Immature female Cooper's Hawk nest with nestlings
Note: This photo is more than 50X the image you can see with your bare eyes as I used a long telephoto lens plus did a little cropping to enlarge it also. Today I found a Cooper's Hawk nest with nestlings in it and I was very surprised today to find an immature Cooper's Hawk defending the nest. I didn't think I was very close to the nest when I started taking photos but I heard alarm calls from a likely parent. After I took a couple of photos a large accipiter came from the nest and flew at me giving alarm calls--it was fast and I ducked because it came quite low. Over the next few minutes as I tried to walk away from the nest (it was in the middle of a bunch of tree limbs so I couldn't just walk straight off, I had to make my way around downed tree limbs) that accipiter came at me several more times, and each time low enough to make me duck for fear of getting my head raked by sharp talons. I barely got to look at the bird and this less than good photo showing this was an immature Cooper's Hawk. And when I uploaded my photos I was able to see that this immature bird had been in the nest with what looks like more than one nestling.
I found the following on the Birds of North America online site: "Usually 2 yr but year-old immatures reported as 6% to 22% of breeding females." I was unaware that less than adult accipiters were able to breed before this. In checking some references it appears that the immature female Cooper's is in the transition from juvenal to Basic plumage. Previously I have watched Cooper's Hawks nest on the Canon City Riverwalk and they even nested directly over the trail more than once. This was quite an experience and a good example of how individual birds have different tolerances to humans as today's bird clearly has a need for more space from human intrusion around her nest. SeEtta