White-throated Sparrow - Photo by Joe Halton
Last call on this winter migrant! Time is running out to catch a glimpse of this sparrow who occasionally visits Skagit County. It’s not the call to tune into, but the song which makes this bird easily distinguishable. The White-throated Sparrow (WTSP) is one of the few birds you’ll hear singing in winter. Along with our local wrens, these birds sing year-round.
Depending where you hail from, you may hear; “Oh Sweet, Canada, Canada, Canada,” or “Oh Sam Peabody, Peabody, Peabody.” These mnemonic phrases are useful when identifying the WTSP’s song. The frequency of hearing and seeing the uncommon WTSP in Skagit County is on the rise. These birds breed across much of central and eastern Canada and into the Northern edges of the Midwest and Northeastern United States. In winter, most migrate to the Eastern and Southern United States. A few find their way to the West Coast. Ornithologists believe most of the West Coast migrants are immature males and first year females who travel farther south and west. Adult males stay closer to their breeding grounds. They are first to return and establish territory to attract returning females.
The White-throated Sparrow is very similar to our common year-round resident, White-crowned Sparrow. Both have white and black stripes on their crowns. However, the White-throated Sparrow has two color morphs, white and black stripes called the White-striped (WS) and, tan and brown stripes called the Tan-Striped (TS). The two color morphs are determined genetically and persist because both WS and TS males prefer WS females and both WS and TS females prefer TS males. Both male and female WS are more aggressive than TS birds. Therefore the WS females outcompete TS females for TS males. These two morphs and their mating preferences are very unique. The adage, “opposites attract” can be applied to breeding WTSPs. All White-throated Sparrows have yellow lores, which is the area between the eyes and bill. They also have their namesake, a white throat which is surrounded by a thin black whisker or malar stripe. Knowing the difference between these sparrows is helpful since a solitary WTSP will most likely be among a wintering flock of White-crowned or Golden-crowned Sparrows. These wintering flocks form feeding hierarchies leaving the less aggressive WTSP on the edges and more susceptible to predation.
In the breeding territories, courtship begins with a female display. She flutters her wings and trills. Females choose the nesting site. The nest is constructed on the ground near the edge of a clearing. A second nest will be built up to 15 feet high if the ground nest fails. The female finds a concealed depression and starts a moss first layer. Next, she constructs a cup using grass, twigs, rootlets, wood chips and pine needles. She lines the inside with soft materials including fur. The clutch size is 4 to 6 pale blue or greenish-blue eggs with reddish-brown specks. The female incubates the eggs for up to 14 days. The altricial hatchlings are ready to fledge in 7 to 12 days. Both the male and female feed the young birds a protein diet of insects, spiders, centipedes and snails. They forage on the ground throwing aside leaf litter by scratching with their feet and using their bills. In winter, their diet consists mainly of seeds and they will visit backyard feeders with cover nearby. During spring migration, they consume tender buds of fruit trees, oaks, maples, beech and elm.
A very interesting hybrid is the combination of a White-throated Sparrow and Dark-eyed Junco. The result is a dull gray White-throated Sparrow with white outer tail feathers and a pale pink bill. These hybrids are very rare and unlikely to be observed in the Pacific Northwest.
In Skagit County, look for the White-throated Sparrow in a mixed flock of sparrows feeding on the ground. If you hear a WTSP nearby, try pishing sounds to draw it out into the open. They are known to be curious and ready to investigate. Practice your pishing by pursing your lips and making squeaking noises. Repeat the sound 3 to 5 times and try different peeps and squeaks. Be sure to try this technique among friends or other pishing birders.
During these last few weeks of winter when you’re searching for signs of spring, tune into the the passerine calls and songs, look closely at the sparrows on the ground and maybe you will be fortunate to see a migrating White-throated Sparrow in Skagit.