Mixophyes balbus
Stuttering Frog, Southern Barred Frog, Silver-eyed Barred Frog
family: Myobatrachidae
subfamily: Limnodynastinae

© 2010 Division of Herpetology, University of Kansas (1 of 1)
Conservation Status (definitions)
IUCN (Red List) Status Vulnerable (VU)
Other International Status None
National Status None
Regional Status None


View distribution map using BerkeleyMapper.


Distribution and Habitat

Country distribution from AmphibiaWeb's database: Australia


View distribution map using BerkeleyMapper.
Population and Distribution
Mixophyes balbus is restricted to the e. slopes of the Great Divide, from the Cann R. catchment in far East Gippsland, Vic., to tributaries of the Timbarra R. near Drake, NSW (Gillespie & Hines 1999). The area of occurrence of the species is about 110 000 km2 (map in Gillespie & Hines 1999). The species occurs from 20 to over 1400 m altitude, from low to high altitudes from s. to n. (Gillespie & Hines 1999). Mixophyes balbus was formerly more frequently encountered in the n. part of its range than s. of Sydney, although this may reflect limited historic searches in the region (Gillespie & Hines 1999). The species has only been found in Vic. on three occasions (Tennyson Ck, Cann R. and Jones Ck) and is now thought to be extinct in that state (Gillespie & Hines 1999). The species has declined and disappeared from a number of locations in NSW where it was common (Mahony 1993; Anstis & Littlejohn 1996; Anstis 1997). Surveys in s.e. NSW since 1990 have located individuals at only a few sites (Lemckert et al. 1997; Daly 1998). While actual estimates of population size are not available, where populations have been recorded recently, the species appears to be in low numbers (Mahony et al. 1997).
Mixophyes balbus is known from Blue Mt, Coopracambra, Dorrigo, Gibraltar, Morton, New England, Washpool and Werrikimbee NP, Bulahdelah, Carrai, Chaelundi, Dampier, Ellis, Forestlands, Hyland, Malara, Marengo, Mt Boss, Mumbulla, Myall R., Olney, Strickland, Watagan and Wild Cattle Ck. SF (Tyler 1997), Barrington Tops, Junuy Junuum, Myall L. NP, Awaba, Barrington Tops, Chichester, Doyles R., Giro, Heaton, Kerewong, Lorne, Middle Brother, Ourimbah, Styx R., Wang Wauk, Wyong SF (F. Lemckert pers. comm.), Butterleaf, Ewingar, Girard, Malara, Moogem SF (K. McCray pers. comm.).

Mixophyes balbus is typically found in association with permanent streams through temperate and sub-tropical rainforest and wet sclerophyll forest, rarely in dry open tableland riparian vegetation (Mahony et al.1997), and also in moist gullies in dry forest (Gillespie & Hines 1999). The ecological requirements of adults and larvae are poorly known. In n.e. NSW, statistical modelling was used to investigate the relationship of M.balbus with 24 environmental predictors (NSW NPWS 1994 in Gillespie & Hines 1999). The species showed a preference for the interiors of large forest tracts in areas with relatively cool mean annual temperatures. These sites are typically free from any disturbance with a thick canopy and relatively simple understorey (Gillespie & Hines 1999). Mixophyes balbus occurs along first order streams and occasionally associated with springs (Mahony et al. 1997). The species is not associated with ponds or ephemeral pools (Mahony et al. 1997). Tadpoles do occur with several species of native fish (Mahony et al. 1997).

Life History, Abundance, Activity, and Special Behaviors
Calling has been recorded from Sep. to Apr. (F. Lemckert pers. comm.). Males call from beside small streams, often from under leaf litter or within holes (Lemckert & Morse 1999). Reproductive biology is very similar to that of Mixophyes fleayi (Gillespie and Hines 1999). Both species construct a nest in the shallow running water that occurs between pools in relatively wide, flat sections of mountain streams (Knowles et al. 1998). 500-550 pigmented eggs (2.8mm diameter) are deposited in a shallow excavation in the stream bed or pasted directly onto bed rock (Watson & Martin 1973; Knowles et al. 1998; Knowles pers. comm in Daly 1998). The stream microhabitats used by this species for oviposition are limited (Knowles et al. 1998). The free-swimming tadpole of the species has been described by Watson and Martin (1973) and Daly (1998). Tadpoles develop in pools and shallow water with the aquatic phase of the life cycle lasting approximately one year (Daly 1998).

