Bird-voiced vs. Gray TreefrogsDryophytes avivoca vs. D. versicolor/chrysoscelis

 On another post, I made the comparison between the two species of Gray Treefrog (Dryophytes versicolor vs Dryophytes chrysoscelis).   But there is a third species of treefrog that is easily confused with those other two, the nearly identical looking Bird-voiced Treefrog (D. avivoca).

 In Texas, we don't really have to worry about this comparison because there has never been a documented record of Bird-voiced Treefrog found in the state.   They get really close - there are records from just north of the Red River in southern Oklahoma and in southeastern Arkansas.  The closest records are within 13 miles of the Texas border, but no one has ever been able to document one in Texas.   I made a trip up to the border area a few years ago after some rains listening intently for the peeping whistles, but couldn't find any.   If I lived closer, this is a project I would work on more often!

But if you did find one, how would you know?  They are very similar looking to both Gray Treefrog species and everywhere Bird-voiced Treefrogs occur, at least one of the Gray Treefrogs could also be found.

For the purposes of discussion hereafter, I will refer to both Gray Treefrog species (D. versicolor and D. chrysoscelis) as the "Gray Treefrogs" to keep it simple.

Here's a couple of clues that help distinguish them:

Size

• the Bird-voiced Treefrog is slightly smaller, roughly 2.5–5 cm (1–2 in)
• the Gray Treefrogs are slightly larger, 3.2–5.1 cm (1.3–2.0 in)

Clearly you can see that although Gray Treefrogs are larger than Bird-voiced, there is some overlap in size making this less helpful.  And there is sexual dimorphism in treefrogs - females are larger than males.   So a female Bird-voiced and a male Gray Treefrog could be roughly the same size.

At the same given body length, the Gray Treefrogs are generally stockier and heavier-bodied than the slightly more slender Bird-voiced. 

Skin texture

• Bird-voiced Treefrogs have skin that is relatively smooth and fine-grained compared to the bumpier skin of gray treefrogs.
• Gray Treefrogs tend to have more pronounced tuberculate skin.

Again, this character has enough overlap to not be diagnostic by itself.  Some Gray Treefrogs have pretty smooth skin. 

Coloration of thigh and groin area

This is probably the most useful diagnostic visual character.  Both of these species have contrasting color mottled on the rear of their thighs and the surrounding area. 

• In Bird-voiced, the background to the mottled patches is lime green, sometimes greenish-yellow with darker mottling
• In the Gray Trefrogs, the background color to the mottled patches is bright orange-yellow.

You can just see the pale greenish-yellow on this Bird-voiced Treefrog from Arkansas,

 

 

and here is the orange-yellow background of the Gray Treefrog (in this case, Cope's Gray Treefrog, D. chrysoscelis). 

 Habitat

• The Bird-voiced Treefrog has a smaller range and it is generally associated with river swamps and closely associated backwaters, mainly along the Gulf Coast of the US from South Carolina to Louisiana and then up the Mississippi river valley to southern Illinois.   It has a very localized distribution with apparently disjunct populations, probably left over from the destruction of its habitat.
• The Gray Treefrogs are found throughout the eastern 1/2 of the North America as far north as Canada.   They are found in a variety of habitats including woodlands, swamps, grassy savannahs, and scrubby brush along waterways.  They are very flexible and have adapted well to human habitats like backyards where there is water.

Voice 

As you would expect on my blog devoted to frog calls, the last and best characteristic to tell the species apart is by call.

The call of the Bird-voiced Treefrog is a series of rapid whistled calls repeated a dozen or more times.  Here's one calling from just 50 miles NE of the Texas border in Arkansas.

The call of the Gray Treefrogs is a whistled trill call.  The difference between the two species, Dryophytes versicolor vs D. chrysoscelis, is the rate of the trill.   The Gray Treefrog (D. versicolor) has a slower pulse frequency to its trill (12-34 pulses per second).   Here is a Gray Treefrog call from near Palestine, Texas.

The call of the Cope's Gray Treefrog (D. chrysoscelis) is a more rapid trill (34-60+ pulses per second), giving it a drier, buzzier character than the bird-like character of the Gray Treefrog (D. versicolor).

I have a blog post comparing the calls and the effect of temperature on those calls for the two Gray Treefrog species. 

So in the narrow area where the Bird-voiced Treefrog overlaps with the Gray Treefrogs, the best way to tell them apart is by listening to their calls.  Hopefully in the near future, I will be able to find the Bird-voiced Treefrog calling in Texas!

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© Chris Harrison 2026