bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Sound Environment of the Foetal Sheep
Authors: Vince Margaret A. , Armitage Sally E. , Baldwin B.A. , Toner J. , Moore B.C.J. 
Published: April 2008

Abstract
The sound environment of the foetal lamb was recorded using a hydrophone implanted a few weeks before term in a small number of pregnant ewes. It was implanted inside the amniotic sac and sutured loosely to the foetal neck, to move with the foetus. Results differ from those reported earlier for the human foetus: sounds from the maternal cardiovascular system were picked up only rarely, at very low frequencies and at sound pressures around, or below, the human auditory threshold. Other sounds from within the mother occurred intermittently and rose to a high sound pressure only at frequencies above about 300 Hz. Sounds from outside the mother were picked up by the implanted hydrophone when the external sound level rose above 65-70 dB SPL, and the attenuation in sound pressure was rarely more than 30 dB and, especially at low frequencies, usually much less. However, attenuation due to the transmission of sound through the body wall and other tissues tended to change from time to time. It is concluded that the foetal lamb's sound environment consists of (1) intermittent low frequency sounds associated largely with the ewe's feeding and digestive processes and (2) sounds such as vocalisations from the flock, human voices and other sounds from outside the mother.
Host Selection as an Adaptation To Host-Dependent Foraging Success in the Cattle Egret (Bubulcus Ibis)
Authors: Burger Joanna , Gochfeld Michael 
Published: April 2008

Abstract
In southern Africa, the commensal foraging cattle egret has a wide variety of potential ungulate species from which to select its hosts. We found that the preferred hosts involved just a few of the available species. We predicted that ultimately the selection of hosts should be adapted to maximize egret foraging success. Selection is hierarchical with birds first choosing a general area in which one or more host species may be present. They then choose a host herd, and finally select an individual which they accompany as long as its actions are suitable and prey items are disturbed. The decision process remains flexible. Egrets freely switch hosts moving from one cow or wildebeest to another. We found the predicted correlation between egret and host walking rate (steps/min.), and also that feeding success was related to number of egret steps. We looked for evidence that egrets would select species and individuals that allowed them to move at the optimum rate for foraging. We found egrets achieving maximum success at walking rates between 10 and 30 steps per minute. When hosts moved more slowly or more quickly, feeding success was low, and egrets switched hosts more frequently. We censused wild animals in game parks and domestic animals on farms, and found a similar overall abundance (individuals/km). Wild animal herds provided fewer suitable hosts (individuals moving at the optimal rate for the egrets). We conclude that there are three components to host selection. Hosts must be available in adequate numbers and must be easy to locate. They must be suitable in terms of providing egrets with good foraging situations. They must be reliable in terms of remaining in the same general area day after day and in terms of consistent rates of locomotion. Although wildebeest, zebras, and buffalo fit one or two of the criteria, cattle fulfill all three. We speculate that the widespread increase in cattle farming in the past century may have facilitated the world wide population explosion of the cattle egret.
The Coevolution of Receptivity Signalling and Body-Size Dimorphism in the Chalcidoidea
Authors: Van Den Assem J. , Jachmann F. 
Published: April 2008

Abstract
In the Chalcidoidea (small hymenopterous parasites of the developmental stages of many kinds of insects) two evolutionary trends can be traced: reduction of male size, and switch of the courtship position of the male relative to the female from rear to front. The positional shift is related to the development of antennal movements produced by the female at the onset of sexual receptivity. The signal function of these movements was shown with experiments including the use of dummies. The experimental results are discussed in relation to selective pressures shaping courtship and mating behaviour in the Chalcidoidea.
Effects of Species-Specific Vocalizations On the Behaviour of Surrogate-Reared Squirrel Monkeys
Authors: Herzog Michael , Hopf Sigrid 
Published: April 2008

Abstract
This is a contribution to the study of the communicative behaviour in a primate, the squirrel monkey (Saimin). It will be shown whether socially inexperienced infants respond differentially to species-specific vocalizations. Six squirrel monkeys were separated from their mothers and conspecifics on the day of birth and surrogate-reared up to their 3rd month of age. In order to counteract general deprivation effects, the subjects received visual, auditory and vestibular stimulation, in addition to the constant presence of the mother surrogate and manipulanda. From the 2nd week on subjects were presented a test object 3-6 times daily. The object was so designed as to elicit behaviour which would usually be directed to conspecifics. When the subjects were able to locomote freely in their cage and approach the object on their own, the following experiment was carried out: Upon each physical contact by the subject with the object, a sound was played back by a loudspeaker hidden in the object. During any 8-min. session only one of five preselected sounds was used. The effect of two vocalizations, caw and cackle, known to be aversive in squirrel monkey groups, was compared to that of two non-aversive ones, twitter and play peep, and a neutral control tone. Caw and cackle resulted in low overall contact and less varied and less playful activities toward the test object. Subjects also were facing the objects more from a distance and spent more time in contact with the mother surrogate as their security figure. Twitter and play peep resulted in an opposite pattern. These findings indicate a genetically preprogrammed basis for perception and processing of species-specific vocalizations.
Quatic Foraging in Garter Snakes: a Comparison of Specialists and Generalists
Authors: Drummond Hugh 
Published: April 2008

