European badgers live in gregarious groups
and display some signs of hierarchy with a dominant boar
(usually an older larger individual) and a dominant sow (having
the first choice of breeding sites and usually the older
animal), heading the group in higher density areas.
The European badger is one of the few species
of mustelidae to show any form of social interaction at all,
although their cooperative behaviour can be classed as somewhat
limited. The marking and defence of the territory, excavation
and sett maintenance are responsibilities shared by all members
of the social group, but beyond this the reason for sociality in
badgers has been hard to understand. Groups of badgers living in
high population areas exhibit well defined social groups but in
other less favourable areas the European badger can be found
showing the normal solitary mustelidae behaviour where individual
animals defend their own territories. So what advantage does
group living hold for badgers?
Right: An
inquisitive looking pose from this adult. Keek-a-boo!
The most plausible theory put forward is that
the main reason for this group living is due to the fact that
badgers occupy patches of different habitat, and are much more
efficient at defending all these patches as a group than they
would if they lived solitary. In other words the badger’s food
resources are widely distributed in discrete patches. These
patches are essential for the badgers to be able to find food
within the different seasons of the year. A single badger could
not defend a territory this large and so the responsibility is
shared as a group. However when areas are less favourable they
may revert back to normal solitary mustelidae behaviour.
The proportion of sexes within social groups
is variable from group to group but the most common proportion
is two males and two females. Numbers can vary though and for
adult males it can range from 0 – 5 individuals and for adult
females 0 – 7 individuals, however it has been noted on
occasions that all male ‘bachelor’ groups and also all female
groups do form.
Although most individuals remain within there
native social groups throughout their lifetime, movement of
badgers between social groups is not uncommon and can be
classified as either true dispersal (permanent) or visiting
(temporary). Visiting by males takes place more often during the
peak of the mating season at the beginning of the year and helps
prevent inbreeding between within individual social groups.
Males which disperse permanently often do so singularly, however
females form coalitions of two or three individuals, often
sisters and mainly choose to disperse into territories that
contains only one female in the group, thus increasing the
success of displacement.
Territories
Badgers live in territorial groups called
clans (also commonly referred to as social groups) consisting of
up to 15 individuals, together they occupy and defend a
territory against neighbouring badgers. Badger social groups are
by definition exclusive and do not overlap. Members of the group
show high fidelity to their native home range and actively
defend against other social groups by marking the boundaries of
there territories with an elaborate scent marked system of paths
and latrines.
Latrines are made up of one or more small
pits dug by the badger into which excretory products are passed.
They are often placed along natural boundaries and margins such
as field edges and fence lines.
Left: A well worn path created by badgers when moving between
their sett in the woods and foraging areas.
Male badgers patrol their territory boundary
regularly during the main breeding season (February – March) and
mark the borders of the territory with dung. If a stray boar
from another colony is encountered the ensuing fight can be
particularly fierce.
However there are
always exceptions to the rules and territories are often less
profound out of the breeding season, when boars are not actively
defending their sows. Also during times of food shortage badgers
have to roam further and so ranges become larger and thus
boundary marking and patrolling of the territory perimeter
becomes physically impossible. Latrines then become restricted
to good worming patches or food areas that are seasonally
abundant.
Breeding
Reproduction in
badgers is unusual and involves a phenomenon called ‘delayed
implantation’. Badgers mate at any time of the year but the
embryo does not implant into the womb and start growing until
winter.
This means that
all cubs are born at the same time of year – mostly from January
to March. Litter sizes range from one to five with the average
number of cubs being born to a group as three.
The system of delayed implantation maximises
the badger’s chances of being successfully mated and also
ensures that cubs are born at the best time of year for
survival.
When cubs are
born, they are blind, pink with white silky fur and measure 12cm
long with weight varying from 75 – 132 g. The eyelids are fused,
and do not open until around 5 weeks of age (although this does
not mean the cubs are able to see fully because they will remain
underground in the dark for several more weeks).
