The nature of restraint will depend upon the procedure and the bird species involved. Restraint techniques can range from confinement in an enclosure through various types of physical restriction, to chemical immobilization. Any decision to use physical or chemical restraint in a research project should be based upon the knowledge and skill of those persons handling the birds, the goals of the investigation, and the availability of appropriate equipment and facilities. Investigators must use the least restraint that is necessary to do the job in a humane and effective manner, with the least stress to the bird.
Because some species of wild birds are capable of inflicting serious injury to themselves or those handling them, some form of restraint is usually necessary. The well-being of the bird under study is of paramount importance and it must be emphasized that improper restraint, especially of frightened or stressed birds, can lead to major physiological disturbances, including hypothermia or hyperthermia, stress, shock and capture myopathy. In addition, the capture and/or marking of some species of birds may alter their behaviour and predispose them to predation . Investigators should not allow unsupervised, inexperienced persons to handle birds until adequately trained to restrain, manipulate and release the birds properly. Special training and experience is required for the handling of large birds such as raptors, cranes, ratites, large anatids and galliforms.
It is best to handle wild birds quietly and without sudden movements, utilizing the minimum number of personnel that are required to safely handle the bird. When birds are restrained by hand, the hold must include the wings and legs in order to prevent damage to these appendages. Certain species may have specific requirements for physical restraint, including those with long legs and necks. Birds breathe by a bellows-like action of the ribs and sternum. Therefore, care should be taken so that the method of restraint does not interfere with the ventilatory movements of the sternum or impede the respiratory air flow. Birds that are allowed to struggle excessively can potentially injure handlers, injure themselves and/or become hyperthermic.
Darkened chambers and/or blindfolds tend to alleviate stress and subdue birds and should be used whenever possible. For relatively innocuous procedures, large species can often be calmed by enclosing the head in an opaque hood. Hoods are also useful for reducing struggling during pre-surgical evaluation, preparation, induction and post-operative recovery. Small to medium sized birds can be enclosed in cardboard or fabric tubes or comparable devices. When using a cloth bag, sack, tube or hood to restrain and settle a bird, care must be taken to prevent both hyperthermia and excessive damage to the plumage. Severe loss or disruption of the feathers may result in the death of the bird following release, due to hypothermia or a reduced ability to fly.
Gloves are appropriate for handling certain species such as raptors, to reduce the potential for handler injury. In addition, gloves will help to reduce the risk of transmission, between humans and birds, of potentially harmful bacteria such as Staphylococcus aureus, which affects raptors, or Salmonella spp. which affects humans. However, in general, the use of gloves is discouraged because they may promote the spread of disease between birds and/or reduce the tactile sensitivity of the handler.
Safety goggles should be worn when handling birds with long beaks, and ear protectors or plugs should be used when working near species capable of loud calls.
Prolonged distressful restraint should not occur. In some cases, it may be advisable to use general anaesthesia for restraint in the field. If so, the anaesthetic chosen should be one that permits a rapid return to a normal physiological and behavioural state. The bird should be kept under observation until complete recovery occurs. Invasive procedures require initial physical restraint but usually require analgesia and/or chemical immobilization (see Chemical Restraint Section).
The administration of anaesthetics to wild animals for restraint purposes can be accomplished safely; however, the use of chemicals do present risks to both animal and investigator. Field immobilization is almost always performed in less than ideal conditions. Only rarely can the investigator examine animals prior to anaesthesia, give accurate dosages in a controlled environment, and intensively monitor animals during anaesthesia events.
Every anaesthetic agent has specific advantages and disadvantages, and there is no single agent that is suitable for the chemical immobilization of all bird species under all circumstances. Safe and effective drug dosages will vary with the species, age, sex and body condition of the bird. In addition, there can be seasonal variations in their response to certain agents. A prolonged recovery time or need for special equipment may make some choices impractical for use in the field. The effects of drugs on many avian species have not been determined. When information concerning the effect of an anaesthetic drug on the study species is unavailable, it is recommended that pre-experimental testing using low dosages of the drug is initiated under the supervision of a veterinarian experienced in avian anaesthesia.
