Yellow-rumped Warbler numbers are beginning to ramp up this week and should peak around April 20-25 then drop off rapidly. You may notice flocks moving through the tree canopy and hear their wispy soft song. Most will be Audubon’s (with the yellow throat patch) but watch for the Myrtles (with the white throat patch). Both Audubon’s and Myrtle’s are fairly common wintering birds in our area. The Audubon’s Warbler breeds at higher elevations throughout Oregon and as far as Northern B.C and south as the Sierra’s. The Myrtles migrate a greater distance than Audubon’s, breeding in Canada and Alaska.
Orange-crowned Warblers are moving through in good numbers this week. Orange-crowned migration should keep steady until the first week of May. The main migrant and local breeder belongs to the lutescens group, which winters from Central California to West Mexico, though a few may spend the winter in our area.
Common Yellowthroat numbers will be peaking over the next 10 days. They are already easy to find in their preferred wet grassy areas and edges of wetlands. But watch for them passing through nativescaped yards and neighborhood patches. Portland area breeding birds and passage migrants that continue to Washington and up to Southeast Alaska are arriving from Southern California and Northwest Mexico (Sonora and Baja).
Cliff and Barn Swallows
Cliff and Barn Swallows are arriving in breeding areas along our rivers and fields. Watch for these aerial acrobats as they catch insect prey on the wing. Barn Swallows arriving in Oregon may come from as far away as Colombia. Incredibly, Cliff Swallows arrive from wintering grounds in Northern Argentina. Learn more about Cliff Swallows at the Cliff Swallow Project cliffswallow.org
Wintering and migrating Golden-crowned Sparrows will rapidly decrease over the next 10 days. There are still a few lingering Golden-crowned Sparrows that wintered in our area, but soon most will represent birds that wintered in California and are passing through the area. Golden-crowned Sparrow primarily breed from Northern British Columbia to Alaska.
Ruby-crowned Kinglets are moving through in good numbers now. Their numbers should peak in the next 10-14 days. Wintering and migrating Ruby-crowned Kinglets in the Portland area represent two populations. One group is an altitudinal migrant, probably nesting somewhere in the Cascades of Oregon or Washington. The other group (grinnelli) winters in our area south to California and breeds in British Columbia to Alaska. They leave the lowlands of Portland and the Willamette Valley by late May.
Brown-headed Cowbirds have been arriving over the past week. Expect them to increase and become more noticeable over the next few weeks. Many of the cowbirds we see in Portland probably come from populations that wintered in Central California and West Mexico. Some years small numbers winter in the Willamette Valley.
Pine Siskins like most finches are highly nomadic. Much of their foraging for seeds involves tree crops, such as cedar, fir, and hemlock cones and alder catkins. These crops are unreliable and can even fail, sometimes sending Pine Siskin flocks across the country looking for food. Some years winter flocks never arrive in our area, but in most years Pine Siskins arrive in good numbers in spring; often associating with goldfinches. They stay through May before going to higher elevation to nest and feed on Hemlock cones.