Friday, July 6, 2012

FEEDING BEHAVIORS OF THE PEREGRINE

STATUS UPDATE:  We have 14 free-flying peregrines. All are doing well, and some of our earliest released birds have been seen "specking out", or flying so high in the sky you can no longer see them. We have one bird in the release box who should be ready for release within the next few weeks, plus four new arrivals to round out our project goal of 20 peregrines. Two of the new arrivals came today, and will be placed in the hack boxes for observation after they are weighed and banded.

As for eating, our birds are eating 20-25 quail per day. This amount will decrease as these birds develop and hunt on their own. We have evidence our earliest releases are honing their hunting skills with the discovery of birds they captured on their own.

Which leads us to a discussion about peregrines feeding behaviors as they develop.

As the peregrine learns to hunt, they will start tail-chasing and grabbing at each other in mid-air.

Two young peregrines tail-chasing.



At the same time, they are grabbing bugs and chasing small birds. With practice, they learn to capture and kill their prey. In the beginning, it will be small birds such as sparrows and chickadees, then they will progress to a little larger birds like robins and black birds. This is a fast developmental period for these young peregrines because sparrows, chickadees, and robins are not large enough  to sustain these large birds as a food source. They soon develop the skills to hunt and kill pigeons, quail, and in the case of females, even larger prey such as ducks. The female's larger body size allows for them to take the larger prey, but they will hunt less often when compared to the males.

We occassionally hear concerns about the peregrine's impact on the local bird populations. Peregrines will, on average, take one or two pigeon-sized birds a day. Small songbirds are not regularly taken by adult peregrines as they would have to catch upwards of 20 plus birds per day. This would not be an efficient use of their energy or time. Remember, their primary purpose and focus is reproduction and survival. Lastly, the peregrine falcon was native to the Black Hills area. They are top predators, which are crucial to the checks and balances of bird populations. This is evidenced by the exponential growth in the rock pigeon and mourning dove populations in western South Dakota.

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