by Patrick Higgins

It was dark. Glen Stacell and I were rolling slowly down Janes Scenic Drive with lights dimmed in his pick-up truck. There was just the soft crunch of tires on gravel. The silhouettes of cabbage palms and cypress contrasted against the evening sky.  Each of us had an arm out a side window holding a small black device aloft listening for clicks.  We were reconnoitering our upcoming new moonlit tram tours and searching for some of Fakahatchee’s bats.

Eastern pipistrelle, Fakahatchee’s smallest bat. Photo by Dr. J. Scott Altenbach

Eight of Florida’s 13 species of bat frequent the Fakahatchee; the Seminole bat (Lasiurus seminolus), Big brown bat  (Eptesicus fuscus), Brazilian free-tailed bat (Tadarida brasiliensis), Evening bat (Nycticeius humeralis), Eastern pipistrelle or Tricolored bat (Pipistrellus subflavus), Northern yellow bat (Lasiurus intermedius), Rafinesque’s big-eared bat (Corynorhinus rafinesquii)  and the endangered Florida bonneted bat (Eumops floridanus).

The Seminole bat, Northern yellow and pipistrelle are solitary roosters utilizing clumps of Spanish moss, dried palm fronds and old tree cavities.  The others are colonial roosters. The Brazilian free-tail and Big-eared have now adapted to man-made structures.  The Brazilian likes bridges and picnic shelters, and is particularly partial to the crevices under barrel tile roofs, a penchant shared with bonneted bats. The Big-eared strays less far from its preferred forest habitat and is more likely to use old cabins and sheds. The evening bat is less picky and sometimes found in the folds of patio umbrellas.  All are slow reproducers with typically a single pup born each spring.

Like all bats they are the subjects of many misconceptions, even being referred to as flying rodents. Bats are in fact in an order all of their own, Chiroptera, from the Greek aptly meaning hand-wing, and may be closer related to primates than rodents.

They are a diverse group accounting for almost 20% of all known mammal species and can be divided into two suborders; the megabats or flying foxes of the old-world tropics, sometimes referred to as fruit bats, and the ubiquitous microbats which include all of Florida’s species.

Our bats are small; ranging from our smallest, the Eastern pipistrelle with a 9” wingspan but weighing in at a mere ¼ oz, to our largest, the Florida bonneted bat with a 20” wingspan but, still only about 1 ¼ oz weight. Despite their diminutive body mass bats are extraordinarily long-lived. Some bats weighing less than an ounce have lifespans of 30 years.

Flying foxes in particular put paid to the myth ‘as blind as a bat’. They have excellent binocular 3D color vision.  But even the smaller eyes of our microbats have highly refractive lens and are densely packed with rods. They have good night vision, but nobody goes around saying, “as sharp as a bat’s eyes at night.”  Microbat eyesight is however made largely redundant by their ability to echolocate: to use reflected sound waves to map their environment in the same manner as dolphins.  This remarkable sixth sense allows them to determine distance, size, shape, texture, speed and direction.

Not only are bats not the harbingers of evil portrayed in horror films, they are highly beneficial, providing many important ecosystem services. Not least of these in Florida is that our species are all insectivorous typically consuming their own body weight in insects every night.  Depending on the size of the bat and size of the insect this can total several thousand ‘bugs’, many of which may be agricultural pests.  In other parts of the world they provide pollination services as well.

As Glen and I proceeded, our scanners periodically rippled to life, with the distinctive slower pulses of bats in the search mode, followed by increasingly frantic chirps as they closed on their targets, culminating in a feeding buzz which ends abruptly when the insect is scooped by wing or tail membrane into its mouth.  Occasionally we also picked up insect noise when it intruded into the bats’ frequency range, but this was a like a low muffled roar and easily distinguishable.

We think of nocturnal predators as being quiet, but bats are noisy, broadcasting at 110-120 decibels, which is the same level as standing next to a jackhammer. So it’s a good thing that most of their calls are ultrasonic and well above 20 kHz, the upper limit of human hearing.  It makes perfect sense being so loud if you’re trying to resolve a moving object as small as a mosquito.

Our Swiss bat detectors are only the size of cigarette packs but quite sophisticated, as well as quite expensive, although I won’t say quite how much in case my wife reads this.  They automatically scan the full chiropteran echolocation frequency range, which varies by species. They then transform the chirp into our audible range, modulate its volume, and display its frequency. This provides a clue to identification, but only a clue as the call ranges of many bats overlap.  However, armed with this and the knowledge of what bats are likely to be found in any given area, one can make a pretty good guess.  Even more sophisticated bat scanners can record wave patterns that can be downloaded onto a computer for analysis and positive identification.

