Wednesday, June 24, 2009

John Blakeman answers some more of our questions

Several of you have sent me really interesting questions about hawks in general, and "our" hawks in particular. I forwarded these to John Blakeman, our source of so much expert knowledge. John is a raptor biologist, a Master Falconer, and lives in Ohio.


Do red-tails have predators, other than man?

No, essentially none. By and large, they are the largest, strongest birds in the skies over their territories. They can fend off any other bird that might wish attempt (tragically) to confront them. They are the masters of all they see.

In the West, golden eagles can kill red-tails, but seldom do. Here in the East, bald eagles and red-tails often nest in close proximity, in complete disregard of each other. In my area of northern Ohio, near Sandusky, a bald eagle occupied an existing red-tail’s nest. The eagle added more sticks, bringing it up to eagle size. But the red-tails just went 200 yards to the other end of the woodlot and quickly built a new nest and raised eyasses there.


The one bird of concern is the great horned owl, a true monster of the night sky. These powerful raiders of the darkness can kill anything less than 10 lbs., including a sitting red-tail formel on her eggs. But natural selection has brought about a rather remarkable detente, a genetically understood state of affairs between these two avian predators.

A great horned owl could easily kill a sleeping red-tail, but this virtually never happens, for an interesting reason. In the distant past, when the big owls killed off the local red-tails, they then found themselves without any nests. As it happens, great horned owls, thieves that they are, are unable to actually build a nest. They don’t have the instinct to pluck off sticks and arrange them into a functioning nest. The attribution of wisdom is misplaced with owls. They are totally dependant upon other species or conditions for their nests. That’s why great horned owls start nesting as early as December, allowing them to confiscate a red-tail’s nest before it’s used by the hawks.

Great horned owls that killed red-tails were subsequently unable to find a good nest to use. They therefore died out. So, these owls no longer kill or harass red-tailed hawks. They still, from time to time, steal nests in the winter, requiring the hawks to build a new one. But this works out really well, as red-tails are very good nest builders (well, except for first-time nesters, where the nests often fall apart – but that’s another story).


And is man a predator of red-tailed hawks?

Not any more, to any noticeable degree. That’s exactly why these hawks have come into central Philadelphia. Until recently, red-tails were trapped, shot, or poisoned by certain groups. By a few, they were thought to consume desirable game animals and chickens - vermin, to the hawks.

But that’s no longer the case. Very, very few hawks today are shot, trapped, or poisoned. The countryside is now saturated with adult red-tails. There are no longer any unoccupied red-tail habitats out of town. Consequently, young red-tails, including those from this nest this year, will have a difficult time finding a place to nest and raise their own families.

If our eyasses head out of town to breed in two or three years, they will find the countryside loaded with resident red-tails. The only unoccupied habitats are those left in cities. Pale Male, the world-famous red-tail in Central Park in New York, began this urban incursion almost 20 years ago. Red-tails are coming into cities and learning how to live there across North America. But none of these urban residents have been so accommodating as the Franklin Institute family.

Because of their success, there is the greatest chance that the two haggards will resume breeding and nesting once again next year at the FI.



10 comments:

  1. OMG! Thanks so much for posting this Della. I LOVE to read John's commentary on all things Red Tail. This was informative as well as funny. Poor dumb Great Horned Owls! Our family has really done their share to make Philly a great place to live work and play. Carditoo

    ReplyDelete
  2. John's contributions have been outstanding for furthering our hawk education. Who knew how dumb Great Horned Owls were!

    ReplyDelete
  3. Della

    Have goose bumps. Thrilled you and John Blakeman have connected
    to keep our hawkaholic family informed. Thanks so much for your
    leadership in this regard and to the hawkaholic regulars who are keeping
    up the vigil. So neat that John personalizes his remarks to us.

    ReplyDelete
  4. I'm loving this blog!

    One of the neatest sights I've ever seen were all manner of hawks and vultures catching a thermal over Walnut Canyon in AZ. There must have been fifty or more, riding it up and down, like an elevator. Right then, I was hooked on hawks.

    These Franklins have been quite a treat for me.

    We see lots of redtails, but up close, because we live in the woods, we see sharp-shinneds and kestrels, mostly.

    ReplyDelete
  5. Lynne - I believe what you saw over Walnut Canyon is called a "kettle." I've never seen that, but have always wanted to - it must have been magnificent!

    ReplyDelete
  6. Not far away from Philly at Hawk Mountain, they have such sights during the raptor migrations. More info at: http://www.hawkmountain.org/
    Even if you don't time your visit to see a "kettle" there is great hiking and bouldering on the mountain. Always worth the trip!

    ReplyDelete
  7. This sounds like An Outing for the Hawkaholics!

    ReplyDelete
  8. Della, great job reporting on yesterday's action. I returned this morning; much quieter on the parkway, but the hawks were everywhere!!!! They cam out of the trees at the 21st St. end of the site starting at 5:15. They were everywhere; hated to leave but have to visit Mom on Sunays. It's definitely worth the trip, hawkaholics.

    ReplyDelete