bluuebunny/crossref_metadata_2025_split huggingface dataset:
Brood Division and Parental Care in the Period Between Fledging and Independence in the Dunnock (Prunella Modularis)
Authors: Byle Philip A.F. 
Published: April 2008

Abstract1. Brood division was observed in 12 out of the 21 broods of dunnocks. It was stable over the whole period of fledging to independence. 2. Undivided broods were significantly more likely to occur earlier in the season than divided broods. 3. Brood size had no significant effect on the age at which chicks reached independence. 4. The weight (on day 6) of chicks in undivided broods influenced the age at which they reached independence, but no significant relationship was found in divided broods. 5. The provision of extra food significantly reduced the age at which fledglings reached independence, indicating that territory quality may affect the timing of independence. The effects of extra food on brood division were unclear. 6. There was no differential splitting of the brood between the dominant male and the female in polyandry and polygynandry or between a monogamous male and his female. Males and females fed the chicks at similar rates. 7. Beta males who had helped to feed the nestlings were more likely to continue to help feed fledglings in larger broods. 8. There was a tendency for male parents to care for male offspring and female parents to care for female offspring.
Reproductive Tactics of Male Savanna Baboons
Authors: NOË Ronald , Sluijter Albertha A. 
Published: April 2008

AbstractThe strongly related parameters rank, age and period-of-residence determine which reproductive tactics a savanna baboon male will use primarily. Baboon males go through the following phases with respect to the use of mating tactics, as they are longer in the group and thus grow older and, as a rule, drop in rank: Phase 1. Peripheral, relatively little social contact, low mating success, building up of a social bond with a few females. Phase 2. High mating success, based on individual fighting ability, social bonds mainly with females that are, or will soon be, sexually attractive. Phase 3, variant a. (Males that were very successful in Phase 2). Considerable time devoted to guarding infants conceived in phase 2 and to the mothers of those infants. Mating activity drops sharply compared to Phase 2. Phase 3, variant b. (Males that did not go through a very successful Phase 2). Low mating success through whatever tactic, relatively peripheral. Phase 4. Relatively high mating success, partly through collaboration with other males. Considerable time is invested in the care for potential offspring and their mothers. Phase 5. Diminishing share in the total mating activity in the group. The support for infants is spread over a relatively large class of infants conceived after immigration. Social contact with a large number of females. The data did not show the relation between agonistic rank and mating success predicted by ALTMANN'S priority-of-access model. A modification of the model is presented, which allows for coalition formation among males that are too low in rank to be successful on their own. This model could not fully explain, however, the exceptional success of some middle ranking males. The theory of Coalition games can give insight in the processes that lead to distributions of mating success that depart from the modified priority-of-acces model. The lack of agreement between the data and the original priority-of-access model cannot be explained by higher selectivity of the high ranking males. The only qualitative parameter of consorts obtained, according to which high ranking males had an advantage, is the time of the day on which mating activity takes place. This is a direct result of the way in which males obtain their consorts. Consorts are often formed in the sleeping trees during the night or in the early morning. In that situation single, strong males have an advantage in conflicts against coalitions of lower ranking males. Lower ranking males have a relative advantage later in the day, when conflicts are fought out on the ground.
Interventions in a Herd of Semi-Captive Plains Zebras
Authors: Schilder Matthijs B.H. 
Published: April 2008

