A
365 day study of Badger (Meles meles)
activity using a fixed trail camera: A short report
By Mark Smith
Summary
A Bushnell
trail camera was installed on a regularly used track way in a hedge line
between a wet meadow and arable field. The camera recorded 24 hours a day and
all species triggered by the camera were recorded.
Badger
data was collated to show overall seasonal patterns and changes in daily
activity cycles. The data showed three main points relating to territorial
behaviour and supported established research into Badger activity.
1.
Peak activity occurred in February coinciding
with the birth of cubs underground prompting a strengthening of territorial
boundaries reflected by increased transit past the camera as the boundary was
patrolled and the edge latrine pit was visited more often
2.
Daily over night activity exhibited two peaks
of activity in spring and summer relating to foraging and territorial behaviour
interspersed with rest periods
3.
Frequency of activity was relaxed in the
autumn and winter but the length of nightly activity increased up to 12 hours
of activity per night in line with shorter days and the need to forage more to
maintain bodyweight.
More
analysis to compare year on year data is needed to improve the data set and
specific studies of latrine pit usage
would enable a clearer picture of territorial activity to be assessed.
Introduction
Badgers live in social groups called
clans of between 2 and 23 individuals (mean: 6). Badgers maintain a territory
of 30ha in optimum habitat up to 150 ha in marginal ones (Harris & Yalden, 2008; Johnson
et al, 2001). The boundaries of these territories are demarked by well
worn paths and shared latrine pits. The size and configuration of the territory
is determined primarily by the distribution of food (Harris & Yalden, 2008).
Badgers are mainly crepuscular and
nocturnal emerging at around dusk and returning to their setts before sunrise (Neal & Cheesman, 1996; Johnson et al, 2001). In
this short report the findings from a year long camera trap study of all
species recorded moving along a hedge line have been analysed to investigate
the activity of the badgers of a sett located 270m from the camera.
Methodology
Between the 21st April 2014 and the 19th April
2015 a Bushnell Nature View HD camera was placed on continuous record. The
camera was set to record all animals and birds that passed its field of view.
It was located at SP292671
(52.301295, -1.570757). The camera was mounted 1 metre off the ground on the
trunk of a Beech tree and was orientated to face northwards facing along a well
used track way in the hedgerow between a wet meadow and an arable field.
The camera was set to record 30 second video clips with a 1
second refresh time.
8MB SanDisk memory cards were changed every week and the
clips reviewed. All species sighted and identifiable were recorded. Notes on
specific behaviours were noted.
Over the year the camera was inoperable for 42 days. Outages
were due to setting errors and battery failures. Total coverage is therefore
88.5% of the year. In this time the camera recorded 152 badgers. Individual
badgers were not identified in this study, just presence/absence information.
Figure 1 shows a rough sketch map of the study area. The camera
can be seen located on the hedge line and the sett further down the same hedge
line. It highlights the main track ways used by the badgers and other mammals
as well as key behavioural locations such as latrine pits and areas where
regular foraging seems to take place.
Figure 1 Site Map showing camera location and points of interest
Results
The data from the study was
tabulated in Excel and the formatted to express activity as an expression of the
number of badgers recorded by the camera by week and each hour. In this way it
is possible to map activity over the year and throughout the cycle of a day.
Figure 2 shows the activity over
the year. Figures 3 - 6 shows seasonal differences in daily activity expressed
as a mean number of Badger sightings per hour in each three month block.
Figure 2 Graph showing the activity of Badgers over the year
Figure 3 Daily activity cycle for Spring
Figure 4 Daily activity cycle for Summer
Figure 5 Daily activity cycle for Autumn
Figure 6 Daily activity cycle for Winter
Figure 2 shows a significant peak
of activity in February and a smaller one in late April to May. The rest of the
year activity was relatively stable.
The graphs for daily activity
cycles indicate a range of patterns. Firstly autumn and winter activity is
generally lower than spring and summer. Both spring and summer show two peaks
of activity. In the spring these peaks are at 22.00 hours and 03.00 hours and
for summer 22.00 hours and 04.00 hours. Daily peaks are less evident in the
autumn and winter.
The length of activity across a
day increases in length over the year between 8 hours in spring to 12 hours in
the winter.
