bluuebunny/crossref_metadata_2025 huggingface dataset:
Territorial Advertisement and Mate Attraction in the Bat Pipistrellus pipistrellus
Authors: Lundberg Karin , Gerell Rune
Published: May 2010

A South Swedish population of the vespertilionid bat Pipistrellus pipistrellus was studied by means of bat boxes from April to the beginning of October in 1984. The mating system of the pipistrelle bat is a “resource defence polygyny”. Three territorial males were studied to determine the relative importance of two potential resources, food and roost sites, for male reproductive success. The day roost was found to be the crucial resource for the male's chances to get access to females. A territorial male advertises the location of his day roost to the females by a songflight display. The male who spent most time in songflight display was visited by the greatest number of females.
Species Recognition by Song in the Veery (Catharus fuscescens: Aves)
Authors: Nally Ralph C. Mac , Weary Daniel M. , Lemon Robert E. , Lefebvre Louis
Published: May 2010

Territorial male veeries (Catharus fuscescens) were presented with three series of reorganised songs to determine the functional properties of song structure. Songs consist of three parts: a low frequency initial phrase, a higher frequency middle phrase, and again a lower frequency end phrase. The latter two consist of vibrato syllables. Three series of experiments were performed, using various combinations of song syllables. In Series I, songs consisted of repetitions of a single syllable, one from each part of the song. Veeries responded to syllables from the middle and end phrases as to normal songs, both in localisation and in vocal responses. However, they showed little localisation and vocalisation responses to the introductory syllables. In Series II and III, veeries responded significantly more to songs in which syllables from the middle and end phrases were presented in proper sequence, rather than not. The minimum requirements for intraspecific recognition were determined in relation to the number and order of syllables in the song.
Avian Helpers at the Nest: Are they Psychologically Castrated?
Authors: Reyer Heinz‐Ulrich , Dittami John P. , Hall Michael R.
Published: May 2010

In cooperatively breeding pied kingfishers (Ceryle rudis) blood plasma levels of LH and testosterone (T) were compared among three types of males: breeders, primary (= related) helpers and secondary (= unrelated) helpers. These categories did not differ in LH, but primary helpers had significantly lower T titers than breeders and secondary helpers. The low levels were paralleled by small gonad sizes and no sperm production, suggesting that primary helpers were not able to fertilize eggs.

The differences in T levels could neither be attributed to stochastic variation nor to differences in age, stress, molt, or reproductive activities. The most likely explanation arises from the observation that primary helpers are behaviorally dominated by breeders, whereas secondary helpers are not.

The adaptive significance of low T titers and reduced fertility as a result from being dominated is discussed on the basis of empirical data and theoretical models. We argue that primary helpers in the pied kingfisher, and subordinate helpers in many other cooperative breeders, apparently are not “unwillingly” suppressed in their sexual development; they rather “choose” delayed reproduction when the costs from sexual competition with breeders exceed the benefits from cooperative breeding. In contrast, helpers that benefit more from competition than from cooperation, as secondary helpers do, cannot be expected to show reduced fertility.
Social Organization of the Bat,Carollia perspicillata(Chiroptera: Phyllostomidae)
Authors: Williams Charles F.
Published: May 2010

The social organization of the frugivorous bat,Carollia perspicillata, was studied by frequent visual censuses of a population in northwestern Costa Rica. A pattern of resource defense polygyny was found, based on male defense of roosting sites in caves and hollow trees. Protected roost sites were apparently limited. Harem compositions were relatively labile and female groups did not appear to be cooperative. Harem males were among the oldest and heaviest members of the population and these attributes were also correlated with the size of the harems they defended.
Cultural Diffusion of a Novel Food‐finding Behaviour in Urban Pigeons: an Experimental Field Test
Authors: Lefebvre Louis
Published: May 2010

The cultural diffusion of a novel food‐finding behaviour, piercing the paper cover of a box containing seed, was experimentally provoked in two flocks of pigeons (Columba livia): a closed aviary flock and an open urban flock. In the urban flock, piercing behaviour spread to 24 previously naive individuals. The rate of cultural diffusion was more rapid in the urban flock than in the aviary. In both situations, many individuals simply fed from the discoveries of birds that pierced, but this effect slowed diffusion less in the open urban flock because experienced piercers left the flock and naive birds entered it. Individual trial‐and‐error learning and natural shaping can be ruled out as mechanisms of diffusion in the present case.
The Feeding Behaviour of a Sit‐and‐Wait Predator, Ranatra dispar (Heteroptera: Nepidae): The Combined Effect of Food Deprivation and Prey Size on the Behavioural Components of Prey Capture
Authors: Bailey Paul C. E.
Published: May 2010

