bluuebunny/crossref_metadata_2025_split huggingface dataset:
Song Repertoire of the Bobolink: a Reassessment
Authors: Trainer Jill M. , Plltz Brenda S. 
Published: May 2010

AbstractPrevious studies have reported that male bobolinks, Dolichonyx oryzivorus, sing only two stereotyped song types. Here we reassess this description of the bobolink repertoire, using methods of sampling and classifying songs better suited to describing song diversity. Recording the songs of 51 males from five prairies in Iowa, we examined within‐ and between‐individual variation for each of three levels of bobolink singing organization: phrases, phrase sequences and repertoires. A single song was composed of 1–15 phrases selected from about 10 locally used phrase types. Shared phrases were used with similar frequencies among different males at a locality. Two‐, three‐ and four‐phrase sequences were used repeatedly in the song variants produced by individual males. Unlike other investigators, we considered each song unit composed of a unique sequence of phrases to be a different song variant. Some individuals had two basic song patterns which were varied to create an assortment of song variants. Other individuals had repertoires too complex to be described by two basic patterns. Eighteen males for which we obtained samples of 20 or more songs sang between 8 and 43 different song variants. Computing an index of singing versatility derived from information theory, we found that these individuals varied considerably in the versatility with which they delivered their song variants. Males with high versatility used a greater variety of phrase transitions and repeated song variants less often than males with low versatility. This method of describing song repertoires and singing versatility provides the potential to test hypotheses regarding the role of the bobolink song repertoire in communication and mate choice.
Cere Colour as a Basis for Extra‐pair Preferences of Paired Male Budgerigars (Melopsittacus undulatus: Psittacidae: Aves)
Authors: Baltz Aliza P. , Clark Anne B. 
Published: May 2010

AbstractMale budgerigars may be limited in the time they have available to pursue extra‐pair copulations because of conflicts with other reproductive behaviour. If males could selectively court only immediately fertilizable extra‐pair females they should do so. The cere colour of a female budgerigar may be used as a cue to her reproductive readiness. We experimentally tested the hypothesis that males prefer females with dark ceres, which are indicative of developed ovaries, over females with light‐coloured ceres, characteristic of birds with undeveloped ovaries. In a pairwise choice experiment between females that had their cere colour artificially manipulated, pair‐bonded males were more likely to choose the female with the dark‐coloured cere.
Lack of Mate‐guarding in a Territorial Passerine Bird with a Low Intensity of Sperm Competition, the Pied Flycatcher; (Ficedula hypoleuca)
Authors: Chek Andrew A. , Lifjeed Jan T. , Robertson Raleigh J. 
Published: May 2010

AbstractWe examined a Norwegian population of pied flycatchers (Ficedula hypoleuca) for behaviour associated with the paternity‐protection tactic of mate‐guarding and found that this tactic was absent. The absence of mate‐guarding and the fact that pied flycatchers do not have a high rate of copulation make this population unusual to the extent that the current literature implies that, in birds, one or other paternity guard should be present. Comparison of our population with a Swedish population that does exhibit mate‐guarding lends some support to the notion that differences in nesting density may drive the relative risk of extra‐pair copulation, leading to the need for paternity guards such as mate‐guarding. However, we conclude that, whilst the results of both our study and the Swedish study are consistent with the nesting‐density hypothesis, there is at least one other plausible hypothesis that fits the available data. Specifically, we direct attention to the role of the female in determining overall patterns of pair behaviour and, potentially, the rate of extra‐pair paternity, challenging the primacy of male—male competition as the driving force behind the sperm‐competition dynamics of this species.
Social Learning of a Novel Foraging Skill by White‐throated Magpie‐jays (Calocitta formosa, Corvidae): a Field Experiment
Authors: Langen Tom A. 
Published: May 2010

