Natural Predator Ate Through All Black Skimmer Nests On Marco Island

Jul 6, 2015

CORRECTION: The trash cans on Marco Island beach are the responsibility of Collier County and not the city of Marco Island. 

A natural predator has wiped out all of the nests from a group of shore birds on Marco Island Beach. They come every summer between May and July. The Florida Fish and Wildlife Conservation Commission says it's the largest nesting colony of Black Skimmers in the state. The bird is a species of special concern in Florida because if its low numbers. 

On the north end of Marco Island Beach, Audubon Florida biologist Adam DiNuovo stands a few hundred feet from the shore. He stood at this same spot three times a week for the last two months, counting Black Skimmer nests. But now, he has a pretty different view.

"Right now we're just kind of looking at a big empty beach where three weeks ago was a very busy bird beach," said DiNuovo. 

He said there were about 600 pairs of adult Black Skimmers. The birds nest in groups to try and fend off predators from eating their young. The main predator this year is crows.  

Credit Jean Hall / Courtesy

"So typically when I came out, the birds were very riled and they weren't sitting well. And anywhere between eight and 16 crows would be landing and walking through the colony eating eggs and chicks," said DiNuovo. 

The Black Skimmers attempted to nest three or four times along the shore, but they eventually gave up and left the beach, he said. 

DiNuovo said it only took about four weeks for crows to eat their way through the colony.

Crows feast on eggs and chicks every year. It’s usually not a problem. But this season, the large number of crows was unusual, DiNuovo said. 

"It's the worst crow predation in a bird colony that I’ve ever seen," he said.  

About 100 meters away from where the birds once nested is a city trash can. DiNuovo said crows are attracted to the trash.  

"I watch the crows leave the trash can and then fly into the colony for a while, eat eggs and then come back, he said.  "So they were just going back and forth."

Nancy Douglass with the Florida Fish and Wildlife Conservation Commission (FWC) said she recognized trash cans played a huge role in Black Skimmer predation this year.

"We will work with the city of Marco to try to encourage them to either remove trash cans or put predator proof trash cans out there," said Douglass. 

Marco Island city trash cans attract crows to the beach, according to Florida Fish and Wildlife Conservation Commission. (CORRECTION: The trash cans belong to Collier County.)
Credit Adam DiNuovo / Audubon Florida

She said FWC has a few solutions they’re going to test out next year. One of the ideas is to plant fake eggs that taste bad to the crows, hoping to discourage them from coming back.

Another theory is to hang a dead crow in the area. It could show these intelligent creatures it’s not a safe place for them.

The last resort, Douglass said, is to kill the crows. She said it’s important to remove them because it’s critical the Black Skimmers reproduce.

"Not only is it important to maintain the population that we have but we really want to see it grow so that it can get to a place where it is stable and is no longer listed," said Douglass. 

Black Skimmers are still loafing around Marco Island. The sleek black and white birds can be seen skimming the water to catch fish. As for nesting, they’ll try again next year.