bluuebunny/crossref_metadata_2025_split huggingface dataset:
Matched Counter‐singing Signals Escalation of Aggression in Black‐capped Chickadees (Parus atricapillus)
Authors: Shackleton Scott A. , Ratcliffe L. 
Published: May 2010

AbstractBlack‐capped chickadees (Parus atricapillus) have the ability to shift their songs up and down over a wide range of absolute frequencies. Males can shift their songs over 465 ± 52.9 (SE) Hz. During the dawn chorus, males shift their songs by 80 Hz or more every 41 ± 8.8 (SE) songs, but it appears that males can sing at any frequency within their range. Frequency shifting may allow males to match counter‐sing with rival males; that is, to switch song output to match that of a rival. During simultaneously recorded dawn choruses, however, there was no correlation over time in the frequency of neighbouring males' songs, nor was there a correlation over time in the size of shifts between their songs. Moreover, males did not match the frequencies of songs presented on a played‐back tape at the edge of their territories during the dawn chorus. Matching was observed during some bouts of counter‐singing between males. In these cases, matched counter‐singing was highly associated with escalation of the conflict. We suggest that frequency matching in this species may be a graded signal that allows the singer to direct aggression towards a particular rival.
Habituation, Recovery and the Similarity of Song Types within Repertoires in Red‐winged Blackbirds (Agelaius phoeniceus) (Aves, Emberizidae)
Authors: Searcy William A. , Coffman Stephan , Raikow David F. 
Published: May 2010

AbstractMale red‐winged blackbirds (Agelaius phoeniceus) respond to playback of conspecific song on their territories with the song spread, a graded aggressive display in which males extend their wings to expose their red epaulets while singing. We show that the intensity of song spread display declines with repeated presentation of one song type, and recovers when song types are switched. Recovery is greater for switches between song types that are acoustically dissimilar than for switches between song types that are acoustically similar. Recovery is no different for switches between two song types taken from the repertoires of different males than for switches between song types recorded from the same male. Analysis of acoustic features also indicates that song types recorded from different males are not more dissimilar than are song types from the same male. Our results do not support the idea that repertoires of red‐winged blackbirds are composed of similar song types in order to facilitate individual recognition. Rather, repertoires may be constructed of dissimilar song types, so as to help maintain the response of listeners despite habituation.
Timing of Spawning and Host‐nest Choice for Brood Parasitism by the Japanese Minnow, Pungtungia herzi, on the Japanese Aucha Perch, Siniperca kawamebari
Authors: Baba Reiko 
Published: May 2010

AbstractA field study of the breeding ecology of the Japanese aucha perch, Siniperca kawamebari, and brood parasitism by the Japanese minnow, Pungtungia herzi, on nests of the perch was carried out from 1989 to 1991. Observations of perch nests under natural conditions in 1990 showed that brood parasitism by the minnow was concentrated on host nests in which nest owners had just begun their nesting cycle. When spawned in a perch nest with recently spawned perch eggs, parasite eggs always hatched earlier than host eggs. An experiment with imitation perch eggs in 1991 confirmed that changing colour of host eggs was the cue for the parasites to distinguish between different developmental stages of host eggs. Parasite eggs rapidly disappeared without guarding by a host male (Baba et al. 1990). This loss was caused by predation by fishes. Parasite fry left the nest immediately after hatching, so parasite eggs spawned in a host nest in an early stage should be well guarded until they hatch. In the field, minnows deposited their eggs in perch nests which had larger numbers of newly spawned perch eggs. Since the perch males always deserted their nests when their own eggs disappeared, the parasite's choice of host nests with larger numbers of host eggs may ensure survival of the parasite eggs. The timing of egg deposition and choice of host nest by the minnow appear to be adaptive in terms of brood parasitism on nests of the perch.
Parabiosis and its Proximate Mechanisms in Four Kalahari Desert Tenebrionid Beetles
Authors: Rasa O. Anne E. 
Published: May 2010

