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Showing papers in "Behaviour in 1993"


Journal ArticleDOI
TL;DR: The concept of dominance has contributed greatly to our understanding of social structure in animals as discussed by the authors, leading to an ongoing debate about the usefulness and meaning of the concept, and several definitions of dominance have been introduced.
Abstract: The concept of dominance has contributed greatly to our understanding of social structure in animals. Over the past three decades, however, a variety of concepts and definitions of dominance have been introduced, leading to an ongoing debate about the usefulness and meaning of the concept. Criticisms aimed at one definition of dominance do not necessarilly apply to other definitions. Existing definitions can be structural or functional, refer to roles or to agonistic behaviour, regard dominance as a property of individuals or as an attribute of dyadic encounters, concentrate on aggression or on the lack of it, and be based either on theoretical constructs or on observable behaviour. Thirteen definitions of dominance are reviewed, and their usefulness assessed with respect to their descriptive value. The predictive and explanatory values of definitions are specific to the questions asked in each particular study and are not considered as criteria to judge the usefulness of the dominance concept. By virtue of its high descriptive value, the original definition of dominance by SCHJELDERUPP-EBBE (1922, Z.Psychol. 88: 226-252) emerged as the basis to formulate a structural definition with wide applicability and which reflects the essence of the concept: Dominance is an attribute of the pattern of repeated, agonistic interactions between two individuals, characterized by a consistent outcome in favour of the same dyad member and a default yielding response of its opponent rather than escalation. The status of the consistent winner is dominant and that of the loser subordinate. Dominance status refers to dyads while dominance rank, high or low, refers to the position in a hierarchy and, thus, depends on group composition. Dominance is a relative measure and not an absolute property of individuals. The discussion includes reference to the heritability of dominance, application of dominance to groups rather than individuals, and the role of individual recognition and memory during agonistic encounters.

681 citations


Journal ArticleDOI
TL;DR: MatMan is a program for performing a variety of ethological analyses of frequency (interaction) matrices and transitionMatrices and calculation of expected and residual values in transition matrices with defined or undefined diagonal.
Abstract: MatMan is a program for performing a variety of ethological analyses of frequency (interaction) matrices and transition matrices. These analyses include linear hierarchy indices for dominance matrices (APPLEBY, 1983), reorganization of a dominance matrix such that the subjects are in rank order, matrix correlation methods such as Mantel's test (MANTEL, 1967) and rowwise matrix correlation (DE VRIES, 1993), methods based on information theory (STEINBERG, 1977), and the calculation of expected and residual values in transition matrices with defined or undefined diagonal. In addition, MatMan offers some useful options for manipulating matrices. Import of matrices from The Observer (NOLDUS, 1991) and SAS is, within certain limitations, possible. Export of matrices is possible to the programs CORAN (1985), Vegrow (FRESCO, 1989), NCSS (HINTZE, 1987), SAS and SPSSPC.

333 citations


Journal ArticleDOI
TL;DR: In this article, the authors studied the dispersal behavior of tigers in Chitwan National Park, Nepal and found that females tend to settle next to their mothers, which reduces the genetic variance of a male's offspring.
Abstract: Dispersal in tigers was studied in Royal Chitwan National Park, Nepal. Thirty six adult and young were studied to monitor movements and social interactions relative to dispersal. Fourteen subadults were followed from before their dispersal until they died or established post-dispersal territories. Subadult tigers became semi-independent of their mother when her next litter was born. They usually remained within her natal area until the subsequent litter began to move with her at about 2 mos of age. Animals dispersed between 19 and 28 mos. Males dispersed farther than females and settled in poorer habitat. Three of 4 females settled adjacent to their mothers; in two cases the mother shifted her territory allowing the daughter to take over a large portion of the mother's former territory. Wounds on young prior to dispersal indicated that aggression prompted dispersal. Fjghts were observed between dispersers and residents. After fights, dispersers always left the resident's area. All 4 dispersing females established breeding territories. Females settled next to their mothers tending to reduce the genetic variance of a male's offspring. Eight of 10 males became localized in temporary, post-dispersal territories; 4 of the 8 survived. Two males died of poisoning and 2 from intrasexual aggression. Surviving males either expanded temporary territories or shifted to new areas to establish breeding territories. The Chitwan tigers are an isolated remnant of a population once continuous across the lowlands of Nepal. Effective population size was estimated to be <30 animals. Tigers did not disperse across cultivated areas but did travel through degraded forest habitat. No animal dispersed outside the Chitwan region and there appear to be effective barriers separating Chitwan from the two nearest populations 150 and 250 kms distant. The Chitwan population is probably one of the largest tiger populations remaining in the world. Isolation and small size threaten these populations with stochastic events that may lead to further reduction in population size.

