ABSTRACTS
OF PAPERS PRESENTED
Edited by Pro Igel, Germany
The incidence of disease and injury
in wild hedgehogs and the use of a new index to assess weight/size relationship
Toni Bunnell
University of Hull, Faculty
of Health, Cottingham Road, Hull, HU6 7RX, England UK
Email: T.Bunnell@hull.ac.uk
The incidence of disease and injury was
assessed in 168 wild hedgehogs over a three-year period between 1998 and
2000. The aim was to determine the main reasons why hedgehogs were being
taken toYork Animal Home by members of the public. All the animals were
treated at the author's hedgehog sanctuary. Of these 61% were nestlings,
25% juveniles, and 14% adults. Nestlings showed a significantly male-biased
sex ratio (m:f = 1.5:1), while juveniles and adults did not. However, there
was a significant male bias (1.4:1) for all age categories combined.
The most common ailments were malnutrition
(27%) and dehydration (15%), while ticks (14%), nematodes (11%), ringworm
(4%) and sarcoptic mange (6%) also occurred regularly. Road accidents and
other injuries each affected 4%. The overall survival rate was 94% and
84%, 48 hours and 20 days after admission respectively. Most nestlings
(74%), juveniles (55%) and adults (58%) survived and were released back
to the wild. Anthropogenic factors appear to contribute substantially to
the incidence of injury and misfortune in all age groups and emphasise
the need for measures directed at maintaining hedgehog populations.
A new index, based on the relationship
between the weight and size of a hedgehog, has been developed. The measurement
of the latitudinal circumference, divided by the longitudinal circumference,
in a tightly curled hedgehog, provides an index which should be no less
than 0.80. This index is useful for assessing an animal's nutritional status
and chances of post-release survival.
The presentation will be based on two published
studies:
BUNNELL T. (2001): The incidence of disease
and injury in displaced wild hedgehogs (Erinaceus europaeus), Lutra, 44
(1): 3 - 14.
BUNNELL T. (2002): The assessment of British
hedgehog (Erinaceus europaeus) casualties on arrival and determination
of optimum release weights using a new index, Journal of Wildlife Rehabilitation,
25 (4): 11 -21.
Exposure and effects of heavy metals
and organochlorine compounds in European hedgehog (Erinaceus europaeus
L.) populations.
Helga D’Havé1, J. Scheirs2,
A. Covaci3, M. Lenjou4, D. Van Bockstaele4, P. Schepens4, R. Verhagen2,
R. Blust1 and W. De Coen1 (Belgium)
1Helga D’Havé, R.
Blust & W. De Coen, Laboratory for Ecophysiology, Biochemistry
and Toxicology, Department of Biology, University of Ant-werp, Groenenborgerlaan
171, B-2020 Antwerp, Belgium
2J. Scheirs & R. Verhagen,
Evolutionary Biology Group, Department of Biology, University of Antwerp,
Groenenborgerlaan 171, B-2020 Ant-werp, Belgium
3A. Covaci, Toxicological
Center, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk, Belgium
4M. Lenjou, D. Van Bockstaele
& P. Schepens, Laboratory for Experi-mental Hematology, Faculty of
Medical Sciences, University of Antwerp, Antwerp University Hospital, B-2650
Edegem, Belgium
Contact Email: helga.dhave@ua.ac.be
The emission of anthropogenic chemicals
has caused worldwide pollution of our ecosystems. Exposure studies of these
chemicals on wildlife have a long tradition, focussing mainly on chemical
analyses of tissue residues. Although the effects of these pollut-ants
on the individual and the population are of increasing con-cern, impact
studies on terrestrial wildlife are scarce. Further-more, there is a need
for non-destructive methods as to assess the global impact on mammals.
The overall goal of this field study is
to investigate the effects of persistent pollutants on the hedgehog. Both
individual and popu-lation level effects will be investigated and related
to exposure levels as measured from hair samples. To achieve these goals
non-destructive methodologies will be developed.
During 2002 a field study of 5 hedgehog
populations was conducted along a heavy metal pollution gradient in Antwerp,
Belgium. All study sites consisted of similar habitat type, i.e. park areas.
