E. Cloacal Lavage Studies of the mode and timing of insemination are important for analysis of population trends, transfer of genetic information, and mating systems. Like stomach pumping, lavage is not invasive in the sense that it does not require penetration of an epidermal barrier. As with stomach pumping, it should produce only a slight and temporary discomfort when performed by a properly practiced person. Injection of experimental substances is widespread in research on birds. Subcutaneous and intramuscular injections are simple in the laboratory and cause little trauma.
Intravenous injections require some acquired skill.
Intraperitoneal injections require justification because some drugs may irritate the viscera and because of possible mechanical or chemical damage of the viscera. For longer term studies, however, repeated injections are often necessary, requiring multiple capture at frequent intervals. This in itself may cause serious disruption of normal activities. Whenever possible, such implants should be made sub-cutaneously because intraperitoneal implants are often encapsulated by connective tissue. Implants inserted under the skin of the flank or side of the thorax are most effective and are easy to remove after the experiment is terminated.