Last week, I watched as a sharp-shinned hawk made his daily foray through my yard, trying to nab one of the birds visiting my feeders. The birds dashed for cover and the hawk missed his target and alighted on the fence to plot his next move. Meanwhile, 3 black-capped chickadees that had reached safety in the branchy crown of the willow began a furious chorus of their characteristic “chicka-dee” call. But why were these tiny birds drawing attention to themselves while a deadly predator sat less than ten feet away? If you learn to speak a few words of “Chickadese,” you might be surprised at how much they were saying.
When we think about bird sounds we usually think about their songs. But birds make different sounds for different reasons, and in some cases, ornithologists have figured what these sounds mean. Songs are a vocalization that birds make when trying to attract a mate, or tell neighbors that this is their territory and “get off my lawn!” When chickadees sing it sounds like a clear whistled “fee-bee” or “fee- bee- bee.”
Chickadees also make what is described as a “gargle” call, but to me sounds like a super-speeded up recording of someone talking. This call is used in aggressive encounters between chickadees and seems to mean something like “get out of my space bozo!” The gargle call is apparently also used frequently between members of a mated pair—I am not sure what this says about the state of chickadee marital relationships.
When danger is near, say a predator is on the attack, chickadees will make a high pitched “seee” alarm call. High pitched, “thin” sounds like the “seee” call are harder to localize- many species of birds use similar sounds as alarm calls. Ornithologists believe these types of calls allow birds to warn others without giving away their location to the predator.
The “chicka-dee” call is used in multiple situations, but it is frequently used as a “mobbing call.” Birds use mobbing calls when they want to attract attention to a predator. Most predators need the element of surprise. If the prey spots the predator before the attack, the predator usually gives up and moves on. When chickadees are mobbing a predator, their chickadee call is essentially saying “Hey guys! There’s a hawk over here! Let’s go yell at him so he knows we see him!”
About a decade ago, ornithologists at the University of Montana noticed that sometimes the “chicka-dee” call has just a couple “dee” notes at the end: “chicka-dee-dee,” and sometimes it has more: “chicka-dee-dee-dee-dee-dee.” They presented chickadees with a variety of different predators and discovered that the number of “dee” notes in the call corresponded to the level of threat the predator posed. So if chickadees were mobbing a great horned owl, the calls would have fewer “dee” notes, i.e. “chicka-dee-dee” because great horned owls hunt small to medium sized mammals, rarely chickadees. Whereas if the chickadees were presented with a perched merlin, a falcon that specializes on small birds, they would add lots of “dee” notes: “chicka-dee-dee-dee-dee-dee.” Chickadees that heard mobbing calls with more “dee” notes responded with more intensity.
When the chickadees in my yard started calling in response to the sharp-shinned hawk, I started counting. Sure enough, their calls had 4-5 “dee” notes, very similar to what the ornithologists recorded in response to high threat predators. A sharp-shinned hawk is definitely a big threat to a chickadee, if he can catch the bird unaware. But these bold little chickadees were having none of that. They agitatedly hopped about in the willow tree, “chicka-dee-dee-dee-deeing” with all their might. “We see you! We see you, you dangerous hawk! Now scram! You can’t surprise us!” I swear if chickadees could hold flaming torches, they would have been waving them at the hawk, they were such an angry mob. And after a few minutes of this, the hawk seemed to shrug his shoulders and then flew off to hunt somewhere else.
This post originally appeared in the March 15 issue of the Grand Junction Daily Sentinel. You can read the original research paper on chickadee alarm calls here: https://hocking.biology.ualberta.ca/courses/zool407/uploads/winter07/lecture/Templeton%20et%20al2005.pdf