222 citations


Journal ArticleDOI
TL;DR: Although entomopathogenic nematodes have a broad potential host range, differences in search behavior may result in a narrower actual host range.
Abstract: [Entomopathogenic nematodes (Heterorhabditidae and Steinernematidae) are insect parasites that appear to use both cruising and ambushing search strategies. Cruising species Heterorhabditis bacteriophora, Steinernema feltiae, and S. glaseri spent more time crawling (88.8, 80.3, and 92.5% of observation period, respectively) and therefore traveled farther (22.4, 18.6, and 24.3 mm, respectively) and searched a larger area (18.3, 13.7, and 26.6 mm2, respectively) than ambushing species. Ambusher species S. carpocapsae and S. scapterisci traveled shorter distances (4.8 and 4.7 mm, respectively) and searched smaller areas (3.0 and 2.5 mm2, respectively) because they spent most of the observation period nictating (77.5 and 78.2%, respectively). Nictating infective juveniles raise greater than 95% of their body off the substrate and maintain a straight posture. A nictating species S. carpocapsae was up to 43 times as effective at finding mobile insect hosts compared to a non-nictating species H. bacteriophora. When unable to nictate host-finding of mobile insects declined from 35.7±7.19 to 3.9±1.11 infective juveniles per host. Nictation, by reducing the surface tension forces holding the nematode to the substrate, can increase the nematodes ability to attach to passing insects. S. carpocapsae also tended to search more effectively along a surface than through a matrix. Although entomopathogenic nematodes have a broad potential host range, differences in search behavior may result in a narrower actual host range. Ambushers being more specialized for mobile insects on the soil surface and cruisers for more sedentary and/or subterranean insects., Entomopathogenic nematodes (Heterorhabditidae and Steinernematidae) are insect parasites that appear to use both cruising and ambushing search strategies. Cruising species Heterorhabditis bacteriophora, Steinernema feltiae, and S. glaseri spent more time crawling (88.8, 80.3, and 92.5% of observation period, respectively) and therefore traveled farther (22.4, 18.6, and 24.3 mm, respectively) and searched a larger area (18.3, 13.7, and 26.6 mm2, respectively) than ambushing species. Ambusher species S. carpocapsae and S. scapterisci traveled shorter distances (4.8 and 4.7 mm, respectively) and searched smaller areas (3.0 and 2.5 mm2, respectively) because they spent most of the observation period nictating (77.5 and 78.2%, respectively). Nictating infective juveniles raise greater than 95% of their body off the substrate and maintain a straight posture. A nictating species S. carpocapsae was up to 43 times as effective at finding mobile insect hosts compared to a non-nictating species H. bacteriophora. When unable to nictate host-finding of mobile insects declined from 35.7±7.19 to 3.9±1.11 infective juveniles per host. Nictation, by reducing the surface tension forces holding the nematode to the substrate, can increase the nematodes ability to attach to passing insects. S. carpocapsae also tended to search more effectively along a surface than through a matrix. Although entomopathogenic nematodes have a broad potential host range, differences in search behavior may result in a narrower actual host range. Ambushers being more specialized for mobile insects on the soil surface and cruisers for more sedentary and/or subterranean insects.]

220 citations


Journal ArticleDOI
TL;DR: There is a general, underlying relationship between male dominance rank and access to mates in savanna baboons, and this is inarguably the primary determinant of mating success among high-ranking males, while the mating success of subordinate males is determined both by rank and the extent to which coalitions are expressed in the group.
Abstract: Data on sexual consortships in a troop of chacma baboons are analyzed in relation to a priority-of-access model and to critical demographic and social variables. The data show a robust association between adult male rank and mating success, and a close approximation to priority-of-access type mating. Principal findings were: (1) Mating activity peaked during the four most likely days of ovulation, and was greater on conceptive than on nonconceptive cycles. (2) On each day of estrus, males of the alpha rank consorted more frequently than did males of other ranks for both classes of cycles. (3) Moreover, on each day of estrus, alpha males consorted at higher rates on conceptive cycles than they did on nonconceptive cycles. (4) Male dominance rank and consorting success were positively correlated, including a perfect rank correlation on conceptive cycles. (5) Mean consort duration was also positively correlated with male dominance rank. (6) The most striking aspect of male mating patterns was the predominance of alpha males. Male dominance rank and consort success were in qualitative but not perfect quantitative agreement with predictions of a priority-of-access model. Alpha males consorted on 86% of the days and 94% of the conceptive cycles they were expected to, and were selective of conceptive over nonconceptive cycles. (7) The size of the adult male cohort had no effect on the consort success of alpha males. (8) Alpha male consort success was reduced during intervals when two or more females were synchronously in estrus. Inconsistent results from other savanna baboon field studies have often led to the conclusion that dominance rank is not important as a determinant of male mating success. Analysis of the literature indicates that some of the reported variability among studies is explained by factors that are associated with differences in group demography. In addition, the importance of male dominance rank has often been treated superficially in discussions emphasizing alternative mating tactics, due in part to the uneven representation of published accounts emerging from individual study sites. I conclude that there is a general, underlying relationship between male dominance rank and access to mates in savanna baboons. Dominance rank is inarguably the primary determinant of mating success among high-ranking males, while the mating success of subordinate males is determined both by rank and the extent to which coalitions are expressed in the group. Rank/mating measures tend to be strongest in the chacma subspecies, among which male-male coalitions over mates are unknown. Male-male competition based in both solo and coalitional tactics appears to dominate the expression of individual partner preferences.

