Bird of Prey FAQs & Elaborate Answers - #2
How come you don’t know whether that bird is male or female? and Do you ever feed the raptors live prey?
Working as an environmental educator at a nature center, and teaching people about the ambassador animals that my team and I care for is a never dull job. I get asked a LOT of questions, and sometimes don’t have the time to give my full, behind-the-scenes, silly anecdote-filled answers. So here they are, for you to enjoy!
Do you have a question you’re dying to know the answer to? Ask me in the comments!
How come you don’t know whether that bird is male or female?
It’s hard to tell, okay? It’s not obvious like it is on a mammal. All the machinery is up inside of the body cavity, meaning invasive surgery would be the most definitive way to tell, and even then it’s not always obvious. Many bird species reabsorb large parts of their reproductive systems in the winter. What? It’s not like they’re using it. It’ll regrow in the spring.
Also, most raptors are not sexually dimorphic by plumage—meaning the males’ and females’ feathers look the same in every season. Snowy Owls, American Kestrels, and Northern Harriers are conspicuous counterexamples, and there are probably others that have color differences in light spectra humans are incapable of seeing. But most have either no observable differences, or differences so subtle that humans have to study individuals for long periods of time to get a good grasp on them.
Sometimes the only outward physical difference between male and female raptors is size, with females being as much as 30% heavier than males. This is weirdly called “reverse” sexual size dimorphism, because it is the opposite of the size trend in us humans, but like humans it is rule subject to breakage—some women are pretty tall, and some male eagles are pretty beefy. In addition, some species have different voices between the sexes—one’s call is slightly higher or lower pitched, in general, compared to their mate’s. But to be certain of a bird’s biological sex, we would need to do surgery or an expensive DNA test, both of which we generally elect not to do to our ambassadors. (We wouldn’t treat them differently anyway.)
There is however one unobtrusive way to tell a male from a female raptor: when Oscar the Barred Owl lays an egg, you start to reconsider giving your birds gendered names.
Do you ever feed the raptors live prey?
The raptors in care at the nature center can be put into two categories: the first are actively being rehabilitated from injuries sustained in the wild, and they will be released back into the wild as soon as they are ready. For many of these patients, the kinds of injuries they are recovering from may hinder their hunting ability, and so we test them to make sure they can still catch live prey. A Broad-winged Hawk with serious head trauma is put in a special outdoor enclosure, and a black or brown mouse is released into the enclosure with it. The hawk either catches and eats the mouse or doesn’t. Pass or fail.
The second group of raptors we care for are non-releasable birds. These birds were brought to us as patients at some point in their past, but because of the severity of their injuries, they were unable to pass the live prey test or are unable to fly. They are not eligible to be released into the wild. This is a conclusion given many, many days of thought, re-testing, and troubleshooting before a bird is ultimately deemed non-releasable by the rehabilitator and a veterinarian. The live prey test, as it is called, is the only circumstance under which we feed live prey to the birds at the nature center.
(On purpose.)
The non-releasable raptors’ enclosures are built in such a way as to not only contain the bird, but to prevent other animals from getting inside. If you’ve ever had a weasel in the chicken coop, you understand how important it is to prevent even a mouse from getting inside an enclosure with the intended occupant. For the most part, “prey” does not just wander into the enclosures with our birds. You’d think it would not be in their best interests anyway—what chipmunk in its right mind volunteers to go exploring around the Red-tail enclosure?—but it happens. An opossum once discovered that our Common Ravens get broccoli and tomatoes with their diet and found a way inside to partake in their meal. (The ravens were happy to let him have the broccoli. Even birds have trouble eating their vegetables when told).
Our older Red-tailed Hawk, the sun-colored matriarch of our education raptor team, once caught a red squirrel that had squeezed and gnawed its way into her outdoor enclosure, for some unknowable reason. Though none of us witnessed the deed, the evidence was plain—a fluffy tail discarded in a corner, the hawk standing tall, wide of stance, hackles spread like a dazzling fan behind her head, screaming at the top of her lungs. Our younger Red-tail had a similar encounter with a frog. My colleague was trying to shoo the little pickerel frog out of the hallway in front of the birds’ enclosures, and it made the worst, last mistake of its life: jumping directly into the Red-tail’s enclosure. She caught the frog before it had hit the ground.
The Red-tails, at least, knew what they were doing. They were born in the wild and raised by Red-tailed Hawk parents that doubtless plumped them full of such delicious wild meat when they were young. Our Harris’s Hawk was raised in a different type of society, and this is reflected in his manners.
The Harris’s Hawk chases a rabbit lure. Like his wild cousins who hunt jackrabbits in the Sonoran Desert, we demonstrate for visitors his agility and strength through a lure behavior, during which he chases a “rabbit” on a rope. The rabbit holds about as much resemblance to a real bunny as a light bulb does to the sun, but the hawk has learned over the years that the brown fuzzy thing moving through the grass at speed has a big piece of meat tied to it, and therefore catching it is important.
In our New England climate, the desert-native Harris’s Hawk must be housed in a heated indoor enclosure throughout the winter, and before his current luxury suite was constructed, he wintered inside the rehabilitation clinic. A few of our other long-term residents lived in the clinic as well, including an overly friendly pigeon. Said pigeon was making her usual rounds of the clinic one day when the door to the Harris’s Hawk’s enclosure was briefly opened. To everyone’s horror, he dove out the crack and grabbed the pigeon in his talons, pinning the chunky little mass of feathers to the floor. The hawk, eager for his reward at such a marvelous catch, began turning the pigeon over, this way and that, dutifully searching for the piece of meat he knew would be tied to it.
The pigeon was ultimately released without a scratch on her.
This is not to say that we never intentionally feed live prey to our raptors, for enrichment’s sake, in a supervised and controlled setting. The thrill of the hunt is one more thing we can offer our birds who can no longer be in the wild, and even those raised by humans still have the urge to swoop and catch at a moving thing. Even if that urge gets misdirected.
One morning I found a yogurt container on my desk that had air-holes poked through the lid. There was a sticky note on it announcing this was from one of our volunteers. Peaking inside, I could see three large crickets wandering around amidst some halved blueberries, to give them a little nourishment and water while they awaited their fate. Our American Kestrel is fond of crickets. His species is consumes many insects in the wild, so I happily scooped up the container and sauntered off toward the mews to give him his bugs.
The kestrel was intrigued by the container, sidling down the perch attached to his windowsill as I set it down and pried off the lid with a pop. The crickets inside froze for a moment but began to move as soon as they felt the world settle again. Before I could straighten up, the kestrel leapt off the window perch, dove at the container, grabbed a talon-full and flipped around, zinging back to the window. Satisfied that he’d be occupied for a moment, I glanced into the container to see how many he’d grabbed. There were still three crickets.
On the windowsill, the kestrel mantled over his prize, a gesture of spread wings and tail meant to hide the treasure from competition such as myself. He was picking tiny pieces of something off with his hooked beak and discarding them on the floor. I strained to see over his shifting feathers what it was that he had.
“Are you—hey! You can’t eat blueberries!”
He turned fully away from me to better hide the berry, and continued to search for its meaty center.
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Hilarious! One has to wonder why the AMKE, having probably never ben exposed to either crickets or blueberries, chose the blueberries. Perhaps human imprinting goes deeper than I thought…?