Sunday, March 4, 2007

Protecting Cavity Nesters from Cats

Cats can easily jump on top of a nestbox that is at least 5 feet high. Some can jump as high as 6 feet, and Keith Kridler heard a report of one that could jump 7 feet (especially off of a hard surface). A cat can use its curved claws to reach into the bird house and hook fledglings and nesting adults. An agile cat can leap into the air and catch a Tree Swallow dive bombing to protect its' nest.

While birds that nest or feed on the ground are at greatest risk, fledglings that can not fly well are also a target. Possible signs of a cat attack on a nestbox include missing nestlings with the nest still intact or messed up. Grass below the nestbox may be trampled. There are usually some feathers around. Dead adults (missing or matted feathers or wounds) may also be found. Eggs are usually left, but may be broken.
Any bird handled by a cat should be brought to a wildlife rehabilitator immediately. Unfortunately, because many cats have nasty bacteria and viruses in their mouths and tend to bat prey around (causing severe internal injuries), about 80% of their victims die even if they receive immediate treatment. But it is still worth a try.
Many people believe that a love of wildlife and cats outdoors are incompatible. It is not possible to monitor a nestbox 24/7. If you are unwilling to protect bluebirds from being attacked by cats, it is probably better to remove nestboxes rather than invite birds to nest in an unsafe situation.

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