Hedgehogs were searched for with powerful flashlights and caught by hand
for investigation. Each individual was tagged (PIT tag), sexed, while body
mass and length variables were measured. Hair, spine and blood samples
of 10 animals per site were collected. Individual toxin loads were studied
through the analyses of hair and spine samples, while blood samples for
biomarker measurements were taken from the saphenous vein. The concentrations
of 12 heavy metals (Ag, Al, As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn) were
determined in the hair samples by means of ICP-MS. Individual toxicant
loads of PCBs and the or-ganochlorine pesticides DDT, hexachlorobenzene
and hexa-chlorocyclohexane were measured with GC-MS. The haemato-logical
parameters under investigation were: hematocrit, haemo-globin concentration,
mean corpuscular volume, mean corpuscu-lar haemoglobin and mean corpuscular
haemoglobin concentra-tion (haemocytometer). The lysozyme activity was
estimated as a parameter of the humoral immune system by means of a fluores-cence
based assay. The hormones under investigation were tes-tosterone, estradiol,
T4 and T3 (ELISA assay). By visiting each population approximately once
in two weeks, population parame-ters, like sex-ratio, recruitment and density,
were recorded. Addi-tionally dead hedgehogs, road traffic victims and animals
that died in rehabilitation centres for wildlife, were analysed so as to
quantify the relationships between pollutant levels in organs and hair.
The most contaminated sites were characterised
by high hair concentrations of Cd, Pb, As and Ag. Moreover, high hexachlorobenzene
concentrations, and to a lesser extent high hexachlorocyclohexane concentrations,
were observed in hair samples from some sites. Mean DDT and PCB levels
were moderate and did not differ significantly between sites (p<0.05).
Haematological parameters and lysozyme activity showed no significant difference
among populations. The hormones testosterone and T3 were significantly
different between populations. Furthermore, among the populations, increasing
HCH levels were correlated with increasing testosterone and T3 levels and
a decreasing sex-ratio (less females). These results suggest that hedgehog
populations might suffer negative effects from pollutants. Furthermore,
our data from dead hedgehogs suggest that hair is a suitable indicator
of internal contamination of mammals to both organochlorines and heavy
metals. Overall, the hedgehog seems to have the potential to be a valuable
bio-indicator of pollution in terrestial ecosystems.
Diseases of hedgehogs (Erinaceus europaeus)
determined from material submitted to the Institute of Pathology, School
of Veteri-nary Medicine Hannover, Germany, between 1980 and 2001
Carola Döpke1, Andreas Thiele1,
Michael Fehr2, Peter Wohlsein1, Joachim Pohlenz1
1Dr. Carola Döpke,
Andreas Thiele Dr. Peter Wohlsein, Univ.-Prof. Dr. Joachim Pohlenz, i.R.,
Tierärztliche Hochschule Hannover, Institut für Pathologie, Bünteweg
17, D-30559 Hannover
2Prof. Dr. Michael Fehr,
Tierärztliche Hochschule Hannover, Klinik für kleine Haustiere,
Bischofsholer Damm 15, D-30173 Hannover
Contact Email: carola.doepke@web.de
This study was designed to obtain an overview
of common dis-eases in hedgehogs in the area of Hannover, Germany, and
to contribute to statistical evaluations of the incidence of diseases in
this species. This survey was based on 373 necropsies and the results of
investigations of 41 tissue samples submitted to the Institute of Pathology
of the School of Veterinary Medicine Han-nover from January 1st 1980 to
December 31st 2001.
Poor nutritional status and cachexia were
found in 38.1% of ne-cropsies. In 71.3% there were alterations of the digestive
tract, mainly caused by enteritis and hepatitis. These originated pre-dominantly
from infections with Salmonella species. In 39.9% a pulmonary endoparasitosis
was detected. This was recorded separately from other findings in the respiratory
tract. Non-parasitic respiratory tract alterations were present in 31.4%
of the cases. 20.9% of them were pneumonias of different types.
In 26.3% skin lesions were diagnosed. These
were predominantly of parasitic or inflammatory character. In 24.1% of
necropsied hedgehogs, urinary tract lesions were found. These were either
inflammations or nephroses. In 10.7% of the examined hedgehogs generalized
bacterial or mycotic infections were cause of death. Most of septicaemias
were caused by Salmonella species.
In 10.2% of the examined animals there
were inflammatory or degenerative changes of the central nervous system
and the sensory organs. In 7.2% the cardiovascular system was affected.
