From: Peter.Macinnis@p0.f508.n711.z3.fidonet.org (Peter Macinnis)
Newsgroups: k12.ed.science
Subject: Re: Frogs
Date: Tue, 03 Nov 92 21:12:00 PDT
Organization: FidoNet node 3:711/508.0 - The Bay, Neutral Bay NSW

AB>      so you want to know more about frogs?  We really don't know
AB>much about them either, but they are fascinating to learn about.  They are a
The following Frog Watch material comes from the draft of Martyn
Robinson's "Field Guide to Frogs of SE Australia", which Reed Books
will publish one of these years, complete with oodles of colour pictures.

Frog Conservation
In the late seventies and early eighties, scientists around the world
noticed a sudden decline in the populations of frogs and other amphibians.
At first, they thought these reductions were local variations, of little
significance.  It was only after all this information was pooled that
concern spread.  In some cases the cause of the decline was obvious: things
like drained breeding sites, changes in land use, acid rain, drought,
salination and pesticides.  Each of these has either killed frogs or
tadpoles, or made it harder for frogs to breed.

What was harder to explain was the decline and even apparent extinction
of frog species in seemingly pristine natural settings in nature
reserves and national parks.  Information is now being gathered by Frog
Watch programs in several states.  From this information, we will be
able to build up a picture of the status of various frog species and
populations.  We will be able to see where they are declining and where
some species seem to be spreading in range or increasing in number.

Beyond this study, there are several other things which can help frog
numbers.  Don't drain breeding sites of water.  Don't introduce new
fish species to ponds and creeks.  Don't use pesticides if you can help
it (frogs do a good job of eating many insect pests).  Don't collect
frogs or tadpoles from National Parks.  The absence of suitable breeding
sites may be a limiting factor for some species.  A backyard fish pond
without fish will often be colonised by local frog species.  If mosquitoes
are a problem, a few small 'gentle" fish can be used that will be unlikely
to worry tadpoles beyond hatchling stage.  The White Cloud or Mountain
Minnow (Tanicthys albonubes) is ideal and cheaply available from most
aquarium shops.  Do not introduce this or any other fish into natural
water bodies -- we have enough introduced fish pests as it is!

You can even design a pond that will suit one group of frogs over
another.  A raised or free-standing pond will be more accessible to
tree frogs, a sunken pond will suit ground-dwelling frogs, and a pond
with reeds and other vegetation growing out of it will suit swamp-
dwelling species.  In most cases frogs will rapidly find and colonise
the appropriate pond.  If a delay occurs or local frogs have been
severely reduced then some locally caught tadpoles can be added.  Don't
introduce frog species from other areas.  It may cause severe problems
for local species.  Before you introduce any tadpoles to your pond,
check with your local wildlife authorities, as most states have some
level of protection on frogs and tadpoles: you may need to obtain a permit.
When tadpoles grow legs and begin to absorb their tails, the grounds around
the pond should be well watered, to boost their survival rate.  Above all,
keep records of their progress.

Field Observation
Frogs can be found almost anywhere in Australia in both urban, rural
and bushland situations, although there have been declines in some
areas and some species.  The best places to find frogs are likely
breeding sites, particularly after rain.  You will most probably hear
frogs as you approach the site and they can be found by the water's
edge, in or on nearby vegetation, or under rocks, logs and other cover.

It is often easier to find the frogs at night time, because they are
more active then, and their eyes often reflect back the torch beam as
two golden spots of light.  Triangulation is another useful method to
find a calling frog.  Two or more people gather around a calling frog -
care must be taken here as the frog will stop calling if alarmed.  As
the frog calls each person points to where they hear the sound.  Where
these "lines of direction" intersect will usually be where the frog is.
The same procedure can be followed at night with torches.

Once the frogs are located, several pieces of information need to be
recorded, if possible.  Location, time of day, water temperature, air
temperature, weather conditions, calling site and species name.  At the
very minimum, you need to write down the location, the species name,
and the date when it was seen.

This information should be recorded in your field record sheet, or in a
field notebook.  The information built up over time will be a valuable
record of the requirements for each species, and their status.  A useful
item of equipment, particularly if you are having trouble seeing the frogs,
is a portable tape recorder.  Notes can be dictated into it for writing
into a notebook later, and frog calls can be recorded for comparison with
existing identification tapes.  If you play the taped call back to the
frog, it will usually answer, letting you locate and identify it.
If you can, you should make an estimate of how many individuals are in
the area, using a four-point scale which ranges from "rare" to "a few",
to "common", to "very large numbers".  You may find that the status
changes during the year, as many species have set breeding times.

Captive specimens
To learn more about frog behaviour, to observe metamorphosis, or to
help identify an unknown species, you may need to keep either tadpoles
or frogs in captivity for a short time before releasing them.  If you
plan to do this, check first to see if it is legal to keep frogs in
your state.  As this book went to press, there was legislation
operating in NSW and Victoria, which actually makes it illegal even to
handle eggs, tadpoles or frogs, let alone to keep them without a permit.





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