172 citations


Journal ArticleDOI
TL;DR: In this paper, the authors compare defecation patterns at boundary and hinterland latrines, in order to test the hypothesis that these two types of latrine have a similar function.
Abstract: Badgers (Meles meles) defecate, urinate and scent mark at latrines which seem to have a territorial function. The main aim of the present study was to compare defecation patterns at boundary and hinterland latrines, in order to test the hypothesis that these two types of latrine have a similar function. We investigated latrine use by means of a year-round survey of all the latrines in 7 badger territories, by bait-marking of 15 territories, and by monitoring latrine use in 6 radio-collared badgers belonging to three social groups. The spatial distribution of latrines within a territory was bimodal, with the greatest densities oflatrines close to the outside, and close to the centre, of the territory respectively. Boundary latrines were larger and more consistently used than hinterland latrines, but these differences could be accounted for by the fact that boundary latrines are visited by the members of more than one social group. Defecation at latrines was subject to seasonal variation, with a major peak in latrine use in spring and a minor peak in autumn. The spring peak was largely attributable to an increase in the use of hinterland latrines, the autumn peak to an increase in the use of boundary latrines. Males visited boundary latrines considerably more often than did females, but both sexes visited hinterland latrines equally often. Overmarking occurred equally often at both types of latrine and involved animals from the same as well as from different groups, but there was a significant tendency for more between-group than within-group overmarking. Overmarking occurred mainly on fresh, as opposed to old, faeces deposits. The sex and seasonal differences in use of boundary latrines suggest that these function at least partly as a form of mate-guarding, to deter neighbouring males from entering a territory for mating purposes. It is less clear why females mark at hinterland latrines. One possibility, consistent with the observed spatial distribution of hinterland latrines, is that they function to defend the main burrow system, which is used for breeding; another is that they carry information about social status. Overmarking probably serves to obliterate the marks of competitors, which are members of neighbouring social groups in the case of boundary latrines, but may be members of the same social group in the case of hinterland latrines. We conclude that previous ideas about the function of territoriality in badgers, and about the information conveyed by latrines, are oversimplified.

152 citations


Journal ArticleDOI
TL;DR: The results suggest that the song and song repertoire of male starlings serve primarily an intersexual rather than an intrasexual function, and it also appears that variations in the size of the aviary can modify the behavioural responses of starling males.
Abstract: We confronted individually-caged male European starlings, Sturnus vulgaris, with conspecifics of both sexes in order to study singing behaviour during intrasexual and intersexual encounters. Males spent more time at the nestbox, sang more songs and more song types during female presentations than during control periods (observation periods with no conspecifics). Males also sang more songs in the nestbox and flew more to the nestbox with green nest material. During male presentations, only the time spent at the nestbox and the carrying of nest material increased significantly. Males spent more time at the nestbox, sang more songs and more song types in response to a female stimulus than to a male stimulus. Males also sang more songs in the nestbox and flew more to the nestbox with nest material during female than during male presentations. These results suggest that the song and song repertoire of male starlings serve primarily an intersexual rather than an intrasexual function. However, in contrast to a previous study, our results suggest that singing also serves as an intrasexual signal to deter rivals at close encounter. We also tested the hypothesis that the 'whistles' and the 'warbling song' have separate intrasexual and intersexual functions, as has been suggested in the literature. We found no evidence for a specialized intrasexual function of the whistles nor for a specialized intersexual function of the warbling song. From this study it also appears that variations in the size of the aviary can modify the behavioural responses of starling males. New information with regard to the use of green nest material by male starlings is given.