Previous work has shown a significant effect of hunger on the predatory behaviour in a sit‐and‐wait predator Ranatra dispar, the water stick insect (Bailey 1986 a). The experiments reported here were designed to investigate the combined effect of prey size and hunger on the predatory behaviour in order to identify which behavioural components are effected. It was found that the hunger level determines whether R. dispar will initially be aroused or not but the distance at which the arousal takes place is influenced by the size of the prey. This is believed to reflect the capacity and interrelation between visual and mechanoreceptor, sensory organs. The decision to strike at a prey is, although again influenced by hunger, significantly affected by prey size. The distance of the prey when the strike takes place is affected by hunger not the size of the prey. The outcome of the strike is determined by the size of the prey, not the hunger level of the predator. This is believed to reflect the relationship between strike trajectory, leg morphology and prey size. Food deprivation affects all components of predatory behaviour of R. dispar leading up to prey capture, by increasing not only distance of response but also the number of strikes, hits, and captures per unit presentation of prey. It does not affect capture efficiency which remains at about 70 to 80 %. Food deprivation also increases the range of prey sizes that R. dispar responds to and attempts to capture. The effect of food deprivation is considered to reflect a motivational change in responsiveness to particular prey stimuli usually described as a sensitization of particular stimulus‐response relations rather than the food deprivation affecting the sensory mechanisms. The predatory success in relation to size of model prey suggested a hypothetical size that could be captured, irrespective of predator motivational level, which is based primarily on the relationship between the shape of the grasping leg and size of prey.
Seasonality of Mobbing Intensity in the Pinyon Jay
Authors: Cully Jack F. , Ligon J. David
Published: May 2010

In the wild, pinyon jays (Gymnorhinus cyanocephalus) mob owls at all times of year, but our observations of wild birds suggested that the mobbing response was strongest during the breeding season. To test this, we placed four groups of five wild caught adult pinyon jays in environmental chambers during late autumn when their testes were regressed. These birds received photoperiods of 12, 12, 13 and 14 h for 30 days prior to being exposed singly to a live great horned owl (Bubo virginianus). Three groups of five birds were maintained under natural photoperiods in outdoor aviaries and were tested with the owl in Aug., Sep. and Nov. Birds on long artificial photoperiods mobbed more strongly than birds exposed to shorter photoperiods. The jays under natural photoperiods showed the opposite response: those tested in November mobbed significantly more strongly than birds tested in August. Jays with the weakest mobbing responses were molting, and those with the strongest responses seemed to be closest to reproductive readiness. There was no correlation between gonad size and mobbing intensity, but our results suggest a strong relationship between reproductive readiness and mobbing intensity in pinyon jays.
Mallard Duckling Response to Distress Calls with Reduced Variability: a Constraint on Stereotypy in a “Fixed Action Pattern”
Authors: Gaioni Stephen J. , Evans Christopher S.
Published: May 2010

Mallard duckling distress calls consist of a series of stereotyped notes and are usually given in calling bouts. When two or more ducklings are separated from their brood and begin to distress call, they alternate their calls, with each bird inhibiting its own vocalizations during those of another bird. In two playback experiments we reduced the acoustic variability found in distress calls and examined the effect this had on the alternation response of ducklings. In Exp. 1, one treatment involved an unedited tape‐recording of a natural bout of 8 distress calls. Three other treatments involved edited tapes in which (a) the original 8 calls were presented, but at a constant intercall period, or (b) a single call was repeated 8 times at the natural (variable) intercall periods, or (c) a single call was repeated 8 times at a constant intercall period. The two tapes on which the same call was repeated 8 times elicited significantly weaker alternation responses from ducklings than the two tapes on which the original 8 calls were presented; the manipulation of the intercall period had no significant effect on the alternation response. In Exp. 2, analogous manipulations were performed to remove the variability between the notes within a single distress call or between the internote periods within that call. Ducklings alternated significantly better with the unedited distress call than with the distress calls in which variability had been removed. These results suggest that the variability found within many “Fixed Action Patterns” may serve an important antihabituation function.
Rate of Supply of Sugar Solution and Behaviour of Collector Wasps (Paravespula germanica)
Authors: Pflumm Walter
Published: May 2010

The rate of supply of sucrose solution at an artificial food source was varied by means of a pump, while the concentration of the solution and the temperature at the food source were kept constant. The behaviour of the collector wasps was found to change in correlation with the supply rate, in several respects.

As rate of supply increases

the duration of sojourn at the food source decreases;

the volume of solution removed per h increases;

the number of single visits during a sojourn and per h decreases;

the duration of single visits increases, except that at extremely high supply rates the single visits become shorter.

The waiting time (Saugwartezeit) does not depend on supply rate.