AbstractThe cooperatively breeding white‐throated magpie‐jay (Calocitta formosa) uses a variety of foraging tactics to find, harvest, and process food. Members of territorial groups forage together and may gain information about how to acquire food by observing each other. A field experiment was performed to determine whether a novel skill, door opening to gain access to food, was more rapidly acquired by members of groups in which a trained individual performed the skill. A higher proportion of jays in groups with behavioural ‘models’ (trained birds that opened doors in the presence of group members) acquired the door‐opening skill than those groups without models. Young birds acquired the behaviour more frequently than older individuals. Aggressive behaviour at feeders may have affected the spread of the behaviour by reducing the likelihood that individuals performed the behaviour in the presence of other group members but may also have encouraged subordinate individuals to attempt door opening rather than ‘scrounge’.
Directional Preferences in the Autumn Migration of the Red Admiral (Vanessa atalanta)
Authors: Benvenuti Silvano , Dall'Antonia Paolo , IoalÈ Paolo 
Published: May 2010

AbstractThe paper describes the orientation performance of the red admiral in the course of its migratory movements through the Italian peninsula, a region where systematic studies of this butterfly species have not been carried out before. Our results show that red admirals exhibit seasonal bidirectional migratory movements between breeding and wintering grounds. Orientation performances, directional preferences in the autumn and spring were recorded and discussed; in addition, we have documented a progressive eastward shift of the main flight direction, during the autumn migratory season, which appears to be related to air temperature. Speculative explanations for this shift of flight direction, which has never been recorded before, are given.
Sound‐pressure Levels and Song Preferences in Female Red‐winged Blackbirds (Agelaius phoeniceus) (Aves, Emberizidae)
Authors: Searcy William A. 
Published: May 2010

AbstractFemale red‐winged blackbirds (Agelaius phoeniceus) were tested for response to songs of male red‐winged blackbirds differing in sound‐pressure level (SPL) of playback. Subjects gave significantly more copulation‐solicitation displays in response to playback of songs at 85 dB SPL than to playback of the same songs at 72 dB SPL. The strength of the preference, as judged by the ratio of response to high and low SPL playback (1.15:1), was lower than that of preferences for high SPL shown by insects and anurans. Female red‐winged blackbirds responded preferentially to a conspecific song relative to a heterospecific imitation, even when the imitation was presented at an SPL 13 dB higher than that of the conspecific song. By contrast, female redwings did not maintain a preference for multiple conspecific song types over single types when the single song types were presented at the higher SPL. These results are compatible with Klump & Gerhardt's (1987) suggestion that the intensity independence of female preferences varies with the relative benefit females obtain from each preference.
Do the Anemonefish Amphiprion ocellaris (Pisces: Pomacentridae) Imprint Themselves to Their Host Sea Anemone Heteractis magnifica (Anthozoa: Actinidae)?
Authors: Arvedlund Michael , Nielsen Lis Engdahl 
Published: May 2010

AbstractJuvenile anemonefishes detect their host sea anemone by olfactory stimuli; in order to investigate whether this behaviour is innate or acquired, the anemonefish species Amphiprion ocellaris was bred in two different ways: 1. With no host sea anemone present at all (–A); and 2. With the specific host sea anemone Heteractis magnifica present in the hatching aquarium, so that these eggs were laid and hatched close to the sea anemone, as in nature (+A).The two different types of juvenile A. ocellaris were presented to the odours of the host sea anemone H. magnifica in two sets of short‐term experiments with the host (a) visually hidden in a net cage, and (b) visible but physically separated from the anemonefishes. In both cases, a water flow was established between fishes and host. The +A‐fishes found their host by olfactory and not by visual stimuli. In both series, the –A‐fishes showed a significantly lower affinity behaviour towards the odour compounds from the host sea anemone than the +A‐fishes did.A third type of experiment was a direct confrontation between fishes and host; here, the –A‐fishes were indifferent towards the host sea anemone for almost 48 h, while the +A‐fishes acclimated to the host sea anemone within the first 5 min of the direct confrontation.The results of this study suggest that Amphiprion ocellaris imprints itself olfactorily to its species‐specific host sea anemone Heteractis magnifica, and, furthermore, may be genetically disposed towards olfactory recognition of the host sea anemone.
Ineffective Maternal Care of a Subsocial Bug against a Nymphal Parasitoid: a Possible Consequence of Specialization to Predators
Authors: Kudo Shin‐ichi 
Published: May 2010