AbstractIn a herd of semi-captive plains zebras interventions, which occurred within the harems, were investigated in order to answer the question why zebras interfered. These interventions are of interest because they regulate the contacts between companions and because, as corrective and preventive measures, they reveal the normative principles underlying the behaviours by which animals structure their social environment. An attempt was made to deduce 1) the internal norms of the interferer; 2) his short term aims; 3) his tactis and 4) his perception of the social environment. The analysis revealed that in the case of an affiliative interaction foals, yearlings and adult mares started to interfere if a friend had an affiliative contact with another zebra. In view of the interferer's behaviours it was concluded that their aim was to break off the ongoing interaction and that zebras tended to protect friendship bonds. Foals and yearlings further interfered if their mother was being threatened, attacked or sexually approached by a stallion. In view of the interferer's behaviours its aim was to prevent iminent interactions or to break off ongoing interactions. This suggests that these interventions were of a protective nature. The interferer's behaviours in both contexts ware very much alike. Mares tended to interfere if their foal/yearling or adult daughter was threathened or aggressed or if a mare friend was being sexually approached by a stallion. This type of intervention was of a protective nature. Stallions in a multi male harem showed a high tendency to interfere in courtship interactions. From the resemblance between interventions in courtship and in aggressive interactions it is concluded that, at leat in a number of cases, the individuals have perceived courtship behaviour by the stallion as a threat towards the mare involved.
Song Variability and the Response To Conspecific Song and To Song Models of Different Frequency Contents in Males of the Bushcricket Requena Verticalis (Orthoptera: Tettigoniidae)
Authors: Schatral Andrea , Bailey Winston J. 
Published: April 2008

AbstractVariability in the temporal structure of the song has been investigated for the Australian bushcricket Requena verticalis (Listroscelidinae: Tettigoniinae: Orthoptera). Chirp interval and chirp duration of an individual male vary between two days. Males differ in their readiness to call. Sporadic singers sing consistently only in the presence of another calling conspecific or when acoustically stimulated, while steady singers call readily under acoustic isolation. Sporadic as well as steady singers change their chirp interval in the presence of another calling conspecific. Steady and sporadic singers are able to differentiate between 16 and 28 kHz, the two main frequency components of the song. There is evidence that the effect of the natural song on the temporal pattern of the call may be due to the 28 kHz frequency component. Individual variation in the temporal parameters is within 0.1 s, and the changes caused by acoustic stimulation are of similar magnitude. Further studies are necessary to evaluate if males and/or females uses these differences to discriminate between conspecifics.
The Functions of Song in Male House Wrens (Troglodytes Aedon)
Authors: Johnson L. Scott , Kermott L. Henry 
Published: April 2008

Abstract
To assess the functions of song in male house wrens (Troglodytes aedon), we examined the pattern of song output during different stages of the breeding cycle and behaviour patterns of focal males and conspecifics that were associated with song. We recorded 2093.5 bouts of song from 11 different males in 12 breeding cycles during 3 years. Most song sung prior to pairing is sung at a high volume and is given spontaneously (i.e. is apparently not produced in response to the behaviour of any conspecific). Production of high volume spontaneous song ceased immediately for at least 7 days when the male paired, but resumed immediately upon loss of the mate. Paired males sang high volume spontaneous song after mates began incubating, and almost always sang this song within 10 m of an unoccupied nest site. Several males attracted second mates to these nest sites and immediately ceased their output of high volume spontaneous song. These observations strongly suggest that high volume spontaneous song functions in mate attraction. Male house wrens do not appear to use song on a routine basis to communicate with neighbours or other males. However, they do appear to direct song at other males when territories are threatened. Song is sung at intruders in the territory and at neighbours just establishing a territory of their own. Most song sung after pairing appears to be directed towards mates. We suspect than males use song to inform mates that there is no immediate threat of predation, allowing mates to move quickly to and from nest sites. We discuss the role and benefits of descriptive, correlative studies in assessing song function.
Herd Structure, Leadership, Dominance and Site Attachment of the Camel, Camelus Dromedarius
Authors: Schulte Norbert , Klingel Hans 
Published: April 2008

