Monitoring peregrine falcons in the Yukon Charley rivers national park. Raptors suffered population declines around the 70s due to DDT and other harmful contaminants. Due to many raptors being migratory they absorb nutrients and contaminants from all over the world. These populations were directly affected by our dark past but they were able to leave our dark past behind them. Scientists and general public like you have nurtured these birds back into their rightful place atop golden bluffs.