Since someone brought it up, I'll throw in my observations on Cooper's Hawks. I think they are another of those species that used to keep themselves mostly to the foothills in the breeding season but that are now expanding into urban areas on the plains. The difference is obvious when comparing Bird Atlas 1 and Atlas 2.
This year I had a nest at my place with 4 young. Strangely enough, there was another nest only 1 block away! This one had at least 2 young, perhaps more. That's 10 Cooper's Hawks in a very small area. An article I read said that the territory of an urban Coopers was something around 350 hectares or about 1.3 square miles, so this seems quite over-crowded! While the young were in the nest, the parents would often use the same perch to pluck and gut their prey. This was right over the road so each morning I could look at what was left on the road (the butchery, I called it!) to see what they were eating. Mostly Towhees, Doves, Robins with an occasional baby rabbit. (Although there was once a squashed bulb of garlic so I wondered if they were acquiring gourmet tastes!) All Doves and Robins and Magpies (formerly extremely common) disappeared completely from the area -- haven't seen any in over a month. Towhees are still hanging on but noticeably fewer. Small birds don't seem too scarce. (Yesterday one of the young Cooper's was being mobbed by 15 Bushtits.) The adults now seem to have disappeared, but the 4 young are always in my yard, screaming their whiny adolescent noise all day long. A few days ago one was under a tree eating something it had caught and I walked right up to it to see what it was (Towhee). Got within 3 feet and could have reached out and picked up the hawk. It made a tent over its prey with spread wings and tail -- not about to let any of the other young ones share. As much as I have enjoyed watching them from mating and nest-building to fledging and clumsy efforts at hunting, I'm hoping they'll migrate soon and let some other birds come back! Mary Kay Waddington -- You received this message because you are subscribed to the Google Groups "Colorado Birds" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/cobirds/54cc9b6f-f525-473c-baf2-c03c7e2b2752%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
