Christmas in a Warm and Dry SW Florida

As our drought continues in SW FL, freshwater ponds are continuing to decrease in volume while tidal areas remain full. This is clear with an examination of minimally tidal Lemon Lake in Amberjack Preserve where the water is at a high level due to low evaporative water losses this time of year. In summer the lake may even dry up leading to a massive concentration of wading birds feeding on stranded fish. You will notice a rim of macroalgal growth around the edge of the lagoon due to high levels of nutrients running off from the land, including from Lake Okeechobee..

In comparison, the water level of a constructed fresh water lake in Ann and Chuck Dever Regional Park in Englewood is quite low. Consider a planted cypress tree considerably above the water level with two cormorants perched in the top. The base would normally would be in the water about two feet deep. This former higher water level is recorded in the “lichen line” on the trunk. Lichens are intolerant of immersion in water and die when submerged. Thus the position of the lichen line records the highest water level reached recently. Periodically lower water levels are quite beneficial for wading birds as can be seen in a series of photos I took of birds feeding in the shallows. There was a mixed species flock of numerous glossy ibis, black bellied whistling ducks, great and snowy egrets, wood storks, little blue herons, anhinga, cormorants and gallinules. It is interesting that such a beautiful array of birds was present in a pond not managed as a nature preserve- indeed this and nearby ponds are alternately overgrown with dense cattails and then poisoned by Charlotte County to open them up. This part of the park is designated for “active” human use and is adjacent to a dog park. Yet it attracts considerable wildlife. This illustrates a growing environmental movement in which human dominated landscapes are encouraged to be managed in part for wildlife.

The male anhinga drying its wings along the bank is an interesting tale. For years it was believed these birds lacked oil glands and thus had to dry their wings after fishing. In fact anhinga and cormorants have evolved fur like feathers which absorb water and allow them to be neutrally buoyant in water and thus hunt fish more efficiently. But in consequence they must dry these specialized feathers after swimming to be able to fly.

Some other interesting birds I noticed recently were white ibis perched in mangroves along Lemon Bay. They have become very efficient in foraging in yards as well as shallow aquatic habitats. I have an immature red shouldered hawk that hunts in my yard regularly and apparently is successful in catching small prey- it certainly has my iguanas running scared! A new species that arrived this week was a flock of red winged blackbirds. They gather in large groups in winter and forage around the countryside. This young male with its bright red epaulet just showing visited my dripping water bath. This red mark is used as a sexual display in defending territory and in attracting females. Redwings may be considered “trash birds” by some but in my opinion they are beautiful ! Another very pretty bird seen up close is the mourning dove- considered as “cannon fodder” by hunters.

Butterflies are somewhat scarce this time of winter. I did find several rarely seen mangrove buckeyes down along the bay. This very habitat specific species has only recently (about 250,000 years) split off from the its parental stock of the widespread common buckeye. The caterpillars feed on black mangrove and obviously specialize in living just along the mangrove fringe. Another very different food specialist is the orange barred sulphur which feeds on sennas/Cassia as a caterpillar and flies very fast, presumably to diminish predation by birds. I still see many monarchs in my yard and some new exciting information has become available on their migration. A tiny bluetooth transmitter with a solar panel is enabling tracking of individual monarchs (see map of tracking data). I had thought that all FL monarchs were sedentary but these data show that some monarchs from eastern N America are transiting FL on their way to Mexico ! It seems likely that there are local monarchs that remain in FL but that needs to be tested by placing transmitters on them.

A new bug has appeared on my giant milkweeds- the large milkweed bug, Oncopeltus. They are one of the specialized insects that feed on milkweed and as such are quite interesting if somewhat less than desirable since they can be a pest. Note that they also are brightly colored to advertise the toxicity they gain from eating milkweed.

While hiking near Lemon Lake I noticed some insects attracted to large yellow flowers of the non-native seedbox, Ludwigia. These plants thrive in nutrient enriched waters which are common in southern Florida. Their flowers are a prime place to look for pollinators- in this case a specialized Caribbean scoliid wasp, Dielis dorsata (https://treasurecoastnatives.wordpress.com/2021/07/17/invasive-exoticwasp-on-purpose/). The reference points out that this wasp was actually introduced from Puerto Rico to control sugar cane beetles! How much it may impact native scarab beetles we would not want to destroy is uncertain, but this illustrates the complex web of species interactions that humans have interfered with. If life were only simple !

The good news is that this time of year in SW FL many people are still up north or visiting the grandparents and it is quiet here and the weather is superb. Look at a photo I took of the beach just across the street from my house- very peaceful ! But wherever you are I hope you can get outside and just enjoy nature !