Though not the only reason for the peregrine falcon's decline, the pesticide DDT had passed through the food chain and weakened the shells of peregrine eggs, leading to the loss of many young before they could hatch.
The curtailment of chemical pesticides and the success of nest boxes like Thermal’s have led to an impressive recovery of the peregrine falcon population.
MRMC Thermal’s peregrine falcon nesting box is part of a state-wide falcon recovery program managed by biologist Greg Septon. Read this Wisconsin Falconwatch – 2018 Nesting Season Report (PDF) to learn more about Wisconsin peregrine falcon nesting activity and the 111 young that were produced.
April 24, 2019:
A fourth egg arrived on April 12th!
April 11, 2019:
Three eggs have arrived. A fourth is expected. Hatch date anticipated between May 13 to May 15.
March 26, 2019:
A new adult male has been identified at the Thermal nest box: Donald. On March 21st, there apparently was a battle between Donald and another male in the nest box. Donald was the victor and maintains control of the site. The unbanded female is assumed to be the same female from last season.
Asa, the previous adult male at this location, was either displaced (chased off), killed or did not survive the winter.
A side note: Donald nested last year at the MillerCoors nest site in Milwaukee where he killed the resident male and took over the site.
We now await the arrival of the first egg, which is likely to be mid-April.
On the left is a picture of Donald and the unbanded female displaying in the nest box.
On Saturday, March 9, 2019, a banded male (left) and an unbanded female (right) appeared at the nest box. We are awaiting identification of the male ID band.
Egg-laying occurs anywhere between March 12 and mid-May. 2019 nesting season is here!
"Asa", a banded adult male has been nesting at the Thermal plant for the past five years, and an unbanded female produced three healthy chicks in the nesting box in the spring/summer of 2018. The banded female named Tahoe, who had nested there with Asa the previous four years, had died before the nesting season began.
Webcam images of the falcons nesting and caring for their young are typically available March through July.
Nesting Box Webcam
Through the box’s webcam, you can watch for the falcons to return, eggs to be laid and hatched and activity in the nesting box as the chicks grow during nesting season (March through July). Note that the webcam image below is not a streaming image but does refresh every 60 seconds; refresh your browser window to capture ongoing views.
Viewer discretion is advised.
Due to the sometimes-violent nature of birds of prey, some webcam content may be difficult to watch. Please be aware webcam content is not monitored or screened.