109 citations


Journal ArticleDOI
TL;DR: The effects of age and context on the stereotypies of caged mink were examined in order to assess the developmental changes undergone by the behaviour, and to find context-specificity that might suggest its motivational bases.
Abstract: The effects of age and context on the stereotypies of caged mink were examined in order to assess the developmental changes undergone by the behaviour, and to find context-specificity that might suggest its motivational bases. Caged mink perform stereotypies consisting of a variety of movements, most commonly pacing and rearing, running in and out of the nestbox, and stationary head-twirling or nodding. Stereotypies are largely performed as feeding-time approaches, and many mink do not show them at all once fed. Stereotypies become more frequent and less variable with age; and in adults, individuals with the highest levels of stereotypy show the least variable forms of the behaviour and are most likely to perform it in more than one context, i.e. not solely in the pre-feeding period. These data suggest that mink stereotypies become 'established' with age, in the manner described for stereotypies in other species. However, the behaviour of kits does not follow the pattern seen in adults: kits performing stereotypies in more than one context do not have particularly high levels of the behaviour, nor are their stereotypies particularly unvarying. In addition, post-feeding stereotypies are commonly shown even by very young animals. Thus it cannot be the case that mink stereotypies are performed first in the pre-feeding situation and only later in other contexts via a process of emancipation. This conclusion is further supported by the finding that the forms of the behaviour often differ pre- and post-feeding. The specific forms and contexts of mink stereotypies suggest certain motivational bases for the behaviour. The rise in stereotypies as feeding time approaches and the sustained levels seen when the animals are not fed indicate hunger as an important factor, and in one dataset, the individuals whose stereotypies were solely pre-feeding used the most Longitudinal movements (i.e. pacing and its variants). This suggests that stereotypies, and pacing movements in particular, may stem from appetitive, food-searching behaviour. In contrast, Stationary movements such as head-twirling are performed more in the hours after feeding, and in one group of mink their levels declined over the pre-feeding period as feeding time approached. The physical appearance of such movements suggests they might be derived from attempts to escape the cage. Thus mink stereotypies areprobably seen in a range of contexts because they develop from several different behaviour patterns, with different motivational bases. The link, in adults, between performance in this range of contexts and the degree of establishment of the behaviour may be explained in one of two ways. In one adult group the data suggest that animals with stereotypy in more than one context incorporate the typically post-feeding Stationary movements into their pre-feeding behaviour, as if emancipation of this movement had occurred. However, data from the other adult group do not support this hypothesis, and the degree of establishment and the number of contexts in which stereotypies are performed may not be causally linked at all, but instead the independent products of individual propensities to develop stereotypic behaviour. Sex and site differences have yet to be fully explained. Females show consistently higher levels of stereotypy than males, as if perhaps they find the environment more frustrating. There are also enormous differences in the frequency and incidence of the behaviour on the two different sites studied.

108 citations


Journal ArticleDOI
TL;DR: The call repertoire, the age-sex distribution of frequencies of call-types, the contexts in which the calls are given, and the most detailed description yet of any great ape's within-group vocalisations are described, suggest two main contexts of production, namely situations of potential separation and potentially agonistic situations.
Abstract: Individuals in social groups of a number of species produce and exchange among themselves frequent, quiet vocalisations. The function of most such vocalisations, here termed 'close' calls, remains obscure, because of the lack of any obvious context of behaviour associated with their production. In this first of two papers that attempt to determine the function of these calls in wild girilla groups, we describe the call repertoire, the age-sex distribution of frequencies of call-types, the contexts in which the calls are given, compare the above measures with available descriptions for the other African great apes, the common and bonobo chimpanzees, and briefly speculate on possible functions. We provide sonograms and 21 acoustical measures of 15 calls in total, including eight 'close' calls, recorded from identified individuals of two habituated heterosexual groups of wild gorillas (Gorilla gorilla) of average composition for the region. In so doing, we provide the most detailed description yet of any great ape's within-group vocalisations. The age-sex classes differed in their use of 'close' calls: adult males called the most in total, immatures the least; and while most classes gave all calls, they gave them at differing frequencies. The differences were consistent across the two-year study period. We suggest two main contexts of production, namely situations of potential separation, and potentially agonistic situations. Thus animals called when far from others and before changes in group activity, and they called when unusually close to one another, especially while feeding. In comparison to the closely related common and bonobo chimpanzees, gorillas apparently had no calls specific to subordinate individuals behaving submissively: subordinate gorillas gave calls in such a situation, but they and dominants gave the same calls (at our current level of analysis) in other situations also. Acoustically and functionally, the gorilla's 'close' calls can be separated into 'syllabled' grunts and non-syllabled' longer calls, we suggest. 'Syllabled' calls might function to maintain contact between animals, to coordinate activity, and to act as mild threats; 'non-syllabled' calls might function as appeasement signals, and to cohere and coordinate group movement when given at good feeding sites, both by attracting animals to the site, and by inhibiting competition at it.