AbstractSocial structure and relationships in a herd of captive camels were studied in Kenya. During day and night the herd split up irrespective of kinship. Partner preferences existed only in those camels who had previously been kept in a small group separated from the herd. Dominance relationships are anonymous with four levels: a) dominant breeding bulls, b) females and bachelors, c) subadults, and d) calves. No stable leadership was observed, but individual preferences in the walking order existed when the camels left and entered the enclosure. During the night most camels showed an amazing attachment to a particular resting site; in a new boma they used corresponding sites. During moon nights activity was greatly increased.
Stabilization of Sexual Preferences By Sexual Experience in Male Zebra Finches Taeniopygia Guttata Castanotis
Authors: Bischof Hans-Joachim , Clayton Nicky 
Published: April 2008

Abstract
Male zebra finches, Taeniopygia guttata castanotis, were normally-raised by zebra finches or were cross-fostered to Bengalese finch, Lonchura striata, foster-parents until 40 days of age. Following isolation until day 100, half the birds in each group were housed with a zebra finch female for seven days, isolated for three days and then housed with a Bengalese finch female for seven days. The other birds were exposed to females in the reverse order. Subsequent double-choice tests showed that all the normally-raised birds preferred zebra finch females whereas the preferences of cross-fostered males depended on the order of exposure to the two females: those exposed first to a Bengalese finch female preferred Bengalese finch females whereas of those exposed first to a zebra finch female, some preferred zebra finches, some preferred Bengalese finches and some showed no marked preference for either female. In order to examine the question of why the latter group showed such marked individual variation in their sexual preferences, a further group of males were cross-fostered to Bengalese finches and exposed to a zebra finch female and then to a Bengalese finch female and their behaviours were observed from day 21 until day 40 and for the two, seven-day periods with the females. The results show that, when comparing brothers within clutches, the one that begs and is fed more by by its foster-parents develops a stronger preference for Bengalese finch females and that the more song phrases a male directs to the zebra finch female during the first seven-day period, the stronger the sexual preference for zebra finch females in the double-choice tests. Hence, our results confirm and extend those of IMMELMANN et al. (1991) and KRUIJT & MEEUWISSEN (1991) that sexual imprinting may be a two step process. As a first step, information about the parents is learnt during a sensitive period early in life. In a second step, this information has to be tested for its validity for the selection of a sexual partner during first courtship encounters. It is this second step where the previously stored information is stabilized in memory. Giving conflicting information during the first and the second step, one can show that interactions between the young male and its parents as well as with its first sexual partner influence the final preference it shows in subsequent double choice tests.
Assessment of Patch Profitability and Ideal Free Distribution: the Significance of Sampling
Authors: Gotceitas Vytenis , Colgan Patrick 
Published: April 2008

AbstractWhen allowed access to two food patches differing in food availability, groups of six adult, female, threespined sticklebacks (Gasterosteus aculeatus, L.) distributed themselves between patches according to the ratio of patch profitability, as predicted by the ideal free distribution (IFD) model. However, when individual fish were subsequently prevented from physically sampling patches differing in both food availability and the number of conspecifics present, patch choice did not conform to IFD. Instead, individuals preferred the patch with the greatest number of conspecifics present, regardless of potential foraging rewards. Preference for patches with the greatest number of conspecifics was, however, only evident when conspecifics were feeding. An outline of the decision process used by sticklebacks when selecting among food patches is presented.
Mutual Reciprocity of Grooming in Female Japanese Macaques (Macaca Fuscata)
Authors: Muroyama Yasuyuki 
Published: April 2008

AbstractGrooming interactions among female Japanese macaques (Macaca fuscata) were observed and compared between affiliated and unaffilitated non-related pairs, mother and adult female offspring paris, and mother and immature offspring pairs. Unaffiliated (rarely interacting) members of pairs were likely to approach and then groom the other, in contrast to affiliated (frequently interacting) pairs, who more often approached and then solicited grooming from the other. The return receipt of a benefit just given, in the form of reciprocation of grooming, was immediate in non-related pairs. The brief interval between the occurrence of reciprocation facilitated the estimation of receiving as much benefit as was given in the case of rare grooming. However, such was not the case for related pairs. Adult female offspring solicited grooming from mothers more than immature offspring. The findings are discussed with reference to previous theories about the evolution of altruistic behaviour.
Response of Male Indigo and Lazuli Buntings and Their Hybrids To Song Playback in Allopatric and Sympatric Populations
Authors: Charles Baker Myron 
Published: April 2008

