Geoscience Reference
In-Depth Information
STUDY PROTOCOLS AND TECHNOLOGICAL ADVANCES
Depending on study objectives, target species, and possible problems associ-
ated with the handling and marking process, it is not always necessary or desir-
able to apply marks to animals. For example, in some studies genetic or min-
eral markers in animal tissues, excreta, or blood, may allow for identification
of individuals or populations. However, reliable identification using genetics
is, at present, labor intensive and costly, can require recapture, and is largely
untested under field conditions. As another alternative, it might be possible to
use naturally occurring variable color markings or unique morphological fea-
tures for recognition of individuals. For example, some amphibian species are
amenable to visual recognition of individuals, and photographs or sketches can
be used to record characteristics of individuals in a population (Forester 1977;
Tilley 1977; Andreone 1986; Loafman 1991). Individual recognition via nat-
ural markings also has been used occasionally for fish (Nakano 1995) and
some bird species (Scott 1978), but has probably found its greatest utility with
large mammals (Pennycuick and Rudnai 1970; Clutton-Brock and Guiness
1975; Ingram 1978). For mammals, researchers usually rely on unique facial
features to identify individuals; in most cases the method appears reliable
although validation is desirable and there are limits to the number of animals
in a population that are individually recognizable. Pennycuick (1978)
reviewed limitations and difficulties associated with the use of natural mark-
ings in free-ranging animals; where the use of this technique meets study
objectives, it is more desirable than artificial marking.
It is essential that field personnel be adequately trained in the proper han-
dling and marking of animals (Ad Hoc Committee on the Use of Wild Birds
in Research 1988; Livezey 1990; Friend et al. 1994; Samuel and Fuller 1994).
This may involve practice with captive individuals of the targeted or surrogate
species, or animal models. Improper marker application by poorly trained field
personnel can result in serious problems for study animals (Perry and Beckett
1966), and well-trained personnel not only minimize the potential for nega-
tive marker effects but also are able to process and release study animals more
rapidly (Korschgen et al. 1996a, 1996b), thereby reducing potential negative
effects of handling and marking.
Although significant progress has been made in the development of less
harmful marks, additional steps are necessary. Few technological developments
can contribute to minimizing effects of mutilations, although routine use of
surgical instruments and sterile conditions lessens occurrence of disease and
mortality. Development of smaller tags and bands can contribute to less inva-
sive marking. In the past, one constraint of reducing tag size was the ability to
