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Zygodactyl

 

Downy woodpecker using its specially adapted feet to hang onto the tree, even upside-down. Photo by National Wildlife Photo Contest entrant William Osterloh.

By Ranger Steve Mueller

 

Red-bellied, Downy, Hairy, Pileated, and Northern Flickers are common woodpeckers present at Ody Brook and in many wooded neighborhoods throughout the area. Some are seen more frequently than others.

Downies are seen daily when visiting suet and black oil sunflower seed feeders. The males have a red spot on the back of the head, females do not, and young males have red on top of the head. Watching for color and feather patterns from the comfort of your home is easy. I combine watching with breakfast and lunch. 

Feeder watching is a casual activity. On the windowsill is a pair of binoculars within reach so I can quick get a better view. Some details are difficult to observe without aid. The white spots on black wings of the Downy and Hairy Woodpeckers helps narrow identification quickly to those two species. Body size and bill length further help distinguish the two that have nearly identical patterns. 

Somewhat hidden is black flecking on the underside of white tail feathers of Downies. The under tail feathers are pure white on the Hairy. From a top view, the tail is black on both species except for white outer tail feathers that might show black spotting on Downies but it is sometimes obscure. Binoculars help get a look at the under tail. The black flecks are a definitive identification feature. The birds are not always cooperative in how they stand on the feeders for me get the view I desire. 

Other features helpful for separating the two species is their bill and body lengths. Downies are smaller and shorter than the Hairy. Bills on Downies are less than half the length of the head. The Hairy Woodpecker bill is large and greater than half the length of the head. This feature can be difficult to assess so using the black or lack of black spotting on the under tail is more reliable. 

The Red-bellied Woodpeckers have white markings on a dark back but theirs appear more like white irregular lines running crosswise. These birds are much larger than the Downy or Hairy. Some people confuse them with Red-headed Woodpeckers that have completely redheads while the Red-bellies only have red on the back of the head in females and on the top and back of the head on males. When they fly, a muted white can be seen on the rump. 

A more obvious white rump is distinctive on the Northern Flicker. Flickers in our region are the yellow-shafted subspecies that display flashes of yellow on wing feather shafts in flight. If large trees compliment the neighborhood, you might get to enjoy the crow sized Pileated Woodpecker. It is mostly black but flashes white in flight and it stands on the sides of trees. Crows need branches for standing.

A zygodactyl toe helps all woodpeckers stand on the side of trees. It is an important nature niche adaptation. Nearly all bird species have three toes facing forward and one backwards. Woodpeckers also have three toes pointing forward but one of those is flexible enough to rotate so it can be pointed backwards. 

When toes are positioned with two forward and two backwards, it provides a better anchor for gripping the tree trunk when the birds bang their beaks against the bark. The flexible zygodactyl toe is a significant adaptation aiding woodpecker survival. 

The exceptional toe is not unique to woodpeckers. Owls have one that helps them with the capture and holding of prey. Parrots share this unique feature but we will not see those birds in this cold climate. 

Seeing the toe adaptation in action is difficult but a pair of close focusing binoculars will make it easier to observe when birds perch on the side of trees or at feeders near the window. Something special is always waiting to be discovered in the yard by those observing the wondrous creatures that abound. 

Natural history questions or topic suggestions can be directed to Ranger Steve (Mueller) at odybrook@chartermi.net – Ody Brook Nature Sanctuary, 13010 Northland Dr. Cedar Springs, MI 49319 or call 616-696-1753.

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