AbstractThe hybridizing semispecies indigo and lazuli buntings (Passerina cyanea, P. amoena) were studied in song playback experiments in allopatric and sympatric populations. In allopatry, males of both species responded strongly to conspecific and weakly to heterospecific songs. In sympatry, indigo, lazuli and hybrid males reacted equally and strongly to both indigo and lazuli songs. Alteration of song structures, by presenting indigo syllables in lazuli temporal pattern and lazuli syllables in indigo temporal pattern, showed that the response of allopatric indigo and lazuli males was determined primarily by syllabic (phonological) cues in the test songs and not by the temporal pattern. The overall pattern of male response in sympatry and allopatry provides some understanding of the observed degree of reproductive isolation between these species.
Mate Choice in Aidablennius Sphynx (Teleostei, Blenniidae); Females Prefer Nests Containing More Eggs
Authors: Kraak Sarah B.M. , Videler John J. 
Published: April 2008

Abstract
Criteria for female mate choice were investigated in a natural population of a Mediterranean blenny, Aidablennius sphynx. Removable test tubes in concrete blocks were offered as nests. Each tube was guarded by a male and females laid eggs in the tubes. Nests with larger broods received significantly more spawning females. The numbers of eggs laid increased with brood size from empty nests to intermediate brood sizes, but this tendency is reversed if nests contain very large broods. Nests with and without broods were exchanged experimentally among males. The number of eggs a male received, after an empty tube was replaced by a tube with eggs, was significantly higher. Conversely, the number of eggs received after a tube with eggs was replaced by an empty tube, was significantly lower. Male display did not increase the probability that females spawned. Male size did not correlate with the numbers of eggs received. It is discussed that female preference for large broods might be adaptive because the number of eggs present in the nest is probably a reliable predictor of the survival chances of the eggs.
Genèse De La Ségrégation Sexuelle Et Différences Comportementales Chez Des Enfants D'Age Préscolaire
Authors: Legault Frédéric , Strayer F.F. 
Published: April 2008

AbstractLa présente étude vise à clarifier le processus de la ségrégation sexuelle chez les jeunes enfants en relation avec l'émergence des différences sexuelles dans l'activité comportementale. Les interactions sociales de neuf groupes d'enfants comprenant 92 filles et garçons répartis en trois niveaux d'âge sont observées pendant plus de 130 heures, lors de périodes d'activités libres en garderie. L'inventaire comportemental comprend, après regroupements, sept catégories comportementales préalablement définies par STRAYER (1980). les analyses font ressortir un contexte de ségrégation initiée par les filles vers l'âge de deux ans. A trois ans, les garçons et les filles participent à ce processus. De plus, à partir d'une mesure du taux d'activité dirigé vers les cibles de chaque sexe, nous n'avons constaté aucun évitement actif de l'autre sexe mais plutôt une recherche qui croît avec l'âge de partenaires de son propre sexe. D'autre part, on remarque une plus grande activité en agonisme chez les garçons à partir de l'âge de deux ans. Ces résultats sont discutés à la lumière des principaux modèles explicatifs actuels des différences sexuelles.
Delayed Breeding in Avian Social Systems: the Role of Territory Quality and "Floater" Tactics
Authors: Zack Steve , Stutchbury Bridget J. 
Published: April 2008