But this aerial combat is not all one sided.  Many insects can detect the bats signals and take evasive actions or apply countermeasures.  Some moths will fold their wings and suddenly drop to the ground. Tiger moths take a different tack. Their larvae feed on toxic plants that make them taste nasty so they emit a series of clicks to warn off an approaching bat.

Earlier in the day Glen had a sugared a few trees along our route with a homemade concoction of rum, molasses and brown sugar.  I would rather have drunk it, but he painted it on several trunks in the hope of attracting moths. The idea was to see what the bats might be feeding on.  It worked well up north, but we didn’t have any luck with it that night, so will revert to the time-honored tradition of a white sheet and backlight for our tours. We had better success with the fireflies and were able to attract a few towards us using a keychain LED flashlight, but you have to get the flash pattern just right for the particular species.  We look forward to sharing our new skills with our moonlight tram riders and boardwalk-after-dark strollers.

Night Ramblings
by Patrick Higgins

View of South Oxfordshire from atop the Chilterns at Watlington Hill. Photo by Patrick Higgins

Late July found me stumbling down a sunken way with Martha in the pitch dark of a moonless night. Our rough path was hemmed in by ancient yew and beech trees. We were in the Chiltern Hills of South Oxfordshire – an area designated as being of Outstanding Natural Beauty, a Site of Special Scientific Interest and a Special Area of Conservation about 15 minutes from our son’s house in Watlington where we were staying.  The broad bottomed ditch we were negotiating dated back to Saxon times.  In the darkness with the clinking of key chains and water bottles one could almost hear “the tramp of Saxon foemen, Saxon spearmen, Saxon bowmen” although more commonly this path would have been trampled by generations of Saxon farmers taking their animals to market; merchants with their wares travelling between settlements and woodsmen hauling timber and charcoal.

Further down, the sunken way was bisected by an old Roman road, now resurfaced and travelled by cars. For some unknown reason the Roman routes are always straighter than most of our modern English highways. Behind me, back up the hill, our ditch led to the Ridgeway, Britain’s oldest byway dating back over 5,000 years, which stretched from the Norfolk coast to that of Dorset, linking up Neolithic sites like Stonehenge and Avebury.  It’s hard to escape history in England, but we were in search of the glow worm (Lampyris noctiluca), cousins to Fakahatchee’s fireflies in Aston Rowant National Nature Reserve.  However, in the dark my mind kept wandering to the Fakahatchee because I had to give a talk locally on the Everglades Ecosystem and was also planning some new night-time interpretive programs for the upcoming season back in Florida.

The Reserve is a mosaic of chalk grassland, beech woodland and Juniper scrub sitting atop 300 feet of chalk, formed 350 million years ago from the compressed calcite shells of microscopic Foraminifera that lived in the warm, shallow seas that once covered southern Britain.  Chalk grassland is a unique and fragile habitat, important for both its beauty and wildlife value. It is the product of centuries of grazing by animals on nutrient poor chalk soils and is characterized by a short turf rich in herbs, flowers, butterflies and grasses, and like the Fakahatchee also in orchids, although here they are all terrestrial.

Comparisons between the ecosystems continued to flood my thoughts as we bumped along. In one we employ prescribed burns to maintain the habitat. Here, it’s the grazing of a large flock of speckle-faced sheep and a few Dartmoor ponies that controls the spread of young scrub and keeps chalk grassland healthy.

Aston Rowant, at only some the 500 acres, is a classic example of the threat to biodiversity through islandization and habitat fragmentation. Especially as even this small, precious parcel is sliced into two by a massive cut for the six lane M40 motorway from London to Oxford which paralleled our route just over the rise. It was further affirmation why the Fakahatchee is important; not just because of its unique plant communities, but also as Florida’s largest State Park because of its scale. When it comes to maintaining biodiversity, size does matter!

Back in Florida swallow-tailed kites would just be beginning to assemble for their annual 4,500 mile return migration to South America. Here there were Red kites (Milvus milvus).  They had been reduced to just a handful of pairs in Wales through past persecution. It was mistakenly believed that they were a threat to gamebirds and livestock, but recently they have made a remarkable comeback. Through a reintroduction program using chicks taken from northern Spain there are now some 250 breeding pairs in the Chilterns.   With a 5 ½ foot wingspan Red kites are a much larger bird than our swallow-tail, weighing 2 – 3 pounds versus 10–20 ounces and their ecological role is different too. Rather than being canopy feeders they are primarily carrion feeders, filling the role of vultures, although they will take small mammals too if caught in the open. The locals who once persecuted them now throw the bones from their Sunday joints out on to the lawn to watch them swoop in, a practice sadly that does not encourage the kites’ dispersal into new territory.

