[bcbirdclub] A Fall Nature Ramble in Florida

  • From: wdunson@xxxxxxxxxxx
  • To: wad4@xxxxxxx
  • Date: Mon, 10 Nov 2014 13:22:47 +0000 (UTC)

I have for some time been dissatisfied with being primarily interested in one 
aspect of natural history such as birds or plants. The variety of fascinating 
creatures I have encountered this week illustrates the difficulty of 
restricting your scope of curiosity. I admit the problems of identifying some 
of the critters and plants can be daunting, but the advent of internet interest 
groups and simplified identification manuals makes this manageable. 

My son, who was visiting from Utah, found this pair of horseshoe crabs 
(Limulus) in tandem near the southern tip of Little Gasparilla Island. Of 
course these are not crabs at all but harmless relatives of the 
spiders/arachnids which are very ancient marine inhabitants. The smaller male 
has two appendages to hold on to the female until she crawls up on the beach to 
lay her eggs. The bluish blood has special clotting properties which are quite 
valuable in medicine, and the eggs are invaluable also in feeding migrating 
shorebirds. The shed exoskeletons are seen more often than the live animals so 
it was a special treat to find this pair. 

I never cease being amazed by dragonflies and was fascinated by this immature 
common green darner. This is a very old lineage of insects which is predatory 
both as aquatic larvae and as the aerial adult. Their behavior is highly 
visually oriented and the enormous compound eyes made up of 30,000 individual 
ommatidia are remarkable. The legs are covered with spines which help in 
holding prey caught and often consumed in flight. Green darners migrate long 
distances and are capable of complex social interactions. They have become 
popular objects of observation by those who have mastered birds and want to 
find new intellectual fields to conquer. 

One of the insects most opposite to dragonflies in terms of mobility is the 
walking stick which is slow moving and camouflaged. You may often find these as 
mating pairs in Florida and they are sometimes called devil-riders, possibly 
due to the ability of the large female to squirt toxic terpenes into the eyes 
of an attacker. So be careful when you examine them! 

I spend a lot of time working in our yard and often find interesting critters 
such as this small greenhouse frog introduced from the Caribbean. It likely 
immigrated in the root balls of plants brought in by nurseries along with the 
worm-like Brahminy blind snake. It is quite unusual among amphibians since it 
lays terrestrial eggs that hatch directly into tiny frogs without an aquatic 
tadpole stage. The advantage of this in habitats with damp soil but which lack 
fresh water pools is obvious and allows them to colonize areas unavailable to 
other frogs. 

Two snakes turned up in our yard, a very young corn snake, one of the rat 
snakes, and a black racer. The corn snake has a series of dark lines on the 
head, one of which passes through and obscures the dark pupil of the eye. The 
black racer has a dark area on the upper part of the head, including the dark 
pupil and a reddish iris. Both of these patterns must make it harder for prey 
or predators to detect the snake when it is motionless. The corn snake is much 
more arboreal than the racer and this likely provides some habitat separation 
which limits competition for food between them. 

I was excited to find an adult male Florida box turtle on Palm Island. Although 
males often have a reddish iris at least some of the year, the reliable way to 
sex them is by the concave shape of the bottom shell or plastron. The purpose 
of this obviously is to facilitate mating which must be quite difficult given 
the rigid shells. Indeed poet Ogden Nash penned the famous lines, 

The Turtle 
by Ogden Nash 

The turtle lives 'twixt plated decks 
Which practically conceal its sex. 
I think it clever of the turtle 
In such a fix to be so fertile. 

While sitting at the computer recently I heard a familiar sound which I knew to 
be the call of a bald eagle. I rushed outside and looked up at the osprey nest 
which sits immediately over our house in a tall Norfolk Island pine. There were 
two eagles sitting in the nest engaged in some bill fencing which soon led to 
mating. The eagles then left and did not seem interested in taking over the 
osprey nest which they occasionally try to do. The relationship between these 
two predators, which compete for fish as food and sometimes for nest sites, 
reminds me of the uneasy relations between lions and hyenas- in other words not 
friendly! 

So try expanding your horizons and learn a new animal or plant from a taxonomic 
group with which you are not familiar. It is not as hard as you might think and 
it will be very rewarding. 

Bill Dunson 
Englewood, Fl & Galax, VA 

http://lemonbayconservancy.org/news-blog/nature-notes-by-bill-dunson/ 





Attachment: Horseshoe crabs in tandem at Little Gasp Pass 11.6.14 Bill Dunson Jr aa.jpg
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Attachment: Darner common green Palm Isl 11.6.14 Bill Dunson IMG_3558 cc.jpg
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Attachment: Walkingstick FL Don Pedro Isl 11.7.14 Bill Dunson IMG_3605 aa.jpg
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Attachment: Greenhouse frog from FL yard 11.8.14 Bill Dunson IMG_3650 cc.jpg
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Attachment: Corn snake hatchling from FL yard 11.8.14 Bill Dunson IMG_3624 aa.jpg
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Attachment: Black racer head from FL yard 11.8.14 Bill Dunson IMG_3637 aa.jpg
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Attachment: Box turtle Palm Isl FL 11.7.14 Bill Dunson IMG_3572 aa.jpg
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Attachment: Box turtle FL plastron Palm Isl FL 11.7.14 Bill Dunson IMG_3575 bb.jpg
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Attachment: Bald eagles in osprey nest over Dunson FL home just before mating 11.8.14 Bill Dunson IMG_3617 aa.jpg
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