Researchers requiring chemicals for restraint of birds should have the appropriate training prior to use, as well as training in monitoring and general medical care of birds. In general, it is advised that birds are only anaesthetized under the supervision of a veterinarian experienced in avian anaesthesia. Researchers should consider the following when using chemical restraint in birds:
Many studies require individual birds to be marked for identification. Marking techniques can cause effects, ranging from short-term discomfort, to long-term influences on breeding and survival. It is essential, for the welfare of the birds and the integrity of the research results, that the marking procedure not adversely affect the normal behaviour, physiology, ecology or survival of individuals. In many cases it is possible to reduce the harmful effects of the mark by carefully designing it, giving special consideration to its colour, its attachment position, its mass, and the season in which it is applied.
In general, investigators should not assume that marking procedures will have no adverse effects on their study subjects and should make efforts to evaluate any such influences. Where possible, investigators should assess the effects of new marking procedures on captive individuals before incorporating them into field studies.
It is desirable for the scientific community to encourage ancillary research that specifically addresses the effects of marks and devices. Preferably, such research, which makes comparisons between marked individuals and controls, can be initiated in association with current studies. Because of the difficulty of providing appropriate controls, there are few systematic studies that assess the potential adverse effects of marking procedures. Many of the cautions mentioned here are based on anecdotal observations.
In general, for a marking procedure to be effective, it should meet as many of the following criteria as possible:
The CWS (Canadian Wildlife Service) permitting system requires that researchers planning to band birds attend a training course given by a qualified trainer before banding permits will be issued. All banders and prospective banders must familiarize themselves with the information in the Study Guide. A video, Banding Together, is also available. More information is available on special topics from the Banding Office, the Bird Banding Manual (US Fish and Wildlife Service 1976), or field specialists.
Metal or plastic bands have been used successfully to mark many species of birds. However, certain species, such as vultures, storks, and terns, defecate on their legs and the resulting build-up of material around the bands may result in injury. The ice build-up on metal bands in cold climates has been recorded as another potential hazard, especially in waterfowl. In a few cases, adult birds, reacting to the sight of foreign objects in nests, have attempted to eject banded nestlings. It is also possible that banding may affect the sexual success of some birds.
Aluminum Bands: Numbered aluminum bands are issued through permit by the Banding Office, Canadian Wildlife Service, Ottawa, Ontario. These are the most widely used method of individually marking birds. Birds must usually be recaptured to read the band numbers. It is imperative that bands of the correct size be used; bands that are too small for the species in question may cause serious injury to or even loss of the banded leg. Recommended band sizes for all species of North American birds can be found in the Bird Banding Manual (US Fish and Wildlife Service l976). In general, when appropriate sizes of aluminum bands are used on study birds, there are few indications that they produce adverse effects.
Coloured Plastic and Celluloid Leg Bands: One or more coloured leg bands are often applied to the legs of a bird. They provide a means of individually recognizing birds in the field without recapturing them. They are being used increasingly in studies of bird behaviour and ecology which involve large numbers of individuals. The application of colour bands requires special permission from the Banding Office. When used in combination with aluminum bands, plastic bands must be of the same size. In general, when bands of the proper size are used, few adverse effects of colour bands have been reported.
Leg Streamers: Coloured plastic legs streamers have proven useful in some studies. However, it must be taken into consideration that streamers, particularly if they are too large, or are attached to metal bands, may inhibit flight, cause abrasion to the leg of the bird, or produce behaviour changes.
These may be attached by a clip to the skin, or held in place by loops around the wing bases, to mark waterfowl and grouse. They cannot be used on small birds because they interfere with flight. Back tags on ruffed grouse apparently increased their vulnerability to avian predation to a greater extent than coloured leg bands.
Properly applied plastic neckbands or collars may be used on geese and swans. Smaller waterfowl are liable to get their bills stuck in the collar as a consequence of their attempts to dislodge it. It has also been suggested that the use of neck bands on Black Brant can interfere with reproduction.
Patagial wing streamers of coloured plastic have been used with some success in birds ranging in size from passerines to eagles. However, eider ducks have demonstrated an adverse reaction by sucking markers. The size and shape of the streamer should be adjusted so that it does not interfere with flight. Most birds apparently treat the streamer as a "feather" and preen it into position.