Most of the cases suffered from myocarditis. In 3.9% of the ex-amined animals
traumatic conditions of the locomotor system were diagnosed. In 3.5% there
were alterations associated with the hematopoietic system, and in 3.2%
the genital system was affected.
Tumors were diagnosed in ten (2.7%) necropsied
hedgehogs. Additionally 23 tumors were found in the submitted tissue sam-ples.
‘Wobbly Hedgehog Syndrome’ in African
Pygmy and European Hedgehogs
Donnasue Graesser1, Terry R. Spraker2,
Dolores Gavier-Widen3 (USA)
1Donnasue Graesser, Yale
University Department of Pathology, Yale University Station, PO Box 206603,
New Haven, CT, USA, 06520-6603. (donnasue.graesser@aya.yale.edu)
2Terry R. Spraker, Colorado
State University, College of Veterinary Medicine, 300 West Drake, Fort
Collins, CO, USA, 80523 (tspraker@lamar.ColoState.EDU)
3Dolores Gavier-Widen, Department
of Wildlife Diseases, National Veterinary Institute, S-75189 Uppsala, Sweden
(dolores.gavier-widen@sva.se)
Contact Email: donnasue.graesser@aya.yale.edu
African pygmy hedgehogs (Atelerix albiventris)
are kept as pets in the United States and increasingly in many European
coun-tries. In a study of mortality/morbidity of over 1000 pet African
hedgehogs from 1998-2003, approximately 12% were found to be affected by
a condition known as “Wobbly Hedgehog Syn-drome” (WHS). WHS is a degenerative,
progressive disease of the central nervous system (CNS). WHS first presents
as a slight ataxia, which may be relapsing and remitting in the early stages
of the disease. Over several months, the symptoms become pro-gressively
more severe and may include tremors, decreased movement of the hind limbs,
hemiparesis, seizures, and/or se-vere weight loss. The end result is complete
paralysis and death of the hedgehog.
Approximately 60 cases of WHS in African
pygmy hedgehogs have been submitted for post-mortem examination. The hedgehogs
are emaciated. Gross lesions of the CNS are not observed, however histopathology
reveals leukoencephalopathy in white matter tracks of the brain, as well
as spongiosis in the ventral columns of the spinal cord. Typical lesions
usually involve demyelination and/or axonal degeneration, and are confined
to the central nervous system. WHS does not typically affect the peripheral
nervous system. Although the cause for these lesions is not known, pedigree
analysis indicates that WHS is likely to have a genetic component. In recent
years, a high incidence of WHS has been seen in pet African hedgehogs imported
from the USA to Finland.
A similar WHS-like condition has also been
observed in Euro-pean hedgehogs (Erinaceus europaeus), particularly in
Sweden, where a few cases are reported each year to the Department of Wildlife
Diseases, National Veterinary Institute. Cases of paraly-sis in European
hedgehogs have been entered into the database as early as 1986, and may
have potentially occurred before 1986. Clinical symptoms in these hedgehogs
are somewhat simi-lar to WHS in African hedgehogs, and include paralysis
that is more marked in the hind legs, falling on one side of the body,
and subsequent “circling” on the side because the hedgehog is un-able to
get back on its legs. Seizures have also been reported.
Similarly to WHS in African hedgehogs,
gross lesions are not observed in the paralyzed hedgehogs, but histopathological
changes are present in the central nervous system. However, the histopathology
in European hedgehogs can be distinguished from that in their African counterparts.
The pathological changes in European hedgehogs may include vacuolization
of white mat-ter of variable degree and variable location, affecting both
the brain and spinal cord, and/or inflammatory changes in the men-inges
that may be indicative of a viral meningoencephalitis. Unlike WHS in African
hedgehogs, many cases with clinical dis-ease show only minimal vacuolization
of the white matter.
Further studies include further tracking
of hedgehogs with this condition throughout several European countries
and comparison of the clinical disease and histopathology between the European
and African hedgehogs. In addition, as WHS is being reported in pet African
hedgehogs in European countries, rescuers who deal with African hedgehogs
should be aware of the condition.
Computer simulation of hedgehog habitat
utilisation in urban areas
Görgen Göransson (Sweden)
Dept. Biology and Environmental
Science, University of Kalmar, SE-391 82 Kalmar, Sweden
Email: gorgen.goransson@hik.se
In this paper hedgehog movements are simulated
in an urban area using a digital habitat map and a simple, pilot study,
random walk computer model. The investigated urban area is a small village
situated close to Malmoe City in South Sweden and very close to a motorway
opened for traffic in summer 2000. The habitats are gardens with lawns,
orchard trees and bushes around small houses intersected by bitumen roads.
