To combat the ever-present threat of predation many species produce anti-predator vocalizations and behaviours (mobbing) designed to drive predators away. These vocalizations can encode a predator's threat level, and many species within a community will eavesdrop on this information. To determine how prey species produce, use, and respond to anti-predator information and how individual, social, and phylogenetic factors of different species may influence this behaviour, I conducted a series of robotic-predator presentation and anti-predator vocalization playback experiments in the wild and lab. I predicted that UK Paridae would encode information the same as previously studied species. I found that UK Paridae encode predator information in different ways, and that neither phylogeny nor ecology explained the patterns of similarity in how different species encode predator threat in their calls. Flock structure appeared to affect how species encoded predator threat and while multiple species may be sources of information for familiar flock mates, only blue and great tits met the criteria to be community informants. As blue and great tits need prior experience to recognize novel predators and juvenile great tits avoid novel predators only after seeing adults mob them, tits may use mobbing calls to learn about novel predators. While they responded to mobbing calls, juvenile blue and great tits did not engage in mobbing behaviour although they appear capable of doing so. Furthermore, while individuals varied in their responses to aerial alarm calls this variation was not explained by either their proximity to the call nor their personality. In this close examination of how anti-predator vocalizations are produced and used by UK Paridae, I found variation in these signals. This challenges previous assumptions about how Paridae encode information, raising questions as to the sources of this variation.

No description available.

Competition between Elminius modestus (Darwin) and Balanus balanoides (L) is considered to be an important issue in the invasion of British shores by E. modestus and in explaining the coexistence of both species in the intertidal barnacle niche. Competition is discussed by reference to the concept of ecological performance, which is a term describing all adaptations and physiological and behavioural attributes of each species. Much information on the biology of cirripedes already exists, but the importance of predation and settlement behaviour in relation to competition have not been examined satisfactorily. Consequently these two ecological features are investigated in the thesis. The tolerance of developing embryos to extremes of temperature, and the infection frequencies of the castrating parasite Hemioniscus balani (Spence Bate) are also examined to assess their importance in the ecology of each species. All the available information is then summarised. Comparative assessments of ecological performance are made for each species and for each single feature of their ecology. The assessments are then analysed in an attempt to identify factors which are especially important in regulating competition between the two species. It is acknowledged that the approach is necessarily an over-simplification, but it is broadly concluded that biological mechanisms are more important than actions of the physical environment. Settlement behaviour and susceptibility to predation may be especially significant in influencing competition both during the initial colonisation by E. modestus and in the contest of its coexistence with B. balanoides.

An investigation of certain aspects of the biology of Pomatoceros lamarckii and Laminaria digitata was carried out with particular reference to the factors influencing the settlement of P. lamarckii larvae and to the bioadhesion of both species. The larvae of P. lamarckii were found to be negatively phototaxic throughout their development. A distinctive pattern of settlement behaviour was observed and as the larvae settled they became attached to the substratum by a mucus pad situated in the region of the ventral shield epithelium. Larvae settled gregariously on and close to conspecific adults, but the presence of conspecific juveniles did not induce settlement. Unsuccessful attempts were made, using whole and parts of animals and tubes in a range of solvents, to isolate a chemical settlement stimulus and it was concluded that it is highly unlikely that a chemical cue is produced by P. lamarckii adults. Biofilming was found to be the major factor in inducing settlement and it was demonstrated that substrata biofilmed in the presence of P. lamarckii adults attracted significantly more settlers than did substrata biofilmed in other ways. The adult mediated biofilms were found to contain large numbers of a rod-shaped bacterium which was present only in very low numbers in the other biofilms and it is proposed that this bacterium, or its exopolymers, may provide the primary settlement stimulus. Natural settlement was examined on pebbles at three different locations and the results compared with the laboratory findings. Tenacity was measured for the tubes of P. lamarckii and the haptera of L. digitata. A mean tenacity of 24.75 x 1()5 ± 6.7 N m-2 was recorded for P. lamarckii and a mean tenacity of 4.21 x 1()5 ± 1.9 N m-2 was recorded for L. digitata.