Discussion
The data collected in this study
supports many of the findings of other researchers. It highlights specific
peaks in annual patterns and difference between daily activity levels between
seasons. This study, however, is different to other studies in that it focuses
on a track way rather than a sett. This means that emergence times are
unknown. The camera is located between
two latrine pits and on the border of a change in habitat. Badgers are known to
operate bimodally, with activity either very close to the sett or removed from
the sett especially along the boundaries, this is more pronounced in males (Revilla & Palomares, 2002; Roper et al, 1993) therefore this study
explores the amount of time invested in maintaining a territory. The track way
does not lead to established feeding grounds and foraging behaviour in the
video clips was very restricted (only in the autumn) and most behaviour noticed
was either direct transit along the track or marking.
Annual Pattern
The most obvious piece of data reflecting the badgers is
the large peak in activity occurring in mid-late February. Here activity
increased by 500%. This coincides with the time cubs are born in the setts (Neal & Cheesman, 1996)which is usually in
the first three weeks of February (Harris & Yalden, 2008)).
Footage at this time reflected a general feeling of
increased activity. Passage past the camera seemed quicker and more frenetic.
There was also an increase in the amount of casual marking made by the males.
It is suspected that the birth of the cubs promotes a level of excitement and
activity in the clan. Sows that had just given birth are now able to come out
and feed. They need to maintain their body weight in order produce milk. Boars,
in a burst of protectiveness could be more actively demarking their territory
to ensure the new additions and their home range are adequately defended.
Research supports the idea that males are more active and travel (Neal & Cheesman, 1996; Revilla & Palomares, 2002)
Secondary smaller peaks in April and May likely coincide
with the cub’s first emergence from the sett. No cubs were recorded on the
camera as it is likely to far from the main sett although smaller individuals
were observed later in the year. Emergence from the sett would free up sows
from suckling duties and enable them to forage farther. The peak also
corresponds to recorded activity peaks surrounding the main mating period in
early spring (Harris & Yalden, 2008).
Daily
Pattern
In all seasons the greatest level
of activity is recorded 2-3 hrs after dusk this relates to their emergence time
and reinforces work by Neal and Cheeseman (1996). As the camera is not at the
sett but on a territorial route there is a delay in activity being recorded.
Badgers in spring tend to emerge
around sunset and will forage around the sett a little before dispersing across
a territory to feed and mark. A figure 3 show spring patterns of activity and
shows two peaks of activity across the evening, 22hrs and 2am-4am. Two peaks
reflect the recorded pattern of badger activity in which individuals will
forage for a period of time have a period of rest before becoming active again
just before returning to the sett (Neal & Cheesman, 1996) In this season
females remain closer to the set (Roper et al,
1993) and males spend greater time using latrine pits and marking the
territory (Revilla & Palomares, 2002). Spring has the
shortest activity period at just 8 hours reflecting the females remaining
either close to the sett, giving birth or males and females being engaged in
mating activity.
Through the summer activity time
increases to 10 hours a night and the likelihood of observation before sunset
increases. This activity period is much longer than those recorded by Neal and
Cheeseman (1996) which estimated total activity time to be approximately 6.5
hours. Like spring two peaks of activity occur over the night at 22 hrs and 4
am.
Autumn (Figure 5) shows the
lowest frequency of activity and there is little evidence of any definite peak
in the pattern of the night’s activity. Studies by Roper et al (1993) suggest
that during the autumn male activity reaches a peak of activity along
boundaries, establishing the territory ready to protect the foraging space for
the winter, this data does not however support this. The degree of activity
over the whole night is again longer that summer at 11 hours of activity, this
could be related to the reduction in day length and the increase in foraging
required to build up body weight for winter survival.
During the winter (Figure 6)
activity over the night is at its maximum nearing 12 hours in total, with very
little variation in the frequency of activity across the night. This is
supported by data presented by Neal and Cheeseman (1996) which recorded 11
hours activity per night. Activity occurs between two hours after sunset and
two hours before sunrise.
References
Harris, S., & Yalden, D. (2008). Mammals of
the British Isles: Handbook. 4th Edition. The Mammal Society.
Johnson, D.,
MacDonald, D., Newna, L., & Morecroft, M. (2001). Group size versus
territory size in group-living badgers: a large-sample field test of the
resource dispersion hypothesis. Oikos , 95, 265-274.
Neal, E., &
Cheesman, C. (1996). Badgers. London: T&D Poyser Natural History.
Revilla, E., &
Palomares, F. (2002). Spatial organisation, group living and ecological
correlates in low-density populations of Eurasian Badgers (Meles meles). Journal
of Animal Ecology , 71, 497-512.
Roper, T., Conradt,
J., Christian, S., Ostler, J., & Schmid, T. (1993). Territorial marking
with faeces in badgers (Meles meles): A comparison of boundary and hinterland
latrine use. Behaviour , 127, 3-4.
