The use of such excess weight requires specific justification. Therefore, the use of transmitters should be undertaken with caution and is most appropriate for studies in which the data can be obtained in no other manner or in which data acquisition will be significantly improved. Assuming that transmitters of appropriate size are used, most negative effects of radio transmitters on birds result from the attachment method. Investigators desiring to employ telemetry should consult the sources relevant to their species for methods of affixing transmitters. In general, observation of individuals in captivity should be employed in evaluating the efficacy of attachment methods.
Many species react negatively to harnesses that in some way go around the wings.
Special attention must be given to attachment in species that live in dense vegetation and those that roost or nest in cavities. The code can be detected by a scanner that is passed over the animal's body. The primary responsibility for ethical marking lies with the master permit holder under whose auspices the marking takes place. Similarly, the primary ownership of resighting data lies with the master permit holder. At the same time, the master permit holder has a responsibility to inform persons reporting resightings of the nature of the research involved and the status of the birds whose location was reported, should such information be requested.