Bird Tongues
By Nancy Johnston
Birders quickly learn to use bird bills to help identify species. Bird tongues, if we could easily see them, would also be helpful in identifying species. This blog is to whet your tongue about bird tongues and highlight the diversity that evolution has brought to avian tongues.
First, most birds have pretty prosaic tongues. They look somewhat similar to ours but can have some interesting extra features. As shown in Figure 1, the tips can be fringed or split and the root of the tongue may have backward-facing barbs. It is not clear if the fraying or splitting helps in acquiring and eating food, but the backward-facing barbs are useful for moving food to the gullet. This is needed because birds don’t swallow the way we do. These tongues vary quite a bit in width, thickness, amount of fraying, barbs and their placement, etc. (Note: Drawings are not to scale.)
Figure 1: (A) Northern Mockingbird, (B) Say’s Phoebe, (C) American Kestrel, (D) Anna’s Hummingbird (partial), (E) Nuttall’s Woodpecker, (F) Acorn Woodpecker. Drawings by L.L. Gardner, 1925
Species such as woodpeckers and hummingbirds have more interesting tongues. Most of these birds have tongues that can extend far outside their bill (Figure 2). For these birds, the boney/cartilaginous apparatus that supports the tongue wraps around the skull under the skin, usually terminating in the right nostril (Figure 3). Extending their tongues lets hummingbirds reach into flowers for nectar or lets woodpeckers get insects from crevices in trees.
In the case of woodpeckers (Figure 4), the tip of their tongue can also be barbed or covered in sticky fluid that helps them capture insects. Sapsuckers have shorter tongues with hair-like structures for gathering sap from trees.
Figure 2: Hummingbird with tongue extended and furled together. Photo by Bob Lewis, www.wingbeats.org.Figure 3: Pictures of the tongue and the supporting apparatus (red). A: shows how the horns go around the skull and terminate in the right nostril, e.g., Northern Flicker. B: shows how the horns can go around the eye, e.g., picus. Modification of a picture from etc.usf.edu/clipart/
Figure 4: Red-bellied Woodpecker tongue tip showing the rear-facing barbs used for extracting larvae from trees. Photo by Chris Kargel, www.livingstonbirds.com/photos/red-bellied_woodpecker/
Birds that filter out food particles from mud and water have the most complicated-looking tongues. Their tongues have papillae (barb-like or hair-like structures) of various sizes and shapes that help strain out food particles.…