There are also included vegetated wastelands and unmoved grasslands, small
grazed areas in the village which is surrounded in some directions by cultivated
fields.
The model was designed to generate randomly
directed short walking segments ending up with new randomisation and new
segments. Walks were started at designated nests given at different alternative
locations. Random walks were accumulated for each nest place and a utilisation
index (random visits density) was calculated. The model was generating
shorter walking segments in well suited areas, e.g. providing good foraging
capabilities, and longer segments in less useful habitats. The movement
resistance was positively correlated to the usefulness of ground resources.
That is, the more suitable the habitat is the slower are the animals expected
to move. Availability of shelter (bushes) close to foraging areas was set
to increase resistance.
Distribution of the random walks utilisation
index was negatively affected by unsuitable habitat elements like roads
and uncovered places. This distribution was compared to locations recorded
from real hedgehog movements monitored in the area by radio telemetry for
three different seasons in the period 1997-2002. The simulation model needs
further improvements to be realistic.
Foraging behaviour of introduced hedgehogs
in South Island New Zealand: implications for native species conservation
Chris Jones (New Zealand)
Landcare Research, P.O.
Box 282, Alexandra, New Zealand
Email: jonesc@landcareresearch.co.nz
European hedgehogs in New Zealand have
been regarded with benign indifference since their deliberate introduction
130 years ago. A review of evidence from their native Europe and, more
recently, from New Zealand suggests that they may present a significant
threat to endemic birds, reptiles and invertebrates. Hedgehog diet was
studied in dryland scrub and braided river habitats in the central South
Island using gut and faecal analysis. The most important food items were
Coleoptera, earwigs, Lepidopteran larvae, Hymenoptera, and Orthoptera.
Rare and locally restricted endemic invertebrates were eaten, often in
large numbers. Remains of endemic skinks and geckoes were consumed significantly
more often by female hedgehogs than males in spring. Hedgehogs also prey
on the eggs of endangered black stilts and black-fronted terns and of other
birds nesting on river gravels in braided river systems. Spring foraging
behaviour in these systems was studied by following 10 hedgehogs using
line and spool methods and recording the individual foraging paths with
a GPS. Habitat were used in direct proportion to availability of the most
important food types. Most hedgehogs used scrub and woodland habitats and
rarely foraged on river gravels, although one female used river gravels
almost exclusively. Hedgehog control to protect breeding birds may therefore
be most effective if focussed around nesting sites rather than by diluting
effort in attempting to reduce hedgehog numbers over a large area.
Statistical evaluation and interpretation
of data concerning hedgehogs in need of help, which were taken in by hedgehog
stations in Berlin during a five year period
Monika Neumeier1; data gathering: Gabriele
Gaede2
1Monika Neumeier, Lindenhofweg
50, D-88131Lindau/Bodensee, Germany
2Gabriele Gaede, Arbeitskreis
Igelschutz Berlin e.V., Berliner Str. 79 A, D-13467 Berlin, Germany
Contact Email: ProIgel@t-online.de
For the last 22 years the “Arbeitskreis
Igelschutz Berlin e.V.“ (The Berlin hedgehog protection association) has
taken care of hedgehogs in need. The association is affiliated with between
10 and 12 hedgehog stations. The association has made sure that standards
for hedgehog accommodation, diet and care have been adhered to. For several
years the data from the animals taken in by the various hedgehog stations
has been recorded. The chairman, Gabriele Gaede, has taken on the task
of gather-ing together the most important data in order to produce a set
of meaningful statistics.
This data collection contains information
from a total of 7015 hedgehogs which were taken in by the Berlin stations
over the five year period between 1997 to 2001. Of this number 1317 animals
(18.8%) died.
Between 1998 and 2000, the sexes of a
total of 3605 hedgehogs taken in were also recorded. The gender break up
of the animals taken in was nearly equal, with 49.79% female and 50.21%
male.
