Zygodactyl Toe Arrangement
Most birds have four toes, three pointing forward and one back. A quick look in the snow beneath your bird feeder will confirm this. Exceptions to this rule include woodpeckers, owls and ospreys, among others, whose toe arrangement is 2 and 2: two of their toes (the middle two) point forward, and the outer toes point backwards. The term for this arrangement is zygodactyl.
Different species have evolved this toe arrangement to meet different needs. It enhances the ability of woodpeckers to hold onto limbs and climb up vertical tree trunks, while owls and ospreys can get a better grasp of slippery or wiggly prey. (Woodpeckers can pivot one of their back toes to the side, and owls can pivot one of their back toes forward, as well.)
Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.
Pileated Woodpecker’s Winter (and early spring) Diet
The mainstay (up to 60%) of a Pileated Woodpecker’s diet is Carpenter Ants (especially in the winter) with wood-boring beetle larvae (early spring) not far behind. Flies, caterpillars, grasshoppers, termites, cockroaches and a variety of other insects are also consumed in summer. However, these woodpeckers are not strictly insectivores. During the fall and winter they seek out fruit (and nuts), including the fruit of Wild Grape, Virginia Creeper, Poison Ivy, Poison Sumac, American Holly, Elderberry, Blackberry, Raspberry, Hackberry and Crab Apple (pictured). Roughly one-quarter of a Pileated Woodpecker’s diet may be fruits and nuts. (Thanks to Sadie Brown for photo op.)
Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.
Pileated Woodpeckers Fledging
When your children start to get this feisty, it’s time for them to leave the nest!
Between three and a half and four weeks of age, Pileated Woodpecker nestlings fledge. Their flight feathers are about 75% of adult size when they depart. Some fledglings are capable of sustained flight when they leave the nest, while others may need several days before they can fly any distance.
Initially parents and siblings stay in the vicinity of the nest, but once the young can fly well, they follow adults everywhere. All the young may stay with both parents, or the parents may split up and each take some of the young. The fledglings will remain with their parents into September. (Photo: male Pileated Woodpecker nestling about to fledge while his father watches.) Much gratitude to Amber Jones and Dave Bliven for sharing their deck, their sweet dog Briggs and their magnificent view of this Pileated Woodpecker family with me.
Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.
Pileated Woodpecker Parents Removing Fecal Sacs
Young birds defecate in little packages called fecal sacs. These structures serve several purposes, one being that having waste contained in a sac keeps the nest relatively clean. Often parents consume these sacs when their nestlings are small (when young the birds don’t completely digest the food they eat and fecal sacs may provide parents with a nutritional snack), but eventually the adults usually retrieve them and fly away from the nest before dropping them. (The young of some species of birds in open nests perch on the rim of the nest and defecate.) Two to five days before fledging, Pileated Woodpeckers stop removing their offsprings’ fecal sacs (perhaps as an incentive to depart the nest?).
Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.
Pileated Woodpecker Parents Regurgitating
Nestling meals consist primarily of invertebrates. Adult Pileated Woodpeckers feed their young by regurgitation, inserting their bill quite far into the throats of their young as they deliver food to them. A visit can consist of one to three regurgitations per nestling. (Photo: adult male Pileated Woodpecker feeding male nestling)
Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.
Pileated Woodpeckers Raising Young
Once their eggs (usually 3-5) hatch, Pileated Woodpeckers, like all parents, are kept busy providing their young with food. The nestlings are fed about every hour when small, but this stretches to every two hours after the nestlings are about a week old.
At first the adults enter the cavity to feed their young and only the tips of the parents’ tails are visible. Eventually the young manage to reach the cavity opening and can be seen at the entrance to the nest hole, waiting for food to be delivered. As they age, the nestlings find their voice when hungry and the woods reverberate with their distinctive and very adult-like call (https://www.allaboutbirds.org/guide/Pileated_Woodpecker/sounds). (Photo: female adult Pileated Woodpecker and male nestling)
Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.
