Birds, Butterflies and a Snake in the Grass

December 7, 2014

Nature Notes by Bill Dunson










I am writing this in early December in Florida after a period of rains and some cool fronts. To attract butterflies you must provide flowers for nectar and larval food plants. No sooner had we planted a Mexican milkweed than a queen and three monarchs showed up. This was a good chance to compare the colors and patterns of these two toxic Muellerian mimics. Black and yellow Zebra butterflies were also flying nearby; their toxicity comes from consumption of poisonous passionvines by the caterpillars. The evolutionary warfare between predator and prey has certainly given us some beautiful butterflies!

The best way to attract the spectacular and rapidly flying sulphur butterflies is to plant the larval food plant, sennas/cassias. At Wildflower Preserve there was one senna with a considerable number of large cloudless sulphur caterpillars on the flowers. Note how well they are camouflaged when they are in the flowers; the bands are disruptive of their body shape and the yellow blends with the background. We had recently planted a senna in our yard which attracted a female orange barred sulphur which appeared to be laying eggs. So we are hoping for a crop of little ones soon.

While walking at South Venice Lemon Bay Preserve with a native plant group, one sharp eyed member sighted a real snake in the grass. It was a tiny ringneck snake with its namesake necklace and a beautiful reddish abdomen. It coiled its tail and displayed the red underneath in an apparent defensive display. I am not aware of these tiny snakes being distasteful to predatory birds but this behavior certainly suggests that they are.

Our yard is quite a haven for birds due to our extensive plantings and a prime location on Manasota Key with the Gulf of Mexico to the west and Lemon Bay to the east. I sighted an anhinga near our dock which is an unusual occurrence since they are primarily a freshwater bird. They apparently lack the nasal salt gland that allows marine birds to drink sea water; in salt water their ecological niche (a diver that swims after fish underwater) is occupied by the cormorant. Another example of this phenomenon is the yellow crowned night heron in salt water and the black crowned in fresh water along this coast. Royal terns in salt water and Caspian terns in fresh water also generally fit this model.

Avian winter residents/migrants are starting to become more evident in our yard, especially if you provide a water drip to attract them. Thus we were excited to observe blue headed vireos, yellow throated warblers and house finches coming to drink and bathe this week. Close-up views of these birds can reveal amazing details which are not usually visible through binoculars. The white eye ring of the blue headed vireo is especially striking since many animals have dark eye lines that camouflage the eye itself. We see male house finches that are reddish or yellowish (supposedly a SW US trait) but this individual had a mixture of both colors. The striking yellow throated warbler is somewhat unusual in that the males and females have very similar plumages and are very partial to feeding in palm trees in Florida or in evergreen trees or trees along rivers up north. But they are often so high in the trees that our views at ground level are wonderful.

So wherever your home range is you will now be experiencing some major changes in the fauna of your area. Enjoy the challenges and rewards of identifying and studying the critters under fall and winter conditions.

Bill Dunson

About Bill Dunson

Bill Dunson, born in rural Georgia, skipped 12th grade and went directly to Yale. Bill subsequent-ly received a PhD in Zoology from the University of Michigan, studying softshell turtles. Bill is Professor Emeritus of Pennsylvania State University thanks to a career spent entirely at that institution, teaching and doing research on the physio-logical ecology and ecotoxiciology of reptiles, amphibians and fish. Always curious about nature, Bill has dedicated his life to learning and sharing his knowledge with others. He has served on many advisory boards here in Southwest Florida to preserve the water that gives life to our region.

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