A Snowbird Returns to Paradise

November 17, 2013

Nature Notes by Bill Dunson


It is that time of year again when those of us that migrate southwards from our summer homes begin arriving in SW FL. The transition from northern plants and animals to FL biota is abrupt and somewhat jarring to the mind. I find it takes a few days for me to readjust thinking and become adept at recalling names of FL species. But it is wonderful to escape cold weather and a long period in which northern ecology becomes very quiescent. Now in the fall in FL we can enjoy seeing a wide variety of animals that may become harder to find once even the mild Fl winter sets in.

The butterflies have been just marvelous lately and one example of this is the spectacular orange barred sulphur male shown here nectaring on a firebush flower. These flowers, which primarily bloom in summer, are a long tubular shape which cannot be accessed unless the butterfly or hummingbird has a long tongue. The firebush is one of the most outstanding plants for both butterflies and birds since it provides nectar and berries. It is sensitive to cold and will be frozen back at times in the interior, but along the SW coast it is the “best of the best” for wildlife gardens.

A rare opportunity to see juvenile tarpon is being offered at Wildflower Preserve where a graduate student, JoEllen King, is taking monthly seine samples in Lemon Creek. Within this small tidal creek she has so far caught about 900 small tarpon and implanted about 150 with individual tags that are allowing records of movements to and from the bay. All fish are fin clipped for DNA testing to determine how far they move when they mature. The preliminary results so far are remarkable and reveal how important a seemingly insignificant creek can be in the biology of tarpon. The most crucial aspect of the habitat may be the low oxygen and food present which nurture the air-breathing tarpon while reducing their competitors and predators.

When I wake up at night in our FL house I am usually not confused about whether I am still up north since we have geckos that run around on the walls. These are primarily now tropical house geckos originally from Africa. They are a great natural pest control for bugs if you can tolerate the lizard poops. It is interesting that when we first came to Englewood in the early 1990’s a different gecko, the Indo-Pacific gecko, was more common. It is an all female parthenogenetic species which has now almost entirely been replaced by the males and females of the tropical house gecko, a good illustration of the power of sexual reproduction to foster more genetic variation and better competitiveness. The mechanism by which these geckos can walk on walls is now known to involve additive tiny molecular attractive forces between vast numbers of tiny fibers in the feet and the substrate.

I have a favorite chair where I sit to read and I keep an eye out for interesting critters just outside in the yard. I have a water drip set up and can see birds coming for a drink of freshwater which is a rare commodity on a barrier island. In this case a yellow throated warbler came to drink from the drip, and subsequently took a bath in the pool. This beautiful warbler is associated with palm trees in FL and we observe it high in tall river side trees along the New River in VA during breeding season. But up north I never get a chance to observe it so closely as here in our FL yard.

Another bird that is seen up north but not so commonly as we observe them in FL is the bald eagle. While walking on the beach I saw this juvenile eagle land and look around for a possible breakfast. Young bald eagles do not attain the white head and tail for more than four years so this is probably a juvenile from a nest made last winter. In FL we get a chance to observe a lot of interaction among eagles and ospreys since eagles often attempt to steal fish from ospreys. They are not always successful as I have noticed that a pair of ospreys that breed in a tall Norfolk Island pine directly over our house often are able to fly above the eagles and escape from their attacks.

For the naturalist there is no greater pleasure than enjoying natural scenes with abundant and active animals every day. Florida provides a wonderful respite from the winter chills of northern climes and an opportunity to observe some familiar species and a number of new ones that are found only in southern climates. It challenges our minds to master the new names and see how the new ecological relationships in SW FL are similar to and different from what we have known in other habitats.

Bill Dunson, Englewood, FL & Galax, VA

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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