AbstractFour nocturnal desert tenebrionids with complete ecological niche overlap as adults form daytime aggregations in burrows in species pairs, Eremostibes with Parastizopus and Herpiscius with Gonopus. Parastizopus and Gonopus were the primary burrowers, the associations being initiated by the smaller partners. Association was not dependent on differences in temperature preference between species nor only on the ecological conditions the larger beetles provided. Partner species were preferred over other tenebrionids of the same size. The proximate segregating mechanism was avoidance of the non‐partner by the smaller species. Avoidance was odour‐mediated in Eremostibes, which also showed an equal odour‐based preference for conspecifics and Parastizopus. Odour profile similarity between the two was hypothesized as the mechanism permitting coexistence. An odour‐mediated preference for Gonopus or conspecifics could not be shown for Herpiscius, nor was Parastizopus odour avoided. Here, a higher relative humidity in inhabited burrows was suggested as the proximate factor promoting association. A possible advantage of aggregation for desert tenebrionids is discussed.
Rats Work for Food They then Reject: Support for the Information‐primacy Approach to Learned Industriousness
Authors: Inglis I. R. , Shepherd D. S. 
Published: May 2010

AbstractThere is good evidence that in many situations, animals prefer to work for food even when identical food is freely available. This phenomenon is called ‘learned industriousness’ or ‘contrafreeloading’ and has been found in several species. This study shows that wild rats will also work hard for contaminated food that they associate with sickness and subsequently reject, even when wholesome food is continuously available at no extra cost.Seven wild rats (Rattus novegicus) lived for 4 wk in cages containing two operant levers and associated pellet dispensers. The rats earned all their food by lever pressing for 45‐mg food pellets on a variable‐interval 10 s (VI10s) schedule in each dispenser. After 1 wk, pellets containing a sub‐lethal dose of an acute rodenticide were available for 12 h (the test period) from the preferred dispenser, before being replaced by normal food pellets. This procedure was repeated 1 wk and 4 wk later. The number of lever presses, pellets delivered, and pellets consumed at each dispenser were recorded for 12 h prior to the test period, during the 12‐h test period, and 12 h after the test period.The rats quickly learned to shift their feeding preference during the test period away from the dispenser that provided the rodenticide pellets. However, during the second half of the test period, lever pressing at this dispenser increased, even though the pellets thereby obtained were still rejected. This divergence between the lever pressing rate and the pellet consumption rate increased over the three trials.This ‘learned‐industriousness’ behaviour is not easily explained by the self‐reinforcing hypothesis, by the obligate species‐specific response hypothesis, or as some artefact of the operant situation. It is suggested that the lever pressing towards the end of the trial, for pellets that were rejected, enabled the animals to gather information about a rare, but very important, event, namely, the presence of dangerous food at a previously preferred and normally safe feeding site. The data lend support to the information‐primacy theory of learned industriousness.
Migratory Orientation of Passerines at Dusk, Night and Dawn
Authors: Åkesson Susanne , Sandberg Roland 
Published: May 2010

AbstractThe orientation of four different species of nocturnal passerine migrants was investigated in spring and autumn by orientation‐cage experiments at dusk, night, and dawn under natural clear skies. Our objective was to examine the orientation behaviour at different periods of a nocturnal migration flight, and to relate the orientation to visual orientation cues (the position of the sun). In robins, the mean orientation was W (autumn) and NW (spring) in the evening tests, N (both autumn and spring) in the middle of the night, and NE (both autumn and spring) at sunrise. The northerly mean orientation at night in both spring and autumn, agreed well with the expected migratory direction for robins (reoriented migration in autumn) as shown by ringing recoveries. A clockwise shift in mean orientation throughout a nocturnal migration flight period (spring and autumn) indicates that the birds may not compensate fully for the azimuthal change of either sun or stars at the horizon. Migratory activity was highest at dusk and dawn, with a reduction in activity in the middle of the night. Spring tests revealed a significantly higher incidence of migratory activity during the second h after sunset than in the autumn tests, indicating longer flights in spring when the birds are approaching the breeding areas. For pied flycatchers, redstarts and lesser whitethroats, the directional choices during spring were between NW and N in evening tests while the dawn experiments showed mean directions towards NE or E. A compromise orientation was observed during both spring and autumn between the expected migratory direction for the season and the position of the sun at both sunset and sunrise, resulting in orientation more to the north of the sun in spring and more to the south of the sun in autumn.
Impact of Predation Risk on Emergence by Little Brown Bats,Myotis lucifugus(Chiroptera: Vespertilionidae), from a Maternity Colony
Authors: Kalcounis Matina C. , Brigham R. Mark 
Published: May 2010

