Good Lord! With the visions this conjurs up, I just couldn't resist not
passing this one along!! I hope I actually read and interpreted it
correctly. LOL!! New Zealanders NEVER cease to amaze me with their
tireless abilities and ingenuity for coming up with and actually implementing
some of the most remarkable, amazing, innovative, and original measures in
research tools, often far surpassing anyone anywhere on the planet! Perhaps
one of those virtues of insularity I guess. --Richard Rowlett
---------------------
Forwarded message:
From: euan at Chch.plaNet.org.NZ (Euan Kennedy)
Sender: seabird at uct.ac.za
Reply-to: euan at Chch.plaNet.org.NZ
To: pagodroma at aol.com
Date: 97-06-13 22:58:19 EDT

RESTRICTING COMPETITOR ACCESS TO PETREL BURROWS

Chatham petrels (CPs) Petrodroma axillaris are one of NZ's rarest petrel
species. They survive only on Rangatira Island, a small nature reserve in
the Chatham Islands, 800 km east of NZ.

CP breeding is seriously threatened by broad-billed prions (BBPs)
Pachyptila vitatta, a similarly sized, more aggressive and abundant
species. The indications are that burrow competition between the two
species will lead to extinction of CPs in fewer than 50 years.

Without human intervention, CP eggs and chicks cannot be safeguarded from
eviction by BBPs. Breeding pair and burrow fidelity in CPs is considered to
be anomalously low as a result of persistent interruption and failure of
breeding attempts.

Since 1990, 40 breeding pairs of CPs have been located and their breeding
attempts followed. Their burrows have been replaced with artificial
structures, first, to prevent the collapse of the natural burrows; second,
to allow more efficient and less disruptive
monitoring of burrow conents, and third, to deny BBPs the use of burrows
when their CP owners are at sea over winter. This is achieved by placing a
plastic mesh gate in the Novadrain entrance tunnel.

This burrow competition is presently the subject of research at Lincoln
University, funded by New Zealand's Department of Conservation and
supervised by Kerry-Jayne Wilson. Researchers and managers are attempting
to devise electronic or mechanical
means of excluding BBPs from CP burrows. Nightly surveillance of CP burrows
is quite evidently unsustainable as a protection measure.

We consider that the best option for excluding BBPs from CP burrows may be
to employ an electronic means of releasing a gate on the burrow chamber.
This would require us to fit an appropriate triggering device to the
rightful owners of each burrow. Since all new CPs captured are banded, the
fitting of a transponder tag or some similar device would not require a
major diversion from our present management. Does anyone know of technology
which would allow the stainless steel leg band to trigger a metal-detecting
release mechanism?

Alternatively, can transponders be adapted to trigger such a device?

A further option may be to deploy a deterrent device triggered by a bird
entering the burrow but disarmed by the band or transponder. Is it simpler
for the transponder to turn on or turn off such a device or gate?



........

Kerry-Jayne Wilson
Department of Entomology & Animal Ecology
P.O. Box 84
Lincoln University
Canterbury
New Zealand.

Phone 64-3-3252811
Fax 64-3-3253844
E-mail: Wilsok at Lincoln.ac.nz


Euan Kennedy
Chatham Petrel Recovery Programme Co-ordinator
Department of Conservation
Private Bag
Christchurch
New Zealand

Ph: 0064 3 379 9758
Fx: 0064 3 365 1388

E-mail: euan at chch.planet.org.nz