Five experiments were conducted to investigate the effect of novelty on visually-mediated taste-avoidance learning in domestic chicks. In experiments l a and b, chicks were reared with either uncoloured or blue fluid in their home cages, and then required to discriminate between blue and uncoloured fluids that were either palatable or unpalatable (quinine-adulterated). For some chicks the distasteful fluid was novel in appearance, for others it was familiar. In both experiments chicks readily discriminated between a novel unpalatable fluid and a familiar palatable one, but failed to discriminate between a familiar unpalatable fluid and a novel palatable one. This failure to discriminate resulted from avoidance of the palatable fluid. In neither experiment did novelty enhance the rate of avoidance learning. Experiment 2 tested more directly the effect of novelty on speed of avoidance learning. Chicks were reared on either red or blue palatable fluid, then tested with either red or blue distasteful fluid. Avoidance learning was more rapid when the distasteful fluid was novel in colour, in both red-reared and blue-reared chicks. Experiment 3 investigated the inability of chicks to discriminate between a familiar unpalatable fluid and a novel palatable one, demonstrated in experiment 1. Chicks were required to discriminate between different-coloured palatable and unpalatable fluids when both were familiar in appearance (experiment 3a) or when both were novel (experiment 3b). Discrimination occurred in the first case but not in the second. In addition, avoidance learning was slower when both unpalatable fluids were familiar. I conclude that (a) novelty faciliates visually-mediated taste-avoidance learning in chicks and (b) the failure of chicks to discriminate a novel palatable fluid from a familiar unpalatable one depends on the relative novelty of the palatable fluid and not on the relative familiarity of the unpalatable one. The results are discussed in the context of warning coloration and are explained in terms of an interaction between unlearned and learned avoidance tendencies.
EIBL-EIBESFELDT (1961) and THORPE (1963) have suggested that nest-building in various species is reinforced by stimuli associated with the acquisition of a finished nest. HINDE & STEVENSON (1969, 1970) have proposed, by contrast, that individual nest building activities may persist and act as reinforcers regardless of whether or not they lead to nest formation. Evidence for these views is discussed. Five experiments designed to test HINDE and STEVENSON'S view arc described. In Experiments I and 2, naive female mice were given access to hoppers of paper strips for 14 days. Carrying of strips into the nest box declined rapidly to zero as the nests reached completion, but gathering of strips from the hoppers continued at the original level. It is concluded that carrying and subsequent events associated with nest acquisition are not necessary for the initiation and maintenance of gathering. In Experiments 3 and 4, access to paper strips was made contingent upon performance of an arbitrary operant (key pressing). The majority of subjects continued to key press and gather paper after the cessation of carrying, but at a reduced level. Furthermore, key pressing to gather only occurred if the operant-reinforcer distance was very small. It is concluded that gathering per se is less reinforcing than gathering plus carrying and building. In Experiment 5, amount of gathering per reinforcement was varied by using different widths of paper. Number of reinforcements per session was positively related to paper width, providing further evidence that gathering is reinforcing. It is concluded that gathering is at least to some extent autonomously controlled, and that it is a weak positive reinforcer. However the results also suggest that other reinforcing events are present at a later stage in the nest building sequence. Some theories concerning the causation of selfsustaining activities, and their implications for unitary drive theories, are discussed.
We observed the behaviour of a colony of Mongolian gerbils (Meriones unguiculatlts) for 18 weeks, in an enclosure provided with facilities for burrowing, nest-building, foraging, wheel-running and other behaviour. Records were taken of both social and individual activities, and in particular of activities occurring during encounters between pairs of individuals. I. The colony originally consisted of eight animals, but severe fighting rapidly reduced the numbers to two males and two females. The colony then remained stable until week 18, when an adult male attacked the offspring of one of the females. Fighting was never observed between animals of opposite sex. The fighting was probably due to overcrowding, and suggests that in natural conditions gerbils do not nest in groups of more than a few adults. 2. Routine encounters between individuals revealed a number of sex differences, but few conspicuous individual differences. Agonistic behaviour was rare, and the observations gave little evidence for the existence of a dominance order. 3. When a female was in oestrus one male consistently attacked and chased the other, and consequently gained almost exclusive access to the female. The sequence of mating responses is described, and it is suggested that genital sniffing by the male enhances the receptivity of the female. Ventral marking by the female and drumming by the male occurred at unusually high levels during mating. 4. Each female produced two litters, but only the first two survived. The litters were dropped and the young housed in a nest-box outside the normal colony burrow, the entrance to which was kept blocked. Both litters were carried to another nest-box in the second week after parturition, and carried back again prior to the birth of the second litters, but the reasons for this behaviour were unclear. The males assisted in nest-building activities, but never entered the maternal nest-box. We suggest that the failure of the females to care for their second litters was due to overcrowding. 