About Woodpeckers, Flickers, and Sapsuckers
Birds That Climb Tree Trunks, Hammer on Wood, and Eat Insects
Jun 24, 2009
Woodpeckers inhabit wooded ecosystems in North and South America, Europe, Africa, and Asia. There are 218 species. A solitary bird moving up a vertical trunk with its tail pressed against the bark and its beak busy pecking at the wood is probably a woodpecker.
Physical Characteristics of Woodpeckers
Though there are exceptions to every rule, the woodpecker family shares many common physical characteristics:
- Woodpeckers usually have four-toed feet with two toes pointing forward and two pointing back, or slightly sideways. Their feet enable them to cling to vertical tree trunks of various sizes.
- Their tail feathers are wedge shaped and have very strong shafts. When pressed against the tree, the tail holds the woodpecker’s body away from the trunk and provides support.
- Woodpecker beaks, designed to pry, chisel, or excavate wood, are stout and strong.
- A barbed or brushy end makes their extraordinarily long tongues efficient at snagging and spearing insects and their larvae, and licking up sweet tree sap.
Feeding Behavior of Woodpeckers
All woodpeckers eat insects, but their preferences in this and other food influence where they’re likely to be seen:
- Woodpeckers (those with woodpecker in their common names) exhibit the familiar foraging habit on tree trunks. They probe, pry off bark, or open large cavities in search of arthropods (insects, spiders, and their young). Most carry food to young in the nest with the beak.
- Flickers eat many ants and are often seen foraging on the ground. They probe ant nests and stick their long tongues down to catch ants inside. These birds, along with the larger woodpeckers, regurgitate food for young.
- Sapsuckers eat insects as well, but they are best known for digging little wells in tree bark in search of sap. They carve a series of wells horizontally till they find sap, then work their way down to follow it. A thoroughly excavated trunk can look like a mosaic of little wells.
Woodpeckers also eat nuts, berries, seeds, fruit, even bird nestlings.
Woodpecker Nesting
Woodpeckers are cavity nesters, often returning repeatedly to the same tree cavity but also capable of excavating a new nest site (usually in a dead tree) should the old one be destroyed or occupied. They spend a week and a half to a month at the job, depending on the species, and leave a carpet of chips in the bottom for eggs and nestlings to rest on. During the breeding season, woodpeckers also drum on trees with their beaks to declare territory and find mates:
- The female lays one egg a day, with the nest being continuously guarded thereafter until the fledglings leave.
- The male and female take turns guarding the eggs and, later, feeding the young. The male spends the night in the nest. (In some species, the female does also.)
- Fledglings are able to cling to trees and fly when they leave the nest after two and a half weeks to a month, but the parents continue to look after them for up to two months, and in some species even longer.
Do Woodpeckers Migrate?
Most woodpecker species don’t migrate, but a few do, particularly those whose preferred food supply becomes unavailable in the winter. Ground foraging Northern Flickers, which need a snow free landscape, and Yellow-bellied and Red-naped Sapsuckers all migrate to the southern United States or farther.
Some woodpecker species, such as Lewis’ Woodpecker move to lower elevations during the colder months, though this may simply be young birds dispersing.
A few species, such as the Great Spotted Woodpecker of Europe and Asia, and the Three-toed Woodpecker of North America irrupt outside their ranges periodically.
Woodpecker Oddities
A few woodpeckers are odd enough to stand out from the rest:
- The Ivory-billed Woodpecker of the Southern United States was believed extinct until a possible sighting in Arkansas in 2004. Five years later, people were still waiting for a verifiable repeat sighting there, or anywhere else.
- The Acorn Woodpecker lives in groups of up to fifteen individuals and drills small holes in the sides of trees to store acorns. Tens of thousands of acorns may stud the side of a single tree.
- Piculets resemble other woodpeckers in many ways, but they are small, their movements in trees are not so characteristic, and they lack the stiff reinforced tail feathers.
- Wrynecks get their name from the interesting habit of defending the nest by making snake-like movements of the head and neck, and hissing.
Sources:
Atlas of Bird Migration. Elphick, Jonathan ed. Buffalo: Firefly Books, 2007.
Firefly Encyclopedia of Birds. Perrins, Christopher ed. Buffalo: Firefly Books, 2003
Smithsonian Field Guide to the Birds of North America Floyd, Ted. New York: HarperCollins; 2008.
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