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Do Yellow-bellied Sapsuckers Really Suck Sap?

9-12-13  yellow-bellied sapsucker tongue IMG_9715My apologies for not posting yesterday — two days without electricity or telephone!

A tell-tale sign of Yellow-bellied Sapsucker activity is the presence of rows of 1/4–inch holes, often drilled in Sugar Maples and birch trees in order to gain access to their nutritious phloem sap. Once the sap begins to flow, sapsuckers insert their tongues into these holes. Here is where their name is misleading, as sapsuckers don’t actually suck the sap, they lap it up with the aid of tiny hair-like projections on the edge of their tongue, which hold the sap by capillary action (see insert). Each flick of the tongue brings more sap into the woodpecker’s mouth.
Because sap is so essential to a tree, wounds are quickly healed over to prevent loss of sap. Scientists still have not figured out how sapsuckers overcome a tree’s defenses and maintain a continuous flow of sap. One theory is that sapsucker saliva may contain a substance that acts as an anticoagulant, preventing sap from clogging up and sealing over the holes the bird creates.

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6 responses

  1. Kathie Fiveash

    Maybe we should rename them saplappers! I have read that sapsuckers also trap insects in the sticky sap that congeals at the sapsucker’s holes when the sap bleeds out. Is this true too? If so, it’s a double whammy for the sapsucker.

    September 13, 2013 at 5:33 pm

  2. Kathie Fiveash

    P.S. That looks like a cottonwood in the picture. I have noticed sapsucker holes on lots of different tree species. They love apples.

    September 13, 2013 at 5:49 pm

    • It’s actually a willow! And yes, they do trap and eat insects in the sap, and hummingbirds also come to feed on both. All kinds of insects, including wasps, yellowjackets, butterflies, flies, ants, etc. are attracted to the sap.

      September 14, 2013 at 12:03 am

  3. So cool that their saliva might contain an “anticoagulant”. Sapsuckers are sometimes considered keystone species because, not only do other species use sapsucker nest cavities, some mammals, bird, and insects obtain sugar from sapsucker wells, and still others feed on the insects attracted to the sap wells.

    September 13, 2013 at 6:14 pm


    Yellow Bellied SapsuckerI My favoritist bird name!!! Just sort of rolls off the tongue!! XXOO me&t

    September 13, 2013 at 7:05 pm

  5. Hummingbirds will follow Sapsuckers in the spring, before the flowers are available, to sip sap from the holes they’ve made.

    September 15, 2013 at 1:03 pm

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