Tree Frogs

I was first introduced to the World Bird Sanctuary by a friend in 2009, and quickly decided that I wanted to volunteer at this amazing facility.  

After volunteering for over a year I was offered the opportunity to become a full time seasonal employee.  After working here as a full time seasonal employee I am often treated like an “old timer,” with the new volunteers coming to me with their questions. 

The Bird-voiced Tree Frog, Hyla_avivoca 

Very often when working outside we will come across small creatures like frogs and snakes. Recently an intern came to me for help identifying a very small frog he thought was a Bird-voiced Tree Frog (Hyla avivoca).  Its characteristics are smooth skin, large toe pads, light spots under the eyes and greenish to yellowish patches in groin and inner thigh. These characteristics are very similar to the Gray Tree Frog.  The Bird-voiced Tree Frog is considered threatened in Illinois (the northernmost portion of its range) due to the clearing and draining of bald cypress-tupelo swamps. The Bird-voiced Tree Frog’s main habitat is the bald cypress-tupelo swamps and nearby wet hardwood forests. This small frog can change color from dark gray to light green depending on background, temperature and moisture. The diet of an adult Bird-voiced Tree Frog includes small arboreal insects and spiders.

 The Gray Tree Frog, Hyla_versicolor

Unfortunately the intern’s find was not a Bird-voiced Tree Frog.  It would have been cool to know we have a threatened species on our property.  However, the species that he had found was the Gray Tree Frog (Hyla versicolor complex)—a common species.  The Gray Tree Frog also has large toe pads, but has a pale spot under the eye and orange or golden yellowish patches in the groin area and inner thigh. This frog is slightly larger then the Bird Voice Tree Frog. 

The habitat of a Gray Tree Frog is the trunks and branches of trees.  A recently transformed (from tadpole to frog) juvenile is bright green. The adults generally mate in woodland puddles, roadside ditches, or other temporary bodies of water. These frogs may change color from dark gray to light green depending on background and temperature. The diet consists of small spiders and insects. Feeding adults and juveniles are often found near house lights and windows where insects accumulate.

Photo showing the golden yellow patches in the groin area 

The IUCN status of the Gray Tree Frog is least concern. The International Union for Conservation of Nature and Natural Resources (IUCN) is an international organization dedicated to finding "pragmatic solutions to our most pressing environment and development challenges."   The organization publishes the IUCN Red List, compiling information from a network of conservation organizations to rate which species are most endangered

Although this intern was slightly upset to learn he had only found a common tree frog, he will most likely continue to look for creatures like this as he gets the outside chores of World Bird Sanctuary’s Education Training Center done, and further his knowledge (and mine) in the process.

Submitted by Jaimie Sansoucie, World Bird Sanctuary Seasonal Staff Member