Field of yellow meadow ant mounds. Photo by Phil Champion

In Florida the instant we step off the road we are on the alert for fire ant nests.  Here there is an unseen benevolent ant, the Yellow meadow ant (Lasius flavus). The chalk grassland and other undisturbed ancient pasture areas are dotted with myriads of small grassy domes that look almost like neatly planted helmets. These are actually ant-hills, some over a hundred years old. Inside of each is a colony of up to 5,000 meadow ants that feed the by farming the sap sucking aphids that live on the roots of the surrounding forbs and grasses.  The ants milk the greenfly for honeydew which they carry back to their colony and in the winter will eat the aphids themselves. Their subterranean activities control damaging insects, open up the soil keeping it porous and their droppings fertilize the grasses’ roots. They also have a curious relationship with the Chalkhill blue butterfly (Polyommatus coridon). Attracted by secretions they will bury the pupa, unintentionally protecting it from predators.

Wingless female glow worm (Lampyris noctiluca). Photo by Barry Crowley

After about 45 minutes bumbling about we finally detected the steady green glow of our target, a glow worm.  It was about a foot off the track, naturally in completely the wrong spot deep in the woodland.  Glow worms of course are not a worms at all but a bioluminescent beetle just like our related firefly.  In their larval stage they are predatory and hunt snails, which why calciferous habitats that favour snails like chalk grasslands are preferred. As adults they rarely feed.
In the glow worm’s case it is only the inch long wingless female that glows significantly.  She had climbed up a dried grass stem about 12 inches above the ground then curled her abdomen slightly upward to display the last few segments of her abdomen where her glowing organs are located in hope of attracting a passing male.  Unlike American fireflies she can’t readily turn her glow on and off – it’s rather like a very slow starting fluorescent tube, which takes about 20 minutes to cycle so they don’t flash.  Misplaced deep in the woods she would be very lucky to have any success.  As well as attracting a mate, the glowing abdomen is a warning to predators to stay away – bioluminescent chemicals taste bad.

Nevertheless, hers is a very efficient light source. Unlike incandescent light bulbs that only, transform about 3% of the energy used into light, bioluminescence is generally 90 to 98% efficient.  The light is produced by a reaction between calcium, luciferin and ATP in the presence of the catalyst luciferase and oxygen, using nitric oxide as a chemical on/off oxygen valve. It is the switching on and off of the oxygen flow which allows American fireflies to flash.  Specific flash patterns are used to identify other members of their species, as well as members of the opposite sex and even. In the case of some Photuris fireflies, it is to mimic the light signals of other firefly species to lure, kill, and eat them.  Studies of America’s most common Photinus species show that females are more attracted to males that flash longer and faster. A flash can bring either sex or death!  We shall be trying a bit of mimicry ourselves on our moonlight tram rides down Jane’s Scenic Drive this season to see if we can attract any eager males.  It’s just a case of getting the response timing right.

Anyways, that solitary glow worm by the trail was the only one we saw that night.  We scoured the open grassland to no avail.  I guess we missed the peak by about a week, but even then observers were only seeing a dozen specimens a night on this site. Light pollution as well as habitat loss is taking a toll on these interesting insects.  We’re pretty lucky in the Fakahatchee.

by Sam Peters

There is some debate about what constitutes a Snag, Is it a dead tree? Is it on the ground? Is it in the water? Is it a loose thread? The Urban Dictionary defines snags as a “sensitive new age guy.” So, there are many definitions … For our purposes, a Snag is a standing dead or dying tree.

A Downed Tree is a log lying on or near a forest floor; however, a downed tree in a body of water is called a snag in certain areas of the South and Midwest. In Alaskan rivers it can be called a preacher. Other areas it is called a sawyer. Both sawyer and preacher derive from the tree or log rising and falling and bowing in a current of a river.

To some people, Snags are ugly and should be removed from a forest. After all, they are not classic, formal beauty; they’re dead. However, trees are the gift that keeps on giving. As they grow, they provide habitat and shelter for many different species; when they die, they still provide shelter and habitat, but now for different animals. Depending on the species of tree, it can last for as long as 70 years. They start out as Hard Snags, which means that they still have the bark and their cambium layer; as they lose their bark and decay further, they become Soft Snags. This is when the most animals begin to move in.

Some of the birds which use Snags are woodpeckers, wrens, barred owl, vultures and hawks. Also many insects, reptiles and amphibians call a dead tree home.

