Why Dippers Dip

Photographs by Donald M. Jones and Lee Rentz

Why Dippers Dip

Bobbing in turbulent water helps conceal this bird from predators. 

Brought to you by BirdNote®
Published: 09/30/2013

This story comes to you through a partnership between Audubon and BirdNote, a show that airs daily on public radio stations nationwide.

Written by Bob Sundstrom

An American Dipper calls across a rushing mountain stream. Its rotund, stone-gray body bobs rhythmically up and down, its feet firmly planted. The bird’s white feathered eyelids flash like a semaphore.

So why do dippers dip?  Let’s consider three theories: One suggests the dipper’s repetitive bobbing against a background of turbulent water helps conceal the bird’s image from predators. A second asserts that dipping helps it sight prey beneath the surface of the water. A third theory holds the most promise. Dipping – as well as the rhythmic flicking of those flashy white eyelids – may be a mode of visual communication among American dippers in their very noisy environment. That dippers make exaggerated dipping movements during courtship and also to threaten aggressors lends support to this theory.

So if one day, as you muse alongside a mountain stream and an American Dipper bobs and winks in your direction, don’t take it personally. It’s probably beckoning to another dipper upstream.

The soundscape featured in today’s show was recorded by Gordon Hempton and provided courtesy of QuietPlanet.com.  We’d like to thank the Bobolink Foundation for making the show possible.

Song of the American Dipper and Riparian Zone Nature SFXs #119 and #17 recorded by Gordon Hempton of QuietPlanet.com; some stream ambient recorded by C. Peterson; Producer: John Kessler; Executive Producer: Chris Peterson

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Type: Author | From: Audubon Magazine

Comments

Can't be the first

Can't be the first suggestion; dippers are nearly invisible against their stoney gray background until they move. Quite a few bird species that frequent riverine habitats dip, bob, or waggle their tail.

You are right; none of the

You are right; none of the reasons are accurate. That was my mistake. But they do seem to be mimicking the river's edge as it bobs up and down. I have observed when a predator is near they freeze and become part of that stoney background and they appear to know the difference between a hawk and a gull. I have watched a dipper drop a freshly caught salmon fingerling and freeze as a hawk flew over head chasing a mallard. He did not move until the hawk was gone.

The first theory is the most

The first theory is the most likely. Watch the water on the rivers edge and see how the water bobs up and down.
The courtship and aggression dips are very different from the dipper's inherent dipping, they include a variety of other movements that tell the bigger story.
A dipper nestling will start to dip as soon as its legs can support it.

Perhaps mate choice based on

Perhaps mate choice based on an indicator of superior dipping to see prey combined with actual prey retrieval and visual communication? Links to the papers would be great.

Thanks, Saw these little

Thanks, Saw these little birds for the first time in late August in a walk around Moraine Lake near lake Loiuse Alberta.

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