After being
suckled underground for approximately eight weeks, they start to
emerge from the sett at the end of April/ beginning of May. This
provides them with plenty of time to feed and to develop
sufficient fat totally independent from their mothers until they
are about 15 weeks old.
Badgers have been shown to exhibit
allopaternal behaviour, ie. Related individuals co-operate with
the mother in rearing her young.
This kind of
behaviour is of potential benefit to all participants, not only
is the mother able to get more food during the time she is
suckling, it also improves the chances of the cubs surviving and
also gives the ‘baby sitter’ essential experience which may help
when she produces cubs of her own.
Above: One of my favourite badger photographs. This young cub
was out foraging alone on the hillside on a bright summers
night. (Available as a stunning 16 x 12" colour print, Canon 5D
and canon 70-200 F2.8 L IS USM with fill in flash)
Young cubs tend not to be so alert as the adults and
when hunting for food with their nose deep in the undergrowth,
you can get fairly close to them. If you remain downwind, stay quiet and approach from behind a
photo opportunity may present itself. Have your settings
adjusted though and be ready to pop off a quick shot.
If the badger spots you only a short moment will be available
as it checks you out then turns and runs or simply gets back to
business. I made a point of placing myself between the cub and the
setting sun and fill flash was used. I'll show you the
difference in the photography section if fill in flash is not
used.
Diet
Although badgers are members of the order
carnivore, they are in fact omnivores, meaning they eat a wide
range of plants and animals. They have a varied diet depending
on what food is available and on the time of year. The badger is
a forager rather than a hunter and as such, badgers are
opportunists when it comes to diet – they will take whatever is
available, which becomes more apparent when food is scarce!
Although immensely adaptable, badgers thrive
best where a mosaic of habitat types are available within their
territories. This allows access to adequate and varied food
supplies throughout the year and is one of the main reasons why
badger setts located in deciduous woodlands bordering arable and
grassy meadows are such a popular choice for sett construction.
Where habitat is more uniformed, it is reflected by lower
population densities and larger territory sizes.
Badgers rely heavily on their extremely good
sense of smell and have a large rubbery nose, which they use to
forage for food. They will walk with their nose close to the
ground sniffing out potential prey only stopping periodically to
scent the air for danger.
A badger’s diet mainly consists of earthworms
and for badgers in Britain, Ireland and most of central and
Western Europe there importance cannot be underestimated, they
are the badgers single most important item of food – the stomach
contents of a single boar once contained over 200 earthworms
taken in a single night! Foraging for earthworms is most
effective on areas of short grass this is why badgers are so
keen on visiting regularly mown and carefully maintained lawns!
Right: A shallow
scrape containing badger dung. This latrine was located about 60
yards from the main sett probably marking a boundary line. The
owner obviously feasted on a high percentage of worms.
Their diet however must be supplemented with
other food items and therefore they also eat insects, birds,
small mammals, fruits and berries, cereals, reptiles and
amphibians although the importance of which is determined by
abundance and season (see charts below showing frequency (%) of
main food items eaten throughout the year).
The effect of
season and weather on a badger diet can not be easily separated,
for example some winters may be mild and provide plenty of food
while others may be severe and food becomes limited.
Generally food
of animal origin is of greater importance than plant food over
most of the year except during late summer and autumn when
cereals and fruits are of major importance in a badger’s diet.
Maximum food intake occurs during the period
of September – November, while the minimum is between December
and February. During periods of drought (especially in June)
badgers may become desperate for food as earthworms become
unavailable but cereal and fruits are not yet developed, badgers
may exhibit odd behaviour. This could include raids on poultry,
scavenging in gardens and much earlier emergence from setts to
lengthen foraging periods.
Exploitation of mammals birds and insects
also show seasonal fluctuations, more mammals are taken in
spring and early summer as young animals are numerous and easier
for a badger to prey upon.
If you are interested in attracting wildlife
into your garden and want to feed badgers, it is safe to give
them dog food, fruit, root vegetables, peanuts and raisins.
Peanuts are particularly nourishing for badgers but please make
sure to provide only small amounts of food so that the badgers
do not become dependant on you.
