Dr. Jerry Jackson

Winter is when many Florida plants become dormant and lose their leaves until spring. In contrast, most of our ferns remain a vibrant green through the winter. This is in part because ferns are plants that live in moist environments and the water buffers them from the cold. A winter visit to a marsh, swamp, or other wetland can be refreshing on a cold winter day in south Florida. While other plants lose their leaves, ferns generally have a more intimate contact with their wet environment. Fern diversity in wet areas can be spectacular – each species occupying a somewhat unique niche, thus minimizing competition with other species.

Gray Squirrels are our most common squirrel and are with us year-round. They have a diversity of adaptations for survival and are sometimes considered a scourge if they nest in an attic, munch on fruits, or take the food we put out for wintering birds. They vary seasonally in color – mostly gray in winter, more brown in summer allowing them to better blend in with seasonal changes in vegetation. The openness of winter habitats and the proliferation of bird feeders often make these squirrels easier to observe.

Pigeons and Doves are members of the same family – Columbidae – and the names “pigeon” and “dove” have little relevance. Those we call “pigeons” are generally larger than those we call doves. Pigeons and doves occur on every continent and many islands and about 300 living species of pigeons and doves are known. Seven species are regularly found in Florida -- five are native; two are introduced. Others are occasionally seen. One – the Passenger Pigeon – was known from Florida, but now extinct.

Animals in south Florida don’t have to worry much about winter cold – and indeed many migrants from areas farther north find suitable living conditions here. But, a trip to the beach or on a rare blustery day sometimes makes one wonder. How do ducks, herons, egrets, and other birds tolerate wading or swimming in cold weather? Aquatic birds, for example, have bare skinny legs with leg muscles placed among insulating feathers. Blood vessels going to and from the very few muscles in the legs and feet lie right next to one another, and cold blood going back into the body is warmed by warmer blood coming from the body – and is nearly the same temperature as the blood circulating in the well-insulated body.

If asked “What plant best symbolizes the winter season?”, most people might say “Christmas trees”, but a fair number might instead suggest holly. Several species of holly are native to North America. Most are evergreen, have thick, somewhat shiny leaves that are resistant to colder climates, and are bordered and tipped with sharp points that protect the leaves from winter plant “munchers”, and in winter bear small red fruits that add to their winter holiday appeal. The fruits are eaten by many bird species and the seeds inside the fruits are deposited with a bit of fertilizer to begin growth in the spring. Some holly species grow into large trees. Others remain shrub-sized. Many are sold and planted throughout North America – including in south Florida. But the only holly that is native to south Florida is dahoon holly – generally a small tree or shrub that is at home in shaded wetlands such as at Corkscrew Sanctuary and areas within the Everglades ecosystem. While dahoon holly has thick, heavy, evergreen leaves – characteristic of hollies, dahoon holly leaves have a pointed tip, but are relatively long and have no pointed barbs along the leaf blades as on the leaves of other holly species.

New World Warblers are often referred to as the “butterflies of the bird world” – a designation because of their small size and diverse colors and patterns. A few warblers nest in south Florida, but several -- including the Palm Warbler, Yellow-rumped Warbler, and Black-and-white Warbler are common winter residents. These three have distinctive plumage patterns and behaviors, making them a great trio to begin exploring the diversity of warblers that pass through on migration. Beware, however: watching warblers as they flit among the branches of tall trees in search of insects can be addictive – and lead to a temporary affliction commonly known among birders as “warbler neck”.

Little Blue Herons are medium in size among herons – bigger than a Green Heron, but much smaller than a Great Blue Heron. The “blue color” of adults often tends towards gray and it helps them blend in with their aquatic environment. This heron is unusual in that its juvenile plumage is all white – a characteristic that allows it to blend in with other white birds – which it readily does, thus gaining “group” protection from potential predators and access to food resources found by the other species. Adults are much more solitary.

The Black Skimmer is a very unusual shorebird – in part because of its exceptionally long, knife-like lower bill and much shorter, slightly-curved upper bill. The knife-like lower bill isn’t for cutting, but for slicing through calm surface waters near shore and in shallow ponds and lakes. When the lower bill strikes a small fish, the fish slides up the bill and the upper bill clamps down on it.

Wild Turkeys are birds that most of us know on sight because of their large size, habit of foraging in groups in relatively open areas, and the display of a male with his tail held up and fanned. Of course we know them because of their prominence at our holiday dinner tables – and in holiday advertising -- especially at Thanksgiving. Males are larger than females – even when not “puffed up” and displaying. Males also have iridescent plumage, multiple colors on their mostly bare head and neck, and a prominent fleshy structure called a snood on the forehead that becomes enlarged and more colorful during interactions. Females are smaller, have duller, non-iridescent plumage, only a blue-gray head and neck, and a smaller, less colorful snood. Studies suggest that females prefer males with longer snoods and that the snood may indicate a resistance to some diseases.In this week’s Wild Things we’ll talk a bit about the behavior and ecology of Wild Turkeys, the origins of their name, and our relationship with them.

Molt is defined as the routine loss and replacement of feathers. It can occur at any time of year, but in most birds a complete molt occurs in late summer and fall and a partial molt may occur in early spring. The timing of each molt is important. In late summer and fall, there is generally an abundance of insects, seeds, and fruit that provides the energy for molt. This molt provides birds with fresh plumage and often colors and patterns that help conceal it in winter environments.