Environmental Stewardship

Chelan PUD has many programs designed to monitor, protect, and help raptors. Raptors are commonly known as birds of prey, such as eagles, hawks, and owls.These large birds are protected by the Migratory Bird Treaty Act, Endangered Species Act, Eagle Protection Acts, and other federal and state regulations. Biologists conduct monitoring for bald eagles, osprey, American kestrels, and other raptors along our reservoirs and within our service areas to comply with federal and state regulations. Chelan PUD has implemented an Avian Protection Plan to evaluate and retrofit structures that can pose risks to raptors.

As winter approaches, bald eagles migrate south to spend the winter along lakes and reservoirs that are not frozen, where waterfowl and fish are available for food. Each winter the PUD conducts bald eagle surveys on Rocky Reach Reservoir, the Rock Island Reservoir, and along Lake Chelan. Winter surveys are conducted by boat along the reservoirs from November through March. The best time to view wintering eagles is during the months of January and February.

PUD biologists gather information on bald eagle abundance, age, distribution, and perch sites along the reservoirs. Peak numbers of wintering bald eagles reach up to 14 along Rock Island Reservoir, 50 along Rocky Reach Reservoir, and 12 along Lake Chelan. This data helps Chelan PUD address SEPA, NEPA, and other permitting issues in a timely and effective manner. Bald eagles were recently de-listed from the Endangered Species Act. Populations of bald eagles in Central Washington have been increasing over the last 30 years.

Most bald eagles migrate north in the spring for the nesting season. However, in recent years, more bald eagles have been staying to nest in central Washington. PUD biologists monitor bald eagle nests within our service area. The nest monitoring efforts allow us to determine nesting success and productivity of this increasing population of resident bald eagles. Power lines near nest sites are also evaluated to determine if they pose a risk to young eagles that are just learning to fly. Data from the monitoring surveys are shared with other resource agencies to ensure best management practices are carried out for the bald eagle.

Osprey are the only bird of prey that feeds exclusively on fish. These large birds nest along streams, reservoirs, and lakes in North Central Washington where they can easily hunt for fish in shallow waters. Osprey often use utility poles for nesting. Osprey nests on utility poles may pose a threat to the birds and can jeopardize system reliability. Chelan PUD biologists monitor and evaluate osprey nests on our utility poles to determine whether or not the nest poses a hazard. This program is a part of our Avian Protection Plan (APP) . If the nest is determined to be potentially hazardous, we manage these nests in accordance with state and federal laws. We provide nest platforms that raise the nests above the top of the pole or provide a separate nest pole where the nests no longer pose an electrical hazard for the osprey. This also reduces risk of fire and prevents power outages for customers. The PUD may also modify the utility structure in a variety of different ways to ensure it no longer poses a risk to the structure or the birds occupying the nest.

American Kestrels are North America’s smallest falcon and the most brightly colored raptor. They can commonly be seen sitting on power lines searching for prey below. They feed on grasshoppers and small rodents in open areas. Chelan PUD provides nest boxes for American Kestrels. The nest boxes are installed on large utility poles in dry, open, grassy areas. The nest boxes provide nesting opportunities in areas where natural cavities are lacking. Leg bands placed on the young birds help biologists across the west track migration patterns and survival.

Installation of a new transmission line in 2006 was necessary to meet increased demand and industry standards.  The Burch Mountain 230kV line traverses Burch Mountain from Rocky Reach Dam to the Andrew York substation in Monitor. The Washington Department of Fish and Wildlife expressed concerns that the designed transmission line could pose a collision risk to migrating raptors. In the fall of 2005, Chelan PUD conducted a unique pre-construction survey using marine radar and visual observers to determine the potential of fall-migrating raptors to collide with portions of the proposed transmission line. The survey took place near the top of Burch Mountain, located north of Wenatchee.

From late August through mid-October 2005, a total of 1,472 migrants were detected. Fourteen different raptor species were recorded, including sharp-shinned hawks, golden eagles, red-tailed hawks, falcons, osprey, and turkey vultures. Raptors tend to migrate between mid-morning and mid-afternoon during optimal conditions for thermals, when visibility is good. They can soar to great heights on thermals, making it hard for the visual observers to detect the birds. The radar unit aided in detecting passing migrants that were hard for visual observers to see. Some of these birds were recorded flying over 900 meters high and up to 57 miles per hour!  

Results of the 2005 survey indicate that collision potential for birds of prey was very low for most sections along the proposed transmission line. Only two spans had an increased risk for collision, compared to other spans along the transmission line. To reduce collision risk, bird flight diverters were installed on shield wires of the new transmission line during construction. The diverters will make the wire more visible to all birds flying near the structure. In the fall of 2007, a post-construction survey was conducted to record migrating raptor behavior relative to the new transmission line.  Data analysis from the most recent survey is currently under way.