Tuesday, June 5, 2012

Peregrine population continues comeback with help of our power plant nest boxes

Photo courtesy of Greg Septon.
Peregrine falcons became an endangered species in many areas of the United States, including Wisconsin and Michigan, because of pesticides, but since the ban on DDT in the early 1970s, populations are recovering.

Known for their speed, reaching more than 200 mph during high-speed dives, peregrines are the fastest animals in the world. Their diet is almost entirely small to medium-sized birds. Peregrines typically mate for life and nest on cliff edges and tall structures, such as the nest boxes installed at our power plants.

We installed our first nest box at Pleasant Prairie Power Plant in Kenosha County, Wis., in 1992, when 15 captive-produced falcons were released. Our first successful clutch of eggs was produced at the Pleasant Prairie site in 1997. Successes soon followed at our other sites: Oak Creek (1998), Port Washington (2000), Milwaukee (2002) and Presque Isle, Mich., (2011). We also have a nest box at a plant in Wauwatosa that has had activity but not yet produced a clutch.

All the boxes were built by our own staff or contractors. Maintenance is handled by local falcon expert Greg Septon. He visits each site in the fall to clean the boxes and replace the gravel nesting substrate.

“We got involved early in the recovery program when potential sites were needed to release falcons,” according to Mike Grisar, senior consultant in our environmental department. “We were hoping that the falcons would survive and return to the nest sites.”

Grisar says that most of the best artificial nest sites are those located on tall structures along Lake Michigan or major rivers, which makes many of our power plants ideal locations for peregrines.

While peregrine falcons have been delisted as an endangered species in the United States, they remain listed as a state endangered species. The nest boxes remain a critical component to ongoing support of peregrine populations. In 2011, only six of 32 known nest sites were found on natural cliff nests – and two of those had nest boxes. Without the next boxes on structures, peregrines would have little opportunity to reproduce.

For nearly a decade, we have had cameras monitoring activity in our nest boxes, and we recently added live streaming video and upgraded several cameras.

“The new cameras help us remotely view the band numbers on the falcons and watch the activity and development,” says Grisar. “Previously, Greg [Septon] had to visit sites numerous times to get this information.”

We share hourly images of all our nest boxes along with the streaming video from Pleasant Prairie on our website.

Peregrine falcon webcams

Since 1997, our sites have produced 169 peregrine falcons, which is about 20 percent of the entire peregrine population produced in the wild in Wisconsin since their reintroduction. In addition, some of our falcons have been observed in neighboring states, helping to sustain and grow peregrine populations in those locations.

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