Monday, June 15, 2015

Water Garden Predators

The Blue Jay Barrens Water Garden will be celebrating its 15 year anniversary this summer.  On August 4, 2000 I installed a liner into the completed excavation and diverted runoff from downspouts in the front of the house to the leak proof pool area.  Two days later, a light rain put an inch of water in the bottom of the pool, and that night, treefrogs deposited several egg clusters.  Since then life in the pool has been in a state of constant change.  Each year is a new experience with new players, both plant and animal, finding a place in this tiny pool.  Most conspicuous in the pool these last few years has been a growing number of predators that feed on the masses of small animals attracted to a permanent body of water.

All plants in the Water Garden are native to this area, with the exception of the Water Lilies.  I’ve had a desire for a pool of Water Lilies for most of my conscious life, so I bought some tubers, planted them in weighted tubs and put them into the Water Garden.  After a couple of years, the Water Lily root mass grew so large that it floated the pots to the surface.  My thought was to transplant the tubers into larger pots with heavier weights, but when I hauled the plants out of the water I found that the lily roots had completely enveloped the pots.  I settled for adding more weight by strapping bricks around the outside of the root mass.  This worked for a couple more years, then up came the root masses with all of my bricks neatly hidden inside.  At that point I decided to just leave the lilies alone.  Now the root masses rise to the surface each summer with the growth of new roots and then sink again in the fall as the roots die back.  Islands created by the root masses are becoming populated with a variety of aquatic plants that don’t mind a winter long emersion.

In last few days there has been a mass emergence of damselflies from the pool.  The shed skin of the aquatic nympth is left behind by the newly emerged adult form.

Both the aquatic and adult forms of damselfly are predators.  Adults capture and consume small flying insects, while the aquatic nymphs feed on insects, tadpoles, fish, worms and anything else small enough to be captured and held.

Adults seem to emerge most often under the cover of darkness.  In the morning, newly emerged individuals can be found resting on stable structures near the water.  It takes a while for the wings and exoskeleton to harden, and for the full coloration of the adult to develop.

Unlike most other damselflies, Spreadwing Damselflies hold their wings slightly apart.  These damselflies are slightly larger than the average.

This is one of the Bluet Damselflies.  This is a small, delicate Damselfly that is quite common here at Blue Jay Barrens.

Male and female bluets join in tandem for mating and egg laying.  This pair is insuring a supply of Damselflies will be around next year.

Aquatic plants growing in pots set on a shallow shelf at the edge of the Water Garden have long since escaped confinement and found their own anchorage.  A tangle of rush stalks and other dead vegetation give a foundation for an assortment of water loving vegetation.  Some were planted when the Water Garden was first filled, but most have arrived by more natural means.

The thick vegetation may be a place of safety for some, but it also harbors a healthy population of predators.  These young spiders have just recently emerged from heir silken egg sack.

Most of these will fall to larger predators or relocate far distant from here, but several will stay and grow to adulthood in the lush vegetation of the Water Garden.

Red-spotted Newts are the top of the line submerged predator.  They can detect the slightest movement and will investigate any creature their own size or smaller.  If they can fit it in their mouths, they will eat it.  I don’t believe you can stuff a newt so full that it would stop trying to eat more.  Males like this one are continually cruising the pool looking for food and for breeding opportunities.

Female newts typically remain more hidden, but they are still alert for anything that may be food.

When newly hatched, salamander larvae are heavily preyed upon by the newts.  As the salamanders  grow, they become a predator as efficient as the newt.  The difference between the two is that the salamander only spends a portion of its life in the pool.  It will soon mature into a land dwelling form and take off for a more terrestrial lifestyle.

Bullfrogs are probably the most aggressive above water predators in the Water Garden.  As long as he can avoid the notice of Minks, Raccoons and Herons, this guy should have no problems.  Anything smaller than this guy’s mouth is in danger of being eaten.  Bullfrogs are typically just temporary visitors and after a few weeks will move on to new hunting grounds.  If it ever rains here again, this frog will probably move on.

Adult Green Frogs have a chance of competing against a large Bullfrog, but those that have just recently transformed from the tadpole stage are just Bullfrog food.  This young frog has just lost the last of its tail stub and is watching for a flying insect to come within grabbing distance.

Gray Treefrogs have a tough time competing in a permanent pool.  Predators make quick work of the newly hatched tadpoles and the adult frogs are in danger of becoming a Bullfrog meal.

Northern Water Snakes will also make a meal of tadpoles and frogs.  There are at least two mature water snakes now living in the Water Garden.  They arrived here as youngsters several years ago and have been growing steadily since.

I’ve resigned myself to the fact that the Water Garden has become a home for top level predators.  That is why I’ve initiated other projects to provide temporary pools to those aquatic creatures that cannot deal with a high predator load.  I’ll just keep enjoying the Water Garden and see what comes next.


  1. Wonderful! I rarely see frogs these days, even around established pools.

    1. Hi, Susannah. We occasionally have years here where frogs are scarce. Unlike you, I don’t have an ocean as a backup site for finding interesting aquatic creatures.

    2. There is that. :) But I still miss the song of frogs in the evening. Maybe I'll look into that idea of a tub in the yard.

  2. More great pictures. We don't have a water feature like this, so it was a treat to see yours and all of it inhabitants.

    1. Hi, KCD. Before building the Water Garden, I had a 30 gallon tub that sat outside the front door and collected rainwater leaking from the house gutter. That small tub attracted a lot of interesting creatures, including treefrogs that filled the tub with eggs every year.