Environmental constraints on lizard foraging behaviour

384 within financial constraints, while at the same time providing attractive and educational exhibits for the public. The question is asked, what should the factors underlying the design of this environment be? This can be sub-divided into: what is freedom? what is captivity? what would the animal (species) choose to have for, and to get from, this environment? Freedom is an evocative term, commonly used with reference to zoo animals to mean the wild environment. Evidence is put forward to show that this environment has many constraints and that the ability of an animal to survive in the wild depends on its ability to cope with environmental change. Moving a species to captivity involves subjecting it to such a change, and there is good evidence that species which adapt more easily to change in the wild, are easier to keep in captivity. The captive environment, to an individual reared in a social group, is a complex interrelationship of the physical size of the cage, complexity, climate, food supply, conspecifics, other animal species and the human public. It is suggested that the main stimuli which are lacking in this environment are complexity and novelty, that the animals have a "boring" and unchanging diet that does not take long to find or eat, and that the main stressful external stimulus is the human public. It is suggested that were the animal to choose, the ideal captive environment would be one which contained more changing structures with more novelty. It is also suggested that much more thought be given to the design and form of barriers between public and animals, not just considering the ease of the public seeing the exhibits, but also the effect that the proximity of large numbers of people might have on captive species. The factors that humans perceive as making better conditions for captive animals are discussed with reference to the animals' viewpoint.

E n v i r o n m e n t a l Constraints on Lizard Foraging Behaviour R.A. AVERY and D.H. BOND

Department of Zoology, The University, Bristol ( Gt. Britain)

ABSTRACT

A standard laboratory arena has been developed for studying behavioural thermoregulation in small lizards,incorporating the provision of radiant heat from tungsten bulbs. Most work focusses on the dynamics of basking, but in order to obtain a complete picture of thermoregulatory behaviour it is also necessary to study the forages with which basks are interspersed. If the arenas are made relativelysimple (i.e.low spatial heterogeneity), spontaneous foraging is reduced (see also Avery, 1985). Increasing spatial heterogeneity by introducing large numbers of small wooden cubes changes foraging behaviour in definable and measurable ways (e.g.changes in mean speed of movement, distance moved during bursts of locomotion, duration of pauses during which the environment is being scanned for potential prey). The sizeof the arena also has an effecton these variables.There is evidence that in largerarenas the distances covered during forages are distributed bimodally. These results demonstrate that it is not only higher vertebrates for which cage design may be an important determinant of behaviour; lizard behaviour patterns may also be sensitive to environmental details,sometimes in quite subtle ways.

385 REFERENCE Avery, R.A., 1985. Thermoregulatory behaviour of reptiles in the field and in captivity. In: S. Townson and K. Lawrence (Editors), Reptiles: Breeding, Behaviour and Veterinary Aspects. British Herpetological Society, London, pp. 45-60.

Hand-Rearing of Exotic Birds and their Re-Introduction to Groups H. G. YOUNG

J. W.P.T., Trinity, Jersey, C.L ( U.K.) ABSTRACT At the Jersey Zoo birds are kept in carefully controlled breeding programmes, with large populations of a small number of species. Annually, through policy or under special circumstances, some offspring are removed for hand-rearing. The mechanics of hand-rearing can become straightforward--but young must be re-introduced to their own species. Imprinting is the major problem and, for a re-introduction to succeed, must be avoided. Altricial young are difficult to imprint but they are easily humanised; parrots are regularly hand-reared with no apparent ill-effects and if integrated with conspecifics early will pair up and breed. Songbirds are reared near to their parents so as to learn details of their songs. Mimics need no early contact, and hand-reared birds will mature alongside parent-reared fledglings who are systematically removed from their parents. Some birds reared in isolation develop or misuse displays, causing alarm among their fellows. Precocial young imprint more easily and are further disadvantaged if reared alone. Some pheasants, e.g. White eared (Crossoptilon crossoptilon) become very aggressive. Chicks mixed even with older and younger peers, however, will adjust well. A knowledge of displays is instinctive in ducks, but geese and cranes must learn these and other behaviours from their parents. Reared too long in isolation they will never re-integrate or will become aggressive, but raised with others and returned quickly to the flock will adapt just as orphaned young would.

Management and Behaviour of Dolphins V. J. MANTON

Zoological Society o/London, Whipsnade Park, Dunstable ( Gt. Britain) ABSTRACT In Europe, to keep Cetacea, two important factors must be closely monitored. (1) The quality of the fish. This varies according to the species (dolphins are catholic feeders), the time of year and the nutritional quality of the individual fish. It is also important to control the temperatures at catching, during transport and at storage, which must always be b e l o w - 18°C, and preferably - 25-30 ° C. (2) The quality of the water; especially the salinity and chemical and physical filtration. Twenty thousand gallons is the minimum per animal for good and easy water con-