Whiskers in the Swamp

Though they were not true whiskers on the animals, that's what they looked like to the summer campers at the Audubon Center at Francis Beidler Forest.  While exploring the forest and swamp near the nature center, we discovered a mere puddle of water in a depression at the base of a hollow tree.  This was all that was left of the water pooled behind the beaver dam and will likely disappear by the end of the day tomorrow.  Elsewhere, water cannot be seen from the boardwalk until the approach to Goodson Lake at the end of the boardwalk.  Naturally, the hole that is Goodson Lake continues to hold ample water to support the American Alligator (Alligator mississippiensis), Longnose Gar (Lepisosteus osseus), Bowfin (Amia calva), Yellow-bellied Sliders (Trachemys scripta scripta) and other aquatic or semi-aquatic organisms.

In the puddle of water behind the beaver dam, we found numerous small fish and a meatier 3-inch long fish.  All were too muddy from their struggles in the shallow puddle to be identified, but we grabbed a few to show the campers waiting a the swamp's drier edge.  While showing the campers the larger fish, we discovered, via a fin jab in the hand, it was a species of catfish.  As the catfish would likely be dead by morning from either the disappearing water or the return of the herons, ibis and raccoon whose tracks were still in the mud from the night before, we put the catfish in a jar of water and hauled it out to Goodson Lake to give it a fighting chance.

As we moved along the treeline at the edge of the power line corridor, campers were able to spot a variety of native insects feasting on an abundance of native plants.  There were pollinators like butterflies, bees, beetles as well as an assortment of other flying insects, including several species of insect-hunting dragonflies.  Native fauna and native flora have evolved together and therefore maintain a system of checks and balances within the ecosystem.  The introduction of non-native flora or fauna can throw the system out of balance as predators may not exist for the non-native fauna or the native fauna may not be able or willing to eat non-native flora, which in turn may crowd or eliminate native flora.  One of the native species the campers found was a Pipevine Swallowtail caterpillar in search of pipevine on which to dine.  It is apparently unpalatable and therefore has little fear of becoming a meal itself.  The whisker-like, fleshly projections give the caterpillar a fearsome look and might give a predator a scare.

Images by Mark Musselman

Mosquito Fish

As we prepare for the tomorrow's start of summer camp session #2 at the Audubon Center at Francis Beidler Forest, we set out the minnow traps baited with sardines.  We will certainly capture a number of crayfish as we did last week, but those crayfish attracted the attention of a Lesser Siren, which is related to the camp's theme of Reptiles and Amphibians.  Other non-target species also find their way into the traps.

During our crayfish identification exercise last week, we caught over a dozen water scavenger beetles (Dytiscidae).  Apparently, they really like sardines!

Today when we set the traps, in one we found what appears to be a female Eastern Mosquito Fish (Gambusia holbrooki) full of young.  Members of the family Poeciliidae give birth to live young.  This species likes the vegetated areas of slow moving or calm fresh waters.  This fish was caught in the minnow trap set in the powerline right-of-way where calm water pools behind the beaver dam and ample sunlight allows plenty of vegetation to grow in the water.  The vegetation ends immediately at the treeline.  Mosquito Fish mainly eat surface-dwelling insects and their larvae.

As we care little for decaying fish and mosquitoes, we're happy to find water scavenger beetles and Mosquito Fish in our swamp!

Images by Mark Musselman

Bowfin Problem Solver

After all the rain in December and January, we did not think we would be discussing low water levels at the Audubon Center at Francis Beidler Forest by the end of April.  Canoe trips are no longer feasible and the swamp looks less and less swamp-like as the water level continues to drop.  The light rain we received yesterday did little to change that situation.  However, the shallow water is a boon for some predators.

The the water level in the swamp drops, some of the shallow channels get cut off from the deeper channels.  Without water flowing in to replenish water lost to evaporation or transporation, the cut off channels become smaller and smaller pools of water.  Any fish or crayfish caught in those shallow pools become easy prey for owls, raccoons, herons, ibis, egrets, otters, snakes, and other fish.  Other fish?

While on the boardwalk observing Prothonotary Warblers (Protonotaria citrea) for Project PROTHO, we saw a Bowfin (Amia calva) moving up a shallow channel.  A third of the fish's body was out of the water when it met an obstacle to its upstream movement.  A log across the channel caused the fish to stop and probe the length of the log in search of upstream access.  We're not sure what the large fish was seeking in the increasingly shallow water, but we have observed Bowfin eating crayfish and there are plenty of crayfish in the diminishing water.  After finding no path through the water, the Bowfin leapt over the log and continued on its way.  The video below consists of a series of still images showing the event.



Images and video by Mark Musselman