Comparison of these wasp data with related observations of honeybees (Apis mellifera) supports inferences regarding the motivation of collector wasps and, in view of the frequency of their single visits, about their suitability as potential pollinators of the flowers from which they collect.
Rattlesnake Rattles and Burrowing Owl Hisses: A Case of Acoustic Batesian Mimicry
Authors: Rowe Matthew P. , Coss Richard G. , Owings Donald H.
Published: May 2010

Burrowing owls nest and roost in ground squirrel burrows, a refuge frequently used by rattlesnakes. When cornered, burrowing owls produce a vocal hiss that has been suggested to mimic a rattlesnake's rattle. To test this hypothesis, we conducted an experiment using two populations of Douglas ground squirrels that differ in their evolutionary histories with rattlesnakes. Both squirrel populations were sympatric with burrowing owls. Squirrels from a population subjected to natural selection by rattlesnakes treated the owl hiss as cautiously as they did the rattle, and responded with greater caution to the rattle and hiss than to two control sounds. Squirrels from a rattlesnake‐free area, however, were less systematic in differentiating among the rattle, the hiss, and the control treatments. Such variation between ground‐squirrel populations provides evidence that the burrowing owl's defensive hiss currently functions as an acoustic Batesian mimic of a rattlesnake's rattle.
Female Cowbird Song Perception: Evidence for Different Developmental Programs within the same Subspecies
Authors: King Andrew P. , West Meredith J. , Eastzer David H.
Published: May 2010

Female Molothrus ater from Oklahoma at the subspecies border with M.a. obscurus were tested for their discrimination of songs from their native area and from Austin, Texas. This 400‐km distance is characterized by a structural shift in the male cowbird's inclusion of the mid‐song element, a structure found in the songs of Austin and the more southern M.a. obscurus populations but not in the songs of Oklahoma or the more northern and eastern M.a. ater populations. Females captured in Oklahoma showed a strong preference for their native song variants. In contrast, captive females from Oklahoma who were housed with Austin males showed no preference, responding equally to Oklahoma and Austin song. The songs of the Austin males housed with the Oklahoma females did not differ acoustically from those of wild Austin males. Thus, a different developmental pattern may operate in this region than in eastern populations of M.a. ater: here, the female may be more open to social influence.
Functional Aspects of Singing in Male and Female Uraeginthus bengalus (Estrildidae)
Authors: Gahr Manfred , Güttingery Hans‐Rudole
Published: May 2010

Both sexes of the African estrildid species Uraeginthus bengalus sing regularly. Song structure and the context of singing were studied in males and females under aviary conditions. It was found that:

Males and females have a similar song differing merely in strophe length, medial length being 1.38 ± 0.47 s in females and 2.58 ± 0.63 s in males.

Males sing during nesting, laying, incubation and broodcare, but also long before, with a remarkable activity peak at the beginning of incubation, whereas females hardly sing at all during the egg‐laying and incubating phases, and their singing peak is long before laying starts.

In 52 % of all cases the male responds to his female's song during the pre‐incubation period. His reaction includes singing, courtship display and elements introducing copulation.
Reproductive Behaviour and Parental Care of Helobdella striata (Hirudinea, Glossiphoniidae): a Leech that Feeds its Young
Authors: Kutschera Ulrich , Wirtz Peter
Published: May 2010

The leech Helobdella striata Kutschera (1985) is a protandrous hermaphrodite. It copulates by hypodermic injection: a spermatophore is attached to the skin of the partner and sperm injected through it. During their male phase, the leeches copulate repeatedly and with different partners.

In the female phase, 3 to 7 cocoons, each containing 2 to 20 eggs, are produced from the female gonopore and attached to the ventral side of the parent. The larvae which hatch from these eggs cling to the ventral side of the parent. After they have used up their yolk supply and have developed into juvenile leeches they remain attached to the parent for a further three weeks. Helobdella striata capture Tubifex worms and give them to the young they carry. This access to food allows the juveniles to grow from a size of 1 mm to 6 mm length while being carried and protected by the parent.

H. striata reared in isolation produce young; at present it is not known whether they reproduce by parthenogenesis or by self‐fertilization.

The probable phylogenetic development of parental care patterns in the Hirudinea is reviewed.
Constant Proportions of Mixed Singers in Tree Creeper Populations (Certhia familiaris)
Authors: Thielcke Gerhard
Published: May 2010

Of 205 tree creeper males in 7 syntopic populations 69 (34%) were mixed singers. Of these, 17 sang complete short‐toed tree creeper song, six sang incomplete and 46 sang only one element thereof. In three populations (Neuenburg, Wendhausen, Kenzingen) there was a dominance of mixed singers, in another population (Lorettowald) a large proportion was present. Only one mixed singer was found in each of the last three populations (Freiburg, Bodanrück, Seerücken).

Three populations had high proportions of mixed singers between 1960 and 1970 and later in 1983 and/or 1984. Two other populations had only one mixed singer in both periods. A small isolated population of 4 to 5 tree creeper pairs (Lorettowald) with many mixed singers was surrounded by populations with low proportions of mixed singers (Bodanrück, Seerücken).

The proportions of different forms of mixed songs in Neuenburg in 1983 and 1984 were almost identical to those in the 1960′s whereas highly significant changes occurred in Kenzingen.