AbstractWhen bats emerge from their roosts in the evening to forage and drink, it appears as though their departure involves brief periods when many individuals emerge interspersed with periods during which few individuals emerge. Clustering is seen in many species of animals and probably has an anti‐predator or information‐transfer function. Regardless of its function, clustering in the emergence of bats may intensify as a result of large numbers of individuals trying to pass through a small exit hole in a short period of time.A total of 31 observations of emergence were made from May to Aug. 1992 and 1993 at a maternity colony of little brown bats (Myotis lucifugus), in Cypress Hills, Saskatchewan, Canada. To determine the effects of a predator on clustering in the emergence, a plastic great horned owl (Bubo virginianus) was used as a predator model and mounted close to roost exits on 8 nights. Recorded calls of a great horned owl were played back towards the roost. The predator model and associated calls did not affect the number of bats that emerged, the median time of emergence, or the degree of clustering in the emergence. There was a significant positive relationship between the extent of clustering in the emergence and the number of bats that emerged. Emergences of more than 25 bats were clustered. Thus, we found no evidence to support clustering during emergence as being an anti‐predator response. However, clustering may be intensified with increased numbers of individuals trying to pass through a narrow space in a short period of time.
Competitive Mate Searching in Thirteen‐lined Ground Squirrels (Mammalia, Sciuridae): Potential Roles of Spatial Memory
Authors: Schwagmeyer P. L. 
Published: May 2010

AbstractMale thirteen‐lined ground squirrels search actively for spatially scattered females during the mating season, and male mate‐location ability is a key determinant of male mating success. These circumstances are predicted to favour male spatial abilities. I conducted a female‐removal study in which females were observed the day before coming into oestrus and then removed for 2 h on the morning they were sexually receptive; males were scored on the sites they visited while searching for removed females. Two hypotheses were tested: 1. males search preferentially at sites where they had encountered the female the day before (i.e. males remember particular locations used by the female); and 2. male searches are guided by long‐distance chemical cues. The results showed little evidence for male attraction to sites used frequently by the female, where residual chemical cues should have been strongest; moreover, males failed to locate oestrous females that were displaced from their home ranges. Consistent with the spatial‐memory hypothesis, male searches were biased toward sites where they had interacted with the female, suggesting that males are capable of using spatial memory to relocate individual females once they become sexually receptive. In addition, both the order of male site visits and male performance on a maze task indicate a potential role for spatial memory in avoiding recently searched sites.
Arena Headings, Vanishing Bearings and Homing Times by Argogorytes carbonarius (Hymenoptera, Sphecidae) after Displacement in Open or Closed Containers
Authors: Schöne Hermann , Schöne Hedwig , Kühme Wolf‐Dietrich , Kühme Lisa 
Published: May 2010

