Ponds are full of young freshwater fish species that have become trapped in shallow seasonal pools. A number of species of wading birds arrive from nearby nesting trees to feast on this bounty. Among them are Great Egrets, Great Blue Herons, Tricolored Herons, Roseate Spoonbills, Ibises and Wood Storks, all swooping down to feast along with the Ahingas and Magnificent Frigatebirds.
Abundant water has created ideal breeding conditions, and wading birds are nesting in some of the largest numbers in recent history. According to Audubon, more than 46,000 nests of seven wading bird species were recorded in 2017. Bird surveyors in the Everglades Protection Area, which includes Everglades National Park and conservation areas to the north, have counted 3,141 Wood Stork nests, more than double the 10-year average, and approximately 8,000 Great Egret nests, about 25% above average. White Ibises are breeding in droves with 34,400 nests spotted. That's 50% more than usual. One ibis rookery contained as many as 18,000 pairs, a possible record for that site. Viewed from an airplane, ibises appeared as little white dots for miles around their colony. They clustered in pools in the sawgrass marshes to gorge on crabs and fish.
The Everglades are North America’s most important breeding area for wading birds. Populations have declined nearly 90% since the early 20th century. Massive efforts are continuing to restore the hydrology of this ecosystem. Experts are hoping the recent bird resurgence confirms the resiliency necessary to rebound.
Ecologists with the South Florida Water Management District believe the system can still be restored if the water is made right. Over the past century, development and agriculture have drained half of the original 4,000+ square miles of the Everglades. The river that flowed south from Lake Okeechobee into the present Everglades National Park and out to Florida Bay has been heavily engineered. Canals, pumps, and dikes diverted water east and west. These drainage projects resulted in an increase of homes and farms along with the attendant pollution. They also hampered water flow into the Everglades which left wading birds with much less wetland habitat and fewer food sources.
(Great White Heron)
For millennia, rain-fed water flowing south filled up wetlands which then gave rise to young fish and crayfish. Receding water levels left pockets of stranded prey. This isn’t as important for egrets and other birds that hunt by sight, but birds like spoonbills, storks, and ibises use their bills to probe shallow water for food. They rely on these pockets to feed their young and teach them how to forage.
Currently, many shallow wetlands never fill which forces wading birds to breed elsewhere. They sometimes wait until deeper pools retreat enough to make foraging possible. This results in chicks fledging later and being less likely to survive. Wetlands may dry up too fast leaving nestlings vulnerable to predators like raccoons and alligators.
Heavy 2017 rains followed by gradual draw-down during the dry season made for ideal nesting conditions. The flush of fresh water helped dilute salinity and gave a jumpstart to prey-fish production in Florida Bay, the Everglades-fed estuary that lies between the mainland and the Florida Keys. Up to 400 pairs of Roseate Spoonbills nested there beginning in November. This was months earlier than recent years and in line with their traditional breeding time.
Birds also resumed nesting on mangrove islands which wentagainst their trend of colonizing inland areas to avoid salty, rising seas due to climate change. With only 6 inches of sea-level rise, their 9-inch bills left them no place to forage. Ocean currents slightly lowered local sea levels and seem to have provided at least a temporary reprieve.
Rising waters could eventually put those islands off-limits for spoonbills, but that didn't start their decline. Lack of freshwater flow from the Everglades into Florida Bay was the cause. Only replenishing that flow can offset the saline ocean water entering the bay. It’s necessary to restore the Everglades in order to counteract sea-level rise and keep out the salt.
The work is not close to being completed. Lack of funding, politics, and red tape have contributed to the slow pace. However, projects expected to be completed in the next 5 years will make a major impact on the area.
Renewing the water flow will boost numbers in current breeding areas and should also draw more waders back to traditional sites. A century ago, Audubon's Thomas Gilbert Pearson reported seeing 100,000 Wood Storks in the shallow wetlands at Corkscrew Swamp Sanctuary, historically home to North America’s largest colony. Since then, an estimated 80 percent of the wetlands have been drained or filled. In most of the last 10 years no Federally Threatened birds have nested at Corkscrew. They’ve opted for marshes and managed wetlands in South Carolina and Georgia. Torrential rains last summer replenished the shallow wetlands and lured many birds back. Most of the 400 nests counted held two or three chicks. This shows that with the right conditions, the birds will nest successfully.
Weather conditions alone can't ensure the birds' return. It’s essential to preserve wetlands, especially shallow wetlands where waders forage early in their nesting season. Despite Everglades restoration efforts, the Big Cypress Swamp Watershed including Corkscrew lost more than 43 square miles of wetlands to agriculture and development during the years from 1996 to 2010.
Currently, an Audubon team is actively restoring hundreds of acres where storks have again begun to forage. These efforts complement a larger Everglades Restoration Plan to replenish the wetlands. The Picayune Strand Restoration Project will rehabilitate more than 50,000 acres.
Today storks, spoonbills, and ibises are emerging from their nests and learning to forage for themselves. Someday they could return to gather food for their own chicks in a new home in a completely restored Everglades. That is definitely good news.
(map: By Kmusser [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0) or GFDL (http://www.gnu.org/copyleft/fdl.html)], from Wikimedia Commons; references: National Park Service; National Audubon Society)