From the data concerning hedgehog weight
at the month they were taken in and their respective death rates, one can
draw conclusions about why these particular hedgehogs were conspicuous
and needed help, and whether or not it was necessary to take them in. When
a comparison is made between the weights of the hedgehogs and the months
they were found, the results show that between the different months they
were taken in, different patterns emerge. The number of animals found also
varies greatly depending on the time of year. About 75% of the hedgehogs
experience serious difficulties between September and December. Of the
hedgehogs taken in during this period about 75% weighed less than 500 grams.
Between January and March it is quiet in
the hedgehog stations, only a small number of hedgehogs (just 6% of the
yearly total) are found.
From April to June the number of hedgehogs
in need with a weight over 700 grams (adult animals) are on the increase.
In June about 60% of hedgehogs found are adults. As well, the death rate
climbs from 25% in April to 38% in June (the highest rate of the year).
The high death rate is explained by the high number of seriously injured
hedgehogs.
The death rate in July at 30% is also very
high. More than half of the hedgehogs in need of help are adults.
August is the month when the most litters
are born in Berlin, 22% of hedgehogs found weigh under 50 g and a further
14% weigh between 51 and 100 g.
The ‘main season’ in the hedgehog stations
begins in Septem-ber. At this time of year baby hedgehogs under 100 grams
make up 32% of hedgehogs cared for and 42% weigh between 101 grams and
200 grams.
The hedgehogs that are brought to the stations
in October make up about one fifth of the yearly arrivals. Only 4.4% of
these are adults.
In November the number of hedgehogs in
need reaches it’s peak. A little more than a quarter (25.6%) of the yearly
total of hedgehogs in need (almost all young animals) are taken care of
and nursed at this time.
As in November, the death rate in December
(at 11%) is also relatively low. The number of hedgehogs brought in is
less in December.
In Germany it is normally assumed that
a minimum hedgehog weight of 500 g at the beginning of November is required
for the young hedgehog to be able to survive the hibernation period. This
threshold is however theoretical. Only 6.7% of the hedge-hogs brought in
between October and December weighed be-tween 451g and 550g.
Releasing Rehabilitated hedgehogs
Janet Peto (England UK)
Hedgehog Welfare, Newark,
Nottinghamshire, England, UK
Email: ehrg.members@virgin.net
In 1996 the number of hedgehogs admitted
to our centre sud-denly grew from under 700 to 1,863 per year. Rather than
refuse animals, we reviewed our procedures to increase efficiency with-out
compromising quality of care. We identified questions about the timing
and minimum weight for release. Before 1996, no ani-mal was released (at
any time) weighing under 450g; a widely accepted minimum hibernation weight
in the UK. All animals un-der 450g in mid-October remained in care over
winter. However, we reasoned that it should be acceptable to release healthy,
fully recovered (or hand-reared) hedgehogs weighing under 450g at a time
when typical wild hedgehogs of comparable age weigh no more. It should
also be acceptable to release animals weighing over 450g after mid-October
if the weather remains mild and wild hedgehogs are still active. To test
our ideas, we implemented a new release protocol in which animals were
released (in the area where they were found) when they achieved good general
health and a weight comparable to contemporary wild hedgehogs of the same
age. Animals were monitored for 7 days in outdoor ac-commodation, prior
to ‘soft release’ using a release box with bedding and dry food was provided
until it was no longer taken. Hedgehogs were not released during harsh
weather e.g. pro-longed drought or severe cold.
Post-release monitoring of these hedgehogs
(marked with type-writer correction fluid) was conducted by the original
finders of the hedgehogs - who were appropriately trained. From July 1996
to January 1997, 306 hedgehogs were released: 90 juveniles (205-260g),
64 subadult males, 82 subadult females (215-300g), 41 adult males and 29
adult females (all under 375g). Results were as follows:
· Week 1: Survival rate: 245 (80%).
61 (20%) were not found, 25 (8%) lost up to 30g bodyweight, 220 (72%) maintained
or gained weight.
· Week 2: Survival rate: 283 (92.5%).
Of the 61 hedgehogs lost during week 1, 41 were found in weeks 2 or 3 and
had all gained weight. Of the 25 animals that lost weight, 22 had regained
or exceeded their release weight, 3 hedgehogs could not be found. Of the
220 who had main-tained or gained weight, only one could not be found.
· Week 4: Survival rate: 216 (70.6%).
