Whispering Juncos

I look forward to the juncos returning to our area each fall, and they are back now. They have been busy feeding on the ground, policing up spilled seeds from our bird feeders.

The breeding range of juncos is mainly the northern coniferous forest. Their winter range covers much of the lower 48 states, but some migrate only as far south as North Dakota. They are among handful of bird species in which North Dakota is their ultimate winter destination.

As a group of juncos search the ground for food, a person can often hear them calling softly to each other. We generally think of bird songs as being rather loud, or what communication researchers call “long-range” song. Long-range songs are often sung by males to declare their presence in defense of a territory or to attract a mate. However, some birds, including juncos, occasionally use short-range songs.

Short-ranged songs may be compared to a human whisper. Depending on the particular situation whispering in humans may be acceptable and appropriate, however, there are situations where whispering may be met with a swift and strong reaction from others. The situation appears to be somewhat similar in junco communication. For example, during the mating season, male juncos use short-ranged songs to court females. But if another bird eavesdrops or overhears those short-range songs, things can get interesting.

We have a little better understanding of these short-range songs in juncos thanks to some research conducted by biologists from Indiana University and Stetson University. Their research was recently published in the American Naturalist.

Males of many bird species occasionally court mated females, and sometimes they are successful. That is true of juncos as well. The researchers discovered that particularly during the mating season when females were fertile, a mated male junco largely ignored the long-range call of another male. However, if the mated male heard the whisper or short-range call of another male, he responded quickly and aggressively to find and confront the whispering male.

“If you are going to come sneaking into my territory and whisper sweet nothings at my mate, you better not let me hear you!”

Chuck Lura

Natural North Dakota is supported by NDSU Central Grasslands Research Extension Center and Minot State University-Bottineau, and by the members of Prairie Public. Thanks to Sunny 101.9 in Bottineau for their recording services.