103 citations


Journal ArticleDOI
TL;DR: Pcking at feathers and dustbathing on feathers persisted and remained related in feather trained chicks although their pecking and scratching predominantly became directed to sand.
Abstract: A model which explains feather pecking development as a process by which feathers become treated as a substrate for dustbathing was tested. Chicks kept in wire floored cages were trained from day 3 of life to dustbathe during one hour daily training sessions on either a skin with feathers or on sand. By day 25-26 sand and feather trained chicks dustbathed equally much during training. Feather trained chicks, however, pecked and scratched less. During 3 consecutive dustbathing tests with feathers and sand presented simultaneously, and, in between tests, with additional experience of the new substrate, feather trained chicks increased their pecking and scratching until test 3 where they pecked and scratched the sand as frequently as sand trained chicks. However, they pecked significantly more at feathers than the sand trained chicks and on average still performed 52% of their dustbathing on feathers. Furthermore, the number of pecks at feathers during the last dustbathing choice test was significantly correlated with the percent of dustbathing (vertical wing-shaking) on feathers. The total number of vertical wing-shakes did not change significantly and was similar to that of sand trained chicks. Sand trained chicks never performed dustbathing on feathers and the experience of feathers did not result in significant quantitative changes in any of the behaviours. In the tests the latency to the first vertical wing-shake increased significantly in feather trained chicks after experience of sand. Experience of feathers, however, had no such effect in sand trained chicks. Finally, the progression over the hour of the last training session and of the 3rd choice test of vertical wing-shaking was slower in feather trained than in sand trained chicks. In conclusion, the proposed model was confirmed by the results: pecking at feathers and dustbathing on feathers persisted and remained related in feather trained chicks although their pecking and scratching predominantly became directed to sand. Furthermore, as expected from the model experience of feathers had no effect on sand trained chicks. It is suggested that an association between dustbathing and feather pecking might be prevented by formation of a strong association between dustbathing and attractive stimuli like sand and peat as early as possible.

101 citations


Journal ArticleDOI
TL;DR: Fish shoals may have leaders over extended time periods by investigating swimming directions of shoals of roach and three-spined stickleback, and giving evidence for front fish having a dominant influence on the direction of the shoal.
Abstract: Fish shoals are usually seen as anonymous leaderless groups in which all individuals have the same influence on swimming velocity and direction. This hypothesis was tested by investigating swimming directions of shoals of roach (Rutilus rutilus) and three-spined stickleback (Gasterosteus aculeatus). In roach, the influence of front and rear fish on the shoal's swimming direction was compared by analysing video recordings. Front fish initiated new directions significantly more often and were followed by rear fish. In a second experiment two shoals of sticklebacks were released from two channels which were positioned at an angle relative to each other. The shoals usually appeared with a short time difference at the opening of the channels and then merged. Initially the two shoals faced in different directions based on the orientation of their respective channel and it was recorded which direction prevailed after the shoals had merged. The shoal that left the channel first, and therefore formed the front part of the merged shoal, clearly dominated the direction. Thus, both experiments gave evidence for front fish having a dominant influence on the direction of the shoal. In the context of sustained position preferences of individual fish, recently observed in roach, this suggests that fish shoals may have leaders over extended time periods.

Journal ArticleDOI
TL;DR: It is suggested that EPCs were not necessarily beneficial, even when there was no apparent risk of a penalty by the mate, and an increase in the probability of mate change when an individual has engaged in EPC's in the previous year.
Abstract: (1) We attempted to identify the possible costs and benefits of Extra-Pair Copulations (EPCs) from field observations on a colour-marked population of Oystercatchers, a long lived monogamous species, where male and female share parental care and territory defence. (2) Despite our broad definition of EPCs, only 7.0% of successful copulations by male breeders and 5.1 % of successful copulations by female breeders were classified as EPC's. (3) Many pairs first copulated more than 2 months before egg-laying. The rate at which breeders engaged in Within-Pair Copulations (WPCs) was highest in the month preceding egg-laying: almost 1 copulation per hour during low tide. Males were increasingly likely to initiate WPCs close to the period of egg-laying. Once the clutch was complete copulation rates dropped to near zero. (4) Most EPCs were observed well before egg-laying. In the month preceding and including egg-laying only 3.3% of all successful copulations by females were EPCs. DNA-fingerprinting confirmed that of 65 chicks (from 26 clutches), only 1 was not fathered by the male partner, but by a neighbouring male, which was seen to copulate with the female before egg-laying. Thus, extra-pair paternity was extremely rare, comprising 1.5% of all chicks. Fingerprinting provided no evidence for intraspecific brood parasitism or quasi-parasitism. (5) Members of new pairs (a minority in the population) were observed to copulate with more mates than were members of old pairs, for the same number of copulations observed. (6) Two case studies suggested that EPCs by males and females of old pairs may be attempts to change mate. One female switched to a new mate after 2 years of EPCs with this bird, while the other female is expected to switch to a neighbouring male in 1992, after 3 years of EPCs with this neighbour. (7) The majority of EPCs by male breeders were in their own territory, while female breeders more often moved to the territory of the male, often the neighbour. This sex difference resembles the sex difference in breeding dispersal: female breeders are more likely to switch territory when switching mate (ENS et al., 1993). (8) Male breeders whose mate was absent sometimes evicted soliciting female intruders instantly. This suggest that EPCs were not necessarily beneficial, even when there was no apparent risk of a penalty by the mate. (9) IfEPCs are primarily attempts to change mate, we predict an increase in the probability of mate change when an individual has engaged in EPCs in the previous year. We surmise that we failed to establish this relationship, because our record of EPCs was incomplete and because attempts at mate change apparently often failed due to intra-sexual competition.