Changing of the Guard: Pileated Woodpecker Parents Share Parenting Duties
Recently I had the opportunity to observe nesting Pileated Woodpeckers, and I thought I would devote this week’s Naturally Curious posts to different aspects of my observations. I would like to thank Amber Jones and Dave Bliven for generously sharing their Picidae residents with me.
From start to finish, both Pileated Woodpecker parents are involved in raising their young and all that it entails. Together they excavate a nest cavity, usually in a dead or dying tree. Both have brood patches (areas on their undersides that lack feathers and are well supplied with blood vessels, allowing efficient transfer of body heat to eggs), and both incubate the eggs during the day (the male has night duty). The parents take turns brooding the nestlings and providing them with food. And finally, once fledging take place, both parents provide and help their young find food for several months. (Photo: male Pileated Woodpecker in nest cavity; female Pileated Woodpecker on nesting tree)
Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.
Pileated Woodpeckers Foraging For Last of Wild Grapes
Carpenter Ants and wood-boring beetle larvae are the mainstay of the Pileated Woodpecker’s diet. Long slivers of wood in trees and logs are removed in order to expose ant galleries, creating large rectangular excavations. The woodpecker’s long, pointed, barbed tongue and its sticky saliva enable it to catch and extract ants from the ants’ tunnels.
While ants and beetle larvae are consumed year-round, fruits and nuts are eaten when available. A study that took place in the Northeast found seasonal shifts in primary food items: fruit in fall, Carpenter Ants in winter, wood-boring beetle larvae in early spring, and a variety of insects in summer.
Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.
Pileated Woodpecker Droppings
Pileated Woodpeckers usually defecate frequently during the day at their foraging sites. As they pry off long slivers of wood to expose carpenter ant galleries, the wood chips pile up on the ground. A substantial pile usually indicates that the woodpecker has been working long enough at this site for there to be some droppings in the pile.
Pileated Woodpeckers eat ants, primarily carpenter, and beetle larvae throughout the year. Fruit and nuts are eaten when available. The primary food shifts seasonally, with fruit mainly in the fall, carpenter ants in the winter, wood-boring beetle larvae in early spring, and a variety of insects in the summer.
Like humans, birds excrete metabolic waste products, mainly nitrogen, which remains after food is broken down. Humans excrete waste nitrogen as urea in urine, which is diluted with water. Birds, needing to be as light as possible for efficient flight, do not have heavy, water-filled bladders. They excrete nitrogen as a chemical called uric acid in a concentrated form with no dilution necessary. The white outer coating of bird droppings is uric acid. The insides of the droppings are the actual feces, or the indigestible parts of a bird’s diet. A Pileated Woodpecker’s droppings at this time of year consist of bits of carpenter ant exoskeletons and a surprisingly small amount of wood fiber (see insert). Birds simultaneously evacuate uric acid and feces from an opening just under the tail called the cloaca or vent.
Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.
Pileated Woodpecker Feeding Hole Embellishment
Large rectangular excavations in trees, indicating Pileated Woodpecker feeding activity, are relatively common. These holes give the woodpecker access to carpenter ants living in galleries within the tree. What are not common are the horizontal lines radiating out from either side of the top rectangular Pileated Woodpecker feeding hole (and, more subtly, the bottom two holes) in the pictured tree.
Pileated Woodpeckers use methods other than drilling rectangular holes to locate insects – they glean branches, trunks and logs, peck bark and scale bark off of trees. But these lines are unusual, to say the least. If anyone is familiar with this pattern, and would care to explain the function of these horizontal lines, it would be greatly appreciated. After racking my brain and checking several resources, I cannot come up with a plausible explanation, though inevitably there has to be one, for no pileated woodpecker, or any other creature, is about to waste precious energy, especially in a winter as cold as this one. (Thanks to photographer, naturalist and keen-eyed John Snell (http://stilllearningtosee.com/about/) for finding and sharing this discovery with Naturally Curious.)
Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.
Naturally Curious with Mary Holland 
What Other Naturally Curious People Are Saying