The seasonal variations in diet, feeding chronology, condition and growth of a fishable population of plaice Pleuronectes platessa in two bays off the North Wales coast were investigated. The population, estimated to comprise 478,630 fish (± 19%) of ages II-XV, occupied an area of 236.73 Km² with an average biomass of 23.36 tonnes (0.11 g/m²). Data on diet and feeding chronology were obtained from fish collected by trawling at known intervals (usually every three hours) during a twenty four hour period. The diet of 'small' (15.5 - 19.4 cm) and 'medium' (19.5 - 20.4 cm) fish was similar in each of the months for which data was collected i.e. March, May, August, November and February. The two chief items were the polychaete Pectinaria koreni and the lamellibranch Abra alba. In addition the 'large' fish (30 - 35 cm) also took Nereis spp. and the bivalve Tellina fabula in significant numbers. The diet varied seasonally in all size-groups; it was dominated by polychaetes in the cooler months and by molluscs in the warmer months. Feeding was considerably synchronised amongst members of the population. Feeding chronology was deduced from variations in average stomach contents with time of day and from the occurrence of food in specific regions of the alimentary canal. In the cooler months - February, March and November - the following phases were recognised: Feeding Peak, Gastric Evacuation, Feeding Pause and Resumption of Feeding. These phases were obscured in May and August probably because higher temperatures led to faster gastric evacuation; this in turn allowed larger meals and increased feeding frequencies, thereby reducing feeding synchrony in the population. Laboratory studies later showed that at a given temperature, the rate of gastric evacuation increases with meal size (gm). (Rate (g/hr) x (meal size)0.6). At all temperatures gastric evacuation time (GET) for a given meal depended on fish size (g). GET was proportional to (fish size)0.42 for a meal expressed as % body weight and to (fish size)-0.068 for a meal expressed as grams. When all other factors were kept constant GET varied as (temperature)-1.03. An empirical length-weight relationship was used to describe seasonal condition factors (W = a L2.946). Peak condition occurred in June and July; condition was intermediate in autumn (deteriorating) and spring (improving) and poor in winter. The condition of the edge of otoliths was used to determine the limits of the growing season. Improvement in condition preceded seasonal growth in length which started in April and was virtually over by September. Growth was asymptotic in all age-groups and the function Y = A - B (e-kt) described the data adequately. Estimates of daily ration were made from field data on average stomach contents. The population apparently cropped 491.15 tonnes of benthic production annually. Energy budget calculations indicated that in energy terms 32.33% of this intake was used for routine metabolism, 9.62% for growth and 0.97% for reproduction. The remaining 57.08% was lost through egestion, conversion and excretion.

Aspects of electroreceptive foraging behaviour were investigated in a benthic elasmobranch, Scyliorhinus canicula (small-spotted catshark). The findings build on current knowledge of sexual conflict in this species and provide novel information concerning differentiation ability, choice and cognition relating to elasmobranch electroreceptive foraging behaviour. Hierarchical catshark behaviours towards artificial, prey-type electric fields (E fields) following stimulation by food-derived scent were recorded under laboratory conditions. Experiment 1: Male-female interactions Foraging behaviour of single- and mixed-sex catshark groups were investigated using electroreception as a proxy for feeding levels. Results indicated significant reductions in foraging levels of being grouped with the opposite sex, in addition to higher responsiveness in females. These attributes are most likely consequences of differing reproductive strategies and resultant sexual conflict. Experiment 2: Choice Catsharks were trained to swim through narrow tunnels and upon exit were presented with two differing E fields simultaneously. Choices were recorded and analysed, and thereby their ability to distinguish between and/or show preferences for fields was determined. Differentiation ability was demonstrated by preferences for stronger rather than weaker direct current fields, and alternating rather than direct current fields. The fish were either unable to distinguish or showed no preference for artificial (electrodes) and natural fields (crabs). Experiment 3: Cognitive ability Response levels and changes in response levels over time of catsharks rewarded for responding to E fields were compared to those of catsharks that were not rewarded. Results demonstrated learning and habituation behaviour improving foraging efficiency over short time scales according to profitability of fields. Failure to retain altered behaviour after an interval indicated short memory windows. These attributes would prove beneficial in a variable environment. Given many elasmobranchs’ continuing population declines and increasing potential interactions with anthropogenic E fields, such information will hopefully benefit both fisheries managers and offshore renewable energy developers.

No description available.

If a baby macaque monkey must be separated from its mother, it should be pre-fed formula before its separation at around day 5-6. If a milk bottle is always present and the infant routinely lifted to the bottle to feed, it will learn to feed itself in about 30 hours. Peer contact before the age of 5 months is desirable and as little as 1 hour per day produces socially adequate monkeys. A peer, adult male, unrelated adult female, or older juvenile can be used as a mother-substitute but if a peer is used, excessive clinging results from continuous contact with the same peer(s), and excessive aggression results if contact is with only one other animal. Self-injurious behaviour (similar to human stereotypy and not human SIB) results when young monkeys cannot direct aggressive play towards another monkey because one is not present during the day when the appropriate direction for such behaviour is practised. If the young monkey is subjected to altered levels of aggression, their subsequent aggressiveness will be similarly changed, even when there is no opportunity for modelling. It is as if there is some mechanism for copying those levels of aggression which they receive. During therapy of isolate monkeys, infants keep aggression levels low. Aggression levels are also determined by visual stimuli, animals that can never see other animals showing no aggression and those intermittently viewing them showing low levels when interacting with others in darkness. Interference with visual interaction by foliage or by visual screens also reduces aggression by at least half in animals such as monkeys and farmed bulls, deer, and chickens where aggression is problematic. Personality, is less able to predict behaviour in macaques than dominance rank. High dominance rank protects animals from stress during fights, while large changes in rank are stressful in new groupings.