The pronounced differences in the songs of tree creepers and short‐toed tree creepers probably do not result from contrast reinforcement. Mixed song is also probably not caused by character (vocal) convergence according to Cody (1969) and Dobkin (1979). Instead, it seems more probable that mixed song results from errors in copying, which are passed on to the next offspring by cultural transmission.
Freeze Branding in Fish, a Method for Eliminating Colour Patterns at the Skin Surface
Authors: Hert Eva
Published: May 2010

Freeze branding with dry ice turned out to be a very suitable method for eliminating pigments in fish. Photographic documentation shows the process of fading of lipophores in the anal fin of an African mouth brooder.
Adaptation of Amplitude Structure of Songs to Propagation in Field Habitat in Song Sparrows
Authors: Shy Eyal , Morton Eugene S.
Published: May 2010

We examined the influence of two habitats, old field and small islands on a river, on the propagation of amplitude and frequency characteristics of song sparrow songs.

At 27 m from the source, songs originally recorded in the field degraded significantly less there than over water in the river. At that distance, songs recorded on the river also degraded less in the field than over water, but the differences were not significant. At 54 m from the source, songs recorded at both sites also tended to degrade more on the river than in the field, but the differences were not significant. Songs from the two habitats differed significantly in the total number of amplitude peaks in a song, in song duration, in maximum frequency, and frequency range. They did not differ significantly in the fraction of peaks in the upper amplitude range, and in the width of the amplitude range.

The results suggest that, in fields, a more typical habitat, songs are locally adapted to communication at about 30 m but poorly so at 60 m from the source. We suggest that this is related to the territory size of birds in the field. The results are discussed in relation to the ranging hypothesis (Morton 1982) that predicts that the least degraded song types would be selected for, and that listeners use degradation to estimate their distance from singers.
Preference for Vertical‐striped Backgrounds by the Oyanirami Coreoperca kawamebari, a Freshwater Serranid
Authors: Kohda Yasutoshi , Watanabe Munetaka
Published: May 2010

The oyanirami Coreoperca kawamebari displays cross‐stripes on its body when afraid; this pattern is also used as a signal to conspecifics. The fish preferred to rest at vertically‐ rather than horizontally‐striped sites, and transparent stripes were more attractive than opaque ones, but no inclination was shown for any particular stripe widths. It is hypothesized that the cross‐stripes first evolved as a pattern furthering crypticity among the vertical aquatic habitat plants, secondarily as a signal to conspecifics.
Genetic and Experiential Features in a Case of Cultural Transmission in the House Mouse (Mus musculus)
Authors: Mainardi Danilo , Mainardi Marisa , Pasquali Antonio
Published: May 2010

The present study analyses the capacity of house mice (Mus musculus) to solve a problem, consisting in opening a door which must be rotated 50 times in the same direction to allow access to the food reward. This capacity emerged spontaneously in 4.8 % of 500 animals belonging to a random bred Swiss population, tested beforehand. The experiment then investigated the effects of genetic and experiential (social) factors on transmission of this capacity from one individual to another. Five groups of approximately 70 animals each were compared: a) controls; b) animals with no experience of the problem but offspring of parents able to solve the problem spontaneously; c) animals with experience of the problem being offspring of parents able to solve it spontaneously; d) naive offspring of parents incapable of solving the problem spontaneously; e) animals with experience of the problem and offspring of parents incapable of solving it. The results showed considerable effects both of genetic and experiential (social) factors with values ranging from only 3.9 % of successful naive mice among offspring of unsuccessful individuals, up to 32.3 % of successful offspring of successful parents, reared with a mother who solved the problem several times in their presence.
Promiscuous Mating among Blue Monkeys in the Kakamega Forest, Kenya
Authors: Cords Marina , Mitchell Betsy J. , Tsingalia H. M. , Rowell T. E.
Published: May 2010

13 females and 12 of 19 males present in a group of blue monkeys (Cercopithecus mitis stuhlmanni) mated promiscuously during an intense bout of sexual activity. Several aspects of their behavior are considered as mechanisms for determining mating patterns. Estrus synchrony coincided with a multi‐male influx, allowing promiscuity. The length of stay and rank of an incoming male were correlated with his number of copulations in the group, while the original resident and highest ranking male was never seen to mate. Thus, although agonistic behavior, especially among males, affected mating success, it did not guarantee copulations. Adjustments of position relative to other individuals also affected who mated with whom. These and earlier observations suggest that there may be more than one way to be successful in mate competition, and lead us to question whether the kinds of behavior we observed have merely a reproductive function.
Role of Early Experience in Mixed‐colony Odor Recognition in the Ants Manica rubida and Formica selysi
Authors: Errard Christine
Published: May 2010

An experimental model of mixed societies of ants was used to test the effect of early conditioning to a mixed colony odor on interspecific recognition after various periods of separation, with Manica rubida (Myrmicinae) and Formica selysi (Formicinae). Recognition was evaluated by recording the behaviour of individuals interacting after they had been grouped in mixed societies. The observed frequency and nature of these interactions depended on the way the societies were made up (whether with the same or different species, and with or without previous exposure to that species). The recognition displayed by the workers was much more altered in interspecific than in intraspecific groupings, which is evidence of the existence of some species recognition. In addition, the adult is capable of recognizing the olfactory characteristics of its group, the group odor would be a mixture of individual odors.
The Biology of a Subtropical Population ofHalictus ligatusSay (Hymenoptera; Halictidae)
Authors: Packer Laurence
Published: May 2010

