Florida Nature in Late January

January 23, 2018

Nature Notes by Bill Dunson

So far in this new year of 2018 we have had some long stretches of cool weather, including light frost inland, interspersed with warm temperatures. I was surprised to see that some plants such as sea grape had brown leaves even at Wildflower Preserve, which is fairly close to the warming influence of the bay. Virginia creeper and poison ivy vines have bright red leaves now, a sure sign of winter. But why do these plants turn red when very few others do in Florida? One theory is that they both have relatively inconspicuous fruits (dark blue and white respectively) and birds are attracted to these fruits by the bright red leaves. This has been termed “fruit flagging” and is an interesting evolutionary strategy also utilized by black gum trees, which have dark fruit and leaves that turn bright red early in fall.
The extent of the light freezes has not been sufficient to kill all of the Spanish needles which are among the more sensitive sub-tropical plants to cold weather. This weedy plant is very beneficial as a nectar source for butterflies. Its flower, being a member of the aster or composite family, has a floral arrangement of many disc and ray flowers together in what superficially appears to be a single “flower.”

I was astonished to see a native green or Carolina anole lizard in our yard, which is filled with hundreds of the exotic brown or Cuban anole. The recent arrival of the brown anole by human agency has driven the green anole from most of its range where the two overlap. These two species are closely related (in genus Anolis) but the brown anole is competitively dominant ( http://www.anoleannals.org/2014/10/25/rapid-evolution-in-anolis-carolinensis-following-the-invasion-of-anolis-sagrei/ ).

We often have ground doves in our yard and it is charming how often you will see two of these tiny doves very close to one another. Of course I cannot be sure these are a mated pair, but it seems likely to be so. Their pair bond is strong and they are certainly “love birds” from our perspective. This may be an advantage in allowing these seed eaters, who feed their young crop milk, to quickly and opportunistically breed whenever conditions are acceptable.

One bird in our yard I have mixed feelings about is the mockingbird, which is famous for its song mimicry and night time serenades. Indeed this angelic aspect of the species was used as a primary concept in the famous novel “To Kill a Mockingbird.” Unfortunately mockingbirds are actually quite aggressive (one neighbor says they are “mean as a snake”- a slander on snakes I think). Thus they are liable to dominate food sources and chase away other birds. When we play god by providing food for birds we must deal with the consequences!

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.

View all posts by Bill Dunson