One summer day a few years ago I improvised a birdbath out of
a large plant pot about a
foot tall and a foot wide.

I put a little branch in it so the birds could walk down the
branch to reach the water.
I often saw the brown thrasher use this watering place to get a
drink.

One day, after a rainy night, I looked down into my
plant-pot birdbath and saw
something new. Frog eggs!

How did they get there?

They were the eggs of the gray tree frog, Hyla
chrysoceles. Hyla, like others of
his tribe, is a good climber. He can climb a wall or a tree, and
even plastic pots.

Obviously some tree frogs had climbed into the pot for a
private pool party. Pond
privacy for a gray tree frog is important, because they make
easy prey for predatory
frogs.

The gray tree frog is adept at finding little ponds that
aren’t being used. And
further, it often avoids breeding in little ponds that are well-
stocked with other kinds
of frogs.

Not only do they avoid predation this way, but their tadpoles
can grow up with less
competition from other frog tadpoles.

So the habits of Hyla got me to thinking. I could make a
special tree-frog pond.

Since then I’ve tried several designs that attract tree frogs
but exclude other kinds
of frogs.

All frog ponds should have a tapering shore so the frogs can
climb out easily. The best
all-purpose edge has a shore set flush with the ground. That way
the frogs can easily jump
in or climb out.

A variety of frogs may colonize this pond, from tiny peepers
to large, cannibalistic
species, like bullfrogs and green frogs.

Avoid cliff-like edges that will prevent escape once frogs
get in. Ponds with
overhanging edges tend to be death traps. Little animals can
jump in, but they can’t get
out.

The key to making a tree-frog pond is to design one that
keeps most kinds of frogs out
while letting tree frogs in. To do this, make a pond with a
vertical edge on the outside.

Here’s one way to make a tree-frog pond. Buy one of the
little plastic pools that
children play in. Instead of submerging it into the ground as
you would for most water
animals, just put it on top of the ground.

Arrange a bank of rocks or bricks around your little pool.
Make it steep. That way, the
tree frogs can climb up. But the nonclimbing, clumsier species
can’t.

Put some branches in the water for extra cover and for the
frogs to cling to. Or you
can make a little island of wood or stones.

How high should the edge be? I think eight to 10 inches
should work. If bullfrogs
should find their way in, raise it another six inches.

This should make a pond that will allow your tree frogs to
have a home-sweet-home all
to themselves.