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Shorebird Nesting Success as of June 15 |
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Least terns and Wilson’s plovers are two species of shorebirds that rely on our beaches for nesting each summer. Because these species are listed by the Florida Fish & Wildlife Conservation Commission (FWC) as Threatened and Species of Special Concern, respectively, portions of area beaches have been roped off and posted as No Entry zones for the summer nesting season.
According to the Reserve’s Team OCEAN Coordinator Lindsay Addison, the posted area at the south end of Key Island is successfully hosting a small colony of least terns and a handful of Wilson’s plovers this year. As of the second week of June, most of the terns’ eggs had hatched, and some of the tern chicks are almost ready to fly. The Wilson’s plovers also hatched chicks, and as of the second week of June each pair still has at least one chick and two pairs have three young chicks each.
Second Chance sand bar, part of the Cape Romano shoals, is also providing high nesting ground for the first time in several years, and a portion of the sandbar was posted to protect the birds nesting there. As of the second week of June, over 100 terns were still sitting on eggs or young chicks. Over 60 older tern chicks were in the colony area. One pair of Wilson’s plovers was raising 3 young chicks, and one pair was still incubating 3 eggs.
July represents the homestretch for many of these birds. Some of the least tern chicks will be flying, but Wilson’s plovers (and also black skimmers) will still be grounded until closer to August. As you enjoy the beach and celebrate the Fourth of July, keep these birds in mind.
Visitors to nesting areas are reminded to respect the postings and to look out for the highly mobile chicks, which often roam outside of the posting. Be especially careful to keep dogs well away from the posted areas to minimize stress to the chicks. When you visit these areas pay attention to the birds’ behavior. If they are flying up or dive-bombing, you are too close. Moving away will calm the birds, and make your day more enjoyable.
As long as boaters and beachgoers continue to respect the “No Landing” signs and posted areas, these birds are very likely to experience a successful nesting season this year.
Nesting Totals to Date:
- Key Island: 23 least tern nests, 4 Wilson’s plover nests
- Second Chance: 200 least tern nests, 2 Wilson’s plover nests
- Caxambas CWA (sand bar) 100 least tern nests, 4 pair Wilson’s plovers
- Sand Dollar/Big Marco Pass CWA: 100 least tern nests, 10 Wilson’s plovers, 200 black skimmers
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Declining Numbers
Throughout the world, many beach-nesting bird species are declining due to loss of habitat caused by rapid coastal development and to increased disruption of nesting activities. Due to declining numbers, both least terns and snowy plovers are listed as Threatened Species by the Florida Fish & Wildlife Conservation Commission (FWC). From March to September, least terns and black skimmers nest in colonies along open, sandy Gulf beaches while snowy plovers and Wilson’s plovers nest nearby.
When beach-nesting birds are disturbed and flushed off their nests by people or dogs, eggs and chicks are exposed to high temperature extremes and predators. Frequent disturbance of birds on the beach, especially disturbance that flushes birds from their nests, threatens their survival. These birds depend on southwest Florida beaches for nesting and to raise their chicks. |
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Monitoring and Protection |
Seasonal Closes
Rookery Bay National Estuarine Research Reserve, in cooperation with FWC, seasonally posts and closes viable beach-nesting bird habitat within the Reserve. Reserve staff aided by volunteers post “Area Closed” signs connected by string and orange flagging to enclose nesting colonies. Colonies are protected from the beginning of the nesting season (early - April) until nesting is completed and chicks have fledged (mid-August). These sites are monitored regularly and the numbers of adults, nests and chicks are recorded.
Additionally, educational posters and hand-outs are provided to local partners and organizations for distribution at beach access points and visitor centers within the community. Ongoing monitoring and evaluation of nesting sites has indicated that the seasonal closure of nesting beaches in conjunction with increased public awareness through education enhances nesting success for beach-nesting birds.
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Least Terns Need Your Help
With more people living and playing along Florida’s shoreline, protecting critical beach habitat for wildlife becomes an increasing challenge. One species heavily affected by loss of coastal habitat is a beach-nesting bird called the least tern (Sternula antillarum). Due to its declining population, the least tern is considered a Threatened species and is protected by the Florida Fish and Wildlife Conservation Commission (FFWCC). It is also protected by the federal Migratory Bird Treaty Act.
In cooperation with the FFWCC, staff at the Rookery Bay National Estuarine Research Reserve annually closes off viable beach area within the Reserve where least terns are nesting. Closures have occurred at the south tip of Keewaydin Island annually during nesting season (April through August) since 2002. Additionally, FFWCC closes and maintains nearby Critical Wildlife Areas on Marco Island and at Caxambas Pass.
Other species of beach-nesting birds are using these areas as well. Black skimmers (Species of Special Concern), snowy plovers (Threatened) and Wilson’s plovers (Status Undetermined) have similar habitat requirements and nest within least tern colonies. All of these species are easily disturbed by beachgoers and colonies can fail.
 Signs, strung together and marked with bright orange flagging, have been installed around the perimeter of each nesting area to alert visitors to keep out. At Keewaydin Island, the shoreline remains open, and existing trails provide access across the island.
These nesting colonies are monitored to determine seasonal reproductive success and assess population trends. Protection of the colony early in the nesting season is the most important strategy employed to optimize success of the greatest number of nests, as well as survival of fledglings. This protection is critical, because as the season progresses, so does the chance of these areas being overwashed again by severe summer storms.
A combination of posting and closure, law enforcement presence, and education is necessary to maximize compliance by the public and enhance beach-nesting bird reproductive success. The Reserve will close and monitor these areas during least tern nesting season each year the terns are present as a continued effort to help protect this state-listed threatened species.
Least Tern Population
Least tern population estimates for Florida are around 10,000 individuals. Found only in the western hemisphere, least terns winter in Central and South America, arriving to nest and raise young on Florida beaches in late March.
Least terns are colonial, meaning they travel and nest together in groups. They have some very specific nesting requirements: wide sand and shell beaches with high enough elevations to avoid tidal overwash, sparse vegetation that provides shade but does not harbor predators, and minimal disturbance from human activity. Beaches that meet these requirements are fast disappearing from Florida’s coast.
Once an appropriate beach is located, least terns construct their nests by making a shallow depression scraped in the sand. With no apparent nesting material, tiny clusters of well-camouflaged eggs can easily be trampled by unwary beachgoers and their pets.
Adult least terns are very protective of their young, and attempt to ward off intruders by dive-bombing. When this occurs, the adult birds are expending valuable energy fending off perceived predators, leaving eggs or young vulnerable to heat exposure. Consistent disturbance often causes the nesting colony to fail.
 Another threat to least tern nesting colonies is tidal overwash. Several areas locally that were once suitable for nesting have been reshaped over time and are no longer high enough or wide enough to sustain a colony. These changes can also occur overnight.
Coastal change events, such as extreme high tides or tropical storms, produce enough heavy surf and high tides to wash away scores of freshly laid eggs. When this occurs, many of the terns are forced to re-nest at adjacent beaches. This occurred at the Big Marco Pass colony earlier this year, and many of the terns were forced to re-nest. Many have relocated to adjacent beaches including Keewaydin Island.
Keewaydin Island is an unbridged barrier island within the boundaries of the Rookery Bay Reserve. Coastal processes over the past year have caused this area to become wider and the new beach is less vegetated. It now provides more suitable habitat than it has in previous years and the island currently hosts close to 100 nesting least terns. This area also serves as a popular recreation spot for boaters, fishing enthusiasts, beachcombers and campers, posing a greater challenge for land managers trying to balance the competition between wildlife and people for limited coastal resources.
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