Saturday, October 01, 2011


One thing you quickly notice when working with predators is that many of them seem hard-wired to attack prey when the opportunity presents itself. This is especially prevalent in predators that do not have a regular feeding schedule. If you may not get another chance to eat in the next week, and there is easy prey in front of you, take it. Even if you have just consumed another meal and could not possibly eat more. This may seem nonsensical to some, but this "attack without thinking" approach is probably what has made many raptors so successful from an evolutionary perspective.
When trapping and handling the various raptor species we come to better understand the different temperaments of the species. While each individual exhibits its own personality, the personalities within a given species are highly similar. My primary study species, the Northern Goshawk, is in a genus known as Accipiter. The three North American species within this genus are reasonably high strung and reasonably hard-wired attack predators. As a result when we are trapping them, we often find that their crop, a storage place in their throat for food, is already full, yet they were trying to attack our lure.
This last Wednesday, while another raptor biology student (Neil) and I were trapping raptors at the Idaho Bird Observatory, Neil captured a hatch year (juvenile) Cooper's Hawk. The crop on the Cooper's Hawk was so full that it even had food in its mouth. Yet this bird was diving to attack a dove! Did it possibly think it could eat more. No, probably not, but it was hard-wired to take prey when it presents itself. Fascinating.
Cooper's Hawk with bulging crop (whole neck area) and a full mouth!

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