216 hedgehogs near the release sites and all had gained over 100g. One
ani-mal had died, apparently after an attack by another ani-mal. Note:
6 animals were returned to care after welfare concerns, but were re-released
in good condition after 10 days care (outside) and increased their weight
in the first week
· Long term: Survival rates were
178 (58%) after 6 months and 76 (25%) after 3 years
We conclude that the new release protocols
result in good post-release survival and welfare, as well as reducing demands
on carers. Returning healthy hedgehogs to the wild as soon as pos-sible
is likely to improve their long-term welfare. None of the re-leased hedgehogs
used the release box after the second night, (but 82 of the boxes were
being used by other hedgehogs). The participation of the general public
in this simple study has been effective and raised public awareness.
Thanks to DFDS Transport, Spike’s World
and Wildaid for spon-soring my attendance at this conference. I am grateful
to all the Hedgehog Welfare carers and members of the general public who
helped carry out this study.
An Analysis of Rescue Centre Records
of Hedgehogs from Jersey, 1995-2003
Nigel Reeve1 and Dru Burdon2 (England
UK)
1Nigel Reeve, The Royal
Parks, Hyde Park, London W2 2UH (England UK), and the School of Life and
Sport Sciences, Roehampton University of Surrey
2Dru Burdon, Jersey Hedgehog
Preservation Group, White Lodge, Waterworks Valley, St Helier, Jersey JE3
1HQ (England UK)
Contact Email: nreeve@royalparks.gsi.gov.uk
In this study we examined data collected
from 3177 hedgehogs admitted to a hedgehog rescue centre in Jersey (Channel
Islands) between October 1995-September 2003. Of hedgehogs admitted, 2128
(67.0%) were released, 1022 (32.2%) subsequently died or were euthanased
and 27 (0.2%) remained in care at the end of the study period. In contrast
to some previous studies, there was no overall significant bias in the
sex ratio of animals admitted (1m:1.05f). Endoparasite infestations were
found in 68% of 2987 animals tested; the incidence varied significantly
with age but not with sex.
Of 1002 animals that were ear-tagged and
released, 156 (15.6%) were re-found in the wild (28 live sightings, 17
dead) or readmitted to the rescue centre. Of the latter, 93 (59.6%) were
subsequently re-released. The median number of days from first release
to final record (some individuals were re-found up to 3 times) was 212.5
(range 8 – 1830 days). 82 (52.6%) records were over a year from the first
release, 35 (22.4%) were re-found after 2 years or more. One male was re-admitted
and re-released more than 5 years after his first release back to the wild.
The sex ratio of both the released hedgehogs and those later re-found was
close to 1:1. The data suggest fair long-term survival prospects for released
animals of both sexes
A total 52.6% of admissions resulted from
natural causes such as parasitic diseases, congenital problems, tumours
and infections. 47.4% of deaths resulted from anthropogenic (unnatural)
factors, e.g. injuries from garden tools, burns, road accidents, disturbance
of nests (causing abandonment of young), injury by domestic animals and
poisoning. These figures closely match those reported by Reeve & Huijser
(1999) in a previous study of mortality records combined from 3 rescue
centres in the UK and the Netherlands. This emphasises the likelihood that
anthropogenic factors, many of which can be prevented, may be causing significant
additional negative pressures on wild hedgehog populations.
How should the decision about the fate
of the hedgehogs on Uist (Scotland) be taken? Should the final arbiter
be the scientists? If so, which scientists?
Hugh Warwick (England UK)
176 Campbell Road, Oxford
OX4 3NR, England UK
E-Mail: hugh@urchin.info
The case of the Uist hedgehogs, splashed
across the media in 2003, raises many vital questions for hedgehog researchers.
While there was general agreement that the animals needed to be removed
from the islands to protect ground nesting bird populations, there seemed
to be an enormous, and fundamental, disagreement as to how this was best
to be achieved. Should they be killed or translocated?
The claims in support of the killing policy,
from Scottish Natural Heritage (SNH), were investigated. Chief among these
claims were:
· The welfare of translocated animals
would be seriously compromised.
· Translocated hedgehogs would
be susceptible to disease.
· Indigenous hedgehogs would suffer
with the arrival of Uist refugees.
· These, and many other claims,
have been shown to be inaccurate.
· While the welfare of some translocated
hedgehogs might be compromised, there is plenty of evidence that indicates
these animals would have a high chance of success on release. Claims that
the release hedgehogs would starve are unfounded.
