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Aldo preens in the sun, one foot comfortably tucked in his belly feathers, after taking a bath.
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Molt

IMG_7104.JPGTwo large feathers fell to the ground in Carson’s mew this week, marking the beginning of her annual molt. Over the next few weeks she will drop all of her feathers to grow a new set. This most recent molted pair of feathers mirrored each other: one curved to the right, one curved to the left. The shape tells me the feathers came from her wings: one from the right wing, one from the left wing.

The asymmetrical shape is most pronounced in the primary flight feathers, those farthest out on the wing where her fingers would be. If we take a look at “P10,” the outermost primary feather, we can clearly see the center shaft running closer to one edge of the feather vane:IMG_7111.JPG

As the bird flies, this is the first feather to cut through the air and the narrower vane (the top side in this photo) will be the leading edge. (So we know this feather came from the right wing.) The asymmetrical shaft assists with aerodynamics and feather stability in flight. One of the next primaries has a slightly different shape:IMG_7110.JPG

The shaft is still asymmetrically placed, but both leading and trailing edges have notches that make the tip of the feather more narrow. When the wing is spread, these outer feather tips separate like individual fingers to reduce drag. It seems amazing that these feathers are so well designed to optimize efficiency in flight.

Find out more about identifying feathers at The Feather Atlas website.

In Blue

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Both snakes were “in blue” this week as they prepared to shed their skin. The phrase refers to eyes that turn cloudy, sometimes with a bluish hue. The rest of their body turns dull, too, as a thin layer of fluid separates the outer skin and new layer forming underneath. The snakes are more vulnerable with impaired vision and can be more likely to bite, so we minimize handling to avoid upsetting them.

Emory the rat snake usually has cloudy eyes for about a week. Then two or three days pass with clear eyes before she sheds her skin. If she keeps to this schedule, she should shed very soon (hopefully in time for her program in Ashland at the end of the week!).

Straight

It should be easy to measure a snake, right? A snake is, after all, just a long skinny tube. Unfortunately they can be rather stubborn when I bring out the yardstick and refuse to stay in a straight line.

Great Plains Rat Snakes like Emory have strong muscles for climbing and holding prey. This time she used them to resist my attempts at straightening her long body to get an accurate measurement. I once tried measuring her skin after a shed to avoid this struggle, but found that the thin membrane stretched and was longer than her actual length. I think I’ll have better luck catching the snakes striking a candid pose in their habitats as they travel flat against the glass. Digger was kind enough to offer this opportunity yesterday (with an official length of 29.5 inches):

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(No reasonable measurement was accomplished with Emory.)

Feaking

After eating a meal in the sun, Carson the Red-tailed Hawk demonstrated “feaking.” A strange but traditional falconry word, feaking simply describes a hawk rubbing her beak on a perch to clean it.¬† This behavior is most often seen after eating to scrape off any bits of food stuck to the beak, and is also a sign of comfort.

Signs of Spring

Despite the chilling temperatures this week, spring is in the air. I was glad to hear the chickadees singing their “Spring’s Coming!” song as a reminder while I shoveled an inch of fresh snow off the sidewalk.

Some migrating birds are returning, including my first-of-year (or “FOY” to serious birders) red-winged blackbird singing last week. I also saw my FOY American Kestrel as Aldo and I drove to Ashland for a program on Monday. That kestrel looked like a fluffy cotton ball as he balanced on a powerline, feathers puffed out to stay warm. I wondered if he regretted coming back so early!

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Peregrine Falcons in southern Wisconsin are well into their nesting season with many pairs already sitting on eggs. I caught a quick glimpse of an egg on this camera in Pleasant Prairie, Wisconsin and have been checking back regularly to try spotting it again. While we don’t know how long our snow will last, birds farther south and optimistic migrators like the kestrel remind us that “Spring’s Coming!”

 

 

Foot Tuck

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I am always looking for signs that the birds are relaxed. Any time their head is down (while eating) or covered (while preening their wings or sleeping), they are more vulnerable to a threat. A predator might take that opportunity to launch a surprise attack, so they only risk covering their eyes when they feel safe. Other comfort behaviors, like Carson’s foot tucked in the photo, indicate that they are comfortable and and not worried about their surroundings.