In the subtropical climate of the Florida Keys,Halictus ligatushas a continuously brooded, multivoltine colony cycle. This results in young gynes and workers being active at all times of year, potentially causing problems for males with respect to mate choice. Males responded to females by ignoring them, touching them briefly or by knocking them off of flowers into the surrounding vegetation, where mating takes place. Over half of the females at this locality are mated although males prefer large, young individuals. Multiple mating of females does occur. Males search for females around flowers and, less commonly, near nest sites. Because females of this social insect offer varied returns to male mating effort, it is not surprising that males exhibit mate choice.
Feeding Territoriality in Female Northern Bats, Eptesicus nilssoni
Authors: Rydell Jens
Published: May 2010

A nursing colony of 26 Northern bats was studied in South‐Central Sweden. The foraging behaviour is described with emphasis on social interactions on feeding grounds. The bats foraged in small feeding territories used night after night. The reproducing females defended feeding territories against other colony members as well as non‐members by means of aggressive chases and vocalizations. A linear dominance order occurred among the females that regularly visited a feeding site. Intrusions into already occupied feeding sites resulted in territorial conflicts (47 %), passive departure by one or both opponents (43%) or mutual acceptance (11%). Conflicts occurred throughout the summer, but became less frequent in July when insect abundance increased.
Sex Differences in Plasma Steroid Concentrations and Singing Behaviour during Ontogeny in Canaries (Serinus canaria)
Authors: WEICHEL KLAUS , SCHWAGER GABY , HEID PETRA , GÜTTINGER HANS R. , PESCH ANNEGRET
Published: May 2010

The relationship between the ontogenetic pattern of sex steroids and the differentiation of sexually dimorphic song in canaries of both sexes was studied. Songs were recorded to assess the temporal course of different developmental stages. Song parameters such as length and frequency of tours were measured. Parallel to behavioural observations, all birds were bled regularly every 20–30 days from the age of 15 days to day 235. The plasma samples were analyzed by RIA to measure testosterone (T), dihydrotestosterone (DHT) and estradiol‐17β (E2). The following results were obtained: 1) In young male canaries we distinguish three different stages of song development: subsong, starting at the age of 30 days, plastic song, and juvenile autumnal song finally giving way to the rigid and stable utterances of the reproductive period in next spring. During ontogeny the length and frequency of tours increase gradually. Female canaries were not observed singing regularly during their first year of life, whereas males sing very frequently. 2) Both sexes show tendencies to elevated titres of testosterone before the onset of juvenile moult. These titres correspond to those of paired males during the reproductive cycle. Song development is not correlated with the ontogenetic pattern of testosterone: the process of crystallization from the amorphic songs uttered by juveniles progresses gradually to the autumnal song in late autumn, when the titres of T in males are low (< 200 pg/ml). Female T and DHT levels during ontogeny correspond to those of the males. 3) There are sex differences in the estradiol pattern. Males show higher titres in several stages of development than females.
Recognition of Queen Larvae by Worker Honey Bees (Apis mellifera)
Authors: NOONAN KATHERINE C.
Published: May 2010

Colonies of honey bees, Apis mellifera, from two patrilines (cordovan and dark) were established and observations were made on the behaviour shown by the worker bees in rearing queen larvae within their colonies. The relationship among the bees within these colonies was either r = 3/4 (super‐sisters) or r = 1/4 (half sisters). The worker bees showed preferential care to the queen larvae that were of their own patriline. Workers of the cordovan patriline showed a stronger preference for larvae of their own patriline than did the dark workers. Cordovan workers also showed a higher rate of visitation, indicating behavioural differences between the patrilines. These results suggest that kin selection is operating on honey bee behaviour used in rearing reproductives.
Social Behavior of the African Electric Catfish, Malapterurus electricus, during Intra‐ and Interspecific Encounters
Authors: Rankin Catharine H. , Moller Peter
Published: May 2010

Using a “resident‐intruder” protocol, we observed spacing strategies and agonistic behavior in the African electric catfish, Malapterurus electricus, as it encountered conspecifics and equal‐sized members of three other species (a bichir, a tilapia, and goldfish). M. electricus defended a familiar shelter site. The catfish employed different locomotor and electric behavioral strategies, depending on the intruder species. In conspecific interactions, M. electricus engaged in ritualized fights, including lateral and open‐mouth displays, occasionally escalating to bites. Electric organ discharges were rare. In contrast, in interspecific encounters contacts were limited to brief touches with frequent use of electric organ discharge volleys. Our data indicate that M. electricus discriminates between con‐specifics and other species. We postulate that such a discrimination may be mediated by chemical and/or mechanical cues.
Early Experience Determines the Song of the Chiffchaff (Phylloscopus collybita)
Authors: Thielcke Gerhard , Zimmer Ute
Published: May 2010