Abstract
In many avian societies, young birds delay breeding beyond the age of sexual maturity. Most previous hypotheses of delayed breeding have emphasized forces that keep young birds from becoming breeders. We develop a model of delayed breeding which includes the future acquisition of a high quality territory as a potential direct benefit of delayed breeding. Strong differences in territory quality, age-correlated asymmetries in resource holding potential, and territory site tenacity set the stage for young birds to either breed immediately on a poor territory, or obtain a high quality territory through reproductive delay on or near the site. A wide variety of species and social organizations reveal common patterns of breeding status acquisition through behaviours as nonbreeders with site tenacity on or immediately near the breeding site. A review of 'floater' strategies reveals that nonbreeders frequently have restricted home ranges that encompass one or more breeding territories, and prior experience at a site improves their chances of acquiring a territory in future years. This pattern of territory acquisition argues for incorporating direct benefits into models of delayed breeding. We discuss the potential applications to understanding delayed breeding in social systems as apparently different as cooperatively-breeding birds, migratory passerines, colonial breeding gulls, and lek-breeding grouse and manakins.
Social Stability and Territory Acquisition in Birds
Authors: Beletsky Les D. 
Published: April 2008

AbstractThis study tested the hypothesis that one strategy birds use to acquire territories is to seek and exploit areas where conspecific social stability is weak. Predictions were that nonterritorial individuals, 'floaters', should be attracted to areas of social instability and that they should obtain territories in unstable areas. An experiment with red-winged blackbirds (Agelaius phoeniceus), designed to test whether floaters are attracted to boundary disputes between territorial neighbors, showed that floaters approached multiple male models in simulated boundary disputes at higher rates than they approached single models. Both drug implants that interfered with testosterone physiology in territory owners and manipulations of breeding habitat rendered certain territory aggregations socially unstable, and floaters obtained territories in those areas. Therefore, evidence generally supported the instability hypothesis of territory acquisition. No evidence was found to support an associated prediction, that a high-density breeding area should attract more floaters and thus suffer a higher territory owner turnover rate than a low-density site. Experiments with models of two species of blackbirds showed that one method floaters may use to establish territories is to settle on boundaries between adjacent owners. The potential generality of the instability hypothesis, and its implications for the expression of avian territorial behavior, are discussed. If floaters are attracted to signs of social instability, then it would be advantageous for territory owners to behave in ways that reduce the appearance of instability.
A Field Test of the Sound Environment Hypothesis of Conspecific Song Recognition in American Tree Sparrows (Spizella Arborea)
Authors: Naugler Christopher , Ratcliffe L. 
Published: April 2008

Abstract
The sound environment hypothesis predicts that the features of song that are important for conspecific recognition should be those that overlap least with the songs of other species in the same location. We tested this hypothesis with song playbacks to free-living male American tree sparrows (Spizella arborea). We first used a discriminant function analysis to determine which song features best separated American tree sparrow songs from the songs of heterospecific avian species at two locations representing different sound environments. Based on this analysis we predicted which song features should be most important for conspecific recognition at each location. We then produced synthetic songs containing alterations in these features. Males, however, did not respond to playbacks of altered features as predicted. Thus, our results do not support the sound environment hypothesis of conspecific song recognition.
The Pace of Life - Reanalysed: Why Does Walking Speed of Pedestrians Correlate With City Size?
Authors: Wirtz Peter , Ries Gregor 
Published: April 2008

AbstractIn a much quoted study, BORNSTEIN & BORNSTEIN (1976) showed that the walking speed of pedestrians is positively correlated with the size of the city. They interpreted the higher walking speed of people in larger cities as a psychological response to stimulatory overload. We also found a positive correlation between walking speed and city size. In addition, we showed that - at least in our sample - larger cities had higher proportions of young males and lower proportions of people older than 60 years. Walking speed and momentary density did not correlate positively. Because walking speed is age- and sex-dependent (Fig. 2), differences in population structure are likely to cause differences in average walking speed. The average walking speed predicted for each city according to its age- and sex-composition correlated positively with city size. The regressions of observed walking speed on population size and of walking speed predicted from age structure on population size did no differ significantly in their slopes (p > 0.95). It therefore seems unnecessary to invoke other factors in addition to age composition to explain differences in average walking speeds of pedestrians.