Conservation/Environment

The license for the Rock Island Dam requires the PUD to maintain a minimum of 11 Canada goose nesting structures along Rock Island Reservoir. In the early 1980’s the Washington Department of Fish and Wildlife (WDF&W) erected goose nesting structures to increase nesting success of Canada Geese. The PUD erected additional nest structures along Rocky Reach Reservoir to off-set expected losses from a potential 3-foot pool rise. The pool rise did not occur but the structures have been monitored annually for goose nesting success since installation. Currently, Chelan PUD biologists maintain and monitor goose nesting in approximately 31 man-made nesting structures along Rock Island and Rocky Reach reservoirs.

In addition to monitoring the nesting structures, the PUD monitors Canada goose nesting success in natural nests. Goose nests that occur naturally along the reservoirs can be affected by project operations and are of concern to wildlife agencies. Goose nesting surveys occur annually during March and April. During the surveys, biologists count the number of goose nests, eggs present in each nest, and locations of the nests. Nests are monitored throughout the nesting season to determine hatching success, number of goslings produced, and reasons for nest failures.

Long-term monitoring of goose nesting habits and success along our reservoirs may be useful to address SEPA, NEPA, and other permitting issues, meet license requirements for hydropower operations, and help to guide project operations that could affect shoreline nesting. This information is also provided to the WDF&W and the U.S. Fish and Wildlife Service (USF&WS) for their management purposes.

The number of goose nests along Rock Island Reservoir has ranged from a low of 40 to a high of 178. Presently, the number of nests averages 60 to 70 per year, producing about 300 goslings. Goose nests along Rocky Reach Reservoir have ranged from a low of 30 to as many as 80. Currently, the average nest count along Rocky Reach Reservoir numbers about 50, producing about 225 goslings annually.

Primarily, geese found along our reservoirs are Great Basin Canada geese. They are native to the area and can be seen frequently along the shoreline, in the parks, or flying overhead. These geese are residents of the valley and winter here along with migrants from further north. The geese prefer to nest on the ground on small islands along the reservoirs, but also nest on cliff ledges and elevated nesting structures. There, they are well-hidden amongst large rocks and shrubs from predators. They begin nesting in late March, laying from 4-7 eggs. Most eggs hatch by the beginning of May. The geese will then spend the summer along the shores, eating both aquatic and terrestrial vegetation. The young are able to fly at 65-70 days of age.

The license for Rock Island Dam requires Chelan PUD to maintain a minimum of 60 wood duck nest boxes along Rock Island Reservoir. Chelan PUD has provided and monitored wood duck nest boxes since 1983 on Rock Island Reservoir. The PUD conducts annual surveys to collect data on the wood duck boxes.

Surveys take place from April to June to determine wood duck use and nesting success. Nests are monitored throughout the nesting season to determine hatching success, number of ducklings produced, and reasons for nest failures. Biologists count the number of nests and eggs, and record the individual nest box number. Wood duck hens will return to the same nest box year after year. Often, biologists will place a leg band on the hens to track their nesting success over time and to learn about seasonal movements and survival. The results of the wood duck surveys are reported to the WDF&W and the USF&WS for management purposes. On average, 25 PUD wood duck nest boxes are occupied annually. Since the program began in 1983, nest boxes have produced over 3,000 wood duck ducklings.

Wood duck males are brightly colored and are considered by many as the most beautiful duck in North America. Females are less conspicuous with their brown coloration, grayish head, and white teardrop surrounding the eye. The female’s call is distinctive, however. When startled, the female will make a squealing noise (similar to a pig) as she flies away to better hiding cover.

The wood ducks are secretive, preferring the quiet and shallow backwater areas such as those found at the Confluence State Park Nature Area. These ducks are cavity nesters, and will use cavities in large trees such as cottonwoods. However, there are a limited number of large trees with natural cavities for the ducks to nest in along our reservoirs. Nest boxes supplied and maintained by Chelan PUD provide secure nesting cavities for wood ducks. Biologists ensure the boxes are built to a standard to reduce entry by predators and damage from the elements. The boxes are mounted on trees or posts where they are less likely to be disturbed.

This gives the hen and ducklings better chances for survival. Often, the trees or posts are wrapped with protective devices. Metal wrapping and fencing prevents damage to large trees from beaver. They also reduce the ability of predators from climbing the trees to destroy nests. Boxes that are protected receive the best use by the wood ducks.

The hens return to their natal territories in the spring, and begin laying eggs in their chosen cavities in late spring. Typical clutch sizes are about 12 eggs. The eggs are incubated for 28-32 days. The young all hatch nearly at the same time. They stay in the box until they dry out and fluff up. When the female has surveyed her surroundings to ensure no danger is near, she flies down to the water and calls to her babies. The tiny ducklings climb out of the box using their toenails and drop to the ground. Sometimes they have to drop almost 50 feet to reach the ground. They scurry to the water to swim with their mother, where they spend the season eating insects and aquatic vegetation.