Journal ArticleDOI
TL;DR: In this article, the occurrence of social interactions after agonistic conflicts in Japanese macaques was studied and the results obtained with the two methods were very consistent, showing clear evidence for reconciliation and redirection.
Abstract: We studied the occurrence of social interactions after agonistic conflicts in captiveJapanese macaques. We collected data on one group during the mating and the non-mating season and on another group during the mating season only. We compared the social interactions of the victim soon after a conflict with the social interactions of the same individual during control periods, using two different methods. The results obtained with the two methods were very consistent. We found clear evidence for the occurrence of reconciliation and redirection. However, there was no evidence for consolation even when we considered only affiliation between the victim and its own kin or between the victim and the aggressor's kin. Separate analyses for the two groups and the two seasons yielded very similar results.

Journal ArticleDOI
TL;DR: The results suggest that when an animal utters a coo spontaneously, it remains silent for a short interval and when no response occurs, she is likely to give further coos addressing groups members, and the possibility that an animal is able to alter acoustic features of responding coos and matches those of preceding coos is suggested.
Abstract: Vocal exchanges of coo calls in female Japanese macaques were observed in two populations. Temporal patterns of occurrence of these vocalizations during vocal interaction were studied by analyzing inter-call intervals between two consecutive coos. When the second call was uttered by a different caller from the first (DC sequence), most of the second calls occurred at intervals shorter than approximately 0.8 sec, and the remaining ones at intervals longer than approximately 0.8 sec. These results indicate that the second coos of DC sequence are of two different types, and that second calls separated by short intervals may occur in response to the first call, whereas second calls separated by a relatively longer interval may occur independently of the preceding call. When an animal responds to a coo given by another, she appears to do so within a certain period of time. When two consecutiove calls were uttered by the same caller (SC sequence), the second coos rarely occurred within 0.8 sec, but mostly at longer intervals. These results suggest that when an animal utters a coo spontaneously, it remains silent for a short interval and when no response occurs, she is likely to give further coos addressing groups members. Acoustic analysis of two consecutive coos in DC sequence showed that the second coos given by a different caller and occurring within 0.8 sec significantly correlated with those of first coos with respect to several acoustic parameters. This correlation was not observed when coos occurred at intervals of more than 0.8 sec. This phenomenon was confirmed by a playback experiment. The results suggest the possibility that an animal is able to alter acoustic features of responding coos and matches those of preceding coos.

Journal ArticleDOI
TL;DR: Evidence is provided that Portia uses a trial-and-error method as part of its strategy for deriving appropriate signals for different prey, and appears to be an example of deception involving at least a limited form of learning in invertebrates.
Abstract: Portia is a jumping spider that invades other spiders' webs, makes vibratory signals that deceive the resident spider (aggressive mimicry), then attacks and eats the spider. Portia exploits a wide range of prey-spider species. Evidence is provided from observation and experimentation that Portia uses a trial-and-error method as part of its strategy for deriving appropriate signals for different prey. To use this method, Portia first broadcasts an array of different signals, then narrows to particular signals as a consequence of feedback from the prey spider. Feedback can be web vibration or seeing spiders move, or both. This appears to be an example of deception involving at least a limited form of learning, an uncommon phenomenon in invertebrates.

