Iguana Population Growing on Sanibel; City Staying Course With Control Efforts

by SC Publisher Shannen Hayes

Residents have been expressing concern over the large number of iguanas on the island, which made them a topic at the Sanibel City Council meeting in January.

“I have heard a lot of complaints from citizens about iguanas and coyotes, more about iguanas than coyotes,” said Councilman Mike Miller. “The obvious question is: Are we getting better about removing iguanas or are there more iguanas?”

Sanibel established an Exotic Lizard Management Program in 2007, after confirmed sightings of Nile monitor lizards. The last confirmed sighting of one was in 2008 on a police camera on Periwinkle Way after it had been struck by a vehicle.

Director of Natural Resources Holly Milbrandt said the Nile monitor lizard “gave us great concern because it’s a voracious predator and could have serious impacts on wildlife on the island.” But there has not been any evidence of an established population of the Nile monitor lizard since 2008.

Milbrandt said the green iguana population also began to expand at the same time, but in the hierarchy of concern, they are primarily herbivores which consume vegetation, and prefer the non-native, but popular, colorful flowers like the hibiscus.

“A lot of our non-native, but common, landscape plants are favorite foods of the green iguana,” she said. “But that is not to say we don’t have some ecological concerns about (them). They are certainly not native to this area, but to Central and South America.”

While the green iguana is largely herbivorous, they will take opportunities to expand their dietary choices such as protected native plants and tree snails. Milbrandt said a big concern on Sanibel is they may compete for habitat with gopher tortoises by overtaking burrows.

“I think that was the impetus for the (Exotic Lizard Management) program,” she said. “But a majority of the calls we get from citizens are largely related to the nuisance aspects of having a large population of green iguanas.”

In addition to vegetation, they can negatively impact sea walls and other structures through burrowing. They are very fond of water, whether it be a canal or swimming pool, and it’s common for them to defecate in those areas. And like most reptiles, they are carriers of salmonella.

Milbrandt believes the iguana population is growing on the island. But the city’s contracted trapper Chris Harlowe has been working to reduce the population these past few years.

“(Harlowe) has two responsibilities,” she said. “There is a balance we try to strike between responding to residents’ complaints, which may or may not result in capturing an iguana, and on city or private property where we know there is a large number of iguanas and would maximize results.”

From September 2020 to November 2021, 1,043 of the 2,231 iguanas removed were from commercial and residential properties. Vacant lots in the Beachview neighborhood and the adjacent Sanibel Island Golf Course account for 31 percent and 12 percent on city-owned lands. Periwinkle Park, The Dunes Golf Course and land owned by the Sanibel Captiva Conservation Foundation make up the remaining 10 percent.

“The Casa Ybel Road area, especially Beachview and Sanibel Island Golf Course, is a hot spot,” said Milbrandt. “A lot of work is done there by the trapper.” He achieves efficiency in that area because of the amount of land and the ability to use his preferred removal method of an air rifle.

Under his contract with the city, Harlowe typically spends one eight-hour day per week on the island for a minimum of $400 per day. That per day minimum may be exceeded based on the number and size of exotic lizards or iguanas eradicated.

The city has been spending nearly $40,000 per fiscal year (November to November) since 2019. However, a little more than half was spent in FY2020 because the program was suspended for five months due to the pandemic. That led to a $70,000 budget in FY2021 to “make up” for the suspension time.

Mayor Holly Smith questioned the budget and if better efficiency could be achieved. “How do we best use those funds,” she asked. “Do we focus on (city) lands and educate residents on alternatives? How do we focus on hot spots and use the money efficiently?”

Milbrandt said additional manpower and dollars would help in making additional headway. “One of the challenges is we do not have a good sense of how many iguanas we have or what level of effort and amount of dollars it would take.”

Sanibel Conservation Officer Veronica Runge told council members there is awareness of the frustration felt by some residents over the response time to complaints.

“The time period in which (Harlowe) can respond to a resident complaint is typically three weeks, but it can vary from two to four weeks depending on the volume of requests,” she said.

Runge encouraged the use of the online form on the city’s website, which has a lot of questions to help identify where iguanas are on a property. The online form also ranks requests by the date received.

Additionally, Runge discussed behavioral modifications, such as looking at landscaping for exotic plants desired by the green iguana or using deterrents such as reflective surfaces. Milbrandt warned against homeowners trapping iguanas on their own because it can not be released any where else.

Council raised the idea of better educating citizens on alternatives, such as other wildlife removal services available to them. Mayor Smith said homeowners should be careful when privately contracting a wildlife removal service.

“They should be vetted and approved by the city. We certainly want to have approved vendors,” Smith said.

Council did not take any formal action on the iguana situation, but decided to “stay the course” in control efforts and make more information available on the city’s website.

Coyotes will be discussed at the Tuesday, Feb. 1 city council meeting.