· There is no evidence to support
the claim that they would be more susceptible to disease – and it is worth
noting that this is not a requirement for other projects run by SNH.
· The idea that indigenous hedgehog
populations would suffer was accompanied by graphic descriptions of hoards
of incomers swamping residents. This ignored the carefully planned release
structure that would involve two or three animals being released in carefully
selected environments and being offered supplementary feeding.
Despite some of the worlds best-respected
hedgehog experts calling into question the planned killing, SNH have persisted
– and continue to make many scientifically dubious claims. But they do
so under the guise of scientific authority – dismissing critics as well-meaning,
if wrong-headed, bunny-huggers. And the media, in an attempt to be ‘balanced’
feels obliged to print both sides of the story, thus giving the impression
that the divergent views are of equal value.
Is there such a thing as scientific objectivity?
This season (2004) was due to see the start of a study that might have
appeased SNH as to the welfare impacts of translocating hedgehogs. But
they insisted on such extreme levels of investigation that the cost became
unsupportable (and they have always refused to contribute to research costs).
So it makes it even harder to persuade them to halt the killing.
In the end the story of the Uist hedgehogs
is actually about animal rights – there is no doubt that the welfare of
the hedgehogs is compromised less by killing them. But do they not have
a right to life? After all, they are only on the islands because of the
actions of man. And if it is an argument about animal rights, how comfortable
do hard-nosed scientists feel about getting involved?
I would like to thank Spike’s World for
contributing to the costs of my attendance at this conference.
The effect of badgers on hedgehog abundance
and distribution
Richard Young (England, UK)
Central Science Laboratory,
Woodchester Park Research Station, Tinkley Lane, Nympsfield, Gloucestershire,
GL10 3UJ, UK.
Email: r.young@csl.gov.uk
In the UK, the Eurasian badger Meles meles
is a predator of the western European hedgehog Erinaceus europaeus. Previous
studies in the early 1990s showed that badger predation may be influential
in shaping hedgehog populations at a localised scale in rural habitats.
Experimental manipulations of hedgehog populations found that badgers can
directly influence hedgehog abundance through mortality and indirectly
through stimulating changes in behaviour. Surveys revealed negative
correlations between badger density and hedgehog abundance, predicting
that badgers can achieve sufficiently high densities to exclude hedgehogs
from rural habitats. In such areas, hedgehogs would only survive
as isolated populations in suburban habitats, such as villages, which act
as refuges from predation. This research suggested that increases
in badger abundance would have serious consequences for the persistence
of hedgehogs in rural areas of the UK.
The aim of the present study was to investigate
the effect of badgers on hedgehog abundance and distribution at a larger
scale. This involved investigating (1) spatial correlations between
badger density and hedgehog abundance and distribution and (2) the response
of hedgehog abundance to an experimental manipulation in badger density.
The manipulation of badger density was provided by the UK Department for
Environment, Food and Rural Affairs (DEFRA) Randomised Badger Culling Trial.
This trial is examining the effect of culling badgers on the incidence
of bovine TB in cattle.
For the purposes of the present investigation,
five study areas were selected in the DEFRA trial areas in the Midlands
and South-West of England, which support high densities of badgers.
Spotlight surveys for hedgehogs were carried out in rural and suburban
habitats by searching pasture fields (n=82) and amenity grassland in villages
(n=23) (June to September, from 2000 to 2003). Initially, hedgehogs
were at very low density in rural habitats (mean 0.09 0.07 ha-1) in comparison
to suburban habitats (mean 1.54 0.44 ha-1). This is in agreement
with the prediction that hedgehogs would be almost absent from rural habitats
of high badger density. Hedgehog abundance and distribution were
negatively correlated with indices of badger density. Even in suburban
habitats the abundance and probability of occurrence of hedgehogs declined
rapidly as indices of badger density increased in the surrounding area.
The response of hedgehog abundance to manipulations of badger density was
investigated by generalised linear modelling. To date, no response
has been detected in rural habitats with still only very few pasture fields
supporting hedgehogs. In suburban habitats however, hedgehog density
increased in areas where badgers were removed, although this was not statistically
significant. This trend will be investigated further in the final
year of the project. In conclusion, these results, combined with
information from previous research, show that high badger density can have
a major impact on hedgehogs in rural and even suburban habitats.
The implications for hedgehog populations in the UK are discussed
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