Geoscience Reference
In-Depth Information
read numbers or color markings identifying individual animals. However, care-
fully designed protocols can increase effectiveness (Howitz 1981; Ottaway et
al. 1984). The use of PIT tags eliminates size constraints for many animals.
However, other tags also hold promise, such as passively applied (i.e., usually
ingested) group recognition markers (Crier 1970; Lindsey 1983; Follmann et
al. 1987; Johnston et al. 1998). These may prove particularly useful when ani-
mal handling is undesirable and individual recognition is not necessary.
Radiotransmitters probably will remain an important and widely used
form of marking, and technological developments should include aerodynam-
ically or hydrodynamically shaped, smaller, and lighter packages (Obrecht et
al. 1988; Bannasch et al. 1994) and development of new attachment methods.
Because most of the bulk caused by transmitters is attributable to batteries,
packages could be significantly lightened if smaller high-capacity batteries
were developed. However, in some cases significant reductions in transmitter
size or mass are not possible without forgoing battery longevity.
Thorough testing and reporting of animal marking procedures (Korschgen
et al. 1996a; Meyers 1996) provides other investigators information useful for
choosing among various attachments and trying them with a new species or
under new circumstances. Detailed descriptions of procedures (Snyder et al.
1989) and modifications to procedures (Keister et al. 1988; Reid et al. 1996;
Adams and Campbell 1996; Nagendran et al. 1994) provide potential users
with additional options. Finally, the results of applying various attachments in
field situations are very important and should include information about effects
of the capture and handling that must accompany marking (Hill and Talent
1990). Sometimes the procedures associated with capture (Vehrencamp and
Halpenny 1981) and handling (Rotella and Ratti 1990; Caccamise and Stauf-
fer 1994; McGowan and Caffrey 1994) can be as important a component
in the marking process as the marker itself. Our review reveals such a variety
of marker effects (depending on marker type, species, age, sex, attachment
method, environment, and season) that careful development, testing, docu-
mentation, and reporting of experience with markers will continue to be very
useful in identifying and dealing with marker effects. Zoological societies
should assume the responsibility for setting reasonable standards for the mark-
ing of animals by providing detailed guidelines.
MARKER EVALUATION STUDIES
We recommend increased efforts to test for effects of markers, changes in exist-
ing protocols and recommendations, and more publication of the results of