AbstractArena headings, vanishing bearings and homing times were recorded in the digger wasp Argogorytes carbonarius after displacement in ‘open’ or closed (‘box’) containers during two time periods. The periods differed in two ways: 1. wasps were assumed to be inexperienced with the release site during the first period, whereas during the second period they were assumed to be familiar with it; 2. during the first period the arena was open on all sides, during the second it was surrounded by a wall.All wasps chose arena headings and vanishing bearings in or close to the direction of the sun's azimuth during the first period and there was no difference in homing times between ‘open’ and ‘closed’ wasps. These directions also were chosen by all wasps during the second period in the arena and also by ‘open’ wasps at vanishing. ‘Box’ wasps, however, vanished preferably in the sector of home direction. They also reached home faster than in the first period. The results are discussed with respect to landmark orientation and the path‐integration hypotheses.
Suckling in Free‐ranging Beef Cattle — Temporal Patterning of Suckling Bouts and Effects of Age and Sex
Authors: Lidfors Lena M. , Jensen Per , Algers Bo 
Published: May 2010

AbstractSuckling was studied in primiparous cross‐bred beef cattle (Bos primigenius f. taurus) kept on a 1000‐ha grazing area. Observations were made at mean calf ages of 1, 7, 65 and 123 d on 20 calves of each age. Recordings of four different behaviours were made at 12‐s intervals and recordings of butting were made continuously during one suckling bout per calf and age. Two types of sucking, occurring within the same suckling bouts, were distinguished: sucking 1 (rhythmic sucking movements) and sucking 2 (<3 sucking movements followed by release of teat). It was found that sucking 1 made up 18.5–35.2 % of the total suckling time. The highest proportion of sucking 1 was recorded at 65 d of age. Sucking 2 made up 39.3–50.0 % of the total suckling time and it tended to decrease with age. The first recording of sucking 1 was made on average 7.3 (±4.4) recordings after start of a suckling bout and continued for about 5 min thereafter. Sucking 2 was recorded both before, during, and after sucking 1 activity, which is here suggested as being the main period of milk intake. Buttings were recorded during the whole suckling bout, but tended to be most frequent towards the end of the sucking 1 period. Calves did not show any regular suckling pattern at 1 d of age, but at 7 d, a distinct pattern had been established. The calves initiated the suckling bouts, with increasing calf age, more often than the mothers. The suckling bouts were mostly terminated by the calves, especially after 7d of age. Suckling bouts were significantly longer in bull calves than in heifer calves at 7d, but sucking 1 was recorded significantly more often in heifer calves at 123 d. From this study, it is suggested that, in cattle, the temporal patterning of the suckling bout appears to consist of three main parts: prestimulation, milk intake, and post‐stimulation.
Age Structure of Parasitized and Unparasitized Populations of the Field Cricket Teleogryllus oceanicus
Authors: Simmons Leigh W. , Zuk Marlene 
Published: May 2010

AbstractWe compared the age structure of three populations of Teleogryllus oceankus that differed with respect to their exposure to parasitization by an acoustically‐orienting parasitoid fly, Ormia ochracea. Within two unparasitized populations, females were, on average, younger than males. Female age did not vary across the three populations but males were younger, on average, in the parasitized population. Sexual differences in age structure within populations may arise due to differential risks associated with pair formation. Because we only know of a single parasitized population from which we can sample, we can not be sure that some other ecological difference does not account for the observed variation in age structure across populations. However, the decreased age of males in the parasitized population is at least consistent with the notion of viability selection on males.
Evidence of Pre‐mating Reproductive Isolation in Two Allopatric Populations of the Vlei Rat, Otomys irroratus
Authors: Pillay N. , Willan K. , Meester J. , Cooke J. 
Published: May 2010

