I was asked to share what I got for info on my Cooper's Hawk info request so I am compiling the best and greatest hits for your pleasure reading.
This is what I got so far. Very interesting. Thomas: Cooper's Hawks have nested in our backyard pines several times, though not recently. They do most nest construction early in the morning, and are amazingly sneaky about their coming & going, although I have seen them drop from the nest site down to our lawn to fetch a stick. After egg-laying they are extremely secretive. The incubating bird manages to lie so flat in the nest that it is difficult to see even the head or back. Sometimes the only evidence of the bird on the nest is the tail projecting out over the nest. After hatching, of course, they come & go frequently & generally are more obvious. Their call/scold is a "cack-cack-cack," sometimes muted. Fly- by crows get an aggressive response from the COHAs. Climbing to band the nestlings elicits extremely aggressive response from the adults, including talon "scratches." Helmet, leather jacket & gloves recommended. Or just leave them alone. Fred Lesher, LaCrosse, Wis. Thomas In the past 2-3 weeks, at two different sites, I have watched male Cooper's Hawks make numerous trips with sticks to nests (one in my backyard) while a female was perched nearby. Both turned out to be one-day-wonders, as neither site was used. From my experience, males probably make an attempt to select the nest site which then must be approved by the female. Thus, presumably potential sites may be involved. I was disappointed my yard was not chosen. The BNA account on COHA states the following: "Nest Construction Male does most nest building, although female occasionally brings in a stick or a large flake of bark. Male gathers most nest material within a 100-200 m area of the nest. Nest visits by male are brief; associated with nervous, jumpy behavior. When the nest is near-completion, female may use it as a feeding platform (Meng and Rosenfield 1988)." Hope this is useful. James Mattsson Thomas--I am not an expert on any kind of hawks nest building, just wanted to share my own spottings. There is a spot along my route to work that has a hawks nest visible until the leaves fill out on the trees. It is one of those 'merge into the turn lane, look quick over to the right, see what is happening today' observation points, nothing I can really get into details with. I saw for several Springs a hawk on the nest, occasionally spotted a pair, sometimes smaller heads peaking over the top. Then one year it was left unoccupied. The next Spring it hosted a family of Great Horned owls to my delight, although my views were so limited. Then nothing again. This Spring I watched anxiously to see if there was any activity at the nest, and one day was rewarded to see a hawk (red tailed?) adding a stick to the nest. The nest seemed tended to, repaired after a year of laying empty. I thought great--next generation occupants!! Then nothing. No visits, no anything at the time I traveled by. The nest seemed to just lay there. Within the last week I saw again a hawk placing a stick on the nest. I have been wondering the same things that you have: are they like wrens that build mulitple nests to impress the girlfriend, then let her choose the home they will live in? Do they build nests whether they have a mate or not this season? Is the colder weather affecting their decision to lay eggs if they are paired up? It is a big 'hmmm.....' Anyway, it gives me something to ponder on the short trip to work every day. Cindy in N. Mankato Thanks everyone for asking. Thomas Maiello Angel Environmental Management, Inc. Maple Grove, MN
