Environmental measurement in schools: electronics in field studies

Increasing interest in environmental science as a school subject has led to the appearance of ‘environmental meters’ designed to measure conductivity, light level, oxygen concentration, pH, sound level, and temperature. Their uses and abuses are discussed and an insight given into the principles of measurement involved. Criteria for choosing suitable equipment are suggested and where possible cheaper alternatives are mentioned.     

Access denied: the anatomy of silence,immobilization and the gendered migrant

Abstract

This article argues that the status of migrant subjects is characterized by a loss of communication rights and locates the instances where this loss is most visible. It investigates the process of silencing and immobilization of migrants and the particular forms it takes for female migrants through the disenablement of communicative acts. In this process the detained migrant loses her status as an interlocutor, irrespectively of the instances and processes that allow her–or demand of her–to speak. The state of exceptionality assigned to detained migrants is supported in the criminalization of migration laws and securitization, which together with widespread policies of incarceration in the West have become the antipode of the fundamental principles of free movement and expression. Silence and immobilization constitute the ‘standard’ rather than exceptional conditions of people on the move that shadow them across every step of their way, geographically, politically, culturally, legislatively, socially.     

Maternal responsiveness of sows towards piglet's screams during the first 24 h postpartum

In this study we focused on sow responsiveness towards piglet screams which are proposed to have an important link to posture changes and early piglet crushing. A sow's responsiveness to screams of her piglets was investigated along the first 24 h after birth, the period of highest mortality, in 15 lactating sows housed in farrowing crates. We compared the sow's response to playbacks of screams of trapped piglets to her response to a control sound during birth, 8–12 h postpartum and 20–24 h postpartum. We did the same with playbacks of screams of fighting piglets during nursings 8–12 h postpartum and 20–24 h postpartum. The sow’ responsiveness to screams of own trapped piglets was analyzed within the whole 24 h and to screams of fighting piglets 30 min between 8 and 12 h postpartum and 30 min between 20 and 24 h postpartum. A sow was scored as responsive if she changed her posture in response to the stimuli. Sows had a four times higher response towards playbacks with screams than towards the control stimulus. The proportion of the sows’ responsiveness to screams (44%) of trapped piglets did not change significantly between birth, 8–12 h postpartum and 20–24 h postpartum. Sows responded to 28% of playbacks of fighting piglets by terminating a nursing independently from the time after birth. Playbacks and real screams of own piglets were similarly effective in evoking a response for both types of screams. There was no significant association between the sows’ responsiveness to screams of trapped piglets and piglet mortality nor between screams of fighting piglets and weight gain. In conclusion our results indicate that sows maintained their responsiveness towards piglet screams during trapping and during fighting for teats within the first 24 h. Playbacks and real screams were similarly effective in evoking a response. We discuss the importance of the sound characteristics of piglet screams related to the sows’ response.     

Implications of conspecific background noise for features of blue tit, Cyanistes caeruleus , communication networks at dawn

Communication among animals often comprises several signallers and receivers within the signal’s transmission range. In such communication networks, individuals can extract information about differences in relative performance of conspecifics by eavesdropping on their signalling interactions. In songbirds, information can be encoded in the timing of signals, which either alternate or overlap, and both male and female receivers may utilise this information when engaging in territorial interactions or making reproductive decisions, respectively. We investigated how conspecific background noise at dawn may overlay and possibly constrain the perception of such singing patterns. We simulated a small communication network of blue tits, Cyanistes caeruleus, at dawn in spring. Two loudspeakers simulated a singing interaction which was recorded from four different receiver positions simulating potential eavesdroppers. During the recordings, resident blue tit males were vocalising and created natural conspecific background noise. Levels of conspecific background noise were high and varied among positions of potential eavesdroppers. We conclude that conspecific background vocalisations may potentially constrain the perception of singing patterns and may constitute costs for eavesdroppers. On the other hand, signallers may position themselves strategically and privatise their interactions.     

“Girney” vocalizations among Japanese macaque females: Context and function

One vocalization in the Japanese macaque (Macaca fuscata) system of communication is the “girney.” Previous studies indicated that the “girney” is used for short range communication and that it tends to occur when subordinate animals approach and groom dominant ones and when females without infants approach females who have infants. Data were collected on the social behavior of adult female Japanese monkeys of the Arashiyama-A troop in Texas in order to test those results. The study indicates that “girneys” are the most frequently occurring vocalizations of females during and following the birth season and that they occur primarily in two contexts. Those are the proximity of a female to another female with a new infant and the proximity of a lower ranking animal to a higher ranking one. The contexts are ones in which the risk of aggression is high, and the “girneys” appear to function as appeasement gestures to reduce the risk.     

