Predator controls effective during nesting season on Marco Island

A partnership between the Florida Fish and Wildlife Commission and U.S. Department of Agriculture continues to thrive in an attempt to protect nesting colonies of black skimmers and least terns from fish crows on Marco Island.

Staff from both agencies monitored nesting areas from May 15-May 18 when least terns and black skimmers were incubating eggs.

FWC regional biologist Ricardo Zambrano said staff tasked with protecting nesting areas encountered a handful of crows that needed to be removed during the window and did not see a need to extend the protection period.

“We think it’s been pretty effective,” Zambrano said. “If our staff and volunteers see any problems, we’ll be back.”

Both species of birds have seen drops in populations as a result of predation and are listed as threatened species in Florida.

In 2015, a colony of at least 750 least terns and 950 black skimmers in front of the South Shores Condominiums lost every egg to predation by fish crows.

The previous year, it was estimated that at least 100 nests were predated by Fish Crows on Sand Dollar Island.

As a result of the predation problem, the FWC contracted with the USDA to use firearms and predator control methods to keep the Fish Crows at bay.

These efforts in 2016 and 2017 were also successful after trapping and the use of effigies proved ineffective in previous years.

In Florida, the number of breeding black skimmers was estimated at 3,600 with the population declining by 30 percent over the next 10 years without implementing greater predator controls.

According to the FWC, its breeding colonies are found on Florida's Gulf and Atlantic coasts.

Least Terns are very susceptible to nest disturbance and with the loss of habitat, have turned to nesting on roofs.

Zambrano said if it was difficult to estimate the number of least terns because at least half of its population may be nesting on rooftops.

“It makes it difficult to do an accurate survey, which we don’t ask volunteers to do because we need to be granted access by the property owners,” Zambrano said.

With the change in nesting habits, the FWC created a pilot program in Pinellas County to help make homeowners more tolerant of birds that were nesting on roofs.

To get more accurate data, Zambrano said there has been a statewide effort to improve collection efforts through the Florida Shorebird Database.

The new database was created in 2010 but with volunteers providing some of the data for analysis, it became imperative to have a more standardized approach so that collection methods were more uniform.