The World of Woodpeckers, part 1

Woodpeckers are one of the most well-known bird species even for casual bird-watchers, perhaps because we hear them during our (and their) daily lives even if we don’t see them.  Because most woodpecker species are also pretty fearless around humans, they are some of the easiest birds to attract to a backyard suet feeder, where it’s fun to observe them in action.   The area around Arivaca is frequently visited by many different woodpecker species, and this fall and winter we’ve had Ladder-back Woodpeckers, Red-naped Sapsuckers, Gilded Flickers, Red-shafted and Yellow-shafted Northern Flickers visiting our birdbaths and feeders, along with our ever-present Gila Woodpeckers.  Besides being beautiful to watch and listen to, woodpeckers have an amazing and interesting set of “super powers”!

 

Woodpecker "shock absorbers"

Have you ever wondered how their brain can survive all that hammering against tree trucks and other objects without getting a migraine?  Their extra-thick skull bones, special tissues in their facial structure, and powerful neck muscles work together as a built-in shock absorber, to enable them to hammer away without damaging their brain or other organs. 

 

 

 

Have you ever wondered how their bills can survive all that hammering too? The chisel-like shape and stoutness of their bills allows them to bore into almost any kind of wood, but they are especially attracted to soft, decaying tree trunks that insects have made a home in, and that is easy to drill into.  They're pretty smart about it too!  The video below shows a Northern Flicker drilling out the knot hole in the front of a plywood Barn Owl nestbox, which I am quite sure any Barn Owl would not approve of...

Their strong bill also enables them to do some pretty loud drumming too.  Many scientists believe that since they don’t have a song to sing, drumming on a surface that resonates well, such as a dying tree, stop sign, chimney, metal flashing, etc. may be their best way to establish their territory and/or attract a mate.  In urban areas where houses are close together, drumming on wood siding can produce a “loudspeaker” effect, with the nearby house amplifying the sound to carry for blocks.  Drumming done on the top of your metal chimney can send sound down into your woodstove or fireplace, and make it sound like a steel drum band has started up! Frequently, woodpeckers will experiment with multiple places on a house, telephone pole, etc. to find the best drumming location before they choose the one that carries sound the farthest.  One Northern Flicker in Wyoming could be heard drumming on an abandoned tractor from a half-mile away!  Click on this link to see and hear a Northern Flicker drumming on a highway guardrail

Female Gilded Flicker

Sometimes woodpeckers will drill a nest hole in the side of a house if there are no suitable trees in the area, but unless the exterior walls of your home are infested with carpenter ants or carpenter bees, woodpeckers are not actually trying to drill for food there.  Knowing that their drumming is not intended to puncture your home is small comfort though if you’re trying to sleep in during mating season...

 

Two other remarkable adaptations that woodpeckers have to keep the wood dust they make from causing problems for them is a translucent eyelid called a nictating membrane that they can draw over their eyeballs yet still see, and bristly feathers located around their nostrils like a filter.  

Have you ever wondered how they get those insects out of the holes they drill?  This one is kind of freaky:  Many woodpeckers have a spear-like tongue that is covered with barbs so they can stab their insect prey and easily bring it back into their bill.  Yowza! 

Female Pileated Woodpecker

The barbs and other features on a woodpecker's tongue vary according to their diet and the way they forage for food.  Woodpeckers such as the Pileated Woodpecker, that can chop their way deeply into wood, have shorter tongues with spear-like tips bearing backward-facing barbs.  Those barbs grab insects and grubs the way roses snag into your skin while you're trying to prune them.   Ouch!

 

 

Male Downy Woodpecker

 

 

 

 

 

 

 

Species that feed from crevices and surfaces of trees, such as the Downy Woodpecker, usually have longer tongues with bristles concentrated at the tip to "sweep" insects into their bill.

 

Sapsuckers create their own "tree farms" by drilling tidy rows of holes on multiple tree trunks and then checking them daily for sap oozing out of the holes.  They have brush-like tongues that can sip that tree sap by capillary action, and function much like a paintbrush holds paint!   There's no need to panic though, if a sapsucker is creating its "tree farm" on your property, as most trees survive this shallow intrusion similar to the way that maple trees survive humans tapping them for maple syrup.

 

Though they can climb up tree trunks and hammer away like other woodpeckers, Northern Flickers prefer to forage on the ground for their favorite food: ants.  They use their strong bill to dig into the dirt, and their long barbed tongue with a flattened tip makes it easy to lap up the ants even as they try to flee down into their underground chambers.  Flickers have also been seen drilling into cow patties to eat the insects living inside.  Yum...?   In urban areas, they find oodles of food by drilling out the soft expansion joints between sections of concrete sidewalk, where ants frequently create the entrance to their colony.  Smart birds indeed.

 

How a woodpecker's tongue is attached to their skull

AND the reason that many woodpecker species can extend their tongue deep into the wood or ground is because they have a groove in their head between the skull and skin, so that their long tongue can curl around the back of their head and be stored in that groove when not in use.  For example, Red-bellied woodpeckers have a tongue extending up to three times the length of their bill.  Holy cow!

 

 

 

 

 

AND there's more!

Have you ever wondered how a woodpecker's feet can manage to hang on to a tree trunk at the same time that it's bill is hammering away?  Their toes and tail feathers combine to make this an easy feat for them. 

 

Unlike most songbirds, who have three forward-facing toes and one backward-facing toe, most woodpeckers have two toes facing forward and two facing back, which is called a "zygodactyl" foot.  Because their first and fourth toes are the ones facing back and their second and third face forward, their feet are most excellent for grasping the limbs and trunks of trees.  In addition, their claws, feet, and short legs are very strong, allowing them to easily hop up and around tree trunks and limbs all day long. 

Woodpecker tail feathers are different than most other birds also.  They are especially-stiff because of their cross-sectional geometry, with sharply pointed tips, which makes them function as a prop against the force of their bill hammering away at the trees.

The video below illustrates the way that this "super-grip" enables them to also preen and groom their feathers while clinging to a tree trunk, and can even hold on with one foot while scratching an itch!

 

 

Male Yellow Shafted or "Taiga" Flicker

 

Next month's blog will feature amazing facts about woodpecker nesting behavior, nest construction, and more!

 

For more information about the world of woodpeckers, I encourage you to visit  Cornell University's wonderful ornithology website: www.allaboutbirds.org

Photo and video credits:

• Ladder-backed Woodpecker photo by Emily Bishton
• Woodpecker "shock absorber" drawing by Lizzie Harper
  
• Northern Flicker at Barn Owl nestbox video by William W. 
• Female Gilded Flicker photo by Emily Bishton
  
• Female Pileated Woodpecker by Shenandoah National Park. Creative Commons Attribution 2.0 Generic license
  
• Male Downy Woodpecker by WolfgangWander, GNU Free Documentation License
• Woodpecker tongue drawing by Tailandfur.com
  
• Male Yellow-shafted Flicker video by Emily Bishton