Hello All
Thanks to everyone who sent in information about night vision equipment, it
has been of great help. The replies are included below for anyone else who
is interested.....
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The best stuff for you would be infra-red / body-heat based equipment -
but is ridiculously expensive. (like $25,000). Unlike image
intensification equipment (which uses available light or relies upon IR
illumination) it has excellent range (hundreds of metres) and full depth
of field.
I have a friend in Geneva who is using a hand-held type of equipment to
study foxes in the Canton of Geneva (CH) and has been lent this
equipment by the Swiss military. It is now in general use for detecting
illegal immigrants along much of the EU's border with the east and south
and, for example on the video cameras on police helicopters in the UK.
For *studying* warm-blooded animals at night there is no better
substitute although for shooting them a simple image intensifier is more
than enough.
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I had been studying feeding behaviour of Bar-tailed Godwit in the
Netherlands
(Texel) and in Persian Gulf (Bahrain and UAE)(PhD thesis). I covered all day
(means sunlight part) and tried to do it at night with nightvision.
Unfortunately I used Russian made machine with only 3 to 3,5 magnification
(had
no more money for better equipment) with small spot red light to emphasize
the
image. General it wasn't so bet for that money (around 200$). However in my
opinion the most important is the species you would like to study. In case
of
B-T Godwit even with Russian equ. I was able to see if the bird caught, took
and swallow some small unidentified food (mollusc, crabs etc.) or long worm
(nereidae family). The best foreground is distinctly lighter than bird like
wet
mud with some reflection of moon, stars or town lights. I was able to follow
the birds feeding manner up to 15-20 m. In farther distance with my equ. I
wasn't able to be sure about what that bird had just caught. Nevertheless
B-T
Godwit is rather large species with very characteristic feeding action and
food. In case of let's say Dunlin or Kentish Plover the case is much, much
more
complicated.
Anyway at nights I was able to estimate numbers of feeding and non-feeding
birds up to 50 m distance and It was Ok in my study.
Well, it is nothing special but it is my experience. Hope to help you just a
little bit.
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Contact Raymond McNeil (University de Montreal, Montreal, Quebec) or his
student Robert Michel..both have had a huge amount of experience in this
area.
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I used night vision optics to observe Pectoral Sandpipers feeding at
night in rice fields of Texas and Louisiana. These birds are
relatively small and rice fields sometimes have furrows or clumps of
vegetation that make spotting a bird very difficult. What seems to
work well is a high-power infrared(IR) light that can be shined on the
field to illuminate the bird (as seen through the night vision
equipment), but which is not perceived by the bird, and thus has no
effect on behavior. IR lights are readily available from several
sources of outdoor gear.
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I have not used night vision equipment but there are a number of
suppliers that deal with imaging equipment for video/ CCTV etc.
Mostly this equipment is thermal imaging and I have no idea about
costs Try www.lotoriel.co.uk
At the low tech end of the spectrum field glasses for night
vision are certainly sometimes advertised in wildlife magazines
and no doubt those Combat and Survival magazines. But Ive never read
any of those!
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Just yesterday, I talked to someone who recently obtained a new, state of
the art night vision scope/binocular which was apparently much better than
the stuff available till now. He said that they could now count (and
identify) waders on mudflats at night, up to 500 m away. It could also be
used in combination with a telescope. The equipment is made in America and
freely available there but on the European market restricted to certain
types of users (police etc; so my spokesman had to have an acquainted
official buy the thing and then lend it to them. It was not extremely
expensive, though, about 2000 pounds. For more details contact: Cor
Berrevoets at [log in to unmask]
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I saw your request for night vision equipment information.
I have been studyind waders at night (and day) for the past 3 years during
the winter here in British Columbia Canada, and have an excellent night
scope which allows me to identify to species and also view behaviour. I
have an ITT monocular pocketscope, Generation III, attached to a 4.5x
catadioptic lens. I also use an IR flashlight to further illuminate
particularly dark areas. I purchased it from Current Corporation, based
here in BC. They have a web site at http://www.currentcorp.com/
I have been very pleased with the equipment I have. It is expensive though.
The whole unit
cost me about $10,000 CDN (which is about $7000 US). But if you want to be
able to really see clearly, you have got to have Generation III equipment,
unless you are basically able to get within a few metres of the birds. I
tested Generation II in the field and it was pretty useless -- I couldn't
distinguish birds from potatoes in fields, since the image is so grainy and
unclear. With my scope I can see clearly for a distance of up to 2km,
depending upon weather conditions, which means I can also see flocks flying
in the distance, etc.
The US has strict regulations about where ITT equipment can be used, since
it is considered military equipment, so you may have to go through some red
tape. I suspect going through a UK distributor would help in thus respect.
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Your e-mail requesting advice on night vision equipment has been forwarded
to
me both by Ros Jessop in Australia and Frances Schmechel in New Zealand!
However, you need not have gone further than Exeter!
I am just about to submit a D.Phil thesis on night-feeding in wintering
oystercatchers supervised by John Goss-Custard of ITE and Chris Perrins of
Oxford.
Most of my work was based on the behaviour of mussel-feeders. I made
observations from a tower hide in the middle of a mussel-bed using infra-red
video i.e. an infra-red sensitive camera and a searchlight with a filter
which cut out visible wavelengths. With a 16-160mm f1.8 lens, this was
effective for the purposes of assessing the length of a mussel in an
oystercatcher's bill to about 40m. I conducted some tests which confirmed
that the birds' behaviour was not affected by the lamp. I ended up with
hundreds of hours of night-feeding record (which took ages to analyse!).
The drawbacks of the night video are that it is not portable (with 2 car
batteries for power, it weighs about 80kg) and that it has only a limited
range. Range, however, depends on what you want to record. Simply to tell
whether oystercatchers are feeding or roosting, its range would be more like
80m. Another problem is that, working from a square hide, you have to
decide,
when setting-up, which side of the hide to use. There is so much equipment
in
a cramped space that it is almost impossible to change your mind and make
observations from another side during the course of a tidal cycle.
I also have several image intensifiers. These are rather disappointing for
making observations of feeding behaviour because of their low magnification
-
they are like low power binoculars - the video is more like a telescope.
They
are more useful for counting and as something that can be carried about. The
important point is that, except perhaps under a large moon, they are not
much
good without an infra-red searchlight. The image is all swirling dots and
little contrast. With an i-r searchlight, the image is much sharper, and,
more to the point, the birds' eyes reflect the light so they can be picked
out easily, even in vegtation. The eyes become little beacons.
Image intensifiers are 'Generation 1, 2 & 3'. G1 tend to be large & heavy
(<20kg) but, for our purposes, may well be the best option because they
often
have the best magnification and image quality. G2 & 3 tend to be much
smaller
but the problem always is to find a lens with a long-enough focal length and
large enough aperture. I was lucky to come across an ex-police road camera
lens for £40 (which costs £1500 new!). This is 16-160mm f1.8 but it would be
better if the focal length were longer. These things were designed to enable
soldiers to see tanks etc, not to see dunlin!
I expect one problem for you will be cost (I think you can probably get hold
of some pretty wonderful equipment if funds are unlimited). I have equipment
that I might sell or perhaps loan. Otherwise I could put you in touch with a
supplier. The vital thing is to test and evaluate before you buy.
I suggest that you spell out to me exactly what you want to do - what sort
of
observations you want to make and in what conditions and roughly what is
your
budget - and I will then advise you further.
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