AbstractTo examine the assumption, underlying much ecological theory, that a "Jack-of-all-trades is master of none", a comparison was made of the aquatic predation of four colubrid snakes, two aquatic specialists (Thamnophis couchi, T. melanogaster) and two terrestrial-aquatic generalists (T. sirtalis, and T. elegans). Observations were made in the field, then juvenile snakes were compared under controlled laboratory conditions. The specialists and generalists had qualitatively different foraging repertoires. The specialists made lengthy dives, crawled slowly on the underwater substrate and made long-distance underwater responses to prey: orientation, approach, pursuit, and frontal attack. The generalists dived briefly, with rapid serpentine locomotion, or searched "terrestrially" by wandering along the shoreline and snatching prey from the water surface. Underwater, the generalists' only prey-directed response was sudden short-distance attack, and they appeared to rely on chance encounters with prey. There were significant differences between the two pairs. In comparison with the generalists, the specialists 1) captured more fish, 2) spent more time on aquatic search, 3) spent more aquatic search time diving, 4) spent more diving time on the underwater substrate, 5) made more attacks in every category of search in open water, and 6) attacked underwater from a greater distance. Significant differences were not found in attack frequencies in those search categories where underwater vision is probably unimportant (aerial attacks and attacks in underwater crevices), nor in aerial attack distances. The specialists' behavioral superiority in respect of their specialization supports the "Jack-of-all-trades" assumption. The observations suggest that this superiority is associated with superior underwater visual acuity (which may be due to superior visual accommodation). The generalists' principal underwater searching technique (serpentine diving) appears to be energetically costly, and may only be profitable when aquatic prey are especially vulnerable. Nerodia sipedon, member of a genus that is closely related to Thamnophis but more aquatic, had a foraging repertoire qualitatively similar to that of the generalists. The similarity may be associated with N. sipedon's nocturnal habits and presumed reliance on non-visual prey cues.
A Factor Analysis of Seasonal, Behavioral, Hormonal and Body Weight Changes in Adult Male Barheaded Geese, Anser Indicus
Authors: Dittami John P. , Reyer Heinz-Ullrich 
Published: April 2008

AbstractIndividual measurements of courting, aggression, pairbond displays, body weights and the circulating levels of testosterone, LH, T4 and prolactin in male barheaded geese were subjected to a factoral analysis. Data from the whole year were analysed and then broken up into pre-breeding and post-breeding components and re-analysed. Some parameters remained clumped in the same factors throughout like aggression and pair-bond displays, LH and testosterone, and prolactin and body weight. Others, especially behavioral and endocrinological parameters were only linked on either an annual or seasonal basis.
Sex Roles in the American Oystercatcher
Authors: Nol Erica 
Published: April 2008

AbstractAmerican oystercatchers have extensive parental care. As a result sex roles are similar and highly complementary. During the pre-laying period the roles of males and females, except during copulation, are indistinguishable. During the laying period the roles diverge slightly with males spending more time chasing conspecifics. Presumably the similarity during pre-laying, and the differences during laying, function to prevent the male from being cuckolded. Males begin assisting in incubation as soon as the females begin incubating and then consistently perform the same proportion of incubation throughout this breeding stage. During incubation, females incubate more often than males, and consequently rest less, preen less and fly less than males. During chick-rearing males are involved in more chases than females and take more foraging trips to provision young but wait longer between successive trips. The pattern of foraging by each sex is complementary. Breeding season energy expenditure is approximately equal in both sexes. There is no evidence for conflict between the sexes over the contributions to parental care. Where sex roles diverge the differences in behaviour can be partly explained by the relative energetic efficiencies of each sex performing different tasks.
Acoustic Communication and Mating Behaviour in the Muellerianella Complex (Homoptera - Delphacidae)
Authors: Drosopoulos S. 
Published: April 2008

