Bird Lore: Red-naped Sapsucker

One fine spring day Joan Poor glanced into her yard and spotted an unusual Edmonds visitor, a Red-naped Sapsucker (adult female). With her April 16, 2021, sighting, Red-naped Sapsucker became the 277th species to be documented inside the city limits.

There are four sapsucker species in the contiguous U.S. Our Edmonds resident is the Red-breasted Sapsucker. Red-napeds mostly stay east of the Cascade Crest. Many that are seen in Western Washington are hybrids of these two sapsucker species. Based on photos, the recent Edmonds bird survived vetting as a pure specimen of the Red-naped species.

The Red-naped Sapsucker lives in a range that extends to Central Mexico in winter and to the lower half of British Columbia and Alberta in breeding season. The species is found throughout the Rocky Mountains and Intermountain West.

Sapsuckers are woodpeckers that drill small holes in tree bark, usually in neatly spaced rows. The holes are called sap wells and sapsuckers return to them periodically to feed on the sap as well as on insects attracted to the sap. It is thought that sap makes up about 20 per cent of their total diet. Other birds, including warblers and hummingbirds, will visit sap wells. When feeding young, the sapsucker will forage for arthropods, especially ants. Some of the insects are dipped in sap wells for added nutrition.

When the Red-naped Sapsucker arrives at its breeding area, it drills sap wells in the xylem of quaking aspen and conifers. (Xylem is tissue that transports water and mineral nutrients in vascular plants.) As temperatures increase and sap begins to flow, this bird will switch to phloem wells in aspen and willow. (Phloem is the innermost layer of tree bark that transports sugar sucrose to parts of the plant where needed.) A large amount of energy is expended to maintain sap wells so a sapsucker will defend them from other sapsuckers and other species.

Within three weeks of arrival on breeding grounds, pairs form and nest cavity excavation begins. The pair chooses its nest site based on proximity to foraging areas. It will build a nest cavity in either a dead or a live tree. It prefers trees infected with heart wood decay fungus. Heart rot begins at the base of quaking aspen and moves up the tree with each successive season. Sapsucker cavities move higher each year as the rot moves higher. The Red-naped Sapsucker nests in a variety of conifer and deciduous trees, even though it seems to prefer quaking aspen.

The male chips away at the inside of the nest cavity to create a cushion for the 3-7 eggs. Both adults have brood patches so they share incubation duties. Eggs hatch between 8-12 days. The young remain in the nest from 23-32 days. During late excavation of the nest cavity, once it is sufficiently large, the male sleeps in it, as well as during incubation and when the nestlings are under 25 days old. The female roosts on a tree trunk, typically under the base of a limb. After the young have fledged, both adults and young roost alone on tree trunks.

Woodpeckers move about with intermittent flight. The Red-naped Sapsucker shares this approach. It appears to undulate vertically through its flight path by alternately flapping and not flapping its wings. In the non-flapping phase the wings are fully flexed. It is a skilled flyer that spends a lot of time flycatching in spring. When on a tree, the sapsucker hops vertically up and down the trunk. It also hops when moving along lateral limbs and wooden fence rails.

Sapsuckers drill hundreds of tiny holes in trees and most trees survive easily, in the same way that maple trees survive being tapped for syrup. Despite their name, sapsuckers do not suck sap. They lap sap up with the tip of the tongue. Small hairlike projections on the tongue help hold the sap, similar to how a paintbrush holds paint. Abandoned nest cavities make good homes for species that also nest in holes but do not have a specialized bill to excavate their own homes. Some of these are nuthatches, chickadees, and Mountain Bluebirds. The collective noun for a group of sapsuckers is slurp.

The Red-naped Sapsucker is common throughout its range. The population has been stable over the last 50 years and has increased slightly. It has an estimated global breeding population of two million. Historically, the species was shot as an orchard pest but it is protected now.

Calls and drumming of a Red-naped Sapsucker in Chelan County can be heard here: https://www.xeno-canto.org/613143.

— By Carol Riddell

Carol Riddell manages the bird education displays, on behalf of Pilchuck Audubon Society and Edmonds Parks & Recreation, at the Olympic Beach Visitor Station.