Invasive species
Trampling by domestic stock is likely to have deleterious impacts on oviposition sites of the species (Knowles et al. 1998). Mixophyes balbus tadpoles have been found in sympatry with native fish, and probably have survival strategies to avoid predation from them (Gillespie & Hines 1999). However, the impact of introduced fish, such as Eastern Gambusia (Gambusia holbrooki), carp (Cyprinus spp.) and salmonids is unknown (Gillespie & Hines 1999). Mahony et al. (1997) did not observe introduced fish at any sites where they found M. balbus. In other reports though, introduced fish (salmonids) have been recorded at sites where M. balbus has declined (Anstis 1997). However, M. balbus has also disappeared from many streams which do not contain introduced fish species (Gillespie & Hines 1999).

On several occasions during rainfall events individuals have been found on roads (Mahony 1993; Lemckert & Morse 1999) at least 100 m away from the nearest waterbody suggesting that individuals move widely through the forest when moist conditions prevail (Lemckert & Morse 1999).

Trends and Threats
Several potentially threatening processes have operated at sites where M. balbus has been found, or up-stream in catchments. Logging and associated forest management practices have been carried out in some catchments where M. balbus historically occurred, or currently occurs (Mahony et al. 1997). The health and stability of extant populations in these disturbed catchments is unknown. Forest grazing and land clearance for pasture upstream have also occurred in some catchments (Mahony et al. 1997). Mahony et al. (1997) report that the species is not known from any localities with disturbed riparian vegetation or significant human impacts upstream. This may indicate that the species is highly sensitive to perturbations in the environment. However, populations of this species have also disappeared in catchments with seemingly minimal human disturbance (Mahony et al. 1997). [Gillespie and Hines 1999]

Contributors: J-M. Hero; L. Shoo; M. Stoneham; F. Lemckert; K. McCray


Anstis, M (1997). ''25. Glandular Frog, Litoria subglandulosa.'' Threatened Frogs of New South Wales: Habitats, Status and Conservation. H. Ehmann, eds., Frog and Tadpole Study Group of NSW, Sydney, 213-221.

Anstis, M. and Littlejohn, M.J. (1996). ''The breeding biology of Litoria subglandulosa and L. citropa (Anura: Hylidae), and a re-evaluation of their geographic distribution.'' Transactions of the Royal Society of South Australia, 120, 83-99.

Daly, G. (1998). ''Review of the status and assessment of the habitat of the Stuttering Frog Mixophyes balbus (Anura: Myobatrachidae) on the south coast of New South Wales.'' Herpetofauna, 28(1), 2-11.

Gillespie, G.R. and Hines, H.B. (1999). ''Status of temperate riverine frogs in south-eastern Australia.'' Declines and Disappearances of Australian Frogs. A. Campbell, eds., Environment Australia, Canberra, 109-130.

Knowles, R., Hines, H.B., Thum, K., Mahony, M., and Cunningham, M. (1998). Oviposition of the Barred-frogs (Mixophyes Species) in Southeastern Australia with Implications for Management. Unpublished abstract of a talk presented to the Australian Society of Herpetologists meeting, February 1998.

Lemckert, F. and Morse, R. (1999). ''Frogs of the timber production forests of the Dorrigo escarpment in northern New South Wales: an inventory of species present and the conservation of threatened species.'' Declines and Disappearances of Australian Frogs. A. Campbell, eds., Environment Australia, Canberra, 72-80.

Mahony, M., Knowles, R., and Pattinson, L. (1997). ''4. Stuttering Barred Frog, Mixophyes balbus.'' Threatened Frogs of New South Wales: Habitats, Status and Conservation. H. Ehmann, eds., Frog and Tadpole Study Group of NSW, Sydney, 66-71.

NSW NPWS (1994). Results of Vertebrate Fauna Surveys of North-east NSW Forests. North East Forests Biodiversity Study Report No. 3a, Vol. 1, Site and Transect Based Methods. N.S.W. National Parks and Wildlife Service, unpublished report

Tyler, M.J. (1997). The Action Plan for Australian Frogs. Wildlife Australia, Canberra, ACT.

Watson, G.F. and Martin, A.A. (1973). ''Life history, larval morphology and relationships of Australian leptodactylid frogs.'' Transactions of the Royal Society of South Australia, 97, 25-34.

Written by J.-M. Hero; F. Lemckert; K. McCray; L. Shoo; M. Stoneham; (m.hero AT, Griffith University
First submitted 2002-03-15
Edited by Ambika Sopory, Jean-Marc Hero (2008-09-22)

Species Account Citation: AmphibiaWeb 2008 Mixophyes balbus: Stuttering Frog <> University of California, Berkeley, CA, USA. Accessed Apr 29, 2017.

Feedback or comments about this page.


Citation: AmphibiaWeb. 2017. <> University of California, Berkeley, CA, USA. Accessed 29 Apr 2017.

AmphibiaWeb's policy on data use.