The population of peregrine falcon has seen a comeback in the past few decades, and the raptor may soon be taken off the endangered species list in Illinois.

Nests of the peregrine falcon are sometimes found on Chicago skyscrapers and bridges over the Illinois River in Peoria. A legislative committee may soon strike out the name of the peregrine falcon off the list of threatened species in the coming weeks.

The bird population decreased drastically in the 1960s due to the use of DDT pesticides that weakened the shells of the bird's eggs, resulting in the hatching of fewer chicks.

Scientists in the U.S. had shown concern over the use of DDT since 1940. However, the pesticide was officially banned only in 1972. The peregrine falcon was put on the federal endangered list in 1973.

The U.S. Fish and Wildlife Services (FWS) said that by the mid-1970s, the population of peregrine falcon dropped by 90 percent and only 324 breeding pairs of the bird were found in the U.S at the time.

The ban on DDT, along with conservation efforts, has resulted in the increase of the raptor's population. The FWS reported that in 2013, there were between 2,000 and 3,000 breeding pairs of the peregrine falcon in the U.S., Canada and Mexico.

The Illinois Department of Natural Resources has been thinking of removing the bird from the threatened species list for about three years now. Experts said that in 2012, about 24 breeding pairs of the peregrine falcon produced 47 offspring, which is up from just one breeding pair of the bird producing two chicks in 1988.

Angelo Capparella, an associate professor of zoology at the Illinois State University, said that conservationists have done a great job in increasing the population of the birds.

"It's definitely a good success story," said Capparella.

Capparella also said that the peregrine falcons are also spotted at the university's tall buildings during their migration period.

Photo: Ron Knight | Flickr