This is crucial time of year for two threatened species of shorebirds in Florida

Adam Friedman
Naples Daily News
Black skimmers fly around the nesting colony on Tuesday, July 3, 2018 near Big Marco Pass. Black skimmers and least terns are both state threatened birds, but are the most productive in Southwest Florida. The birds fledge roughly one chick per pair. Though the birds are not easily frightened, fireworks or other objects, such as kites, can disturb them.

Screeching and swooping with its 19-inch wingspan, a black skimmer tries to ward off any animal or person that gets too close to its nesting colony and its newly hatched chicks.

The skimmer is normally a calm bird, but after thousands of black skimmer eggs were eaten by crows in 2015, things have changed.

“They’ve hardened because they’ve had an experience,” said Audubon shorebird monitoring leader Adam DiNuovo.

Every April and May, the largest least tern and black skimmer colonies in Florida settle onto beaches in Southwest Florida — and now their eggs are starting to hatch.

More:Bird colonies wiped out by crows

This year there are roughly 400 black skimmer nesting pairs and 200 least tern pairs, DiNuovo estimated. In 2017 there were 400 to 500 pairs of skimmers and 200 to 300 pairs of terns, according to state figures.

A posted sign indicates the wildlife area for the black skimmer colony on Tuesday, July 3, 2018 near Big Marco Pass.

Florida has designated both bird species as threatened. But the Marco Island population has remained steady and might have increased slightly over the past two decades, said Florida Fish and Wildlife Conservation Commission regional biologist Ricardo Zambrano.

The terns usually lay their eggs in late April and the skimmers in May. But this year Subtropical Storm Alberto flushed the skimmers and terns from their nests.

“The early tropical storms have really hurt the skimmers and terns nesting over the last few years,” Zambrano said. “The hurricanes and tropical storms usually happen later in summer, which doesn’t affect the birds' nest because the eggs have already hatched.”

More:Subtropical Storm Alberto causes erosion, sea turtle nest losses on Collier beaches

The skimmers and terns were able to try nesting again in June. Because there was no substantial tropical storm, the eggs are fine and started hatching this week.

Black skimmers wade in the water on Tuesday, July 3, 2018 near Big Marco Pass. Black skimmers are productive in this particular area because there aren't too many predators, other than fish crows.

Many of the bird's are nesting on a spit of sand that sticks into Big Marco Pass near Hideaway Beach on Marco Island and near Lovers Key State Park in Lee County.

The skimmers and terns nest in groups to protect their eggs. The birds also nest in pairs; one bird sits on the eggs or protects the chicks while the other searches for food.

During rain or storms, the birds can cover their hatchlings to keep them dry.

“Another concern this time of year is thermoregulating because of the heat,” DiNuovo said. “The beach can get as hot as 160 degrees during the day, which will fry the eggs if they aren’t covered.”

2016:Marco Island shorebird nesting colonies battle back from Tropical Storm Colin’s big blow

The chicks are completely reliant on their parents until they can fly. 

“The newborns have to eat constantly to get enough nutrients since they grow so fast,” DiNuovo said.

A skimmer will be fully grown and can fly about 25 days after it's hatched; a tern is fully grown and can fly after 21 days. 

The adult skimmers won’t attack other animals or people, but as threats get closer to their nesting colony, they will do their best to scare away anything near their chicks.

Black skimmers sit on their nests to protect their chicks on Tuesday, July 3, 2018 near Big Marco Pass. If the birds leave their nests for as little as five minutes during the hottest time of the day, the eggs could die.

Crows, coyotes and foxes are the most common predators, waiting for the birds to leave their nests before trying to eat their eggs. Crows will circle the colonies waiting for other animals to flush birds so they can grab their eggs.

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The Florida Fish and Wildlife Conservation Commission tries to protect the nesting colonies by sectioning off parts of the beach.

“Sometimes people ignore the signs and cut across the nesting areas, smashing the eggs or even the newborn birds,” DiNuovo said.

Skimmers will lay four or five eggs a year and terns two or three eggs. 

Monitors hope for the scene they are seeing on the beach now.

“If you just came back here 7-10 days after the eggs hatched, the newborn skimmers would be running around,” DiNuovo said.