Special interest groups
Bat Group
The best news this spring has been the
discovery of a new breeding colony of
greater horseshoe bats in South East
Cornwall. This contained 36 bats in
early July. We now have four breeding
colonies in Cornwall, although three are
quite small. Greater horseshoe bats are
among the rarest in Britain, with a total
population of only four to five thousand.
Two more barbastelles have been
picked up dead, one at Constantine and
one near Looe. There are currently no
known breeding roosts of this bat in
Britain and it is thought to breed in tree
holes. These two records confirm a
widespread but small population in
Cornwall.
The group held a very successful Bat
Detector Weekend at Boscastle on 21st-
23rd June, organised by Jeremy
Williams. The weekend included two
all-night sessions and identified seven
species foraging in the Valency Valley -
greater and lesser horseshoes, long-
eared. Natterer's. Daubenton's and
whiskered bats and pipistrelles.
Daniel Eva
The Boss says: "Don't forget the Trust's bat and
seal adoption schemes the perfect Christmas
present." Photo: Stuart Hutchings
Dolphin Group
It is now over four years since the
bottlenose dolphins arrived and it seems
they are deserting West Cornwall in the
third quarter of each year. Last year
they went to Torbay. "Benty". the
juvenile with a bent dorsal fin,
continues to be spotted regularly since
first being seen in October 1991 as a
newborn. This year a group of six is
still being seen in mid-July and has
spent more time along the north coast than usual.
Bottlenose Dolphins per hour of watching Land's End peninsular.
Over 6,000 hours of watching have been
logged but there are still important
questions to answer. What are the long-term
trends, especially in porpoise
sightings? Will the bottlenoses move on
or are they just extending their home
range? How do bottlenoses behave in
groups of different sizes? Is there a
pattern to the rarer species? And so on.
Next Dolphin Group meeting - Friday
11th October 1996, 7.3Opm, at Five
Acres. All casual reports of dolphin
sightings are welcome - please phone
me on (01736)711783.
Nick Tregenza
Scientific Committee
Cetacean by-catch in fisheries
The present view, based on the Trust's
work and a range of other sources is
that, around the UK and including areas
off the shelf edge, the main by-catches
of oceanic dolphins are in mid-water or
pelagic trawls and in the tuna drift net
fishery, while the main by-catches of
porpoises are in nets set on the bottom.
Baleen whales and turtles get caught
almost exclusively by drift nets.
The complexity of fishery issues
becomes clearer when you consider that
beam trawling, which probably does
least direct damage to cetaceans,
probably does most direct damage to
sea-bed ecology, with consequences for
the survival of post-larval fish etc.
Nick Tregenza
Veryan Wildlife Watch
Veryan Wildlife Watch Group spent
half term watching activity in a blue tit
nest box on live TV via a camera
placed in the box earlier in the year.
An adult bird regularly roosted in the
box from mid-February onwards, and
the first piece of moss appeared on 21st
February. Over the next nine weeks
the pile of nesting material in the box
slowly mounted up. Eight eggs were
laid from 28th April to 6th May when
the female started to Sit. During this
time she was occasionally fed in the
box by the male, but she still made
frequent sorties for short periods.
On 17th May, seven of the eight eggs
hatched and we could count the
frequency of feeding visits by the
parents. The last day that both adults
were seen together at the nest was 23rd
May, and it is possible the mate met
with an accident about this time. The
chicks appeared to grow satisfactorily,
but by 31st May two chicks had died;
they remained in the box, but away
from the nest cup. By 2nd June we
were left with two chicks and on 7th
June the final, lone survivor was
successfully fledged and left the nest.
It was disappointing not to have had a
happier result, but we think the cold
spring this year had reduced the supply
of caterpillars on which the nestlings
are usually fed - indeed we seldom saw
caterpillars fed to the chicks.
Our current activity is the rescue of
painted lady and peacock butterfly
caterpillars from a field where in past
years nettles and thistles have been cut
down when the caterpillars are feeding.
The painted ladies pupated first
between 2nd and 4th July. Just think -
the parents of this generation came to
us from the continent in early June.
We hope to have a "batty" event during
the summer holidays.
Marian James
Life's no tea party! |
Contents |
Special interest groups