Journal ArticleDOI
TL;DR: Tailless lizards modify thermoregulatory behaviour, but obtain the same thermoreGulatory precision as tailed lizards, possibly allowing maximization of physiological processes linked to tail regeneration.
Abstract: The consequences of tail loss on the thermal biology of high-altitude rock lizards (Lacerta monticola) were studied by comparing field body temperatures, selected body temperatures in a gradient, and behavioural patterns of thermoregulation of tailed and tailless lizards in the field. Neither field nor selected body temperatures differed significantly between these groups. Time spent basking, mean duration of basking, and basking frequency did not differ between tailed and tailless lizards. Tailless lizards seemingly adjusted for running impairment by using rocks to a greater extent than did tailed lizards, and low morning body temperatures by increasing maximal duration of basking periods and keeping shorter distances to the nearest refuge. Tailless lizards modify thermoregulatory behaviour, but obtain the same thermoregulatory precision as tailed lizards, possibly allowing maximization of physiological processes linked to tail regeneration.

Journal ArticleDOI
TL;DR: It is demonstrated that shoaling with Schreckstoff-sensitive cyprinids can provide a benefit for sticklebacks, which indicates that they can obtain information about a potential predator threat by monitoring the behaviour of the chub.
Abstract: Awareness of predators in group living species can be brought about in two ways. Either an individual directly senses a predator itself or it gets indirect information by monitoring other group members which have detected a predator. In this paper, I demonstrate such information transfer between two species of fish. A mixed shoal of chub (Leuciscus cephalus) and sticklebacks (Gasterosteus aculeatus) was presented with Schrecksloff, an alarm substance, wide-spread among cyprinid fishes. Sticklebacks are not sensitive to Schreckstoff and their behaviour was observed in the presence of naive and habituated chub. Naive chub responded to Schreckstoff with a strong and immediate fright reaction whereas habituated chub did not. Sticklebacks only displayed a fright reaction when associated with naive chub, which indicates that they can obtain information about a potential predator threat by monitoring the behaviour of the chub. This result suggests that shoaling with Schreckstoff-sensitive cyprinids can provide a benefit for sticklebacks.

Journal ArticleDOI
TL;DR: This study is the first to demonstrate chemosensory recognition of predators by a stickleback (family Gasterosteidae), and indicates that predator diet influencesChemical recognition of unfamiliar predators and that individuals from a predator-sympatric population can recognize predators even when the predator's recent diet has not included conspecific fish prey.
Abstract: Chemical recognition of familiar or unfamiliar predators may allow prey to detect predators under conditions in which vision is of limited utility. In laboratory tests, brook stickleback (Culaea inconstans) from a pike-allopatric population responded to chemical stimuli from northern pike (Esox lucius) with an appropriate anti-predator behaviour (decreased activity) only when the stimulus was obtained from pike that had eaten conspecific stickleback. In contrast, stickleback from a pike-sympatric population exhibited a fright response to chemical stimuli from pike that had eaten only heterospecific fish prey. Our study is the first to demonstrate chemosensory recognition of predators by a stickleback (family Gasterosteidae). Our results further indicate that predator diet influences chemosensory recognition of unfamiliar predators and that individuals from a predator-sympatric population can recognize predators even when the predator's recent diet has not included conspecific fish prey.

Journal ArticleDOI
TL;DR: The female resistance, although for so far largely neglected, may have potential importance in the mate choice and sexual selection of aquatic crustaceans with precopulatory guarding and may lead to selection among male candidates.
Abstract: In a laboratory experiment in I. baltica the precopulatory guarding was preceded by a period of struggles between the sexes as males continuously tried to initiate the precopulatory guarding and females resisted their guarding attempts. This struggling lasted for a few days, during which the females escaped from the males on the average 1.3 times per hour. While the females resisted, the males usually responded by kicking back. Once the precopula started, on the average 43 h before the completion of the female parturial ecdysis, the female resistance stopped. If the guarding male was replaced by another male, the female accepted the new male without resistance or resisted only weakly. Larger males were able to perform longer precopulas, and furthermore, when males were hunger stressed they performed shorter precopulas than control males. The female resistance and the existence of struggles imply a conflict between the sexes over whether or not to start the precopulatory phase. This conflict may occur either because of different optimum precopula duration of the sexes or because of the unwillingness of the females to pair with whatever male. By resisting, females may, at least to some extent, control the duration of the guarding, and the resistance may lead to selection among male candidates. Thus the female resistance, although for so far largely neglected, may have potential importance in the mate choice and sexual selection of aquatic crustaceans with precopulatory guarding.

