72 Microseasons of the Pacific Northwest

In the last week of August, young Ospreys (Pandion haliaetus) that hatched in May and June are practicing hunting in earnest. Fledging typically occurs in late July after 51–54 days in the nest, and for the following weeks the juveniles are dependent on adults for food while they hone the specialized diving technique that will sustain them for the rest of their lives. By late August, the family groups are conspicuous along rivers, lakes, and estuaries — adults making successful dives while juveniles hover awkwardly overhead, plunging feet-first with growing confidence. The osprey's hunting technique is extraordinary: spotting a fish from 30–100 feet in the air, the bird plunges steeply, adjusting trajectory as it falls, and hits the water feet-first at speed — sometimes submerging completely — before emerging with the fish gripped in specialized reversible talons that lock closed on impact. Young birds require weeks of practice before they achieve consistent success. Watching a juvenile work a pool — hovering, adjusting, abandoning the dive, circling again — compared with the immediate efficiency of an experienced adult, illustrates the skill involved. In the Willamette Valley, ospreys are common along the Willamette and McKenzie Rivers, the Columbia River corridor near Portland, and on reservoirs throughout western Oregon. On the Yakima River and Columbia Basin, nesting ospreys are a familiar sight on navigation buoys, transmission towers, and purpose-built nest platforms. In the Puget Sound region, ospreys nest along the Green River, Snoqualmie River, and on several reservoirs. The Deschutes River and Klamath Basin in Oregon hold additional populations. Osprey typically depart the Pacific Northwest for wintering grounds in Central and South America in August and September — the late-August family groups visible at fishing spots will be gone within weeks.