Bird of the Month: Red-breasted Sapsucker
Written by Andy McCormick
Andy McCormick, Volunteer and Former Board President of Eastside Audubon
Specialized for sipping sap, the Red-breasted Sapsucker is a year-round resident of the Pacific slope.
“The sapsuckers are specialized for sipping sap; their tongues are shorter and less extensible than those of other woodpeckers and tipped with stiff hairs to allow sap to adhere” (Walters, et al). A tree’s phoelm sap (sap that contains sugars) is a vital resource for both amino acids and sugar. The Red-breasted Sapsucker accesses this sap by making shallow holes in the bark of a tree and revisits the sap well over several days. In addition to taking sap the birds glean insects which are attracted to the well. Adult sapsuckers will dip insects in sap before feeding nestlings. Other animal and bird species imbibe the sap and Rufous Hummingbirds for one are known to sip from the wells and will follow sapsuckers through the day (Walters, et al).
UNIQUE FEEDING SKILLS
Birders are familiar with the organized pattern of sap wells on tree bark as evidence that sapsuckers have made holes on the tree. Eberhardt (2000) studied the evenly-spaced pattern of sap wells of Yellow-bellied Sapsuckers in Michigan and found that the downward flow of sap will be blocked by scars resulting from the holes. A typical sap well fill flow for about three days and sapsuckers will continue to make holes sequentially directly above previous holes to tap into the accumulated sap above the older hole.
Eberhardt also found that sapsuckers preferred older trees at the beginning stage of senescence. As trees age and parts begin to die, the sap is likely to be richer in the reabsorbed amino acids providing more balanced nutrition for the bird than sap from healthy trees. This study also indicated that the presence of good sap trees may be the major factor in the selection of a nest site.
Red-breasted Sapsucker
Scientific Name: Sphyrapicus ruber
Length: 8.5”
Wingspan: 16”
Weight: 1.8oz (50g)
AOU Alpha Code: RBSA
RESIDENT BREEDER IN WASHINGTON
The Red-breasted is a year-round resident of Western Washington and the least migratory of North American sapsuckers. Birds in the interior of British Columbia and Washington may migrate to lower elevation in winter and some coastal birds will remain in place all year.
Red-breasted Sapsuckers breed in western coniferous forests from sea level to an altitude of 2,900 meters (9,500 feet). Western white pine, lodgepole pine, western hemlock, and Douglas fir are commonly used. They also breed in deciduous forests of cottonwood and aspen, and in orchard trees. They use dead trees or the dead portion of live trees taking one to two weeks to excavate a nest cavity. Both male and female will begin nesting with separate excavations and in an unknown manner select one to complete (Walters, et al). A typical nest will have five to six eggs.
ONE OF THREE
The Red-breasted Sapsucker is a very close relative of the Red-naped (S. nuchalis) and Yellow-bellied (S. varius) Sapsuckers with which it shares the genus Sphyrapicus, a hammer woodpecker, from the Greek sphura, a hammer, and the Latin, picus, a woodpecker (Holloway). The species epithet ruber, is from the Latin for red. These three sapsuckers form a superspecies and until 1983 they were all considered as Yellow-bellied Sapsuckers. However, systematic study found enough distinctions among them to justify the split. Nevertheless, the Red-breasted will hybridize with Red-naped Sapsucker in a contact zone in the Cascades of Washington and Oregon and the Eastern Sierras of California (Alderfer; Walters, et al.).
VOCALIZATIONS AND OTHER SOUNDS
Vocalizations of the Red-breasted Sapsucker vary with the seasons. Calls consist of a variety of chatter, squeals, and Waa calls. However, in winter only a soft mew is common. Drumming serves several functions. Early in the breeding season a male’s drumming signals their presence. Females are also known to drum when interacting with a male and tapping at the nest can signal a change-over in care of nestlings (Walters, et al). Photos and audio of Red-breasted Sapsuckers can be found at the Macaulay Library.
The Red-breasted Sapsucker has a stable population and there are no management programs in place for it. As is true for many birds, human development poses a threat in the form of deforestation and conversion of riparian habitat for other uses.
Photo Credit: Andy McCormick. References available upon request from amccormick@eastsideaudubon.org