7 of 8 juvenile chiffchaff males, caught between Jul. 28 and Aug. 18 in southwest Germany, developed song in acoustic isolation which corresponded to the song of their nesting areas (Figs. 1, 2, 3). They must have learned this song institution between about 44 and 100 days of age. One captured bird with divergent syllables probably had not finished crystallizing its song at the end of the experiment.
Courtship Disruption at the Lek in the Guianan Cock‐of‐the‐Rock
Authors: Trail Pepper W. , Koutnik Debra L.
Published: May 2010

During 4 seasons of study at a large (55 male) lek of Guianan cock‐of‐the‐rock (Rupicola rupicola) in Suriname, we observed 3906 female courtship visits. Of these, 1171 (30.0%) were disrupted by adult males, 430 (11.0%) were disrupted by yearling males, and 289 (7.4%) were disrupted by females. This is one of the highest levels of courtship disruption reported among lek‐breeding birds. Disruption was performed by approximately half of the territorial adult males each year, spanning the full range of mating success and territory location.

Courtship disruption occurs in two contexts among adult male cock‐of‐the‐rock. The most frequently performed disruptions were low‐intensity supplantings and threats directed toward more successful territorial neighbors. These appear to reflect attempts to improve or maintain territorial status within the male social organization. Less commonly, individual males persistently directed high‐intensity disruption toward specific females. Such males succeeded in redirecting the females' mate choice to themselves in 27% of instances. We found no support for the hypothesis that females choose males on the basis of their immunity to disruption. Reproductively successful males received disruption at proportionately equal or greater levels than unsuccessful males.

Courtship disruption by yearling cock‐of‐the‐rock occurred primarily in the context of practice courtship by these non‐territorial immatures. Disruption by females was uncommon and did not appear to deny or even delay access to any male.

We discuss these results in the light of recent proposals concerning the role of courtship disruption in the operation of mate choice and the determination of male dispersion on leks.
Vocal Cues in Cotton‐top Tamarin Play Vocalizations1
Authors: Goedeking Philipp , Immelmann Klaus
Published: May 2010

In cotton‐top tamarins (Saguinus o. oedipus) one finds a significantly increased frequency of occurrence of playful wrestling, where the respective vocalizations are characterized by a high degree of instability in the contour of the fundamental frequency. Approximately 20 s after these instable pitched vocalizations, however, frequency of occurrence is significantly reduced. The ethometric methods and those for the detailed analysis of vocalizations are explained in this paper. It is hypothesized that instable pitch expresses some kind of emotion involved in playful interactions.
Factors Influencing Shell Investigation in the Hermit Crab, Pagurus bernhardus
Authors: Neil Susan J. , Elwood Robert W.
Published: May 2010

Laboratory experiments in which littoral specimens of Pagurus bernhardus were offered shells with blocked apertures showed that animals occupying poor quality shells approached and contacted new shells more quickly, spent longer investigating them, and spent a greater proportion of that time in active exploration of them than did animals in better shells. Animals spent less time investigating shells smaller than the optimal size than they did good quality shells, even though none of the shells could be occupied. Crabs spent less time investigating a new shell when a visible stimulus (a stone, a shell or another crab) was present. Shell assessment was thus influenced by the quality of the crab's own shell, the quality of the offered shell and the presence of other features in the animal's environment.
Social Behavior of Males and Simultaneous Hermaphrodites in the Lantern Bass
Authors: Fischer Eric A. , Petersen Chris W.
Published: May 2010

Serranus baldwini (Serranidae), the lantern bass, is a small, gleaning carnivore found in turtle grass and rubble substrates in the Caribbean. Small S. baldwini are simultaneous hermaphrodites, but large members of this species are males. The males patrol territories in which several hermaphrodites reside. Hermaphrodites spawn as females with the resident males and rarely spawn as males themselves. Unlike the pattern in reciprocating hermaphrodites, courtship is largely a male function in S. baldwini. Males are much more active and aggressive than are hermaphrodites. In reciprocally spawning species, interactions among mates are more symmetrical. The behavior patterns found in the serranines reflect the differences in mating systems in a manner similar to that found in other organisms and is consistent with current mating system theory.
Cooperative Hunting and its Relationship to Foraging Success and Prey Size in an Avian Predator
Authors: Hector Dean P.
Published: May 2010

Aplomado falcons (Falco femoralis) often hunt in pairs when chasing birds; 29% of 349 hunts observed in eastern Mexico involved mated pairs of falcons simultaneously chasing the same prey animal; and 66% of 100 hunts of birds were tandem pursuits. Although true cooperative hunting is uncommon in birds of prey, hunts by pairs of Aplomado falcons consistently showed signs of cooperative behavior such as use of a simple coordinative signal, and some division of labor between participating individuals. Pairs were more than twice as successful as solo falcons hunting birds (44% vs. 19%), however, there was no evidence that cooperative hunting increased the range of feasible prey sizes. The frequent use of cooperative foraging in this and similar species may relate to necessities of efficient nest defense, and food and nest procurement in savannas inhabited by a diversity of nest‐site predators.
Avian Predation on Heteroptera: Experiments on the European Blackbird Turdus m. merula L.
Authors: SCHLEE MARSHA A.
Published: May 2010

Heteroptera are often preyed upon by birds in spite of their noxious scent‐gland secretions. Consequently, the question is raised as to whether or not birds possess physiological immunity to the secretions, simply tolerate any discomfort, or use special prey‐handling techniques.

