There it is! A dark blue body silhouetted against a clear sky with those long legs neatly tucked behind. Unmistakably it’s a great blue heron. And over there, the pure white feathers of a snowy egret with its black bill and golden feet, the neck darting into the shallow water in hopes of a next meal. It always brings a smile to faces as we enjoy our area birds. Maybe subconsciously we are understanding the importance of their presence. And maybe we are making a mental note that we don’t see as many as we used to.
The 2017 nesting season for many of our wading birds is coming to an end. Several agencies will be turning in their reports for evaluation and we will soon know if this was a successful year for these area residents.
We have quite a variety of waders in South Florida. Several species of ibises, egrets and herons call our region their home. In addition, the wood storks, spoonbills, and, to our east, the American flamingo also patrol our waterways for food. From the above list, five of these are considered “indicator species.” The successes and failures of their nests each year have come to represent the health of the entire ecosystem.
Nest counts are a reliable way to monitor these birds. If there are no nests, or just a few, there are fewer fledglings. This means we will have fewer adult birds in the future. Southern Florida was once home to more than 2.5 million wading birds and, sadly, that number is drastically reduced today. Scientists have spent 22 years watching 18 species in the Everglades and surrounding coastlines.
Those indicator species that give an overview of all activity are the wood stork, great egret, tri-colored heron, snowy egret and white ibis. Since we are just ending the 2017 season, many statistics are still unclear but the nesting season of December 2015 through July 2016 showed signs of difficulty for the birds and their habitats.
Although disappointing, this drop is not a surprise. Wetland ecosystems thrive (or not) because of water levels, which can vary depending on a combination of sea level, rainfall and the amount of water moving across the landscape. For the 2015-16 nesting season the region experienced both unusually high and low water levels in patterns that complicate life for birds.
One indicator species, the wood stork, responds directly to rainfall amounts. They thrive in wet summers, when fish are plentiful, and also in dry winters, when fish retreat to smaller pools, making fishing easier and food plentiful for feeding their young. Last year we had a dry summer and a wet winter. The storks missed their nesting time because of a lack of food. Wood storks produced 1,457 nests, which was a 38 percent decrease from their 10-year average.
Other indicator species like the snowy egrets and the tri-colored herons produced about half as many nests as their 10-year average, while great egret numbers were only down seven percent from their 10-year average. Great egrets did better, because of their long legs, and could navigate for food in deeper waters than the other birds.
The loss of the freshwater flow southward from Lake Okeechobee through the Everglades is taking a toll on Florida Bay, and some of its wading birds as well. Eight hundred fifty miles of shallow water that is home to mangrove islands, seagrass meadows and reefs in and around the bay are having trouble surviving. With no fresh water, the bay became so salty that the seagrass beds, a cornerstone of the bay’s overall ecosystem, died and large clumps of the grasses completely uprooted themselves.
This could have a negative impact on birds like the roseate spoonbill that thrived in a nearby lagoon. They have now moved inland because of habitat loss.
In conclusion, we may not need reports from many different agencies to explain our ecosystems. The birds are already telling us that the system is broken. I hope to never see the day when I look up and say “There it is, silhouetted against the clear blue sky…nothing.”
Bob is the owner of Stepping Stone Ecotours and a naturalist on board the Dolphin Explorer survey program. He is a member of Florida SEE (Society for Ethical Ecotourism). Bob loves his wife very much!