that the eye was yellow. This confused me quite a bit because I know mature Cooper’s Hawks have red eyes. I had finally decided that the bird must be a Broad-winged Hawk (even though the tail didn’t look right), when the bird flushed, circled, and called “kek-kek-kek-kek-kek”. When it returned to the nest, it perched briefly on the edge and I saw its pale breast and brown vertical streaks down the sides of the breast! This is in Pine County, Minnesota. I am an MN Audubon bird surveyor working on the MN Breeding Bird Atlas. From what I’ve read so far, it seems that Cooper’s Hawks don’t reach sexual maturity until at least two years of age! So, how old was/is my bird and is it really breeding? What do you think? Sincerely, Carol Carter

    Posted by carolwcarter@gmail.com
  2. Ranger Comment :

    I am in no way an expert on the plumage sequence in Cooper’s Hawks. I have however, seen several nests where one of the adults was still in immature plumage. I don’t think it’s that uncommon an occurrence.
    For the record and according to the Bird Banding Lab, a bird hatched the previous year (say April/May 2012) is in its second year of life as of January 1 (2013) and it is referred to as a Second Year bird (SY) even though it may only be 8 or 9 months old on the first of January.
    With that out of the way, I would suggest that the bird you are seeing is a bird that is not quite two years old, an After Second Year bird (ASY), a bird in its third year of life and not quite into its full adult plumage it may be quite brown overall. It will probably molt into its full adult plumage after nesting.
    Does that help any, Carol?
    Is there anyone out there that would like to add something to this?
    Thanks,

    Posted by Greg Dodge
  3. Thanks Greg,
    Yes, it does help. Although it seems confusing to me to refer to a bird that is not yet one year old as a “second year” bird. But I get it! After I posted my comment to your site I read somewhere (on the internet) that “Cooper’s Hawks reach sexual maturity at 2 years of age, but that females sometimes breed as one-year olds” (this is the jist of what I read – not word for word).
    Thanks for your time and attention. Aren’t birds great!?
    Carol Carter

    Posted by carolwcarter@gmail.com
  4. Ranger Comment :

    Yes, I also found a site that states the ages of sexual maturity, for both sexes:
    Age at sexual or reproductive maturity (female):
    1 years (low); avg. 2 years
    Age at sexual or reproductive maturity (male)
    2 years (low); avg. 2 years
    On average, the females apparently mature earlier than the males.
    Thanks,

    Posted by Greg Dodge
  5. Well Done!

    Posted by Jeff Dodge
  6. I was just sent this blog post of yours and am so glad to know that a good birder like you confused a subadult Cooper’s with a subadult Red-shouldered. Because I sure did awhile back! Here is my blog post with photo. It wasn’t until I uploaded my photo that I realized my first assumption was wrong. From now on, I’ll check those tail bands!

    Posted by Linda Fink
  7. Ranger Comment :

    Good, glad that my mistakes helped out. Typically my first impression is the correct one, but this time it was most obviously not. I guess I wanted to see a Cooper’s Hawk so badly that I made the red-shoulder into one. Live and learn.
    I’ve bookmarked your blog site.
    Thanks, and have a good one!

    Posted by Greg Dodge

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