This study reports the responses of 12 European blackbirds, ranging in age from 45 days to 8 years, to 583 adult Heteroptera from 8 species (Coreidae, Pyrrhocoridae, Pentatomidae). The main results are:

(1) The non‐aposematic bugs were eaten (63.1%) far more often than the aposematic ones (16.3%). Palomena prasina and Coreus marginatus had the highest edibility rank; Eurydema ornatum, the lowest. The highest rate of predation took place in the youngest birds.

(2) The metathoracic secretion of 4 of the pentatomid species functioned as a topical contactirritant of the buccal cavity, head and eyes; the other test species provoked little or no discomfort. Some birds showed little sensitivity to the secretions. Among the behaviors induced were head‐shaking, dirt‐eating, respiratory difficulties, head‐scratching, and eye‐blinking. One bird engaged in “anting” with Graphosoma lineatum. No intoxication resulted from ingestion of the bugs.

(3) Several prey‐handling techniques were used: seize, mandibulate, peck, shake, and wipe. The last three are probably correlated with the distinct physical properties of the Heteroptera. In general, the bugs were handled more during the first trials than during the last. The blackbirds learned to modify their handling techniques in such ways as to avoid or minimize exposure to the insects' secretions.

(4) The caustic action of the scent‐gland secretion did not constitute an effective deterrent. Rejection of the Heteroptera was primarily based on gustatory cues.
Role of the Carrier Frequency in the Territorial Songs of Oscines
Authors: BREMOND JEAN‐CLAUDE
Published: May 2010

Birds cannot emit acoustic signals of very low frequencies. To code a message with such signals they shift them upwards by using a frequency modulation. The new frequency chosen for transmission is the carrier. Its value is adapted to the phonetic and sensory capacities of the bird, as well as to the characteristics of the channel.

The code does not give any significance to the carrier alone, but determines its value. Modulation and demodulation must be applied to carriers of the same value.

The code also determines the carrier wave shape, i.e. its spectrum. Any alteration of this shape reduces decoding possibilities.

To code and decode messages with frequency modulated signals, birds use the same strategies as humans.
Mother‐young Relationships in Captive Ungulates: Behavioral Changes over Time
Authors: Ralls Katherine , Lundrigan Barbara , Kranz Karl
Published: May 2010

Ungulates are frequently classified into two groups: the “followers”, in which young initially stay close to their mother and the “hiders”, in which young remain at some distance from their mother, often concealed in vegetation. To examine differences in mother‐young behavior between the follower and hider groups and among species within these groups, we studied 63 mother‐young pairs, representing 22 ungulate species, for 7 weeks after birth of the young. The follower group had consistently higher scores than the hider group on measures of mother‐young association, and lower scores on the percentage of time the young spent lying; however, there was considerable variation within each group.

In follower species, two measures of mother and young association decreased over time. In hiders, contact between mother and young did not increase over time although the distance between them, while both were lying, decreased. This reduction in the resting distance between mother and young did not always coincide with other changes possibly indicative of the end of the hiding period. The amount of time young hiders spent lying decreased over time.
Choice of Opponents during Competition for Food among American Goldfinches
Authors: Popp James W.
Published: May 2010

Captive American goldfinches (Carduelis tristis) were observed competing over access to a feeder. The goldfinches did not approach the feeder at random. Individuals could determine the rank of a bird on the feeder relative to their own rank and could also distinguish between the ranks of two birds on the feeder. This ability allowed individuals to approach perches occupied by subordinate birds and avoid dominant ones. Individuals could, therefore, avoid aggressive encounters with dominant birds and gain access to the feeder with the least risk. The ability to determine the rank of a potential opponent was probably facilitated by individual recognition.
Evidence for Conceptual Quantitative Abilities in the African Grey Parrot: Labeling of Cardinal Sets
Authors: Pepperberg Irene M.
Published: May 2010

An African grey parrot with experience in vocal labeling and categorization of objects, colors, and shapes has been taught to produce vocal numerical labels for collections of 2–6 objects. This ability generalized to sets of novel objects, to objects in random arrays, and to some heterogeneous collections. The results are discussed in terms of their relationship to numerical concepts in humans and other animals, particularly with respect to counting, language, and “prepared” associations.
Greater Mating Success of Drosophila biarmipes Males Possessing an Apical Dark Black Wing Patch
Authors: Singh B. N. , Chatterjee Sujata
Published: May 2010