AbstractSome data on acoustic communication and mating behavior of two biparentally reproducing species and the clonally reproducing pseudogamous "species" of the genus Muellerianella are reported. Although bioacoustic differences were found in the calling songs between the species, these did not prevent pairforming. Also, differences in mating behavior, such as pre-copulation behavior, courtship activities, frequency and duration of copulation were not sufficient to prevent successful hybridization between both the two biparentally reproducing species and between each of these two species and the pseudogamous "species". The data reported here are related to other biological differences reported previously. According to these data there is some evidence that differences in acoustic communication and mating behavior between the two species are established by ecological influences which in turn have established analogous physiological requirements. These differences are rather weak isolating mechanisms. Regarding the behavioral relation of the pseudogamous species with males of the two parental species it was found that these females behave exactly as the females of M. fairmairei with which they coexist in the field. In interspecific crosses mechanical barriers to copulation are more efficient than courtship differences. Finally it is assumed that pseudogamy is a strong isolation mechanism between the not yet fully genetically differentiated bisexual species of Muellerianella.
Semantics of an Avian Alarm Call System: the Male Domestic Fowl, Gallus Domesticus
Authors: Marler Peter , Pickert Roberta , Gyger Marcel 
Published: April 2008

AbstractVocal alarm signals of male domestic fowl given in the presence of predators and other ground and aerial objects were recorded and analyzed. Studies were conducted under semi-naturalistic conditions and a telemetric technique was used to facilitate high quality sound recording. Cockerels gave ground alarm calls specifically to objects moving on the substrate and aerial alarm calls to objects moving above in free space. Vocalizations were associated with both dangerous and harmless objects. We therefore investigated variation in sound structure of aerial alarm calls with reference to flying predators and non-predators. A multidimensional contingency table analysis revealed a significant tendency for qualitatively different aerial alarm calls to be associated with flying predators and non-predators. Differences in call structure were restricted to the two first units of the alarm call. We tested the hypotheses that variation in aerial alarm call structure might be affected by either the distance separating the bird from the object or the angular size of the object projected onto the retina of the cockerel. Statistical analysis showed that the angular size was a good predictor of variation of the second unit of alarm call. The distance it self was less predictive. The first unit of the alarm call was not affected by either the distance or the angular size of the object. We propose that this part of the call has a more general function of alerting the conspecific companions. We conclude that alarm vocalizations of male domestic fowl refer specifically to a certain type of stimulus object, either moving on the ground or flying. For alarm calls correlated with aerial stimuli the specific angular size of a stimulus object moving in the air is a good predictor of call structure. We suggest that this way of dealing with flying objects as stimuli for alarm calls is the result of a predator detection strategy in which the benefits of an expanded field of vision, an important adaptation for ground-dwelling birds, exceed the costs of alarming to harmless birds and other aerial objects.
Song Learning in Cross-Fostered Zebra Finches: a Re-Examination of the Sensitive Phase
Authors: Clayton N.S. 
Published: April 2008

AbstractMale zebra finches, Taeniopygia guttata, which have been normally-raised or cross-fostered to Bengalese finches, Lonchura striata, learn from a song tutor with whom they arc housed during the sensitive phase, between 35 to 70 days of age. If the tutor is a different species from the father or foster-father however, then the tendency to learn during this time is much less and some males will produce song heard before 35 days. None of the birds in this study learnt after 70 days, although some lost song elements or added improvised ones. These results suggests that specific types of experience influence when a young bird learns its song. It seems that exposure to "poor" song during the sensitive phase stimulates the bird to remember song heard previously and blocks further learning after this time. These results are compared with those obtained in imprinting studies.
Temporal and Spatial Differences in Traditions and Repertoires in the Song of the Thrush Nightingale (Luscinia Luscinia)
Authors: Sorjonen Jorma 
Published: April 2008

AbstractDifferences in the song repertoires of males and in the song-pools of the thrush nightingale populations were studied in 1972, 1983 and 1984 in southern Finland. Changes in male repertoires and in the song-pool of one population were monitored in 1972 and 1980-1985. The thrush nightingales in a local population had repertoires that were more similar to each other than to those of the males in other local populations. The similarity of the repertoires decreased with increasing distance, but there were no clear-cut dialect boundaries between local populations. The song repertoire of a male was more similar to that of the adjacent males than to his own repertoire of the previous year. The similarity of the repertoires of adjacent singers increased during the singing period. This similarity was partly due to the same song-types being used with about equal frequency, but obviously the males were also able to learn new songs from their adjacent singers. After dispersal to a breeding area thrush nightingales learn at least some new song-types, even at the age of two to four years. Some old breeders were able to copy new song-types from the immigrants (mostly young males) or the playback tape. The newly copied song-types were loud and simple in structure, whereas the song-types soon to be abandoned were weak in amplitude. In one population, studied from 1980 to 1985, the repertoires of the males tended to become more similar in successive years. This tendency, however, did not occur in 1984 when the proportion of immigrants in the population was unusually high. The major changes in local song traditions were due to "cultural diffusion" by males originating from areas with other traditions; this diffusion greatly enriched the local song-pool, especially in years when the rate of immigration was high.
Cross-Fostering, Imprinting and Learning in Two Sympatric Species of Cockatoo
Authors: Chapman Graeme , Rowley Ian 
Published: April 2008

