Monday, January 25, 2010

FLASH:Has the Houston Formel Returned? Blakeman, Horvath, and Sally of Kentucky on the New NYBG Mystery Hawk Plus Betty the Crow Uses Three Tools

Photograph by Francois Portman

From downtown hawkwatcher, bloggist, and professional photographer Francois Portman--

Hi All,
The Red-tailed Hawk (left & center, see attached) has been seen regularly around Houston Street/1st Ave. area, there are thoughts that she could be the Houston female
of ps188 nest (at right)
Unfortunately the band # is unreadable!

Hope you're well

We won't know for sure until someone gets a good look at her band, but the hawk on the right certainly looks like the same hawk as the one on the left and center to me.

One of Pat Gonzalez's photos of the current New York Botanical Garden Mystery Hawk

Boy did I blow it. My advice? Don't try to identify hawks at 4 in the morning. Therefore I plucked some photos from here and there to illustrate (to myself in particular) what Red-tails look like in different life phases, illumination, sexes, times of year...

Remember I asked for suggestions from the house on the matter? Thankfully a number of folks took me up on it. But first a few hawks under different conditions.
hotograph by Donegal Browne
A tired Isolde feeds on the nest in April. See the bags under her eyes?

Photograph by Donegal Browne
The same time frame as the photo above, Tristan the tiercel, though hunting ceaselessly doesn't really look the least bit tired.

Photograph by Donegal Browne
In no time Tristan has a rather large rat for the himself, Isolde and the family. Here he goes into a crouch scoping another, is perfectly still, and then, I assume when the prey looks the other way, zips to the next branch over and is perfectly still again. Tristan was a master of stealth.

Photograph by Donegal Browne
Tristan now on the next branch over. Here we have a excellent view of a reasonably good field mark for RTs from the rear in both a juvenile and a mature bird. Though rare, some RTHs do not have it. Tristan had it in spades. See the dark and light patches forming "backpack straps" on his back?

Photo: Donegal Browne
Notice what happened to Tristan's feather color when the light changes. Compare this photo with the two above that are anterior shots of him.

You'll also note that Tristan was just as big on giving beautiful photo ops as Pale Male is.

Tristan's presence is still sorely missed.

Photograph by Donegal Browne
Pale Male sits on Linda 4 in the rain, near the end of the extra month in which he and Lola tended an unsuccessful nest. During the last few days he'd been spending many hours on the nest as Lola was taking extremely long breaks. He'd just brought her food; see the blood on his beak.

Photograph by Donegal Browne
Like the NYBG hawk this is a first year immature January Hawk. Quite different. A formel?
Photograph by Pat Gonzalez
We're back to our current New York Botanical Garden Mystery Hawk who is now not quite so mysterious--First off a missive from wonderful rehabber Bobby Horvath, who has had his hands on many many hawks of all kinds--

Hi Donna,

The bird looks like a juvenile redtail to me but I could be wrong. It's definitely not an accipiter. Too big headed and toed to be sharpie or coop and tail not long enough but sized right for a juvenile goshawk. If its not a redtail my second guess would be a juvenile red shouldered hawk.

One more thing, it appears to be banded on its left leg. Very rare for goshawks to be trapped for banding but red shouldereds do come into rehab pretty commonly so I'd bet its one or the other.


Many thanks Bobby! Extremely helpful.
Photo courtesy of

How about this hawk? It's a juvenile. It's shaped like a buteo. He has chunky yellow toes.

Look at the feathers near his feet. They seem to have a similarity in their greyness to the NYBG hawk above though certainly a darker hawk than that one overall. And it does have some brown and white splotches on it's back. The beginnings of "backpack straps"?

No, actually. This is a juvenile Red-shouldered Hawk. An example of one of the species Bobby spoke about above. His second choice for an identification of the NYBG hawk.
Blog contributor Sally of Kentucky who volunteers at a wildlife rehabilitation center and has dealt with numerous species also sent her thoughts--

Dear Donna,

This juvenile bird's feet seem pretty sizeable to me, heavier than any accipiter I have seen at least in my limited experience, and the tail isn’t as long as say a goshawk or a harrier.
I looked at pictures of these two species and I do not think it is either, nor do I think it is a RSH (Red-shouldered Hawk- D.B.) with those heavy feet. What other hawk could it be in New York if not a Redtail?
Agreed the white on the face seems unusual and I also think it looks different than most juveniles I have seen; perhaps it is just the facial coloring throwing us off? I wonder what Blakeman says.


