Identifying introduced frog species

There are three species of frogs in New Zealand which produce loud calls at and around ponds to attract females and protect individual male territories.

These vocal species belong to the introduced genus Litoria and can be easily differentiated from our native protected species (Leiopelma), which are rare, essentially silent and confined to undisturbed native bush.

The Department of Conservation is also interested in records of introduced frogs because populations may transmit disease, or directly compete or predate native frogs. Report a frog sighting.

Frog identification key

This frog identification key is simple to use. The number at the end of each option tells you which question to go to next. Continue to follow the correct option for your frog and you will eventually arrive at the correct identification.

Question one

External eardrum
displayed as dark
circle behind eye

1. Frog has no external eardrum - go to question 2.
2. Frog has an obvious external eardrum - go to question 4.

Question two

1. Webs on hind toes distinct; longitudinal ridge behind eye not distinct – Leiopelma hochstetteri (Hochstetter’s frog)
2. Webs on hind toes absent or nearly so; ridge behind eye distinct - go to question 3.

Extended ridge
behind eye
present

Question three

1. Relatively small, up to 37mm long; found on mainland New Zealand; colour green, brown, or green and brown – Leiopelma archeyi (Archey’s frog)
2. Relatively large, up to 49mm long; brown, not green except in some juveniles – Leiopelma hamiltoni (Hamilton’s frog; Stephens Island) or - Leiopelma pakeka (Maud and Motuara Islands).

Question four

1. Frog has an overall brown back with a broad dark stripe from nostril, orange thighs; call cricket-like – Litoria ewingii (Whistling frog).
   Listen: L. ewingii 

2. 
   Mid-dorsal stripe present

   Frog has distinct mid dorsal stripe, has prominent bumps or warts on back; call is a set of simple harsh croaks – Litoria raniformis (Southern Bell frog).
   Listen: L. raniformis
   

1. 
   Dorsal stripe absent

   Frog does not have a distinct mid dorsal stripe down its back; back almost smooth; call is a prolonged, descending three-syllable drone – Litoria aurea (Green and Golden Bell frog).
   Listen: L. aurea

More on introduced frogs on the NZ Frog website - includes a video with sounds for identification.