Methods of marking mammals

SYMPOSIUM ON RECORDING ANIMAL BEHAVIOUR This symposium, organized by the Association for the Study of Animal Behaviour was held at Queen Mary College, London, on Thursday and Friday, the 25th and 26th March, 1965 .

RECENT METHODS OF MARKING INVERTEBRATE ANIMALS FOR BEHAVIOURAL STUDIES . By P . F. NEWELL, Rothamsted Experimental Station, Harpenden, Herts .

Marking methods are of two main types ; individual and group-marking. New methods of individual marking are rare and most methods still use coloured paints or mutilation, such as cutting notches in the pronotum of cockroaches. Several new group methods have been described ; fluorescent dusts and paints to study the behaviour of Glassina, Aedes, Drosophila, grasshoppers and boll-weevils, and genetical markers to study the mating range of bees . Radio-isotopes are now extensively used for group-marking a wide range of animals . Recently, autoradiographic methods of detecting small quantities of different radio-istopes, used for studying the dispersion and mating behaviour of mosquitoes, have been published. Predation of

tagged aphids and mosquito larvae and food exchange patterns in social insects have also been studied. My work with P32-marked slugs illustrates some of the problems associated with this marking technique including those of dosimetry, relocation of the isotope within the animals and the effective duration of the tag . The effects of the radio-isotopes on the life-span, breeding and behaviour of tagged animals are inherant disadvantages and should be measured and eliminated as far as possible . Gamma-emitting isotopes are especially useful for studying the subterranean movements of animals . An apparatus was described, and exhibited which injects a small pellet of Ta 1 s 2 wire into the haemocoel of slugs enabling them to be tracked below ground .

MARKING BIRDS. By I. J. PATTERSON, Natural History Department, University of Aberdeen .

The existing method used for marking birds were reviewed and their advantages and disadvantages discussed . A new marker, developed by A . Anderson of Aberdeen University, was described in detail . This consists of a coloured plastic tag attached to the patagium by a stain-

less pin, so that it hangs among the wing covert feathers . These wing tags have been used on Eider ducks, Waterhens, Rooks and Blackheaded Gulls, and are very conspicuous without hindering the bird .

METHODS OF MARKING MAMMALS. By IAN LINN, Department of Zoology, Hatherly Biological Laboratories, Prince of Wales Road, Exeter, Devon.

Mammals are marked for three main purposes (1) so that they may be identified when seen, (2) so that their location at any given moment may be determined, and (3) so that they may be identified when recaptured . The first of these is perhaps the most difficult to achieve . Ideally no marking at all is necessary ; mountain hares may be identified in winter by the individual variation of their natural coat

markings . Failing that, splashes of dye may be used on their white coats . For rabbits, ear tags with large numbers have proved successful . Dye marks are useful also on voles, and are best used on pale mutant strains . Collars in various colours and patterns can easily identify animals from stoats- to deer, but have some snags . Reflecting tape makes collars easily seen with a torch at night . For mammals, the second category will usually involve the use of radio-active tracers, 579



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ANIMAL BEHAVIOUR, XIII, 4

Small amounts of 60Co may be attached to the tails of moles or the legs of small mammals, soldered on to rings-or short lengths of 18 TTu wire may be inserted under the skin . For larger mammals, up to the size of whales, transistorized radio transmitters may be attached. The small size of the latest of these devices permits their use with surprisingly small animals . In the third category, again the ideal is to use natural marks. For weasels and mink the belly pattern is as distinctive as a fingerprint . Tattooing can be useful on rabbits' ears-less so on the patagium of bats . Toes of small mammals can be humanely clipped enough to destroy the nail, but not so much as to seriously mutilate,

and this will often suffice if the numbers to be marked are not too large . Numbered plastic tags have proved valuable in the ears of rabbits and the tails of seals. In the last resort, however, some kind of metal tag or ring is used. Although experience has shown that such tags inevitably cause damage, their usefulness outweighs this . Seal flippers, ungulate and lagomorph ears, small mammal legs and bat wings can all carry tags or rings . The ideal bat band, combining lightness and toughness, has still to be developed ; small mammal rings cause difficulty when the animal is growing-but no method so combines convenience with ease of individual identification .

FILMING ANIMALS. By DEREK TWIST, Granada TV Film Studios .

The value of cinematography to any study of movement is fairly obvious . Since animal behaviour is principally a question of movements, the application of filming techniques to ethology can be numerous . First and foremost it enables a permanent record to be made of a transient action : a record that can be studied repeatedly and analysed, if necessary, frame by frame ; a record that can be filed and duplicated and sent easily to any part of the world. Secondly, the optics of a movie camera can resolve detail in an instant which cannot easily be appreciated by the human eye . Thirdly, by varying the speed at which the film is taken it is possible either to slow down natural movements or speed them up ; often revealing a sequence of events previously unsuspected . But photography has its own problems, not the least of which is the amount of light it

requires . Apart from nocturnal creatures which will only perform at very low light levels, the mere incidence of intense light may introduce an extraneous factor affecting the normal behaviour of diurnal animals . And light usually means heat as well . Even the most modern lens systems cannot have the almost instantaneous adjustment of focal length and aperture of the human eye and in consequence there are sometimes severe restrictions on the depth of focus and field of view when filming. Most of these objections only arise in serious form when photographing small or microscopic animals ; it is comparatively simple to film the courtship of elephants if you're lucky enough to be there when it happens . However, experience and experiment have shown that it is possible to devise means and equipment to overcome a lot of these drawbacks .

RECENT METHODS USED IN OBSERVING FISH BEHAVIOUR . By C. J . CHAPMAN, R. E . CRAIG, C. C. HEMMINGS & B . B. PARRISH, Marine Laboratory, Aberdeen.

Fishery biologists are concerned with studying'the responses of fish to natural environmental stimuli such as light, salinity, temperature and currents, and to unnatural stimuli produced by fishing gear. Acoustic fish detection methods allow observations to be recorded when light intensity or turbidity preclude visual methods, and at much greater range . Echo sounding is thus used for studies of schooling and vertical migration with respect to light intensity . Mounting the transducer on fishing gear provides

information about behaviour near the stimulus . Sector scanning sonar, the most recent device, provides the range and bearing of targets in a plane which greatly increases the available information . However, problems arise in the identification of acoustic targets . Electronic flash and automatic cameras produce long picture sequences at intervals from seconds to hours from which behavioural data can be taken . Less disturbance is caused by short regular flashes than continuous lighting,