How do woodpeckers avoid concussion?

Greater Spotted Woodpecker on tree trunk

The unmistakeable drumming of woodpeckers in the woodland has been our sound track this week whilst we have been walking our fields. The recognisable, rapid tapping at frequencies up to 40 hits per second on a hollow trunk resonates far, announcing  territory, attracting mates and communicating with others.

There are over 180 species of woodpeckers living throughout the world. We recognise them for their classic upright drumming and pecking behaviour and many of us have grown up with famous woodpeckers,  ‘woody’ the woodpecker and  Professor Yaffle ( Augustus Barclay Yaffle) from Bagpuss.

Woodpeckers are part of the Picidae family. They live in and are adapted to a wide range of habitats including forest, urban and even deserts. Woodpeckers are not found in Australia, New Zealand, Madagascar or Antarctica. Many of us will have been lucky enough to see woodpeckers in the UK. The Greater Spotted Woodpecker can be seen visiting garden bird  feeders for suet, peanuts, sunflower seeds or peanut butter.

Let’s have a look at what makes these birds so individual and recognisable in the bird world. Read on to find out about their special adaptations. Some of which enable them to peck up to 10,000 times a day, experiencing up to 1200-1400 times the force of gravity with each peck, without themselves sustaining any damage. A blow 60-100 times the force of gravity would give us humans a concussion.

Shock Absorbing Adaptations

woodpecker on tree trunk

Woodpeckers can strike with at least 1000 times the force of gravity (1000 G’s), and the Great Spotted Woodpecker in the UK can beat their beaks up to 40 times per second when drumming. 

Why do these birds not get headaches or damage their heads?

Woodpeckers obviously have some shock absorbing adaptations worth a mention!

  • A chisel like beak that is hard but slightly elastic self sharpens with repeated tapping rather than stopping suddenly on impact. 
  • Strong neck muscles are larger than other birds and support, absorb and divert shock. 
  • A tighter fit of the brain inside the skull, with less cushioning fluid than other birds, this actually reduces brain movement on impact, preventing what is called ‘contre-coup’ or brain injury injury, where the head suddenly stops moving but the brain continues inside the skull.
  • The skull bone structure is modified to allow absorption of impacts.
  •  The design and proportions of the beak means concussive forces are directed through the lower beak away from the brain.
  • They always strike in an absolute straight line, minimising rotational twisting forces that can damage the brain. 

The combined result of a woodpeckers adaptations means that 99.7% of energy is redirected away from the head and is subsequently redirected to the body mass of the bird avoiding brain injury.

Zygodactyl Feet

Woodpecker close up on feet

Image by; Brucejastrow, Upsplash

The 2nd and 4th toes of each foot are directed backwards and the 3rd and 4th toes remain pointing forwards. This arrangement ( known as zygodactyl) gives woodpeckers a strong grip on trees, poles and posts. A strong stiff tail in combination with these feet that also have thicker talons than other bird species means they can brace against trees as they climb and peck, with an exceptional grip. This stable tripod brace also allows shocks absorption from pecking.

 

Why do woodpeckers drum?

Woodpeckers drumming is a elaborate display to announce territory, attract mates and generally communicate with each other. 

They will seek out a particular type of wood that loudly resonates to carry the sound far. Some will even drum on other resonant object such as metal rooves and bins.  

Other woodpecker adaptations;

Long barbed tongue with sticky saliva

Red bellied woodpecker with tongue out

Red Bellied Woodpecker Photo by Mark Olsen on Unsplash

Woodpeckers tongues can be up to 4″ long, depending upon the species. Although these birds eat nuts, fruit and sap their tongues are fantastically adapted to reach into tiny crevices in search of insects and spiders. Often equipped with backward facing barbs near the tip the tongue can be used as a spear to impale grubs, or even as a rake to catch and extract insects from holes. Some can lick up sap and even sip from nectar feeders designed for hummingbirds. Sapsuckers have the most unusual of the woodpecker tongues, short and bristled, sap can be pulled up via capillary action.

Sticky saliva enhances a woodpeckers ability to grab and retrieve grubs efficiently.

In all vertebrates the tongue is supported by bone and cartilage known as the hyoid apparatus. In  woodpeckers the hyoid apparatus is much longer and wraps around the back of the skull , allowing storage of a tongue that may be many times the length of the birds beak

Excellent hearing

Lesser Spotted Woodpecker Photo by Eliobed Suarez on Unsplash

Woodpeckers listen for their food. They can here insects and bugs moving inside a tree trunk or underneath the bark. Once located they will chisel away at the wood and use their tongue and or beak to retrieve a tasty morsel.

Working together and Storing food

From bapreston, Pixabay

Acorn Woodpecker and a ‘Granary’ Tree trunk pepper potted with holes filled with acorns.

Some woodpeckers will store their food in trees. The Acorn Woodpecker lives in complicated groups and each bird spends most of its time storing acorns into a single tree with many many hoes drilled into it, known as a granary tree. Some of these trees may have up to 50,000 holes in it each containing an acorn for the winter. They work as family groups to store food and also to raise families. The young woodpeckers will stay on for a few years and help raise the next generations of young with their parents. 

Plumage

The most common plumage colours for all woodpeckers are black, white, reds and yellow. Brighter colours are often in flashy patches. Birds that live in tropical regions tend to have more of the brighter colours as the habit here has brighter and more colourful flowers and pants.

UK Woodpeckers to look out for

We are lucky to have woodpeckers in the UK. 

Our largest is the Green Woodpecker, who hunts out ant colonies to dig into and raid. They therefore spend some of their time on the ground. They can be seen in parks and on lawns. 

Green woodpecker on lawn

Green Woodpecker Photo by Regine Tholen on Unsplash 

The Great Spotted Woodpecker can be seen clinging to trees, trunks and branches. They favour areas with mature trees. They will readily visit gardens for sunflower seeds, peanuts, peanut butter and suet.

Greater Spotted Woodpecker on tree trunk

Greater Spotted  Woodpecker Photo by Gerhard G. Pixabay

The Lesser Spotted Woodpecker is the smallest and least common of our woodpeckers. It has a creeping nature along branches and a fluttering flight pattern. 

Lesser Spotted Woodpecker

Lesser Spotted  Woodpecker Photo by Lobos Houska Pixabay.

How to attract woodpeckers to your garden.

Young femaale woodpecker feeding from suet blocks

Woodpeckers, particularly Greater Spotted Woodpeckers will readily visit garden bird feeders. They will happily tuck into peanutssuet and sunflower hearts.

If you have any dead trees in your garden, leave them standing as the bugs and grubs inside will attract them even more. 

Minimise the use of insecticides in the garden, to help ensure an ongoing food supply.

Unfortunately larger woodpeckers have been known to attack chicks and eggs inside wooden nest boxes. If you have found this to be a problem, fitting a metal ring around the entrance or choosing  woodcrete nest box should solve the problem

Woodpeckers will also bring their young to feed at bird feeders in the spring/summer months.

 

We would love to see your Woodpecker photos on facebook!