The Curious Case of the Hare-Goosing Magpie

Black-billed Magpie (not the individual I saw); photo by naql via Flickr CC BY 2.0.

On a recent sunny September morning, I witnessed an extraordinary wildlife encounter in my own Alberta, Canada backyard:

A bird was cagily chasing a foraging hare, repeatedly attempting to pluck its fluffy white tail. The hare, meanwhile, repeatedly repositioned its backside away from the bird, and occasionally leapt into the air in a move I can only imagine was meant to say, "Knock it off!"

Here are just 18 seconds of the wild interaction, which lasted at least five minutes:

The bird in question was a Black-billed Magpie, a species of the corvid family, which includes crows, ravens, and jays and is particularly noted for its intelligence and problem-solving skills.

The hare, meanwhile, was a white-tailed jackrabbit, the largest of Alberta’s three native hare and rabbit species (the other two being the snowshoe hare and the mountain cottontail).

I have been charmed by the magpies––their dapper colors, boldness, and inquisitive nature––since my arrival to Western Canada, although my Canadian husband and all of his friends and relations are dismayed by my affinity for them, calling them regularly and with disdain: “jerk birds.”

Why would a magpie goose a jackrabbit?

Was the magpie simply being a jerk, I wondered? But, if so, it must have some reason?

Determined to find an answer, I consulted the authoritative compendium of all things avian, Birds of the World, and two researchers of my acquaintance who published a study in 2021 called “What the pluck? The theft of mammal hair by birds is an overlooked but common behavior with fitness implications.”

These expert sources helped me sort the evidence for three possible explanations of what I had seen:
A) The magpie wanted some of the hare’s hair to use.
B) The magpie was playing a game to sharpen its foraging skills.
C) The magpie was just having fun at the jackrabbit’s expense.

Explanation A: To Steal Hare Hair and Use It

Many birds line their nests with insulating mammal fur, and one way that they get it is to go directly to the source. In their 2021 study, published in the scientific journal Ecology, Dr. Henry Pollock, Zak Sutton, and their co-authors coined the term “kleptotrichy”––the theft of hair from a live mammal––to describe a behaviour that, they discovered, was widely known on YouTube and popular media but rarely documented by western science.

Their investigation was prompted by witnessing a Tufted Titmouse gradually approach and then industriously pluck the fur from a sleeping raccoon during a bird survey in Illinois. After searching both scientific and popular sources, they found that just 11 instances of fur theft by only six bird species had been recorded in the scientific literature.

(Notably, several more scientific studies documenting kleptotrichy have been published since Pollock et al.’s paper, a hopeful sign that the literature will one day perhaps accurately reflect how common the behaviour truly is.)

When I emailed Pollock about the magpie-jackrabbit encounter I’d witnessed, he confirmed that it had never been recorded before. “This is definitely a previously undocumented case of kleptotrichy,” he wrote, “100%!” And Sutton agreed.

As I wrote to Pollock and Sutton, however, the theft didn’t quite mesh with the standard explanation for why birds tend to steal fur, that is, to insulate their nests. 

The encounter I witnessed happened in September, well past the magpies’ nesting season. Perhaps the magpie wanted the fur to line a winter roost, Pollock agreed, although Birds of the World claims to have no clear evidence that magpies roost in old nests in the nonbreeding season.

Interestingly, Pollock and his research team also noted that in the majority of bird-mammal encounters they surveyed in their study, the target mammal did not respond to the theft at all. Instead, birds were usually able to gather fur for their use without retaliation. To say that the magpie was antagonistic to the jackrabbit...and the jackrabbit was not pleased about it...would be an understatement. (Feel free to replay the video again to see if you agree.)

Explanation B: To Practice War Games

Unconvinced that the magpie was simply gathering fur for a cozy roosting site––given that magpies aren’t known for winter nest roosting, and I did not see the bird make off with any furry prize––I sought further evidence for justifying its behaviour.

As I’ve mentioned, Black-billed Magpies have a reputation among their human neighbours for being cheeky to the point of annoyance. Evidently, they may have a reputation among their fellow non-human animals too.

According to Birds of the World, Black-billed Magpies have been documented “tweaking” the tails of predators, including coyotes, red foxes, and Bald Eagles, to distract them long enough to steal their food. While out for a walk in the woods one winter, I personally saw a magpie harass a coyote.

The hapless hare, I realized, may have been an unwilling participant in a game meant to prepare the bird for assaulting larger, more dangerous targets. Goosing a sizable, harmless jackrabbit would likely be apt practice for targeting more threatening animals in future.

Explanation C: Magpies Just Want to Have Fun

Play is common among clever birds like corvids, for reasons that apparently include just having fun.

Birds of the World specifically reports “play behavior” among young Black-billed Magpies, which have been seen “pulling tails” of Cooper’s Hawk and Northern Goshawk...with no food at stake.

“Maybe as you said,” wrote Pollock, the magpie went after the jackrabbit “because they are just very smart and cheeky birds.”

My Guess: A Combo

Although only the magpie knows for sure why it did what it did (and I can only imagine what the jackrabbit thought about it!), I suspect its main motivation for kleptotrichy was not to collect fur for its own use; if it was, it did not do a very good job––I did not see the bird make off with any appreciable tufts.

Instead, my guess is that this particular encounter was the act of a thrill-seeking bird amusing itself, perhaps while also practicing its predator-teasing moves.

As the video shows, the magpie repeatedly snuck up on the hare for a daring pluck and darted away each time the hare got wise. That tells me that I was perhaps privileged to witness just one scene in the training montage of a coyote-goosing bird in the making.

“In any case,” said Pollock, the footage demonstrates that there is “so much more to learn about this behavior!”