Zero Percent

One thing I love about the animal care community – from bird trainers to zoo keepers – is the ability to find delight in small, peculiar aspects of the daily routine. I practically jump for joy when I cut a piece of rat that weighs 100 grams, the exact meal size for Carson the Red-tailed Hawk. On a really good day, I once prepared food for 10 birds using a single, perfectly portioned chunk for each one.

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I tested my precision again this week while ordering food for the birds. The website has a handy tool showing how much space is left in the shipping box. I pay close attention to this number because frozen meat is expensive to ship and I want to fill the box as efficiently as possible. I usually end up with 2% or 3% free space in the box, not enough¬† for another bag of mice or quail. But this time I was excited to completely fill the box with exactly 0% of free space. How exciting! (Like I said, it’s the little things that brighten an animal keeper’s day!)

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Want to support Aldo and Carson this holiday? Consider making a donation to provide their next meal!

  • $25 would cover 2 months’ worth of Quail
  • $100 would cover 100 mice
  • $250 would cover a whole box of mice, rats, quail, and chicken

Science of Behavior Change: Negative Reinforcement

Last week I wrote about positive reinforcement, giving a reward to increase a behavior, as the most important tool in training our raptors. But every good trainer will have other tools in their back pocket to try when one method doesn’t seem to be working.

You have probably heard an incessant beeping in a car if you pull out of the garage without your seat belt fastened. After a few annoying beeps, you reach over and click the seat belt into the buckle. The beeping stops. You may not have realized it, but the car just trained you to wear your seat belt by using negative reinforcement.

Aldo dislikes having his feet touched, but with training, he usually allows me to check his foot health.

Negative reinforcement removes something unwanted (the annoying beeping stops) to increase the behavior (wearing your seat belt). Next time you get in the car, you are more likely to buckle up to avoid the noise.

I occasionally use this method during health checks with our birds. We need to look at their feet to make sure no sores develop, but Aldo dislikes having his feet touched. My hand must look big and scary to a bird that weighs less than a quarter of a pound. When I move my hand close, he pulls his foot away or steps to the side. I hold my hand in place until he stands still, then I remove my hand. He learns, “if I stand still, the scary hand goes away.” Eventually, he will let me lift a foot with my finger or a pencil.

It is not the most positive way to train the behavior since my hand is still making him uncomfortable. But he learns how to make my hand go away and has control of the situation. I also use positive reinforcement during the session with tasty mouse tidbits when he does a good job.

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Weighing a snake

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How quickly does a 5-year-old hognose snake grow? As animals with indeterminate growth, snakes continue growing throughout their life, though growth slows down in adulthood.

I set out to investigate our snake’s growth patterns. Getting length measurements on Digger proved to be difficult, so I decided to track her weight instead. At the end of the week, after Saturday’s mouse has passed through her system, I extract her from her favorite rock cave to visit the scale. She has so far weighed in around 330 grams (almost three fourths of a pound) and it will be interesting to see how much (or how little) it changes over the next few months.

Aldo and the Mealworms

It was Aldo the American Kestrel’s turn for interesting enrichment this week. In the wild, over half of a kestrel’s prey can be insects. They are particularly skilled in catching dragonflies in flight, but also find a variety of grasshoppers, crickets, and caterpillars. To mimic this part of their diet, I occasionally give Aldo mealworms in addition to his regular diet.

The mealworms seem to be an exciting treat for their novelty, apparent tastiness, and entertainment value. One of the live mealworms this week fell into the textured turf and started to crawl away. I resisted the urge to help, letting him work it out on his own. It was a tense moment as I silently cheered Aldo through multiple attempts to extract the bug. See if he was successful in the video below!

Novel Basking

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Raptor enrichment is always on my mind as I plan interesting things to keep the birds occupied, but it is easy to forget about the snakes that rest quietly in their enclosures. I found Emory the Great Plains Rat Snake cruising around her habitat one morning and wondered what kind of contraption I could construct to change up her routine. Then I realized there was an easier, ready-made enrichment item: the great outdoors!

Both of our snakes hatched in captivity and are accustomed to living indoors. To create a novel experience for Emory, we went out to the backyard and I set her gently in the grass. She wiggled a bit, free from my grasp, but then lay still. Her tongue flicked out a few times before she rested completely motionless. A snake’s thoughts are impossible to read, but I wondered if she was overwhelmed by this new environment or just enjoying it. The texture of green grass, vibrations traveling through the ground, the bright glare and heat of the sun were new experiences that we will continue to explore through the summer and into fall.