As the tree ages, different animals make use of it. For instance, woodpeckers will make use of an area of a snag and when the woodpeckers move on, other birds will enlarge the holes and move in. As they move on, more birds or other animals will make use of the cavity. This can go on until the cavity becomes large enough to house a squirrel, or a raccoon nest.

Some fungi, moss, and lichen live their entire lives on dead trees. Bacteria live in decaying wood, creating fertilizer which will mix with the soil when the tree falls. Shelf mushrooms make use of Snags and Downed Trees. Snags provide food and habitat for almost 1/3 of our wildlife. Over forty different types of birds use Snags at one time or another.

Snags should be protected and left standing for reasons of habitat and forest health. They are used for foraging, nesting, perching, hunting and roosting.

We need Snags to be maintained in a variety of sizes, shapes and ages. A group of larger Snags is more valuable as it provides habitat for a greater variety of species. Small clumps of snags will provide nesting and foraging sites. Snags should exist in various stages of decay, as they support different plants and animals at different stages of their existence. So, different stages for diverse species and different sizes and shapes for the same reason.

A single large Snag is rarely used by more than one pair of the same species.

Forest management now includes Snags. This would include not cutting down dead trees and culling trees in a crowded area, but leaving them standing and creating new Snags. Fire may also be used as fire can both create new Snags and destroy old ones.

What can we do? Depending on where we live, we can maintain Snags and/or create new ones. Please don’t use fire in your neighborhood. However, if a tree dies, leave it alone if it is not a danger to anything or cut it to a size where it will not hurt anything if it falls. You may also kill an unwanted tree yet leave it standing. Some of the ways to kill it would be to gird the tree, top and trim it and of course poison always works. Girding does weaken the tree and if done will rot the tree from the outside in. This will cause the tree to rot and fall much more quickly than when it dies and rots from the inside out, which is the natural way.

The Fakahatchee has many Snags in various states of decay. They occur naturally and are of great service to the forest community. If you look closely, you can see that the Snag is occupied by many animals and if you look twice you may even come to believe that they are beautiful in their own natural way.

Sam Peters is an FOF member from Miami Beach.

by Anthony (Tony) Marx

Aerial photo of the “south blocks” in the Picayune by Marya Repko taken several years ago.

Once considered as useless and a noxious, snake and insect infested source of fevers which must be drained and developed, half of the wetlands that existed at Florida Statehood have been destroyed. However Collier County is blessed with over 72% of its land acreage designated as conservation land – more than twice that of neighboring counties.

There is a stark difference between the 85,000-acre Fakahatchee State Preserve and the adjoining Picayune State Forest, which at 78,000 acres is almost as large. The Fakahatchee is a vibrant, natural world pulsating with life and home to a huge variety of rare plant life and endangered animals; whereas the Picayune, once also a similar wetland, was logged, cleared and partially developed, then abandoned. This transformed it into a dry landscape with upland trees and vegetation. Non-native vegetation including Brazilian Pepper, always present when land is disturbed, also moved in. Over two hundred miles of elevated roads acted as levies to further stop natural water flow between the canals. The difference is most noticeable when you access the Picayune State Forest through its back entrance at the end of Janes Scenic Drive in the Fakahatchee State Park. Outdated maps show a grid of streets which are mostly non-existent. The massive Comprehensive Everglades Restoration Plan (CERP) is changing the landscape in every respect. The bridge, on entering over the former Prairie has gone and the canal plugged, so it is now a series of small ponds.

Photo of equipment filling in a canal by Dennis Giardina.

Heading west, the partial dirt and paved road still shown on maps as Stewart has been leveled flat with the surrounding landscape, and on either side large swathes of scrub have been bulldozed clear of all vegetation and leveled to start sheet water flowing. Progress is occasionally blocked at the next canal bridge, but if you can proceed you’ll find that the formerly paved Everglades Boulevard section leading to Naples has also had its surface removed and the last time I was there it was gated closed. Heavy equipment is seen working here and there, bulldozing and trucking away debris. Close to I-75 instead of water flowing south down canals to the estuaries, the new and powerful pumping stations under construction will send water flowing fanlike south through spreader channels in an east-west direction while the remaining three canals running north to south will be plugged to varying degrees.

Boulevard in the Picayune taken by Tony Marx in 2011.

If you plan to try and reach Naples from the Picayune be prepared to turn back, as the road may be blocked by either a closed gate or sheet water in summer. In time it will return to a wetland environment and the interior will be mostly be inaccessible to vehicles. The full transformation will take several decades but soon the Fakahatchee will benefit from the additional water flowing southeast.

Tony Marx is a Florida Master Naturalist and a Board Member of Friends of Fakahatchee. He was one of the speakers at our Annual Dinner on April 13.