The towers were part of the original Cushman Hydroelectric Project dedicated by President Calvin Coolidge in 1926 and have far exceeded their expected life span.
According to James Blessing, the lead engineer on the new Cushman Hydro Project, which also includes the replacement of the towers along State Route 302, the first visible phase of the work will be when the Pierce County Parks and Recreation crews begin clearing the small county-owned property on the west end of the Purdy Spit. A Tacoma Power biologist has identified this site as having the best chance for attracting ospreys. Ospreys will likely return to build a new nest after the towers are replaced, but the chances are greater if the site is tall, near a previous nesting site and on or very near water.
A second Tacoma Power crew will be investigating the area to take soil samples and figure out the logistics of getting equipment on site to install a separate pole for an osprey nest. The final design approval is expected early next fall and the pole is expected to be installed in the first quarter of 2018.
If the park site proves to be unsuitable, upland sites will be considered. The construction schedule depends on the migratory patterns of the ospreys.
According to master birder Diane Yorgason-Quinn, ospreys are loyal to previous nests rather than to mates, so they return to the nesting sites where they fledged. Yorgason-Quinn has been studying the Burley Lagoon ospreys for 28 years.
Birds from our area winter in Southern California, Mexico and Central America, she said, following the growing seasons. They usually arrive in the Puget Sound Basin shortly after the vernal equinox and nest around the first of April. Eggs hatch in early June and the birds fledge in late July to begin their southern migration at the autumnal equinox.
Bald eagles compete with ospreys when their territories overlap and will periodically take over osprey nests for part or all of a season.