Eastern Chipmunk,
Tamias striatus. The little beasts certainly deserve our thanks and appreciation. Vital cogs of the eastern deciduous forest ecosystem, "chippies" serve valuable roles in seed dispersal and as food for things with a taste for meat.
But chipmunks don't like to be eaten. And they express their displeasure with organisms who might pose them a threat loudly, and with gusto. We've all heard their scolding chitters, and most of these calls - two out of three, it turns out - are pretty intuitive. But their other oft-given sound has always puzzled me, as it is quite different than other chipmunk sounds.
Well, I learned a great thing today, courtesy of
Lang Elliott and his
excellent blog. It's Lang's incredible recording of Hermit Thrushes and companions that was the subject of the previous blog.
It turns out that Lang did extensive field studies on Eastern Chipmunks as part of his research for his masters degree. He tracked the behavior of an upstate New York population, and was able to place their vocalizations into three major categories: high-pitched chips; chip-trills; and clucks. The first two types are pretty intuitive if you've spent much time watching chipmunks. If they see a threat, such as us, they offer up a series of loud chips. Ditto the "chip-trill" calls, although Lang was able to show that one is invariably given as the animal races into a subterranean hiding spot, and now that I know that, that's been my experience, too.
It was the third call type, the "cluck", that always puzzled me. It's a conspicuous forest sound, and I've found that a surprising number of people don't associate the call with a chipmunk. With good reason - it is quite unlike their other sounds. The cluck call sounds like a drumstick being rapped against a hollow log - a deep TOCK, TOCK sound, at rather well spaced intervals.
Well, Lang's known about this since the 1970's and his field studies, and perhaps you did, too, but it's new knowledge to me. The cluck notes are the chipmunk's warning calls for AERIAL THREATS! How cool is that?! Say a Red-shouldered Hawk is perched close at hand. The observant little chippies go on high alert and start issuing hollow TOCK notes to their buddies while the raptor or owl is in the area and of potential danger.
There are three reasons that I am greatly pleased by this knowledge: One, I don't like it when I encounter something frequently and don't understand it; two, I can now share this very cool factoid when CLUCKING chipmunks are encountered; and three, we can use the chipmunks' alerts as a cue to look for nearby raptors!
Thanks, Lang, and be sure and visit his blog
RIGHT HERE and listen to chipmunk calls for yourself.