Drosophila biarmipes males possess an apical black patch on their wings. In a laboratory stock of this species, males without such a patch have been found. Mating success of these two types of male was studied in an Elcns‐Wattiaux mating chamber. Results show that males possessing the dark black patch have greater mating success than those without. This finding suggests that visual stimulus plays an important role in the mating behaviour of D. biarmipes.
Male Aggression, Female Mimicry and Female Choice in the Rove Beetle, Aleochara curtula (Coleoptera, Staphylinidae)
Authors: Peschke Klaus
Published: May 2010

Causes, consequences and pheromonal regulation of male contest and female choice in the staphylinid beetle, Aleochara curtula (Goeze), have been investigated in the field and in the laboratory. At the feeding and mating site (carcass) the sex ratio is male biased. Polyandry is affected by prolonged copulations, spermatophore plugs and anti‐aphrodisiac pheromones transferred from the male, and by female repulse behaviour as well. Aggression of competing males leads to expulsion of inferior males from the carcass. Young, starved and multiply mated males, which need access to the food resource, produce the female sex pheromone. They release homosexual responses, but also avoid intrasexual aggression. On the other hand, females behave aggressively towards individuals bearing the female sex pheromone or repulse their copulatory attempts. Those males of insufficient physiological condition produce a lighter spermatophore and fertilize less eggs. The adaptive significance of female mimicry, male mating tactics, and female choice is discussed.
Dominance and Mating in a Communal Polygynandrous Bird: Cooperation or Indifference towards Mating Competitors?
Authors: Jamieson Ian G. , Craig John L.
Published: May 2010

The effect of dominance on the mating behaviour of both females and males was investigated for the communally breeding pukeko (Porphyrio porphyrio melanotus). Pukeko are polygynandrous with most groups consisting of three to 7 breeding males and one or two breeding females that lay eggs in a single nest. Linear dominance hierarchies are well established within breeding groups.

Alpha females were involved in more copulations than beta females, but this difference did not appear to be a result of dominance status. There was also no evidence of egg tossing or egg destruction by breeding females. There was no positive correspondence between dominance rank of males and their frequency of sexual activity or copulations during the prelaying or laying periods. Dominants did interrupt matings by subordinates, but both qualitative and quantitative analyses of behaviour found no evidence of mate guarding. Furthermore dominants were no more likely to interrupt a copulation involving a subordinate male than they were to passively observe it or not react at all. This led us to suggest that males tended to behave indifferently toward mating competitors. As a result, multiple paternity is predicted to be high in pukeko groups. We also question the standard interpretation that males are behaving cooperatively in communal groups rather than coactively.
Ethological Isolation, Sexual Behavior and Pheromones in the Fasciatus Species Group of the Lizard Genus Eumeces
Authors: Cooper William E. , Vitt Laurie J.
Published: May 2010

Ethological isolation was found among North American members of the fasciatus species group of Eumeces. Ethological isolation was investigated by staging a series of interspecific and intraspecific heterosexual encounters. No male E. laticeps or E. fasciatus courted heterospecific females. In both species, males courted and copulated with conspecific females in a significantly higher frequency of trials than with heterospecific females. However, male E. inexpectatus courted females of all three species, courting conspecific females and female E. laticeps at similar frequencies, but female E. fasciatus at a significantly lower frequency. No females of any of the three species were sexually receptive to heterospecific males, but forced copulation occurred in two of nine courtships of female E. fasciatus by male E. inexpectatus. Thus, ethological isolation in the fasciatus group appears to be complete with the possible exception of occasional forced copulation between male E. inexpectatus and female E. fasciatus. Preliminary evidence on the role of chemical stimuli in maintaining ethological isolation was obtained from experiments involving interspecific transfers of female odors. Male E. inexpectatus courted female E. fasciatus labelled with the odor of female E. inexpectatus in a significantly greater proportion of trials than they courted such females lacking the conspecific female odor. In a similar experiment, male E. fasciatus did not court female E. inexpectatus even if the females bore odors of female fasciatus.
Induction and Maintenance of Maternal Behaviour in the Domestic Hen: Influence of Testosterone and Oestradiol Treatments
Authors: Richard‐Yris M. A. , Leboucher G.
Published: May 2010

Confining an adult hen with two newly‐hatched chicks induced a gradual emergence of maternal behaviour in the hen. The aim of the experiments presented here was to analyse the effects of testosterone or oestradiol treatments on the induction and maintenance of maternal behaviour in hens with no previous maternal experience. The ability of a hen to positively respond towards chicks was not altered by either testosterone or oestradiol injections. However, testosterone therapy prevented both the appearance and the maintenance of the most typical call, clucking. Testosterone injected hens responded to chicks with a contact‐type call, but oestradiol treated ones did not. These results indicate that some aspects of maternal behaviour can be modulated by peripheral levels of hormones.