Window Strikes

During raptor mew renovations a few weeks ago, maybe I shouldn’t have been surprised that the plexiglass windows were clear – really clear. They were so fresh and clean that I couldn’t see them from inside the mew. I worried that the birds wouldn’t see them either, and might hurt themselves flying into them.

Windows are some of the most dangerous obstacles a wild bird will face. Millions of birds die each year from window strikes as they mistake the reflections for open space. Luckily there are many solutions to prevent these collisions.

New buildings can install windows angled downward to reflect the ground or choose window panes infused with UV reflective properties that birds can see but are invisible to us. For existing windows, homeowners can add UV decals or bird-friendly tape to make the windows more visible to birds.

There are also low-tech solutions that can be just as effective. I recently found the “Acopian BirdSavers” method, named after the Acopian family. Wanting to reduce bird collisions with their windows in the 1980’s, the family began hanging decorative beaded curtains outside their windows. This design was simplified over the years to a more classic, rather than groovy, vibe. Modern Acopian BirdSavers are simply made by hanging lengths of parachute cord from the window frame, spaced 4 inches apart. This curtain alerts birds to the window’s presence while having a minimal impact on a human’s view.

I happened to have a roll of parachute cord on hand and crafted a “BirdSaver” on each raptor mew window. The thin cords remind the birds that there is a barrier while not disrupting their views of the backyard.

 

 

 

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Enriching

Every once in a while, I give homemade “toys” to the birds as enrichment. They might decide to play with the object, manipulate it in some way, or ignore it. Each bird has unique preferences. Aldo only interacts with his enrichment if it is tied to his favorite perch, and even then he might ignore it for a few days. Carson is easier to please: she’ll shred anything anywhere in her mew.

This time the birds received egg cartons of varying sizes stuffed with newspaper strips. As expected, Carson hopped down to grab the carton right away, but surprisingly dropped it and ignored it for the rest of the day. Even though she didn’t use the toy very much, I still consider it a successful enrichment because it was something out of the ordinary that occupied her mind – and her talons – for a little while.

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Aldo, however, jumped right in and his newspaper was destroyed in a matter of minutes. Theo the nocturnal owl is rather reluctant to move about during the day so he saved his toy for later. The next morning, it was shredded and scattered around the mew. Their reactions are equally enriching for me as I try to figure out new ways to keep them active and engaged.

The Fair

I was excited to go home to the Twin Cities last weekend to join my family at the Minnesota State Fair. Starting out early in the morning, we found breakfast at the mini doughnut stand and wondered what to do next. My eye was soon caught by a tortoise outside of “Monty’s Traveling Reptile Show.” I always thought this building was a little tacky, with signs worthy of a peculiar circus, and had never been inside. I was surprised when my mom said, “Let’s go in, you’ll love it!”

The atmosphere inside was not the circus I was expecting. Instead, a variety of reptiles lay in individual terrariums with educational signs about each. The number of reptiles represented from around the world was stunning. As I stepped away from the diamondback rattlesnake display (grateful that I live in a place with so few deadly animals), I saw a peaceful Black-throated Monitor lizard snoozing against the glass. There was a clear view of a gaping hole in the side of his head.

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I knew that snakes don’t have external ears, so what could that hole be? It turns out that most reptiles like lizards, crocodiles, and turtles, do have external ears. This lizard’s tympanic membrane, or eardrum, was clearly visible and capable of picking up sound waves through the air.

After a full day at the Fair, I was relieved to return to the quiet town of Cable and to care for my own reptiles. I had to admire Digger’s smooth head which lacked a hole for his ear. His ear structure (hidden behind a layer of scales) is capable of hearing sound waves through the air but is better equipped to sense vibrations transmitted through the ground into his jawbone. Even though he didn’t respond, I’m sure he heard my excited, “Hello, Digger!” when I returned.

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“I AM smiling”

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It always seems like Carson is frowning, but luckily that look doesn’t reflect her mood. Her apparently furrowed brow is built into her skull. Hawks and eagles have a prominent ridge that extends over the eye. This “supraorbital ridge” (supra = above; orbital = eye) acts like the visor on a baseball hat, shielding the eye from direct sun. Red-tailed hawks often soar high in the sky or hunt in open fields where there is little shade, so their built-in visor helps them see clearly on a sunny day.

Even if Carson looks angry while she soaks in the sun, she may very well be saying, “I AM smiling!”

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The supraorbital ridges extend like wings above the eyes as seen from above on this Red-tailed Hawk skull.

Water

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With her confidence growing, Carson has been taking each new step of our training like water off a duck’s back.

Like ducks, all birds have to work to waterproof their feathers. By rubbing their head and beak in an oil gland at the base of the tail, birds spread the water-repelling oil to all of their feathers while preening. Drops of rain will bead on the surface of the feather, rather than sink in, and roll right off. Waterproofing keeps the fluffy down feathers dry underneath and maintains their insulative qualities. The bird stays warm and dry even through heavy showers.

From beak trimming to meeting groups of visitors at the Museum, Carson doesn’t seem to mind. She is still eager for training even after these mild stressors. Just like waterproofing takes some effort to maintain, building our relationship and Carson’s confidence in new situations took time. But we are seeing the rewards now as she takes everything in stride, like water off a hawk’s back.

Shed

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Digger’s most recent shed (Western Hognose Snake)

Both of our snakes, Digger and Emory, have shed recently and it is fun to inspect the tissue paper-like skin. Snakes have a clear scale that covers each eye, and you can see how that scale sloughs off with the rest of the skin. There is even a hardened scale that covers Digger’s “hog nose” that sheds.

Snakes shed their tough outer skin so they can grow and I wondered how quickly our snakes have grown. I found that it is incredibly difficult to keep a live snake straight enough to measure its length, so measuring the shed skin is much easier. Digger’s most recent shed was 30.5 inches; he has grown 4 inches over the last 10 months! Emory has shed even more often and has grown nearly a foot longer since last September. At 52 inches long, she is nearing the typical length of adult Great Plains Rat Snakes, so I expect her growth spurt to slow down soon.

Molting in the Rain

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Aldo the American Kestrel enjoyed a rain shower on Thursday morning. As he spread his wings to soak in the rain, his molting flight feathers were visible. He has short primary feathers growing on his left wing and new rectrices, or tail feathers. About two weeks ago, I found most of his tail feathers on the ground in his mew. Now, new feathers are starting to grow in and give the appearance of a diamond-shaped tail almost like a raven. Aldo’s tail will keep growing, though, until the feathers are all the same length.

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