Inspection of bridge now planned after Aug. 1
An inspection of the Mark Twain Memorial Bridge in Hannibal has been put on hold after the discovery of an endangered peregrine falcon nest on the structure.
The inspection of the bridge began Monday and was expected to last two days. The work stopped after local photographer, David Johnson, contacted a friend who works for the Missouri Department of Transportation (MoDOT) to say he had photographed falcons near the bridge and thought there might be a nest on the bridge.
The MoDOT employee contacted Jeff Meshach of the World Predatory Bird Sanctuary in St. Louis. Meshach spoke with Johnson, who sent him photos of the birds of prey that helped confirm the discovery.
Meshach, who said falcons are very territorial during nesting season, contacted MoDOT and urged to delay the inspection until later in the year for the safety of anyone working underneath the bridge. Meshach praised MoDOT for choosing not to disrupt the nesting falcons.
According to MoDOT, the inspection of the bridge, which happens every other year, has been postponed until after Aug. 1. Peregrine falcons typically nest between February and August.
According to the U.S. Fish and Wildlife Service, peregrine falcons are about 15 to 21 inches long with a wingspan of about 40 inches. Meshach said that falcons are the fastest creatures on earth, having been clocked at speeds of 261 mph.
They live mostly along river valleys, mountain ranges and coastlines.
Their preferred nesting spot is a depression in gravel on a cliff ledge. Many peregrines nest on man-made structures, including bridges, tall towers and skyscraper ledges that mimic their natural sites.
Following a rapid decline in the population of peregrine falcons, in 1970 the American and Arctic peregrine falcon subspecies were listed as endangered under the Endangered Species Conservation Act of 1969.
The number of Arctic and American peregrine falcons began to rebound following the implementation of restrictions on the use of the pesticide DDT and recovery efforts.
The U.S. Fish and Wildlife Service announced in October 1994 that the Arctic peregrine falcon had increased in numbers to the point that it no longer required Endangered Species Act protection.
In August 1999, the U.S. Fish and Wildlife Service removed the American peregrine falcon from the list of endangered and threatened species.
Peregrine falcons are still considered endangered in the state of Missouri, Meshach said.
Marisa Ellison, communications manager for MoDOT's northeast district, said it is not uncommon for work to be disrupted because of discoveries like the one Monday.
"It's not necessarily frequently, but we have had to postpone some operations due to wildlife," she said.
It is not unusual for bridge inspectors to find wasp, hornets and bats underneath bridges.
"In this case, (they found) some partial wildlife that had been food for the falcons," Ellison said.