AbstractLaboratory experiments were undertaken to ascertain whether or not individuals of two allopatric Otomys irroratus populations (Kamberg and Karkloof) distinguish between mates from the same (homotype) and the other (heterotype) population. The study aimed to establish the existence of pre‐mating reproductive isolation mechanisms between the two populations. In both ‘whole‐animal choice’ trials and olfactory discrimination tests, all females significantly preferred homotype stimulus males or odour. Although males of both populations preferred homotype females, males were less discriminating at the start of experiments, possibly because of increased exploratory drive at this time. Furthermore, Kamberg males demonstrated equal preference for both stimulus females during the dark phase of the light cycle; no explanation is given for this phenomenon. Overall, the results indicate the existence of population‐specific courtship behaviour, with olfactory cues apparently playing an important role in mate recognition. It is therefore possible that, should representatives of the two populations meet in nature, they may be reproductively isolated through behavioural means.
Orientation by the Bat Phyllostomus discolor (Phyllostomidae) on the Return Flight to its Resting Place
Authors: Höller Patrik 
Published: May 2010

AbstractBats have a well‐developed spatial memory, which enables them to navigate even when the conditions are extremely unfavourable for orientation. However, if they were to adhere too strictly to a flight path planned from memory and independent of exteroceptive control, they would be in danger of colliding with unexpected obstacles. In the experiments described here, Phyllostomus discolor that had familiarized themselves with an octagonal flight arena developed a clear preference for certain resting sites and were able to fly to these sites without recourse to external orientational cues. Proximal and distal cues were ruled out separately, by rotating the direction in which the bats started out within the arena or by rotating the entire arena in the room. Furthermore, by marking the preferred site with a visible identifier it was shown that even when additional aids to orientation are available, the bats do not make use of them. On the other hand, all the bats tested responded immediately to a reduction of the landing area, demonstrating that they are capable of incorporating exteroceptive information into the orientation process in certain circumstances.
Post‐conflict Social Events in Wild Mountain Gorillas (Mammalia, Hominoidea). I. Social Interactions between Opponents
Authors: Watts David P. 
Published: May 2010

AbstractResearchers have documented elevated rates of affinitive interaction between opponents shortly after aggressive conflicts, or reconciliation, in many primate species. Reconciliation may ameliorate the immediate negative effects of aggression by reducing the chance of further aggression between opponents and thus reducing tension, and may avert or repair damage to long‐term social relationships important to the animals' fitness. Data on post‐conflict interactions between opponents in two groups of wild mountain gorillas(Gorilla gorilla beringei)fail to show reconciliation after conflicts between females, between males, or between immatures, but females seem to commonly reconcile themselves with males after receipt of male aggression. Females and subordinate males often avoid same‐sex opponents after conflicts. Females commonly retaliate against female aggressors, and post‐conflict rates of aggression between females are higher than baseline levels. Females may not need to achieve reconciliation with each other because relationships between co‐resident relatives are resiliant, while those between non‐relatives are mostly neutral to antagonistic. Males are, however, important social partners and protectors of females, and female transfer is common. Thus, the results strongly support the ‘important relationships’ hypothesis for the function of reconciliation.
Post‐conflict Social Events in Wild Mountain Gorillas. II. Redirection, Side Direction, and Consolation
Authors: Watts David P. 
Published: May 2010

AbstractInevitably, members of primate groups sometimes have aggressive contests with each other. Targets of aggression can engage in several types of interaction with third parties to ameliorate its adverse effects. They can redirect aggression, which may reduce the risk of further aggression from the initial opponents and reduce tension, or they can initiate affinitive interactions with third parties, in order to seek protection or reassurance. They can also receive reassuring acts from them (‘consolation’). Researchers have documented high levels of redirection in many primate species, but consolation is thus far known only in chimpanzees. Data on post‐conflict social interactions between targets of aggression and third parties in two groups of wild mountain gorillas(Gorilla gorilla beringei)show that immatures and subordinate males, but not females, redirect aggression at high rates. Furthermore, immatures seek affinitive interactions with their mothers, and adult females seek them with adult males, at elevated rates. Affinitive interactions between females and males seem mainly to have a protective function and are associated with decreased risks of further aggression between female opponents. Redirection by females after female‐female conflicts may be uncommon because targets commonly retaliate against aggressors. Males may offer females protection and consolation as services, and the results support the argument that such services are important when dominance relationships between females are often undecided and retaliation between opponents is common.