AbstractIn the subsocial bug Elasmucha putoni, females lay egg masses on leaves of fruit‐bearing wild mulberry trees. Parent females invariably remained straddling their offspring until the offspring moulted to the second instar on natal leaves. Thereafter, the females usually settled on the stem of shoots which harboured second‐or‐later‐instar nymphs feeding on fruit or aggregating on leaves, and faced toward the base of the shoot. To evaluate the effectiveness of maternal attendance on parasitism of nymphs by a braconid wasp, I divided the boughs of each mulberry tree into two experimental groups: a single bough which was isolated from the others by Tanglefoot treatments and on which guarding females were removed from broods before the second instar, and other boughs on which broods were left intact as controls. The experiments showed that nymphal parasitism was not affected by the presence of females. The position and orientation of females attending second‐or‐later‐instar nymphs is probably effective for detecting predators approaching the nymphs by walking along the stem; however, this posture may prevent the females from detecting parasitoids, which fly and land directly on plant parts close to the nymphs. The ineffectiveness of the females in providing defence against the parasitoid is possibly associated with a specialization of the attending posture to pedestrian predators: a parental defensive behaviour specific to these predators may make the offspring more vulnerable to the parasitoid.
Development of Tonal Quality in Birdsong: Further Evidence from Song Sparrows
Authors: Peters Susan , Nowicki Stephen 
Published: May 2010

AbstractSong sparrow (Melospiza melodia) songs are composed largely of pure‐tone notes. Song sparrows raised in acoustic isolation (i.e. never hearing conspecific songs) tend to produce half of their notes with harmonic overtones, an atypical tonal structure, suggesting that exposure to pure tones is necessary for the development of normal tonal quality. The experiment presented here directly investigated the influence of early exposure to songs with different tonal qualities on subsequent production. Seven young song sparrow males were exposed to 16 normal, pure‐tone song sparrow songs and 6 males were exposed to the same 16 song types with added harmonic overtones. Birds in both groups learned equally well, confirming an earlier finding that tonal quality does not influence selection of models during the sensitive period for song acquisition. Birds exposed exclusively to harmonic song models, however, produced over 85% of their learned notes in a pure‐tone fashion, even though they had never heard pure‐tone sounds. Thus, pure tones do not need to be experienced directly by song sparrows, but exposure to some features of species‐typical song models appears to facilitate the reproduction of models in a pure‐tone fashion.
Age‐related Differences in Playfighting Strategies of Captive Male Red‐necked Wallabies (Macropus rufogriseus banksianus)
Authors: Watson Duncan M. , Croft David B. 
Published: May 2010

AbstractAge‐related differences in the playfighting strategy of captive male red‐necked wallabies Macropus rufogriseus banksianus was examined. Our purpose was to determine whether wallabies adjusted their play in response to their partner's age and, if so, how. The way in which a wallaby played was dependent on the relative age of its partner, and this pattern tended to be the same regardless of whether it was the initiator or reactor of the interaction. If a wallaby's partner was younger than itself it adopted a defensive strategy in which it self‐handicapped by standing flat‐footed, Pawing rather than Sparring, and by not using its full strength. Its greater rate of Shaking suggests that this act may function as an appeasement signal in play. Furthermore, it was highly tolerant of the tactics used by its younger partner and took the more active role in prolonging interactions. If, on the other hand, its partner was older than itself, it adopted an offensive strategy involving vigorous Sparring, increased time in the High‐stance posture and a greater percentage of bouts that were of high intensity. Indeed, it played with even more vigour than when it playfought with wallabies of the same age as itself. Differences in the play of same‐aged partners were in the non‐fighting components of play, while those of differently‐aged partners were in the fighting components. Play between same‐aged partners, however, tended to be more stable and more competitive than that between partners of differing age. These results are discussed with emphasis on the compromises made in order for play to occur and the potential benefits to each partner of play in mixed‐age class encounters. We briefly consider the implications of self‐handicapping in the categorization of macropodid fights as play or aggression.
Signalling Asymmetry in the Communication of the Water Strider Aquarius remigis in the Context of Dominance and Spacing in the Non‐mating Season
Authors: Jabloński Piotr G. , Wilcox R. Stimson 
Published: May 2010

