|
The pateke or
Brown Teal (Anas chlorotis) is an endemic duck formerly
widespread in forested and wetland areas throughout the mainland
and Chatham Island
(Williams 2001, Worthy 2002). Today it is confined largely
to Aotea (Great
Barrier Island)
and parts of eastern Northland, with small numbers existing
on a number of offshore islands (Williams 2001). Populations
on Aotea and in eastern Northland are declining, with low
recruitment and/or adult survival, but the causes of decline
are poorly known (Barker 1998, Innes et al. 2000, Parrish
and Williams 2001, Williams 2001, Ferreira in prep).
An audit
of the Brown Teal Recovery Programme (Innes et al.
2000) identified that the management implemented to date (particularly
predator control) had been inadequate and/or of insufficient
duration to bring about a recovery in pateke populations and
that monitoring was often inadequate. These and other issues
indicated that there was a need for a revitalised recovery
programme focussing on increasing populations in the remaining
habitat remnants: the establishment of additional sites for
managed populations; and strengthening of supporting programmes,
including monitoring.
This document
provides protocols for monitoring pateke in the wild. It
particularly addresses the monitoring at the managed populations
at Okiwi (on Aotea) and at Mimiwhangata in Northland, where
maximum practical predator control is being implemented.
Monitoring techniques are also provided for flock sites elsewhere
on Aotea and in Northland, and for the monitoring of released
birds. Procedures are also provided for monitoring numbers
of some predator species and rabbits. The guidelines exclude
Standard Operating Procedures (SOPs) for the management of
grazing (N. Miller in prep.), predator control, and captive
management (K. Evans in prep.).
2.1
Short-term recovery plan
The recovery
programme for pateke is summarised as ten objectives in the
post audit short-term recovery strategy and workplan (O’Connor
2001). These objectives are:
·
Secure breeding population(s) of pateke at three locations
on Aotea.
·
Secure breeding populations of pateke at three locations
on mainland Northland.
·
Establish a third secure breeding population at a
new managed location.
·
Investigate and identify optimal release techniques
via experimental releases.
·
Determine taxonomic and genetic status of pateke in
Fiordland.
·
Revitalise the existing captive breeding and release
programme.
·
Involve the public more in the programme.
·
Revitalise the Pateke Recovery Group.
·
Undertake specific research to help achieve recovery
of pateke.
·
Develop and apply best practise to pateke conservation
management and research activities.
Monitoring is
an important component of most of these objectives, particularly
robust measurement of teal response to management. A brief
overview is provided below for these objectives:
Currently “maximum
practicable predator control” is in place at Okiwi Station/Whangapoua
catchment area on Aotea. This management includes the control
of dogs (Canis familiaris), cats (Felis catus)
and pukeko (Porphyrio porphyrio) to low levels, whilst
possums (Trichosurus vulpecula) and mustelids (Mustela
spp.) are absent. Paradise shelduck
(Tadorna variegata) and mallards (Anas platyrhynchos)
are controlled by annual shoots. It is proposed to continue
this management regime for Year 2 (and possibly longer) under
controlled grazing regimes and refine as necessary for later
years. The hypothesis being tested is that control of dogs,
cats and pukeko (but not Australasian harriers Circus approximans,
ship rats (Rattus rattus), and large eels Anguilla
spp.) will result in a significant increase in productivity,
survival and flock numbers of pateke with time, compared with
those of previous years, and that there will be few if any
predation events attributable to these species. This management
(or a derivative) will be extended to include additional catchments
by 2003.
Currently, maximum
practicable management is in place at Mimiwhangata and this
has been extended to nearby clusters of pateke at Teal
Bay and Whananaki/Otamure.
This management includes the control to low levels of dogs,
cats, mustelids and pukeko, and there has been a one-off catch
of large eels at Mimiwhangata. Paradise
shelducks and mallards are controlled in annual shoots.
Some by-catch of rats (Rattus norvegicus and R.
rattus) also occurs in fenn traps. A grazing SOP is in
preparation (N Miller pers. comm.) in which sward length will
be maintained within levels considered to be favourable to
pateke. It is proposed to maintain this management regime
for Year 2 (and possibly longer) of the short-term recovery
strategy and workplan, and to review monitoring results and
refine management as necessary. The hypothesis being tested
is that control of dogs, cats, mustelids, pukeko and large
eels (but not rats or harriers) at Mimiwhangata under controlled
grazing regimes will result in a significant increase in productivity,
survival and numbers of pateke compared with earlier years
and studies, and that there will be little if any predation
attributable to the predator species being controlled.
Landcare
Groups and other initiatives are currently increasing the
number of privately managed natural areas in Northland. Although
none of these areas are currently recognised as being part
of the formal recovery programme for pateke, some of them
(e.g. Russell Peninsula,
2,500 ha; Purerua
Peninsula, 3,000 ha)
have the potential to add significantly to the recovery of
the species. Suggestions for monitoring pateke will be made
to each group reflecting the specific situations and needs
of each group, as well as information that would be helpful
to the recovery group.
South
Okarito and Moehau are the two preferred mainland
sites for the establishment of additional mainland populations
of pateke (Maloney et al. 2002). South
Okarito is part of a managed kiwi zone, in which
mustelids and possums are controlled and cats and dogs are
rare (J. Clifton pers. comm.). At Moehau mustelids, cats,
possums and dogs are controlled. Some additional predator
management may be needed over and above that currently implemented
at both sites, e.g. in stoat plague years at South
Okarito. It is planned to release pateke annually
from 2003 at one of these two sites. Options for the second
site will depend partly on the outcome of the first release
programme.
Experimental
releases are underway or proposed to test site establishment
techniques (e.g. feeding apparatus) in support of securing
a third mainland population.
Revitalisation
of this programme is underway, i.e. implementation of the
captive management plan (Dumbell 2000) and completion of the
draft husbandry manual (K. Evans in prep), and recently
captured wild birds will inject new blood into the captive
population.
Currently research
results from studies at Aotea and Northland sites are being
analysed and interpreted. Recommendations from these studies
will help focus management and monitoring and identify additional
research that is needed to assist in either.
Some management
practises, e.g. predator control, have had an infusion of
external expertise to align them to current best practise,
but much management currently lacks definitive best practise
documents. SOPs for grazing management and captive husbandry
are currently in preparation
|