Nasal saddles or discs are commonly used to mark waterfowl. Coloured plastic markers are held in place with nylon monofilament or metal wire which passes through the nasal opening. Improved design has reduced entanglement in aquatic foliage; however, recaptured geese have often been reported to have ripped nares. Male Ruddy Ducks marked with nasal discs were reported to be unable to obtain mates, possibly because of interference with brightly coloured bills and their role in courtship.
The application of non-toxic paint or dye directly to the plumage has been used successfully, although marks last only until the colour fades or the plumage is moulted. Care should be taken to avoid excessive matting of the plumage from the application. Behavioural aberrations may usually be avoided or at least minimized if the marking involves only small areas of the body, in locations that are not thought to be important in intra-specific signaling. For example, there are reports that Red-winged blackbirds whose red "epaulets" had been dyed, experienced difficulty maintaining territories, and that pair bonding in mourning doves can be disrupted by head painting.
Passive integrated transponders or microchips have been used to mark study birds permanently and can be used as an ancillary method of identification. These devices are implanted subcutaneously or intraperitoneally with complications reported rarely. However, birds must be recaptured and special equipment used to identify marked individuals. In addition, the transponders can migrate if applied subcutaneously, and this can make reading them more difficult in larger birds.
The attachment of small radio transmitters to free living birds is a routine method of monitoring the location and movement of individuals. There is little direct evidence that when transmitters are of appropriate size, and are properly attached, they adversely affect birds. Transmitters are applied most frequently to larger species, but the development of units weighing 2 g or less has made them useful for smaller passerines. The addition of an external mass to a bird's body could have an adverse effect on its energetics, and this will increase with the percent body mass of the transmitter. In the case of large birds, transmitters are often less than 1 % of the body mass and the effects are negligible. However, in smaller birds the transmitters may be
5-10 % of the lean body mass. Where possible, transmitters should not exceed 5 % of body mass and those weighing more than 10 % of body mass should not be applied to birds released into the field. Since many birds, including some small passerines, accumulate migratory fat deposits that may equal up to 5 % of their body mass, for specific, short-term purposes this weight guideline could be relaxed. Excellent discussions of methods used in radio tracking studies can be found in Amlaner and Macdonald l980, Cochran l980 and Kenward l987.
A wide variety of attachment methods for transmitters are currently in use, including body harnesses, adhesives or suture materials which attach to the skin or feathers of the back or tail, neck collars, and leg mounts. In diving birds, surgically implanted internal transmitters have been used successfully in order to reduce the physical interference that is associated with external units.
The methods for attaching transmitters to a wide variety of taxa are reported in the literature. It is mandatory that investigators who are intending to utilize telemetry in their investigations investigate those sources relevant to their study species. A review of the pertinent literature will help to identify any potential adverse effects that transmitters may have upon the behaviour, survival and well-being of their study birds. It is strongly recommended that prior to being used in the field, new attachment techniques be evaluated on captive individuals.
Special attention must be given to the attachment of transmitters in those species which live in dense vegetation and those that roost or nest in cavities.
For more information on this topic consult the RIC (Resources Inventory Committee) manual entitled Wildlife Radio-telemetry, Standards for Components of British Columbia's Biodiversity No. 5.
It may be necessary to transport birds as part of an experimental protocol or to move them from capture sites to holding facilities. Transport containers and methods of shipping birds will vary widely from species to species. In general, the containers used in the transportation of birds must protect the occupants from injury and allow the individual sufficient space so that it can assume a normal posture and engage in comfort and maintenance activities unimpeded by other birds. Ideally, birds should be separated. The tops of containers should be padded in those instances where excitable birds or species with delicate bone structures are to be shipped. Space sufficient to permit flight is not usually advisable because the chances of injury are increased. In addition, it may be necessary to restrain the wings of larger species. Adequate ventilation must be provided. For longer journeys, water and food should be provided as required for some species. The inside of containers should be as dark as possible, while still allowing them to find food or water and to move about. Proper arrangements should be made to ensure that birds arrive at destinations during normal working hours, rather than on weekends or holidays.
Wild birds used in captive studies should be as healthy and free of trauma as possible. Some exceptions to this rule include investigations into the effects of environmental stress and disease. It has been shown that passeriforms require 3 - 4 weeks to acclimate to captivity. Housing standards should follow CCAC guidelines and/or institutional animal care standards.