5. Ventral marking occurred at a high rate, and in conjunction with various activities. Marks were deposited over the entire enclosure and on a variety of substrates, but were concentrated at four main sites on mounds of earth near the burrow. There were no sex differences in total number of marks, but the males tended to distribute their marks more widely. Individual differences in amount of marking were correlated with differences in gland size, and with the outcome of aggressive encounters during mating and the occasional fighting. There was a strong tendency for fresh marks to elicit counter-marking by the same or another animal, but novel clean objects were also marked within a short time of being placed in the colony. There was no evidence that marked objects or areas were avoided by other animals or defended by the marker, and we suggest that marking is not primarily territorial in function. 6. Mutual marking, mutual grooming and sandbathing all occurred at the four most heavily marked sites near the burrow. We suggest that these activities, and the tendency for animals to counter-mark at specific sites, might serve to distribute a colony odour consisting of the odors of the individuals, and that this might reduce intra-colony aggression. We found no evidence that mutual marking or grooming reflected a dominance order. Drumming of the substrate occurred as an alarm response, but we saw no evidence of its use as an alarm signal. 7. The most frequent individual activity was digging. The burrow, which was inhabited by all the adults, consisted of from two to eight tunnels leading in towards a central nest of shredded paper, straw and leaves. The tunnels were repeatedly cleared and enlarged, and were often destroyed by digging at other locations. Freshly dug earth was often marked by the digger, and this seemed to elicit marking and digging by other animals. 8. Wheel running occurred only at a low rate, and did not develop a stereotyped character, but was performed by all animals. Contrary to expectations based on laboratory studies the majority of running occurred during the light phase of the cycle, and this was when the animals were most often active in the general sense. We suggest that gerbils are probably active day and night in natural conditions, and that the enhanced nocturnality shown in laboratory studies may be due to the lack of a dark burrow. 9. Other stereotyped activities such as shredding paper, gnawing and scrabbling were rare. 10. The results are summarized and discussed in relation to theories of dominance, ventral marking and sociability, and attention is drawn to the need for more field studies of behaviour in this species.
Badgers (Meles meles) defecate, urinate and scent mark at latrines which seem to have a territorial function. The main aim of the present study was to compare defecation patterns at boundary and hinterland latrines, in order to test the hypothesis that these two types of latrine have a similar function. We investigated latrine use by means of a year-round survey of all the latrines in 7 badger territories, by bait-marking of 15 territories, and by monitoring latrine use in 6 radio-collared badgers belonging to three social groups. The spatial distribution of latrines within a territory was bimodal, with the greatest densities oflatrines close to the outside, and close to the centre, of the territory respectively. Boundary latrines were larger and more consistently used than hinterland latrines, but these differences could be accounted for by the fact that boundary latrines are visited by the members of more than one social group. Defecation at latrines was subject to seasonal variation, with a major peak in latrine use in spring and a minor peak in autumn. The spring peak was largely attributable to an increase in the use of hinterland latrines, the autumn peak to an increase in the use of boundary latrines. Males visited boundary latrines considerably more often than did females, but both sexes visited hinterland latrines equally often. Overmarking occurred equally often at both types of latrine and involved animals from the same as well as from different groups, but there was a significant tendency for more between-group than within-group overmarking. Overmarking occurred mainly on fresh, as opposed to old, faeces deposits. The sex and seasonal differences in use of boundary latrines suggest that these function at least partly as a form of mate-guarding, to deter neighbouring males from entering a territory for mating purposes. It is less clear why females mark at hinterland latrines. One possibility, consistent with the observed spatial distribution of hinterland latrines, is that they function to defend the main burrow system, which is used for breeding; another is that they carry information about social status. Overmarking probably serves to obliterate the marks of competitors, which are members of neighbouring social groups in the case of boundary latrines, but may be members of the same social group in the case of hinterland latrines. We conclude that previous ideas about the function of territoriality in badgers, and about the information conveyed by latrines, are oversimplified.
How are personalities maintained in wild animal populations? A possible mechanism is the existence of trade-offs between fitness components (survival and reproductive success) among behavioural types. We investigated this trade-off in white-rumped swallows (Tachycineta leucorrhoa) by capturing adults and monitoring their reproduction over time. We focused on the personality trait of nest defence against a human. We found that swallows with different levels of nest defence had similar probability to return from migration between two years (a proxy for survival). In one year, swallows that defended their nests more boldly were also more likely to succeed. However, nest defence was not linked to nestling weight or number of fledglings. Thus, we found no evidence of a trade-off between fitness components. It is possible that the investigated relationships become relevant only in extreme years that severely alter the costs and benefits of this behaviour.