AbstractThe role of high‐frequency ripple signals (HF signals) made by males of the water strider Aquarius remigis was studied in the contexts of competition for food and general spacing behaviour during the non‐mating season. HF signals were played back through the ripple‐producing legs of males during dyadic agonisdc encounters, using a signal‐driven wire coil to oscillate a magnet glued to a leg. These signals were in addition to normal signals. The additional signals significantly increased the number of retreats by non‐magneted males, showing that the signals increased the dominance of a non‐territorial male. Hence, our results increase the number of contexts in which HF signals of A. remigis function. Males, but not females, avoided a site occupied by a magneted dead male through which HF signals were played. Thus, the communication system used by A. remigis males during competition for food seemed to be ignored by females, suggesting sex‐specific signals even in a non‐mating context. Evolutionary models of signalling often assume that contestants have evolved the same repertoire of signals in order to resolve conflicts peacefully. This water strider system thus poses an interesting challenge for future theoretical and empirical research on communication asymmetry.
Song Degradation during Propagation: Importance of Song Post for the Wren Troglodytes troglodytes
Authors: Mathevon Nicolas , Aubin Thierry , Dabelsteen Torben 
Published: May 2010

AbstractThe degradation of bird sounds during long‐range propagation depends on different parameters such as density of vegetation, height from the ground and atmospheric perturbations. We investigated whether the wren Troglodytes troglodytes, a bird species which has a high‐pitched song that is very susceptible to degradation and lives in an environment that is very restricting for sound propagation, has any advantage in choosing relatively high song posts. Song degradation was investigated by analysing sound attenuation, duration of notes and silences, spectrum composition, modifications of frequency‐modulated notes and amplitude fluctuations.Our data show that the choice of an elevated song post improves the reliability of all song parameters and increases the propagation distance of the song. It also improves the male wren's ability to hear opponent songs. The results are discussed from an ecological point of view.
Pigeon Homing in the Meteorological and Solar‐geomagnetic Environment: what Pigeon Race Data say
Authors: Dornfeldt Klaus 
Published: May 2010

AbstractIn this statistical analysis, the fastest 25% of homing speeds in 5955 races conducted in West Germany on 194 days in 1973–1990 and the return rates in 18 pigeon races held in 1932–1957 in Italy were examined with respect to distance, cloud cover, wind, sferics, solar and magnetic variables. 1. Under sun, the speeds rapidly increased with distance from 120 up to 240 km and slowly declined beyond 240 km. 2. Correlations between race and wind speeds were maximized by rotating clockwise and extrapolating the local surface wind linearly according to the average wind profile (difference between the mean surface and mean 900 m‐height wind vector). The best predictors indicated the speeds of the winds the birds encountered aloft, which were blowing at lower heights in headwinds than in tailwinds. 3. The air speeds correlated negatively with the effective wind forces roughly in agreement with Pennycuick's theory of bird flight. 4. Rates of atmospherics (2.8–38 kHz, 0.02–0.4V/m recorded in Berlin) correlated negatively with the speeds. 5. Under sun, the difference between the fastest and slowest speed correlated with sunspot numbers (R) in a very active solar cycle (1979–1987), but not in the preceding and following cycles which had lesser activity. 6. Under sun, the speeds correlated directly or indirectly with solar and magnetic activity (25% and 21 % of the samples per year and per homeward direction, respectively), but did so only in 9.9% and 6.9% of samples (respectively) when races to the same home area were sampled over the years. Under overcast, most of the correlations were negative. 7. While magnetic disturbances appeared to coincide with higher speeds inconsistently under sun, they appeared to interfere with the speeds consistently under overcast. Under sun, the seasonal median speeds, unlike the daily median ones, correlated negatively with magnetic activity. 8. Hourly variations of the geomagnetic field components correlated negatively with the speeds in 1973–1975 in western, but positively in eastern and southern, homeward directions. 9. The return rates in Italian pigeon races were best predicted by hourly variations of the horizontal intensity of the regional geomagnetic field and second‐best by sunspot numbers. 10. The significance of the results for understanding the role of the meteorological and solar‐magnetic environment in pigeon homing is discussed.
Interspecific Responses of Ringtailed Lemurs to Playback of Antipredator Alarm Calls Given by Verreaux's Sifakas
Authors: Oda Ryo , Masataka Nobuo 
Published: May 2010

