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Tagged Vultures May Solve Mystery About Why They Attack Cars In The Everglades

tagged vulture .jpg
Tricia Woolfenden

In January, WLRN reported on the curious -- and destructive -- habits of some of the Everglades National Park's vulture population. The birds have been reported to "attack" parked vehicles, picking off rubber and vinyl. The baffling and costly behavior has led Everglades' staff to pass out anti-vulture kits to park visitors. It has also motivated state conservationalists and scientists to look into the matter more thoroughly. 

Everglades National Park and the USDA National Wildlife Research Center (NWRC)  have partnered for a project to monitor the movements and behavior of 142 black and turkey vultures found in the park. It's part of a larger effort by the NWRC to help vultures and humans co-exist more peacefully. 

"The end product of this research is to determine...as to whether the vulture population that is found within the park -- and may be associated with the damage to visitors' vehicles -- is limited to birds residing within the park, are short-term visitors, or, as is hypothesized, a very transient group of birds that make their rounds throughout South Florida," says John S. Humphrey, an NWRC wildlife biologist.

So far, the NWRC has received 61 reports of about 80 sightings from staff and visitors at the park, according to Humphrey. Many of the sightings come from spots like Royal Palm/Anhinga Trail, 9 Mile Pond, and Flamingo, which are popular with tourists and birds alike. But early evidence shows that some vultures are venturing beyond the tagging sites. 

"Tagged birds from other projects around the state have also been reported at Everglades National Park, and Everglades National Park tagged birds have been reported at other project locations as well," Humphrey says.  

The study was initiated in December 2012, so it's still too early to determine whether the tagged birds as a whole are sticking around the area. Humphrey says initial numbers do suggest "a significant number of them utilize the park frequently." Another tagging event is in the works to include an "as yet to be determined" number of birds.

So why are the birds attacking cars, or more specifically, rubber and vinyl car parts? 

"It is believed by some that these products release some chemical cue that is appealing to the birds through UV or heat degradation, though that has yet to be proven," Humphrey says, adding that initial studies conducted at NWRC labs were inconclusive. "If the funding opportunity presents itself in the future, we would be interested in revising the study model to try and better address this question." 

Vehicle destruction isn't the only issue at hand with vultures, the NWRC reports. Wildlife officials routinely receive complaints about vultures harassing livestock (a behavior associated with more aggressive black vultures), defecating on trees and communication towers, and damaging homes and other buildings. There's also a risk of vulture/aircraft collisions to consider.

According to NWRC materials: "Scientists are investigating methods for dispersing vultures from problem roosts and preventing property damage. Scientists are also using satellite telemetry to learn more about vulture movements and the potential for vulture-aircraft collisions."

Despite an increase in human-vulture conflicts, it's important to note that the raptors play a vital role in ecosystems "by cleaning up animal carcasses" the NWRC reports. According to the Florida Fish and Wildlife Conservation Commission, vultures are under state protection. It is illegal to "shoot or harass them without a permit from the FWC. If, however, the vulture is tearing up a screen porch, or chewing up shingles or roofs, then you may want to consider scaring them with pyrotechnics." Likewise, biologists are focused on finding science-based, non-lethal methods to address the vulture issue. 

Park attendees -- or anyone living in South Florida, for that matter -- who want to aid in a resolution to the vulture conundrum can report sightings of tagged birds to the NWRC. The vultures are marked on the right wing with a colored tag "bearing various combinations of letters and numbers."

Citizen observation reports should include details on the time, date, and location of the sighting, as well as the species and the bird's behavior. An easy way to track these details in the event of multiple sightings is by using a smartphone to shoot a picture of the bird (the file will then contain details on exact time and location of the sighting). 

Something else to look out for: Three of the birds in the park also are outfitted with a small solar-powered GPS satellite transmitter located between the wings. Because of the cost associated with the electronic devices, researchers are limited in how many birds they can outfit and track using satellite technology. Down the line, "newer technology" using Global System for Mobile technology will enable scientists to more precisely track birds at a lower cost. 

Submit tagged vulture sightings using a park-issued form, or email john.s.humphrey@aphis.usda.gov or call 352-375-2229.