Recognition and the evolution of distinctive signatures: when does it pay to reveal identity?

A simple evolutionarily stable strategy (ESS) model of identity advertisement is presented, which is applicable to many different situations, ranging from parental recognition of young to recognition of kin by workers in social insect colonies that comprise several genetically distinct lineages. The model assumes that the receiver may respond favourably or unfavourably to the signaller, but that it cannot immediately determine which type of response is appropriate. The signaller, who always benefits by eliciting a favourable response (but is unaware of which type of response is appropriate for the receiver), may choose to reveal or conceal its identity, making the task of discrimination easier or harder for the receiver. The evolutionarily stable outcome of the model depends on the probability that an unfavourable response is appropriate, the relative costs to the receiver of acceptance and rejection errors, and the relative benefits to the signaller of eliciting a favourable response when this is appropriate and when it is inappropriate for the receiver. High costs of acceptance errors to the receiver, and high benefits of appropriate favourable responses to the signaller, favour provision of distinctive identity cues: so, paradoxically, does a high probability that an unfavourable response is appropriate. However, under a wide range of conditions, selection favours the withholding of signature cues, which prevents discrimination by the receiver. Finally, if the signaller must provide some information to elicit a favourable response, but stands to gain more from such a response when it is undesirable, it may do best to provide partial but incomplete information about its identity.     

Resource partitioning of sonar frequency bands in rhinolophoid bats

Summary In the Constant Frequency portions of the orientation calls of various Rhinolophus and Hipposideros species, the frequency with the strongest amplitude was studied comparatively. (1) In the five European species of the genus Rhinolophus call frequencies are either species-specific (R. ferrumequinum, R. blasii and R. euryale) or they overlap (R. hipposideros and R. mehelyi). The call frequency distributions are approximately 5–9 kHz wide, thus their ranges spead less than ±5% from the mean (Fig. 1). Frequency distributions are considerably narrower within smaller geographic areas. (2) As in other bat groups, call frequencies of the Rhinolophoidea are negatively correlated with body size (Fig. 3). Regression lines for the genera Rhinolophus and Rhinolophus, species from dryer climates have on the average higher call frequencies than species from tropical rain forests. (4) The Krau Game Reserve, a still largely intact rain forest area in Malaysia, harbours at least 12 syntopic Rhinolophus and Hipposiderso species. Their call frequencies lie between 40 and 200 kHz (Fig. 2). Distribution over the available frequency range is significantly more even than could be expected from chance alone. Two different null hypotheses to test for random character distribution were derived from frequency-size-relations and by sampling species assemblages from a species pool (Monte Carlo method); both were rejected. In particular, call frequencies lying close together are avoided (Figs. 4, 5). Conversely, the distribution of size ratios complied with a corresponding null hypothesis. This even distribution may be a consequence of resource partitioning with respect to prey type. Alternatively, the importance of these calls as social signals (e.g. recognition of conspecifics) might have necessitated a communication channel partitioning.     

Urine washing and related behaviour in wild moustached tamarins,Saguinus mystax (callitrichidae)

Urine washing (UW) and urinating onto hand (UH) are reported for the first time for a wild callitrichid monkey, the moustached tamarin,Saguinus mystax. Both patterns are very rare and no sex difference in frequency is apparent. The temporal distribution shows a maximum of UH/UW around midday when ambient temperature is at maximum and humidity at minimum. No seasonal effects were observed, but any seasonal effect might be masked by the low frequency of UH/UW. UH/UW are not linked to a single behavioural context and may have multiple functions in thermoregulation/water conservation, cleaning, improving grip, and as a social signal.     

Vocal communication in captive golden monkeys (Rhinopithecus roxellanae)

The Sichuan golden snub-nosed monkey,Rhinopithecus roxellanae, is an endangered Colobine endemic to China. The behavior and biology of this species are little known, and it has rarely been kept in captivity outside China. Results from 42 hr of observations of a male-female golden monkey pair provide preliminary information on the vocal behavior of this species in captivity. Vocalizations by the animals often occurred within antiphonal sequences, which were primarily initiated by the female. Sequences were brief (2–3 calls), showed little or no temporal overlap, and were emitted primarily when the animals were distal from one another, suggesting that sequences may function as contact calls in nature. Some vocalizations appeared to be cryptic, i.e. unaccompanied by mouth or body movement, and these were observed more often than noncryptic calls in both animals. Vocal communication appears to be complex in this species, and remains poorly understood.