Speaking of Ohio Red-tail expert and falconer John Blakeman, here is what he had to say, plus my questions on the matter and his responses--


The mystery hawk is an immature red-tail, almost surely a tiercel.

The general body shape is pure red-tail, along with the head shape, position of the eyes in the head, etc.
The tail feathers aren't long enough or appropriately positioned for an accipiter.

A number of immature red-tails retain a general blue-gray pigmentation of the legs and cere (exposed skin on the beak).

--John Blakeman

I was thinking about the NYBG bird when I woke up this morning and I kept going back to it in my mind-- its body is shaped like Pale Male, Tristan, and Junior, the quick compact model of Red-tailed tiercel, unlike Atlas out near the Triborough Bridge for instance, but the feet seemed so weirdly colored and maybe a little fine toed too.

Thanks so much for the information on the immature pigmentation issue. I had no idea. As far as I remember none of the eyasses in the city I've watched have had it.

But as we know, one of the true wonders of this whole thing is there is always something new about those pesky Red-tails.


The coloring of red-tail skin, as in other birds, is primarily a result of pigments in foods. Hawks eating animals that feed on seeds and vegetation have these phytopigments. But for reasons I haven't yet figured out, a few immatures have rather bland blue-gray pigmentation.

Actually, this is a lack of pigmentation, for unknown reasons. The major factor is the concentrations of these carotenes in food. But it appears that a few immatures don't concentrate these in skin during the first year very well.

And here's a coloration matter I've always wondered about, as have most falconers and rehabbers. Plainly, the skin coloration of wild adults is almost always far more deep and intense than birds kept in captivity, even those fed lab rats and mice. The feet of my new red-tail, Zephyr, are yellow, but not nearly as intensely colored as wild-feeding hawks. Wild birds, somehow, eat things that give them deep skin color (except for a few immatures, such as the one in the photo).

--John Blakeman


Regarding the matter of captive raptors having paler pigmentation then their wild relatives, even those fed lab rats and mice. Here's a thought for what it's worth.

Wild mice and rats have a varied and seasonal diet. Even urban pigeons have a special taste for begonia leaves and other greenery when in season whereas lab mice and rats are likely fed a steady diet of prepared rat or mice chow. While the mouse chow may be perfectly nutritious it just doesn't provide those fresh foods that contain the colored pigments found naturally. And as I think we've discussed before in another context, when a hawk swallows a mouse, vole, or other small rodent, they swallow it whole. So hawks get their veggies from the undigested food inside their prey. And those whole foods, instead of processed ones, would seem more likely to me to contain pigmentation which then colors the hawks. Possible?

P.S. Urban raptors also eat a certain number of pigeon feathers, which do come in a variety of colors. I've seen them get down any number of flight feathers which is always rather amazing to watch. I wonder if those feathers also contribute to a raptor's coloration?

Last but not least, it wouldn't be a blog post lately without something from the amazing tool wielding Betty the New Caledonian Crow--

Contributor Robin of Illinois has found more video. This time Betty uses three tools in sequence to get the goods. no question this bird is a grub procuring whiz!

Donegal Browne


sally said...

Thanks for the rundown analysis of the mystery hawk! I always learn from your blog. My director's husband taught me one year after I had admitted a new fledgling hawk and misidentified it on the paperwork as a Red-tail when it was actually at Red-shouldered, that they are "born with the feet they will have as an adult", so I always look at the heaviness of the feet, length of toes and the tail length and bar/stripe pattern as the first identifier if I am not sure what I have. I still cannot tell a Sharpie from a Coopers unless I can see clearly that the tail is obviously either straight or rounded!

Donegal Browne said...

You're welcome. Thanks for your recap. I too always look at the feet and for some reason the mystery hawk's feet still look finer than they should to me. I suspect it is the lack of the bright yellow that makes them appear that way to me. But now that I'm up on the blue-gray pigment issue I'll compensate next time and realize the feet are bigger than they look without the yellow. :-)