An important objective of animal welfare science is the development of indicators of putative subjective emotional (affective) states. To this end, Paul et al (2005) have proposed devising animal-based measures sensitive to changes in certain cognitive processes found to be biased in characteristic ways across affective state in humans. This thesis investigates the application of this approach. The first three experimental chapters examine judgements of ambiguous stimuli in rodents. In the first two of these studies, it was hypothesised that a treatment designed to induce a positive, or negative, change in affect would be associated with a higher, or lower, probability (respectively) of responding to ambiguous stimuli in a manner in keeping with a bias towards optimism; such biases, across affect, have been found in humans. These hypotheses were not supported, at least not in simple terms, with the results revealing counter-intuitive treatment effects, and variation in response accuracy and efficiency. In the last of these three experimental chapters, we applied a treatment designed to induce a change in food motivation. This altered rats' operant responses in a manner suggesting their behaviour was a least partly goal-directed, and also suggesting that the possibility of motivation-related confounds, when studying responses to ambiguity, was real. The final experimental chapter investigated affect-related biases in the foraging behaviour of domestic chicks. We hypothesised that chicks undergoing a treatment designed to induce a negative change in affect would attack fewer red crumbs (a colour commonly associated with aposematism), and more green crumbs, than a control group. We found the opposite: i. e. the former treatment group attacked significantly more red crumbs. This curious finding was reconciled with reference to the functional architecture of the attentional processes implicated in foraging behaviour. In the final chapter, the implications of these, and related, findings are discussed

Animals use signals to facilitate the fundamental behaviours required for survival and reproduction. In social species, where many individuals interact and have to coordinate numerous behaviours, specialised signals are likely to arise. There are numerous costs and benefits to living in a group, and communication signals that minimise the costs and maximise the benefits of group-living are likely to be adaptive. In this thesis, I use a combination of behavioural observations, playback experiments and acoustic analyses to explore how vocal signals facilitate group-living in a cooperatively-breeding bird species, the pied babbler (Turdoides bicolor). Pied babblers forage together throughout the day, using their bills to find small invertebrates in the substrate, and emitting characteristic vocalisations whilst doing so. In chapter 3, I show that the acoustic structure of these chuck calls changes when a forager comes across certain food items and that the resulting `elevated chuck calls' attract other group-members to the foraging site. Calls are: not always given in situations suitable for sharing, sex-specific in structure, and (although dominant males gave elevated calls more often than expected by chance) males were less likely to be approached than females when giving these calls. These data suggest that elevated chuck calling is not an active signal to promote food sharing, but rather, I suggest, an asymmetry in calling among group members reflects the variation in the costs incurred by calling. Despite the fact that nutritional requirements and other incentives are likely to vary between group members, groups rarely split. In chapter 4, I explore the mechanisms that keep the group together whilst foraging and moving around the territory. I found that dominant individuals are more likely to initiate leading events and more likely to be followed by all other group members, initiating a `successful' lead that keeps the group together. The calls used whilst leading off do not appear to contain a dominant signature, and individuals that call and lead further are more likely to be followed, regardless of their dominance status. The most common patterns in leading and following are likely to reflect the most stable strategy for pied babblers, where dominant individuals hold the highest incentive to lead and subordinates pay thelowest costs of synchronizing movements with others. However, calling provides the opportunity for subordinates to successfully lead in situations where their own personal incentives are high, such as on days prior to dispersal. Pied babblers give a variety of loud calls in various contexts and these can be performed as either solos or group choruses. In chapter 5, I classify eight distinct call types, two of which are unique to males and one unique to females. Three additional calls types were used significantly more by the dominant male of the group, and another most often by dominant females. I discuss the possible functions and implications of the different calling patterns in this species. Group chorusing always occurs if another group is present, but also occurs in some intra-group contexts. In chapter 6, I investigate the function of group choruses, first looking at the patterns in which they occur, the difference in investment between individuals, and the significance of sex-specific call types. In common with other studies, my results suggest that choruses serve multiple functions, both in territory defence but also potentially acting as vocal billboards for the dominant pair to advertise their presence. In this way, choruses may aid in maintaining intra-group dominance hierarchies, and allow dominant females especially to deter opposite-sex competitors in order to retain their breeding position. Groups must defend their territory in order to retain access to resources such as food, breeding sites and sleeping sites, and all group members benefit from this behaviour. In pied babblers territorial signalling involves movement to territory boundaries and then long periods of group chorusing in combination with vigorous posturing displays. In chapter 7, I explore the seasonal patterns in territory defence and show that a reduction in territorial encounters and the strength of response to intruders in the nonbreeding season may be due to an energetic constraint, rather than being driven by breeding behaviours. Taken together, these results suggest that complex groups, where requirements and incentives are likely to be heterogeneous, can function successfully as a group by using signals to mediate the costs and benefits of group-living