This technical bulletin summarises the

findings of field research undertaken

in October 2009 on the current status

of the Mallee Emu-wren (Stipiturus

mallee) within Murray Sunset and

Hattah-Kulkyne National Parks.

The project aimed to improve the

understanding of the population numbers

of the Mallee Emu-wren within the

Murray-Sunset and Hattah-Kulkyne

National Parks and identify the need for

future management actions.

Background

The Mallee Emu-wren is listed as

nationally vulnerable under the

Population monitoring of the Mallee Emu-wren within Murray-Sunset andHattah-Kulkyne National Parks

Environment Protection and Conservation

(EPBC) Act 1999. It is a small elusive bird

found only in the Murray-Darling Basin of

Victoria and South Australia, south of the

Murray River.

Past broad-scale clearance of land for

agriculture has caused the decline of

many animals within the Mallee CMA

region. Currently, the Mallee Emu-wren

is only found in the major conservation

reserves of the region, and these local

populations make up the majority of total

Mallee Emu-wren populations in South-

eastern Australia.

At a glance

• The Mallee Emu-wren is listed as

nationally vulnerable under the

Environmental Protection and

Biodiversity Conservation Act

1999.

• A research survey was conducted

to determine the current status

of the Mallee Emu-wren within

Murray Sunset and Hattah-

Kulkyne National Parks.

• The results of this survey

indicates the main factors

influencing the population size

of the Mallee Emu-wren are the

extent of key vegetation types

of appropriate fire age-class and

short-term climatic conditions.

Above: Female Mallee Emu-wren. Photo: Rohan Clarke.

While a number of surveys of the Mallee

Emu-wren have been undertaken in

north western Victoria, the current status

of this species within the stronghold

population of the Murray Sunset National

Park and Hattah Kulkyne National Park are

unknown. By addressing this knowlegde

gap, this project will assist with the future

management of this species.

M A L L E E C A T C H M E N T

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T e c h n i c a l B u l l e t i n

Technical Bulletin # 2

Method

Records of the Mallee Emu-wren

The use of call play back alarm calls were

used to detect habitat use by Mallee

Emu-wrens. Transects 500 metres in

length were traversed on foot from dawn

until mid afternoon. At the start of each

500 metre transect the Mallee Emu-

wren, Striated Grasswren, Red-lored

Whistler and Black-eared Miner alarm

calls were played for 15-45 seconds

through an amplified MP3 player. For each

observation of a Mallee Emu-wren the

AMG coordinates of the bird’s position,

perpendicular distance of the bird from

the fixed transect line, the number of

individuals present, their sex and the

vegetation type they occupied was

recorded.

Density of the Mallee Emu-wren by

habitat type

The software program DISTANCE was

used for all data exploration and distance

sampling analyses. Data points from all

surveys (2001-2009) were used to create a

distance detection function for the Mallee

Emu-wren, and were used in subsequent

analyses. The detectability function for

the Mallee Emu-wren was compared

within Ecological Vegetation Classes (EVC)

and globally using pooled data from all

years and applied at the stratum level.

Group densities of the Mallee Emu-wren

(groups/ha) were determined by Ecological

Vegetation Class, fire age-class, year and

in combination.

Estimation of population size within

the Murray Sunset and Hattah Kulkyne

National Parks

The total number of groups of Mallee

Emu-wrens for each reserve was

determined by multiplying the average

density for each EVC and fire age-class

by the corresponding area within each

reserve. The population size of the

entire Murray Sunset and Hattah Kulkyne

National Parks was extrapolated by the

number of birds in a breeding group.

Above: Habitat of the Mallee Emu-wren. Photo: Sarah Brown. Insert: Mallee Emu-wren in Spinifex. Photo: Rohan Clarke.

Key Findings

Records of the Mallee Emu-wren

A total of 143km of transects were

traversed at five geographic locations

within the Murray Sunset and Hattah-

Kulkyne Naitonal Parks. Twenty two

groups of Mallee Emu-wrens were

observed at all five locations, all of which

were recorded in vegetation which

included Triodia, with or without a shrubby

understorey.