AbstractTwo species of cockatoo, the galah Cacatua roseicapilla and Major Mitchell's cockatoo C. leadbeateri are sympatric throughout much of Australia. Both species nest in tree-hollows of similar dimensions at the same time of year. Their eggs which are very similar are laid every other day and are not incubated until at least three have been produced. Parent birds often forage a long way from the nest and so the early eggs are largely unattended. Sometimes a pair of C. roseicapilla and one of C. leadbeateri both "own" the same hollow and contribute eggs to the clutch. When confrontation finally arises the C. roseicapilla being smaller, lose out and the C. leadbeateri unknowingly incubate a mixed parentage clutch, and may rear a young C. roseicapilla with their own offspring. Such cross-fostered C. roseicapilla behave as, and associate with C. leadbeateri; they ignore other C. roseicapilla. Parts of their behaviour repertoire are innate, parts are the result of imprinting and parts, of later learning. They learn to fly and to call like C. leadbeateri and they also adopt the latter's much more varied diet. Cross-fostered C. roseicapilla are probably responsible for those cases of hybridisation in the wild between C. roseicapilla and C. leadbeateri that have been reported.
Different Functions of "Alarm" Calling for Different Time Scales: a Preliminary Report On Ground Squirrels
Authors: Owings Donald H. , Gladney A. Beckett , Hennessy David F. , Leger Daniel W. 
Published: April 2008

AbstractThe predator-evoked calling of California ground squirrels (Spermophilus beecheyi) was studied in the field during the reproductive season. Three different sources of data indicated that adults call more after, than before their young have reached the age of first emergence from natal burrows. During exposure to a tethered rattlesnake (Crotalus viridis oreganus) and to a freely-moving dog (Canis familiaris), and in natural encounters with a coyote (Canis latrans) or bobcat (Lynx rufus), calling was more frequent after than before young first emerged. We concluded that California ground squirrels call in order to warn their offspring about predators, like other ground squirrel species do. In order to see the increase in mammalian predator evoked calling after pup emergence, we had to separate calling on the basis of its temporal organization. Nonrepetitive calling involved spacing a few vocalizations irregularly in time. Calls patterned in this way were more common early in an encounter, became more frequent after pup emergence, and more consistently elicited immediate reactions. Such calling was probably used to warn pups. Repetitive calling comprised rhythmic emission of a series of vocalizations. Calls organized repetitively were more common later in an encounter, were not emitted more frequently after pup emergence, and less consistently evoked immediate reactions. These and other differences between the two temporal patterns of vocalizing led us to propose that repetitive calling represented a "tonic" communicatory effort (as in SCHLEIDT, 1973). Repetitive inputs to other squirrels may act "cumulatively" in a longer time scale than nonrepetitive calling, so as to cultivate or maintain vigilance in other squirrels. The repetitive caller could benefit by using the enhanced reactions of these more vigilant squirrels as a source of information about the predator. We propose that predator-prey episodes may be understandable from an "epigenetic" perspective. That is, the first alarm calls during an encounter should shift squirrels from an unwarned to a warned status; subsequent calling must then function in some other way than as a warning.
Developmental Changes in the Caravaning Behaviour of the House Musk Shrew (Suncus Murinus)
Authors: Ishikawa Tomohiko , Matsuo Takashi , Tsuji Kechiro 
Published: April 2008

AbstractDevelopment of caravaning behaviour in the house musk shrew (Suncus murinus) was described in detail and discussed in relation to sensory and motor development. With age of pups, caravaning changed in its formation pattern (I-V) as well as its quantitative aspects such as frequency of occurrence, duration and distance. The shift in formation pattern from II to III was simultaneous with the onset of vision (Experiment I). In darkness, frequency of caravaning significantly decreased at ages later than 11 days. This was due to the selective disappearance of Patterns III and V (Experiment II). These findings suggest the role of vision in caravan formation at the later stage of the period of occurrence. After the onset of vision, caravaning is released mostly by visual motion of the object, whereas caravaning at the earlier stage is released nonvisually. Caravaning and the pup's locomotor activity were suppressed and delayed until the age of weaning in the enclosure set up to simulate the natural habitat. The period of occurrence was reduced by disappearance of some formation patterns observable in the laboratory open-field and the onset of caravaning exactly synchronized with that of spontaneous and independent locomotion. Development of caravaning in the outdoor enclosure closely resembled the development of Pattern V in the open-field (Experiment III). The adaptive significance of caravaning can be fully understood only by comparing behaviours which occur in different situations. Such an approach could bridge the gap between observations in the laboratory and those in the natural habitat. In Experiment I, caravaning was compared between domesticated laboratory animals and animals at the first two generations of nonsib-mating from wild ones. The age-dependent tendency was more distinct in the latter group. This suggests that mother-offspring relations changed in the process of domestication.