March 17 Wakodahatchee Wetlands

This was the last day of real birding on the Florida WFB trip and this small patch of preserved wetlands was chock full of wading birds and other wetlands species. Within an hour and half I counted more than 40 species and up near 250+ individuals. It was approximately mid-afternoon, bright and sunny, with a temperature of around 70 degrees. It was just a sheer number of birds in such a small 50 acre parcel. The biodiversity found here within a matrix of suburbia seemed odd, but the water pumped into this wetlands is highly treated.

With such a high concentration of birds there was a plethora of intense infraspecific and interspecific interactions/competition. One of the most intriguing interactions was a 15 minute battle over a medium sized fish. One Great Blue Heron brought a fish back to its nest on-top of a tree above the water (that is shared with at least 10 other nesting pairs of Wood Storks) and began to fight over it with another Great Blue Heron, not entirely sure if they were a nesting pair. Strong peck like strikes at the body/wings were common, eventually the bill of the first Great Blue Heron was covered in blood. Then a nesting pair of Wood Storks joined in, snagging the fish from the Herons and rightfully defending it for approximately ten minutes. One of the Great Blue Herons showed an aggressive display by rearing backwards while flapping its wings and thrusting its head upwards into the sky. The Wood Storks won this dispute.

While there I also witnessed a brief foraging territorial battle between two Great Blue Herons. The original forager was patiently foraging for fish, standing still, when a competitor approached from the side slowly walking on land. The original Heron turned and jumped 2-3' into the air, splaying out it's wings and flapping them. This jump repeated 4 more times. The competitor returned this display only twice and quickly flew away. There was no physical contact. It is apparent that these territorial disputes, rather over foraging or nesting territory, rarely become physical and rarely does the original individual lose its territory. The dancing display they showed is a way of showing physical strength and dominance, this way neither individual becomes fatally injured. I also witnessed multiple Wood Storks "clicking" their bills together while on their nests. While at first it seemed an aggressive interaction, Dr. Allan Strong mentioned it was their way of recognizing one another and saying "hello".

The Wood Stork and Great Egret both have strikingly white plumages. One would presume that it cryptically hides them against the glare of the sky from fish. However, upon further research and discussion it seems that the white stands out amongst their habitat which makes finding colonies and other conspecifics easier. The Rosetta Spoonbill gets its pink coloration from the carotenoids in the shrimp they eat. It is interesting to ponder whether their pink coloration has an evolutionary purpose, like showing the age class and individual fitness, or its just a byproduct of their diet. Then on the other spectrum there is the Clapper Rail, spotted not at Wakodahatchee but at Little Talbot State Park. Using a recording we got over 6 individual Clapper Rails to call back, all of which where within 10 feet. But, it was impossible to see them in the 2' tall grass. Their dark brown cryptic coloration makes it near impossible to see in the grass and their ability to extend their necks and body laterally makes it impossible to spot movement. Entirely a different strategy compared to the wading birds.

At Wakodahatchee and Anhinga Trail (in Everglades National Park) it was interesting to watch Wood Storks and Black Vultures go about their daily schedules. The Black Vultures have become a serious nuisance to visitors as they peel the coamings off of car doors in the morning with zero apparent reason. However, once noon time came around and the air heated up, thermals formed and they took to the skies to fly in kettles without a single one being left behind. It is apparent that this is a circadian rhythm. The Wood Storks also spent their early mornings on their nests or on the dock preening, sunning, or warming their chicks. Then when the sun came out they began to forage, one individual hunting and the other staying with the chicks. This seemed to continue throughout the day. While at Wakodahatchee a woman commented that in years past most of the nesting birds were Great Egrets, which now almost entirely have been replaced by Wood Storks. Upon further discussion we realized that it was due to a difference in circannual rhythm where the Wood Storks most likely nest earlier and either got to the nesting sites first or that they would leave and the Great Egrets will come later in the year.

During this trip I was able to pish some birds into view on a regular basis. It is incredible how well this works. I believe that most birds respond because it sounds like an alert or distressed bird. This means that there is a predator nearby that these smaller flocking birds need to watch out for, and so they are investigating to ensure they know what and where the danger is coming from. It's similar in reasoning to why the "Magic" recordings of Barred Owls, Red-Shouldered Hawks, and American Crows always works flawlessly. They just want to know where the danger is.

Posted on March 26, 2018 04:17 PM by srotella