Relatively high numbers of other

threatened birds were also recorded

during the survey. Of particular note were

Red-lored Whistlers, Striated Grasswrens

and Gilberts Whistlers.

Estimates of Group Density by habitat type

Results indicate that fire is the

overwhelming factor influencing the

density and distribution of the Mallee

Emu-wren in the Murray Sunset and

Hattah-Kulkyne National Parks. Mallee

Emu-wrens were found to prefer 16-29

year fire age-class although they also

occur in >29 year fire-age classes. In the

>29 year fire age-class, Mallee Emu-

wrens prefer Woorinen Sands Mallee

to Loamy Sands Mallee. Loamy Sands

Mallee tends to occur on the tops of

dunes, whilst Woorinen Sands Mallee

occurs on the dune slacks. This suggests

that the underlying soil structure and/or

environmental attributes influence the

structure or primary productivity of the

EVC important to the Mallee Emu-wrens

in age classes greater than 29 years.

The Mallee Emu-wren does not occur

in vegetation less than 16 years of age

since fire. These results are consistent

with Triodia being at its greatest volume

between 15-30 years post-fire.

Regional Population Size

Results weakly suggests that the Mallee

Emu-wren population may have fluctuated

since first monitored in 2001- with a

possible decline from 2001-2003, followed

by an increase during the period from

2003 until 2009. However, no conclusive

assessment can be made on population

trends due to the lack of statistical

significance. Despite this, the total

estimated population size of the Mallee

Emu-wren for 2009 is comparable with

previous studies. Population fluctuations

of the Mallee Emu-wren are also most

likely influenced by rainfall.

The number of individual Mallee Emu-

wrens detected at Hattah Kulkyne

National Park suggests that there has

been a local decline in the population,

although the total population size

extrapolated from the extent of suitable

habitat does not reflect this.

Despite the lack of statistical significance

in the results, it is reasonable to suggest

that the Mallee Emu-wren as well as

several other mallee bird species, has

undergone fluctuations in number since

2005; and that this is likely to be driven by

short term local climatic events.

Recommendations

Recommendations to assure long-term

persistence of this endangered species

include:

• Prevention of catastrophic widespread

wildfires destroying key habitat and

therefore reducing the distribution and

total population size of this endangered

species.

• Core populations should be given

priority in protection from wildfires and

careful consideration is given before

planned burns are undertaken in these

areas. It is also likely that other core

populations of the Mallee Emu-wren

and other threatened avian species are

present.

• Frequent monitoring by GIS analysis

of the spatial configuration and extent

of suitable vegetation types and fire

age-classes, coupled with on-ground

monitoring, will assist in the detection

of long-term population declines or

threats to population persistence.

Above: Habitat of the Mallee Emu-wren. Photo: Sarah Brown.

• Re-introduction of individuals may need

to be considered where populations

are found to be in serious decline or

locally extinct and unlikely to re-colonise

without assistance.

• To improve the statistical certainty of

population trends, it is recommended

that an improved protocol would employ

intensive replicated surveys of parallel

100m transects at known Mallee Emu-

wren sites.

• Survey reserves in the Big Desert

Wilderness Reserve and Wyperfeld

National Park where Mallee Emu-wrens

are known to occur, but have not been

extensively surveyed.

Acknowledgment

The Mallee Catchment Management

Authority (Mallee CMA) engaged Deakin

University to undertake this project,

with funding provided by the Victorian

Government and Parks Victoria.

Further information

The information for this bulletin has been

taken from ‘Survey of the Mallee Emu-

wren (Stipiturus mallee) within Murray

Sunset National Park and Hattah-Kulkyne

National Park in October 2009’, a report

for the Mallee CMA by Deakin University.

For further information about the Mallee

Emu-wren survey please contact the

Mallee CMA on (03) 5051 4377.

Project PartnersPublished March 2011

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