As I mentioned previously, I'd gone to a fund raising event at an all volunteer staffed bird observatory.
As I walked amongst the exhibits and vendors, I stopped in at the live raptor display area which as usual for this sort of event, has raptors who for whatever reason, a physical problem or because of imprinting issues, are not able to survive in the wild on their own so they are brought by someone who has permits to keep these birds to help educate the public about them.
While I was standing there, a person behind the table told another patron, if I heard it all correctly, that a particular bird had been imprinted on humans who had raised it after finding it under a tree. The educator went on to say that raptors will imprint on anything they see first, including an object like a toaster.
WHAT? Hawks imprint like geese do? They're precocial? How did I miss that all this time? But they don't act like they're precocial. They don't immediately or at least very soon after hatching trot around following their mother? But they imprint as if they were precocial.
A toaster???
This did not sound right at all. Something is amiss.
Therefore just in case I had missed something as large as classic precocial imprinting in raptors.... I mean what if an urban eyass hatched, looked up, and saw a human at a window? Or looked down at the street and saw a human before she saw a parent? This had never happened so I'm even more suspicious about the comments? Raptor educators have to train, they have to take exams...
This could not possibly be true of Red-tails! Wait! Perhaps it was just a helper speaking out of turn? Or perhaps I heard it incorrectly? Will an owl imprint on a toaster. If that were true, perhaps that's how "toaster" entered the conversation then?
But when in doubt about Red-tail behavior no matter how sketchy we think what happened was, or how bad our ears might be, we have the wonderful luxury of sending off a missive to our Red-tailed Hawk expert, Mr. John Blakeman in Ohio, which is exactly what I did. And as usual he sent back an immediate reply, which follows...
Donegal,
No, hawks do not imprint in the classic manner of geese or other waterfowl.
That textbook behavior isn't how eyasses connect and identify with their
parents. If it were, the eyasses would be flying behind the tails of the
haggards all summer, in the manner of imprinted ducks swimming behind the
tails of the female parent.
Eyasses will, however, become "imprinted" to humans who take a hawk from a
nest and then raise it. It's a long story with many details, but in essence the
young hawk connects with and identifies the human as its source of food.
The
human can't fly or otherwise allow the progression of summer-learned normal
hunting behaviors, so the young hawk becomes permanently mind-scarred, focused
solely on the human.
(An imprinted hawk can never be restored to normal
psychology and independent behavior. In my book, I'll tell the story of
"Goldie," an imprinted Red-tail I cared for for 13 years.)
But no, none of that happens when eyasses naturally connect with their
parents in the nest. The imprinting that so occurs is rather weak and quickly
terminated when the eyass fledges and has to learn to hunt and kill for itself
in a few weeks of summer.
And no, a newly-hatched eyass seeing a big, lumbering human on the other
side of a ledge-nest window is not going to "imprint" to that person. It's not
whatever the hawk first sees that is moving; it's whatever first and continues
to feed the hawk that it connects with.
--John Blakeman
Many thanks John, a splendid clarification as usual. I thought perhaps I was loosing my mind. How could I possibly have missed that somehow Red-tails were precocial at least in imprinting and I never noticed???
Speaking of which, while investigating the matter, I ran across the chart below. It breaks down Precocial and Altricial into finer categories.
As Red-tailed Hawk eyasses are hatched with down and have their eyes open they are considered Semi-altricial 1.
While owls are hatched with down but have their eyes closed when hatched, they are considered Semi-altricial 2.
Check out the chart. I found it fascinating.
(What is a Megapode? It is any of 12 species of chickenlike
birds (order Galliformes) that bury their eggs to hatch them. Most
species use fermenting plants, kind of a compost approach to produce heat for incubation,
but some use solar heat and others use the heat produced by volcanoes.)
Characteristics Of
Nestlings
(modified
from O'Connor, 1984)
TYPE
OF
DEVELOPMENT |
DOWN
PRESENT? |
EYES
OPEN? |
MOBILE?. |
FEED.
SELVES?
|
PARENTS
ABSENT?
|
EXAMPLES
|
|
Precocial
1
|
Yes
|
Yes
|
Yes
|
Yes
|
Yes
|
Megapodes
|
|
Precocial
2
|
Yes
|
Yes
|
Yes
|
Yes*
|
No
|
Ducks,
Plovers
|
|
Precocial
3
|
Yes
|
Yes
|
Yes
|
Yes
|
No
|
Quail,
Turkey
|
|
Precocial
4
|
Yes
|
Yes
|
Yes
|
Yes/No
|
No
|
Grebes,
Rails
|
|
Semi-precocial
|
Yes
|
Yes
|
Yes/No
|
No
|
No
|
Gulls,
Terns
|
|
Semi-altricial
1
|
Yes
|
Yes
|
No
|
No
|
No
|
Herons,
Hawks
|
|
Semi-altricial
2
|
Yes
|
No
|
No
|
No
|
No
|
Owls
|
|
Altricial
|
No
|
No
|
No
|
No
|
No
|
Passerines
|
...
t =
Precocial 3 are shown food.
.....*=
Precocial 2 follow parents but find own food.
Many thanks to Stanford for the dandy chart, for more on the topic go to...
http://www.stanford.edu/group/stanfordbirds/text/essays/Precocial_and_Altricial.html
Then I had another rather mind expanding experience today. I'd gone out the back door during the gloaming and saw one Hummingbird run another off the feeder. Not unusual they love going after each other. But then the winner sat on a small branch of the Magnolia near the feeder and just continued to sit. Then he went back to the feeder. Drank. Then went back to a branch and sat.
This hummingbird doesn't look like a Ruby-throat to me at all and that is the only species that is found in the Eastern United States normally and...wait just a minute! That hummingbird looks dark purple..
... I went for my camera. Took pictures, in the dusky light. These are going to be BAD. Went back in, pulled the card, stuck it into the computer and I looked... fully expecting the bird to be a Ruby-throated Hummingbird after all, due to a trick of the light, but.....nope.
Okay, the camera says his back is dark green and his head is black. Is there some shot which isn't of his back?
He's out of focus but blocks of color are evident. I wonder if he is still resting, drinking, resting, drinking? I grab my other camera and go out.
Nooooooo, I forgot to disable the flash on this camera. It isn't really as dark out as it looks, in actuality the same light as above, but the camera just adjusted the aperture as it knew it was going to flash even though I didn't.
Sorry little guy. Thank goodness he is still going about his business.
I go back in the house to let him drink, rest, drink, rest, until he goes into torpor. He has very likely just come on a very long trip.
I grab Peterson's Field Guide to Eastern Birds. Sure enough he is a vagrant. He is a Black-chinned Hummingbird and ordinarily he wouldn't be any further east than Texas.
That is a whole lot of extra little hummingbird wing beats. No wonder he's hungry and tired. I'm certainly glad the feeder was up.
Plus my fingers are crossed for him.
Donegal Browne
