TECHNIQUES FOR MARKING
WILDLIFE
Nova J. Silvy, Roel R. Lopez, and Markus J.
Peterson
Department of Wildlife and Fisheries Sciences,
Texas A&M University College Station, TX
77843, USA
Introduction
 All captive-animal and many field studies
involving wildlife requires individuals be
marked for future identification.
 Because of the wide diversity among
vertebrate species, no single list of approved
methods for marking is practical or desirable.
 The ultimate responsibility for the ethical and
scientific validity of methods used rests with
the investigator.
Considerations Prior to Marking
►
Do the animals need to be marked or
can natural markings be used instead?
►
Do the animals need to be marked as
individuals or can they be marked as a
group?
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Do the animals need to be physically
captured prior to marking or can they be
marked without capture?
How visible do the marks need to be
and do the animals need to be
“recaptured” for the mark to be
observed?
Will the marking method cause pain
and/or decrease survival of the animal?
►
Will the proposed mark affect the
animal’s health, reproduction,
movement patterns, and/or behavior?
►
How long will the mark be required to
last to complete the study and how
durable is the proposed marking
method?
►
Will the proposed marking method
interfere with other studies?
►
Will the marks promote public concern
about the study and will the marks have
to be removed after study completion?
►
Have the appropriate approvals (animal
welfare and state and/or federal
permits) to mark animals been
obtained?
Techniques for Marking Wildlife
► Three
1.
2.
3.
main classes:
Natural
Noninvasive
Invasive
Marking techniques (natural marks)
having the least adverse effect on
animals should be used whenever
possible.
Invasive techniques have the
greatest potential for adverse
effects.
Many techniques require capture,
recapture, and handling that also
might affect an animals’ behavior
and survival.
Separation of these effects from
those caused directly by the
marking method has yet to be
evaluated in most cases.
Marking Permits
► Before
an animal can
be captured and
marked, the
appropriate local (e.g.,
animal welfare
permits), federal,
and/or state/provincial
permits must be
obtained.
► Wildlife
species are
regulated within
state/provincial
boarders by the
appropriate wildlife
agency. The federal
government regulates
capture and marking
of migratory birds and
threatened and
endangered species.
Natural Marks
► Many
animals
exhibit unique coat
patterns or can be
identified by unique
color patterns,
scarring, fin or fluke
notches, antler
configuration,
and/or other traits.
► Natural
markings
are most efficiently
used on individuals
with complex
patterns, and
analysis must be
confined within a
local population or
region.
Unique spots and stripes on 2
bobcats
Marking as Individuals or Groups
► Many
herd/flock
movement and
dispersal studies
only require that
large numbers of
individuals be
marked in a given
area and relocated
later.
► Many
markrecapture or markresight studies
conducted to
estimate population
density do not
require marked
individuals be
differentiated from
another.
Marking Without Capture
►
Remote marking of
animals as individuals or
groups has a long history.
►
►
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Dyes can be introduced
into the animal’s food to
produce dyed fat, teeth,
pelage, and droppings
Marked with paint-tipped
arrows and paint balls
►
Dye-spraying devices
affixed to aircraft
Manually triggered dyespraying device
►
Dyes also can be placed on
eggs and nests, marking
the adults as they incubate
their eggs
Self-affixing collars
Marking After Capture
► If
animals must be
captured, there are
numerous marking
techniques
available. Although
the most suitable
marking techniques
will depend on the
needs of the
investigator.
► Factors
to consider
are duration of
study, ability to
relocate marked
animals, number of
animals to be
individually
identified, and the
effect of the mark
on the animal.
Ideal Marking Technique
► (1)
involve minimal
pain or stress
► (2) produce no
adverse effects on
survival and
behavior
► (3) permanently
mark individuals
► (4)
be easy to
recognize at a
distance
► (5) be easy to apply
► (6) be easy to
obtain and/or
assemble
► (7) be relatively
inexpensive.
Retention Time of Marks
► Two
categories
relative to retention
time:
► (1) permanent
marks as those
lasting the life of
the animal
► (2) non-permanent
marks as all others
► Permanent
marks
include branding,
tattoos, ear
notching, toe
clipping, and other
invasive techniques
although scarring,
tearing, and aging
may reduce their
effectiveness.
Noninvasive Marking Techniques
► Neck
Collars
► Bands (arm and wing,
flipper, leg)
► Nasal Discs and
Saddles
► Back Packs,
Harnesses, and
Ponchos
► Trailing
Devices
► Nocturnal Tracking
Lights
► Tapes, Streamers,
and Bells
► External Color
Marks (Dyes, fluorescent
pigments, bleaching, inks,
and paints)
Oversized neck collar (right) that could allow
animal to place leg through collar. Collar
should fit snug around neck just below head
(left).
Elastic (expandable) radio collar on white-tailed deer
fawn (left) and a caribou cow (right) with radio collar
and a highly visible numbered collar attached that
allows for individual recognition of the animal if the
radio transmitter fails
Expandable neck collars for male ungulates
(left) and non-expandable female ungulate
neck collar with holes for brass-split rivets
(right).
Plastic neck collars on tundra
swans
Standard butt-end bands used on the legs of
birds (left) and butt-end aluminum band
(right leg) and colored plastic band (left leg)
placed on greater prairie-chicken (right).
Nasal saddle on the bill of a female
mallard (left) and female black grouse
with backpack tag (right).
Neck collar and ear streamer on whitetailed deer (left) and bell attached to
collard peccary (right) that allows
investigators to follow herd movements.
Colored dye being applied with brush to the
white portion of a white-winged dove wing.
Invasive Marking Techniques
► Internal
Markers
(chemical, particle, and
radioactive)
► Transponders
► Tattoos
► Tags (ear, wing, body,
jaw, and other
appendages)
► Branding (hot, freeze,
chemical, and laser)
► Tissue
Removal
(feather Imping and
clipping; fur removal; shell
notching; scale, toenail,
and toe clipping; ear
punching and notching;
web punching; tail
clipping; skin
transplantation; and
amputation)
Implanting a transponder (PIT tag) into a
radio-marked fox squirrel (left) and numeric
characters tattooed on the inside of an ear of
a white-tailed deer (right).
Plastic numeric numbered tags attached to
both ears of a collard peccary (left) and a
plastic domestic livestock ear tag used on
white-tailed deer (right).
During the imping process (left), a feather of
a captured bird (left) is clipped and a feather
of contrasting color (right) is attached to it by
means of a double-pointed needle. The right
picture shows a patagial-wing markers on a
least tern.
Freeze branding mark on hip of Thomson’s
gazelle (left) and clipping the toenail (right)
rather than the toe is preferred for short-term
marking studies of small mammals.
Using Multiple Marks
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It is best to use as few
marks as needed to meet
project objectives.
However, there are times
when multiple marks may
be needed.
For behavioral studies,
highly visible marks are
needed to observe an
animal at a distance, but a
radio collar may be needed
to first locate the animal.
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In addition, a more
permanent mark such as
tattoos or PIT tags may be
needed for long-term
studies (e.g., survival
studies).
Use of as few marks as
possible to complete the
objectives of a study.
SUMMARY
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Natural markings are preferred
Marking without capture is next best option
For animals that must be captured prior to marking,
noninvasive techniques are preferred
Noninvasive methods generally are preferred
Advantage of some invasive techniques is that many
are “permanent”
Multiple marks used only when it is absolutely
necessary
Ultimate responsibility on the ethical and scientific
validity of methods used rests with the investigator.