Sunday, June 01, 2008

John Blakeman on Sexing Hawks by Feet, Eileen's Peregrine Update, Poison News Link, WI Dove Sunbath

Can you tell by looking whether this Red-tail Hawk is male or female?

Male or Female?
John Blakeman responds to the question, "Are a female hawk's toes always bigger than a male's toes?


Yep. Those of us who work with raptors, falconers and rehabbers, first look at the thickness and lengths of toes, and the thickness of the tarsi ("ankles") of the hawks we work with. Female raptors "gots big feet," with all due respect to Fats Waller:

"Who's that walkin' round here, Mercy

Sounds like baby patter
Baby elephant patter; thats what I calls it
Say up in Harlem at a table for two
There were four of us
Me, your big feet and you
From your ankles up,
I'd say you sure are sweet
From there down; there's just too much feet
Yes, your feets too bigDon't want ya, 'cause ya feets too big
Can't use ya, 'cause ya feets too big
I really hate ya, 'cause ya feets too big

Male or Female?

Male or Female?

Male or Female?

Blakeman continues his note with a response to my ideas about the reason for reverse sexual dimorphism, he and I have been round and round on this one for literally years.

Here's what he has to say--
You've re-opened the Why are Females Bigger? can again. And you've posted all of the usual arguments -- ones that I and my raptor research cohorts argued about for hours; but to no conclusive end.

The biggest problem is this. All of the other arguments seem to work, to offer survival advantages to bigger females and smaller males. Nice.

But the fact remains that the smaller male must still feed his larger mate and any number of newly-hatched eyasses for the first two weeks or so after hatching. During that time, the female must remain on the nest and keep her hatchlings warm and dry. The male has to feed that entire family, but he's smaller and more limited in what he can capture and bring up to the nest. This doesn't seem to be a survival advantage for any party.

'Tis yet an unsolved biological quandary, at least for me.

--John Blakeman

John, I can't resist responding to what may be an assumption on your part which may or may not be true. (Maybe I should duct tape my fingers together...but not yet.)

I think there is an assumption here that in all pairs the male must do all the hunting during the first few weeks of his eyasses lives. This is not true in all pairs. It does seem to be mostly true for Pale Male and Lola so I will respond to that case.

Just because a male is smaller and doesn't nab bunnies and the largest prey on a daily basis doesn't mean he isn't a terrific hunter that can't feed his family on what the smaller prey he does hunt, particularly in spring when there are all those young unsavvy pigeons and squirrels readily available to feed his family. (I use the NYC examples as that's what I've observed.) Plus a male uses fewer calories while doing it.

While Lola sits eggs sometimes I think Pale Male lives mostly on her left overs. Why he doesn't just go and get another pigeon, I don't know. He's perfectly capable of catching more of them which he does once the eggs hatch. Perhaps he's saving them for later when the babies need feeding? Though that does seem unhawklike or at least contrary to one aspect of hawk character that we take as true.

Of the other two pairs I've watched numerous seasons, both Charlotte and Isolde have hunted while the males minded the kids. Charlotte because sometimes she doesn't like what Junior has brought her and Isolde because Stormin' Norman isn't the best at remembering he's supposed to feed her.

But onward and upward, Peregrine Watcher Eileen with another wonderful update. It's baby banding day in Rochester!

Peregrine Images Courtesy of Rochester Falconcam

Good evening Donna-

Today was an exciting day for Rochester's was banding day! Now I know some people are opposed to banding wild birds, but this is part of tracking the recovery of Peregrine Falcons after their near extinction. An added bonus is being able to follow the offspring when they establish their own nests. The family tree of Mariah and her 2 mates Cabot-Sirocco and Kaver, is growing to quite amazing proportions.

Mariah and Kaver have 3 females and 2 males this year. Mariah put up her usual aggressive defense of the nest, clunking several of the banders on the helmet while they were removing the eyases. Kaver was watching from the top of the tower, ready to take a turn defending the nest if needed. It has generally been my observation that the falcon does most of the nest defense when the intruder is close to the nest. The tiercel tends to look to the distance and escort intruders away before they can get too close. This may be because his primary job is hunting and delivering food to the family and the falcon's job is the immediate needs of her eyases. There was one odd scene this year where Mariah landed on the nest box and kakked at one lone fellow who stayed behind to gather samples from the nest box and clean the cameras. I don't recall ever seeing her come this close to a human while standing still. It may be that she was surprised as he was just returning from around the corner.

As is tradition in Rochester, the eyases were named. It's not an attempt to anthropomorphize the birds, but is a way to involve the public, particularly children, in the life of these wild creatures. Two of the names this year were chosen by classes of school children in the Rochester area. This year's names are Seneca (f), Diamante (m), Quest (f), Zephyr (m), and Susan B. (f).

I'm attaching a picture of Mike Allen and Barbara Loucks of the NYS DEC banding one of the eyases and a picture of all five later in the day. A full recap of the banding can be seen at with some amazing photos taken during the banding.

That's all for now!

All the best


Remember Brett Odom's photo of the Mourning Doves, feathers spread, taking a sunbath on Fire Island?

This is way in May that a Wisconsin Mourning Dove takes a sun bath. No spread feathers, but rather, feet on a heat retaining substance, like a rock or concrete bird bath w/heater, while sitting in the sun. I can't wait for August, perhaps by then I'll get to see the Mourning Dove spread-feather-sun-bath.

And stalwart Irregular R. from Illinois sent in this rat poison news link from CNN-

Donegal Browne

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