Sunday, November 23, 2008

Red-tail Update-Kay and Jay in Tulsa, Parthenogenesis in Kimodo Dragons, and Crows and Cutlets Part II

Photograph by the Tulsa Forum's Cheryl Cavert
Earlier this season Kay and Jay check the nest for needed renovations.
And Thunder's parents were back again today, well actually at this point Catbird sent me a correction, there is some question whether it was just Jay, or Kay and Jay or...

Everyone is waiting for Cheryl Cavert to check out the evidence as she knows the birds by sight better than most of the others.

In the meantime, here is the original Red-tail Update from Forum participant Catbird--

Mid-morning Friday, both Kay and Jay were spotted at the tower nest (Jay briefly, Kay for as long as about a half hour), fiddling and inspecting and gazing around in the high Tulsa winds.

We had some screen shots from mid October of the nest and it was then still pretty much as Thunder had left it...scattered hither and yon. But today there are clearly signs of nest maintenance having been done.

There is a definite nest bowl shape again, and the nest sides are higher, and the scattered twigs are all tidied up from the tower floor grating. Now we wait and watch for signs of greenery having been brought to the nest, right? And sky dancing?

That's right. Sky dancing first and an evergreen bough most probably as things get close.

Screen capture courtesy of MSNBC

Back in 2006, two female Kimodo Dragons in two different UK zoos produced parthenogenic young. In other words the process was asexual, there was no male Kimodo Dragon involved. Flora and Sangei did it all on their own, thank you.

When I read about it, I felt quite vindicated. I'd remembered having a rather heated discussion with my main zoology professor defending turkey farmers who swore they'd had virgin hens produce young. Dr. Gross wouldn't even consider the possibility, while I saw no reason why not as lower forms such as aphids, plants, various invertebrates did it all the time why couldn't higher forms possibly do it once in a while. And then a decade or so later DNA testing arrived. Yes, by 2006 one virgin turkey hen's reputation had been saved by DNA and two Kimodo Dragons had done it in a single year, pushing scientists to admit that not only did it happen, but just maybe it wasn't such a rare or abnormal occurrence after all.

And the kicker with Kimodos was that not only did the two dragon ladies reproduce asexually, they then went on to produce sexually. Something the lower forms tend not to do. Wow. This was big.

Then I ran across a quote from one of the scientists that had published in Nature about the DNA testing. I guess I'd just assumed that the asexually produced young were rather like clones and would be little versions of their mother. And of course all females. Not the case. They found that the DNA was slightly different from the mom in each case but it could only have been the mother's DNA as it wasn't even close to the other Kimodos that were at the zoo. And it's not like there are stray Kimodos running around, and sneaking into zoos when no one is looking having sex. Ten feet long, two hundred pound lizards are rather hard to miss.

After Science Friday on National Public Radio reminded me about this yesterday, I ended up talking to my seventeen year old daughter about it on the phone. Like me, she's intending college degrees in theatre and biology and her bio questions have gotten a lot tougher lately.

And she said, "Wait a minute mom, how can the DNA be slightly different. Is it mutations?"

Gulp. I wasn't really sure. So I started digging.

I don't have access to the paper in Nature here in Wisconsin so thank goodness for the internet and the BBC. The BBC, even in short articles, acts like their readers actually have brains and can understand at least basic science.

Here's the deal. Female Kimodos have a W and a Z chromosome. So when they reproduce by parnenogenesis, each of the chromosomes double. Creating WW eggs and ZZ eggs. Now remember females are WZ's so no females. Male Kimodos are ZZ. WW eggs aren't viable. So the offspring in asexual reproduction in Kimodo Dragons is always male.

And here are some links--Enjoy!

Here's where we left off. Stump Crow was, I thought, swallowing another big blob of fat that she had so laboriously worried off the meat and compacted with her beak. After looking at the sequence that comes next, I'm not so sure that's what was happening. We'll see what you think.

Ground Crow has also been pulling the fat off the cutlets too, but I think he has actually been swallowing his portion.

Look at Stump Crows cheeks and neck. I'm wondering if she isn't storing the fat in there somehow. Remember when Mr. Goldfinch kept poking one sunflower seed after another down his throat? And it occurred to me that Goldfinch shuck sunflower seeds before they eat them. After close observation, I realized that being he had no pockets and who wants to make more trips than necessary, he transported them to winter storage by carrying the complete seeds down his throat and then expelling them when he got to his storage facility.

Is Mrs. Stump Crow doing something similar with the fat?

Wait! Ground Crow looks like he may be collecting fat in his beak at the moment.

Mrs. Crow takes off from the stump.
Why is it that Crows let their feet dangle longer than most birds when they take off? What? They're heavy bodied birds and they have to get some flight momentum before even considering using other muscles for superfluous activities like stowing their feet?

The squirrels are completely shameless right now. Gluttony and the self absorption to steal from the feeders with me standing right there.

Look carefully, see Mrs. Stump Crow's legs and tail? I think this may be where she went the last time she left the stump for a few moments.

Yes, she's now going back into the same area of overlapping branches. Is she stashing the fat?

While the Stump and Ground Crow are otherwise involved, out of nowhere another Crow flies in, grabs a piece of cutlet and flies right back out through the Spruce boughs. He seemed rather like a Crow Pirate.
I get distracted by how fat the squirrel is getting. I wonder if squirrels have soft fat or whether if you touched them there is so much under the skin they'd feel as hard as a rock.

In the meantime, Ground Crow has hopped onto the stump only to be thwarted by Stump Crow who is back from the tree and has her foot on the meat.

And look, her cheeks and throat don't look puffed up anymore. She edges closer to Ground Crow. He hasn't hopped off yet so she makes a half hearted nab at his feet with her beak and it jumps off to go work on the piece of cutlet that is already down there.

A don't-even-try-it look at me...

And she's back to work.

Remember Pirate Crow? He's gone off to the playground with his cutlet and is enjoying it under the swing set.

Did the Stump Crow change while I wasn't looking?

What do you think? Looking back, maybe there was a change. Sheesh. Why do they have to all look alike? Actually, when I first started hawk watching all Red-tails looked alike to me too. I'm hoping that the more I look, the more perceptive I become about the differences between individuals for this species as well.

I don't suppose they'd all wear different color nail polish to help me out would they?
Not a chance.

D. B.

1 comment:

Anonymous said...

Is the stump crow placing the fat on a twig in the first picture of her in the tree?