Geoscience Reference
In-Depth Information
and Shamis (1977), Calvo and Furness (1992), and Bub and Oelke (1980) for
birds. These sources will lead the reader to the literature dealing with many
species, many marking methods, and various considerations associated with
different techniques, different species, and study objectives.
WHICH MARKERS TO USE?
It is worthwhile to reiterate some important factors that Nietfeld et al. (1994)
and others noted as important when deciding which markers to use for a study.
Expense can be an important consideration because marking materials can
range widely in cost (e.g., tags versus radiotelemetry via satellites). The proce-
dures required to initially capture and mark animals and to obtain results from
intensive field observations or recapture efforts also are important. Markers
should be easily assembled and attached, recognized in the field, and durable
enough to remain functional throughout the study. Additionally, all marking
techniques should result in minimum pain or stress to the animal during
application and use. Finally, markers should not cause abnormal behavior
or affect survival. Clearly, it is difficult to address all these criteria satisfactorily
before the initiation of a study, so some marking has undesirable effects on
animals and research results. The adverse effects of marking often are species-
specific and might occur only in conjunction with certain behavior (e.g.,
courtship) or environmental conditions (e.g., extreme temperature). Also, the
magnitude and importance of such effects are highly variable among marker
types. We present examples of marking techniques and their effects on verte-
brate species. This material will help address questions about adverse effects
that were raised by Young and Kochert (1987) and Nietfeld et al. (1994): Does
the information obtained from the study justify marking of animals? Can the
effects of marking be identified during data analysis? If marking effects are
accounted for in the analysis, can the study objectives still be achieved? Such
questions should be posed at the outset of any study involving the marking of
animals. If one or more answers to these questions is negative or unknown, an
alternative marker should be sought or the effects of the marker under consid-
eration should be evaluated thoroughly.
EFFECTS OF MARKERS AMONG TAXA
We reviewed a sample of articles that had as a primary objective the evaluation
of marker effects. The articles consisted of qualitative or quantitative assess-
ments of the effect of specific marker types on study animals. We acknowledge
