From: Stan Kostka firstname.lastname@example.org Seattle WA
Unintended consequences often result from of our actions. Developing a relationship with a Cooperís Hawk (Accipiter cooperii) was certainly not part of the plan when I began building a Troyer V top starling trap in January of 2001, but thatís exactly what happened in the end.
Before installing a cluster of martin nestboxes in a state highway bridge project mitigation area along a nearby river, I decided to first try and thin the local starling population. The trap was set on a friends farm nearby. The trap worked great, it caught plenty of starlings. (The only change I would recommend is to build it tall enough to stand up in, or figure out some way to get the starlings out, without having to go in and get them one at a time. Scrambling around bent over inside a cage full of starlings is not a pleasant task.) I hadnít considered that the caged starlings would so quickly attract predators. Less than a week after the trap was up and running, a Cooperís Hawk was making frequent visits to inspect the contents. I often would find her perched there atop the cage upon my arrival to remove trapped starlings each day. Knowing little about Cooperís , I judged her to be a female primarily by her size, which was easy to determine as she perched there atop the trap, the exact dimensions of which I knew. She was 18 inches, or larger. Her presence was somewhat of a problem, as no starlings would approach the trap while she was there. But there were usually starlings in the trap when I came to check it, so she was not rendering it completely useless. So I put up with her. What else could I do ? She always flushed to a nearby tree and watched me empty the trap of all but a few birds. One day, unable to control my ever-present curiosity about events in the lives of wild birds, I placed a freshly killed starling on top of the trap, just to see what would happen.
Iíd been told accipiters would only take live birds, but that might depend on how hungry she was, I thought. Following a 45 minute wait, well out of sight, a good distance away in my truck, the dead starling was still there. I left it, perhaps for one of the barnyard cats that also visited the trap on occasion.
Next day the dead starling was gone, and the hawk was back. I repeated what Iíd done the previous day, with the same results.
Next day the dead starling was gone again, and the hawk was back again. Once more, I left her a dead starling, but this time I didnít wait around to watch. I left and drove a short distance to town to run some errands. Back an hour later, and the dead starling was gone ! The hawk was nowhere to be seen. This made me think maybe the hawk had taken the dead bird, rather than one of the cats, who are generally out of sight at mid-day.
Next day no hawk. I emptied the trap, and left no dead starling.
Next day the hawk was back , and I left another dead starling. This time I waited, and after about 40 minutes, she came from her perch in a nearby tree and made off with the dead bird. Ahah ! Accipiters WILL take dead birds, at least those freshly killed, in close proximity to other live ones.
Controlling starlings is something I had been doing at home as well, with three nestbox traps set near outbuildings and chicken coop. There are no martins nesting at my residence, rather Tree and Violet Green swallows. Starlings are controlled here to protect the woodpeckers that use the snags along the edge of the pasture and garden. On more than one occasion have I watched Hairy Woodpeckers excavate cavities , only to have them usurped by starlings. Initially I shot the starlings, then started trapping them. In 2001 the first cavity seeking starling was trapped February 10, and amazingly, in 2002 the same nestbox trap got the first starling on exactly the same date. Now, instead of killing the birds and leaving them along a nearby woodland trail for whatever predator that came by, I built a cage and kept the starlings alive. Soon I had a dozen starlings in the cage. Initially I fed them a combination of poultry layer pellets and cracked corn, but the birds did not do well. Many died in spite of the fact that they had food and water, a place to stay out of the rain, and an insulated box in which to roost at night. The feed was changed to dry cat food, and the starlings then flourished. They loved the stuff, the cheapest brand of dry cat food available. Only one starling died in captivity after the food change, in spite of an extended period of unusually cold rainy weather.
Within a week, I was amazed to observe a Coopers hawk sitting on this cage of starlings in my yard. These predators donít waste any time. I assume it was a different bird from the one Iíd seen at the farm, since my house is five miles from the original starling trap. The hawk at my house was another presumed female, as large as the first. Now each morning before I left for work, a freshly killed starling was placed on top of the cage. The cage was set out at the edge of the yard, near the woods, easily viewed from the house. Some afternoons when I returned home the starling was gone, other days it remained. A freshly killed bird went up each morning. I never saw what was taking the dead starlings for the first week. Then, one Saturday morning, I set up a starling and went back into the house around 7 oclock. Within 25 minutes, while pouring a cup of coffee in the kitchen, I heard the caged starlings explode into alarm calls. I hurried to the window, just in time to see a large bird flying into the woods with some small black thing in its grasp. The dead starling was gone.
Over the course of two months, 38 starlings were taken off the top of that cage, and I observed a hawk do the taking 22 times. During the passing weeks, the interval between when the starling went up and when the hawk took the food grew shorter and shorter. In the end, the hawk was taking its meals before I got back to the house. On a few occasions, it would be perched on the cage at first light, apparently waiting. Upon my approach it flushed to a nearby tree, always the same perch, where it sat and watched me prepare its meal, returning to take the dead bird as I was walking back to the house. Usually the hawk came to the cage in the morning, but not always. Sometimes she arrived in the early evening, always accompanied by an explosion of starling alarm calls.
Whether there was more than one hawk in action here , I cannot say with certainty. At times the size and plumage seemed to vary, but that may have been the result of lighting, whether clear or rainy , and the differing air temperatures at the times of the various sightings. The birds tend to fluff up somewhat in cold weather. While the bird(s) approached the cage from at least three different directions, she always departed down the hill away from the house, cutting left through a gap in the trees into the woods and out of sight. On only one occasion was I able to locate a pile of starling feathers along the lane that runs down through the trees.
By mid May, the starlings stopped coming, the martins began arriving into the region to take up all my spare time, and the Cooperís Hawk feeding ended.
Since then Iíve thought a lot about what happened. How was this different than putting out seed for other wild birds in the area, which I do on occasion during the winter months ? These Cooperís hawks seemed to find the caged birds very quickly. Was this something new to them, making them quick studies, or did they have previous experience ? I remember a client years ago telling me he gave up his hobby of pigeon keeping, because he felt in the end all he was doing was feeding the hawks in his neighborhood. He was unable to let his pigeons out of their cages, without losing them.
This year, 2003, was a very slow year for trapping starlings here at my house. Either past trapping efforts have had some effect, or the local starling population is in decline. I expect the latter, following the closing of some dairy farms in the area. For whatever reason(s), only 15 starlings showed up in traps at my house this year, compared to over 100 in each of the two previous years. There was no hawk feeding this year, but Iím thinking about it for 2004 if I can come up with enough starlings, as a way to scratch my wild bird itch, and pass the time during the last couple months of waiting for the martins to return.