AbstractThe ringtailed lemur, Lemur catta, and Verreaux's sifaka, Propithecus verreauxi verreauxi, are diurnal prosimians living sympatrically in Madagascar. Species‐specific alarm calls emitted by each of these two species in response to aerial and terrestrial predators differ acoustically. Behavioural responses of ringtailed lemurs evoked by playbacks of conspecific alarm calls differ when the vocalizations were produced in response to aerial predators as opposed to terrestrial predators. We conducted playback experiments on two populations of ringtailed lemurs, using two types of sifaka alarm calls. One population consisted of free‐ranging groups which lived sympatrically with sifakas, the other was a colony group which had no contact with sifakas. The results illustrate that the former group of lemurs can perceive what type of predators the sifaka calls refer to, whereas the latter group was not able to recognize the difference in the calls.
Chemosensory Recognition of Familiar and Unfamiliar Conspecifics by the Scincid Lizard Eumeces laticeps
Authors: Cooper William E. 
Published: May 2010

AbstractThe ability of broad‐headed skinks (Eumeces laticeps) to distinguish familiar from unfamiliar individuals of the opposite sex and themselves from other individuals of the same sex using only chemical stimuli was examined experimentally. Cloacal chemical stimuli were presented to lizards on moistened cotton swabs and numbers of tongue‐flicks performed in 60 s were recorded. Males emitted significantly greater numbers of tongue‐flicks in response to chemical cues from unfamiliar females than of female cagemates. Response rates of males housed with females and males housed alone to chemical stimuli from unfamiliar females did not differ. Chemical stimuli from unfamiliar males elicited significantly more tongue flicks from males than their own or deionized water, but their own stimuli elicited no more than the odourless control. Females tongue‐flicked significantly more in response to cloacal chemical stimuli from unfamiliar males than from male cagemates. The findings indicate that both sexes of broad‐headed skinks can discriminate between chemical stimuli of familiar and unfamiliar individuals of the opposite sex and that males can distinguish their own cloacal chemicals from those of unfamiliar males. The possible functions of these chemosensory capacities, including location of mates by scent‐trailing and assessment of the presence of sexual competitors, are discussed in relation to the social behaviour of E. laticeps.
Why Do Female Birds Reject Copulations from their Mates?
Authors: Wagner Richard H. 
Published: May 2010

AbstractFemale birds frequently reject copulations from their mates, suggesting a conflict between the sexes. This study analyses behavioural data of socially monogamous razorbills, Alca torda, to examine whether females rejected their mates because of conflicts over fertilization or the pair bond. Among pairs, females rejected 9–70 % of their mates’ copulation attempts and prevented their mates from completing 42–100 % of successful copulations. Copulations terminated by females were half the duration of those terminated by males, and females terminated fewer first copulations than subsequent ones on the same day. These findings indicate that females were motivated to copulate less frequently and for shorter durations than their mates. The sperm competition hypothesis predicts that females reject their mates to increase the probability of being fertilized by extra‐pair males. This hypothesis was not supported because females rejected extra‐pair males similarly to their mates. The female‐mate‐guarding hypothesis predicts that females guard their pair bond by copulating frequently with their mates, thereby depriving the males of time and energy to copulate with and form bonds with other females. This prediction was consistent with a significant negative correlation between the percentage of copulation attempts that females accepted from their mates, and the number of extra‐pair copulations that their mates attempted. However, this correlation was not caused by a trade‐off of males copulating with their mates instead of attempting extra‐pair copulation because males attempted most extra‐pair copulations on days when their mates were absent. A new hypothesis is proposed, namely, that females reject their mates to test the male's commitment to provide essential parental contributions after egg‐laying. The ‘testing‐of‐the‐bond’ hypothesis is consistent with the findings but requires testing.