Journal ArticleDOI
TL;DR: Social groups of the communal stripe-backed wren were investigated to investigate the recently-discovered shared paternity between dominant and subordinate males, and the mating system in wren groups was either monogamous or polyandrous, depending upon the relatedness between subordinate males and the dominant female.
Abstract: We made behavioral observations in 37 social groups of the communal stripe-backed wren during 1990 and 1991 to investigate the recently-discovered shared paternity between dominant and subordinate males (or "SMs"). We found two distinct kinds of social groups that differed in terms of social behavior: "mother" groups, which contained only subordinate males that were sons of the dominant female (termed "DF-sons"), and "stepmother" groups, which contained at least one subordinate male unrelated to the dominant female (termed "DF-stepsons"). In mother groups only dominant males courted dominant females, mate-guarding was infrequent and aggression by dominant males toward other males was absent. On the other hand, stepmother groups were characterized by frequent association with and courtship of dominant females ("DFs") by both dominant males ("DMs") and DF-stepsons and relatively frequent aggression by dominant males toward DF-stepsons. DF-stepsons, moreover, sired 15% of all young in stepmother groups. Thus, incest avoidance dictated the behavior of subordinate males, and the mating system in wren groups was either monogamous or polyandrous, depending upon the relatedness between subordinate males and the dominant female.

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TL;DR: The apparent preference of white- Striped females for tan-striped males suggests that there are benefits to negative asortative mating other than those that might arise from differences in aggressive performance.
Abstract: Morph and sex-specific differences in aggressive performance were examined in the white-throated sparrow. Among the four morph/sex classes, white-striped males had the strongest response to white-striped models and were the most likely to approach and attend song playbacks independently. The slightly weaker responses of tan-striped males and white-striped females were similar to each other. Tan-striped females were the least aggressive. Aggression by white-striped females enabled tan-striped male x white-striped female pairs to perform as well, or better, than white-striped male x tan-striped female pairs. Tan-striped males paired earlier than white-striped males. An increased prevalence of territorial tan-striped males corresponded to the arrival of females on the breeding grounds. The data are consistent with the hypothesis that negative assortative mating benefits tan-striped males through the supplemental aggression of white-striped females. However, the apparent preference of white-striped females for tan-striped males suggests that there are benefits to negative asortative mating other than those that might arise from differences in aggressive performance.

Journal ArticleDOI
TL;DR: Intensity of male-male competition and sexual selection were studied in the field cricket, Gryllus pennsylvanicus, in an outdoor arena and demonstrated that direct and total selection was highly variable and often relaxed.
Abstract: Intensity of male-male competition and sexual selection were studied in the field cricket, Gryllus pennsylvanicus, in an outdoor arena at four sex ratios, male-only (5:0), male-biased (5:2), unity (5:5) and female-biased (5:10). Fighting frequency was highest at male-biased and unity sex ratios. Fighting success was correlated with male body weight at all sex ratios. Calling duration and searching distance decreased with increased female numbers. Opportunity for selection was highest at the male-biased and lowest at the female-biased sex ratio. Selection gradients and differentials were calculated and demonstrated that direct and total selection was highly variable and often relaxed. Direct selection favored male weight at the male-biased sex ratio and total selection for weight occurred at unity. There was no selection on male weight at the female-biased sex ratio. Total and direct selection for increased calling duration occurred at the male-biased sex ratio. Only total selection for calling duration was found at unity, whereas direct selection acted against calling duration at the female-biased sex ratio. Selection did not act on searching at any sex ratio. Natural variations in sex ratios occur and fluctuations in selection on correlated male traits may maintain additive genetic variation for traits important in male-male competition.

Journal ArticleDOI
TL;DR: In this paper, the authors examined components of the stimulus-response mechanism and their effects on feeding rates to nestlings in cooperative singular-breeding green woodhoopoes Phoeniculus purpureus, and showed that both auditory and visual stimuli played important roles.
Abstract: 1. I experimentally examined components of the stimulus-response mechanism and their effects on feeding rates to nestlings in cooperative singular-breeding green woodhoopoes Phoeniculus purpureus, and showed that both auditory and visual stimuli played important roles. 2. Breeding status did not influence the way in which adults responded to the various stimuli. 3. Adult woodhoopoes fed foreign nestlings which had been transferred as frequently and with as much food as their own nestlings. 4. Observational evidence from two different studies showed that recent-immigrant nonbreeders provided young with as much food as other established nonbreeders. Thus, there is no evidence that nonparental feeding behaviour is related to nest-site specificity, kin discrimination, or prior association with breeders in this species. 5. Demographic data gathered over a period of eight years (1981-1989) for a total of 258 "group years" suggested that helpers did not gain any direct or indirect fitness benefits as a result of their nonparental feeding contributions to young per se. 6. I conclude that nonparental feeding behaviour has persisted as unmodified parental feeding behaviour in this species and suggest that this may be the case for most other singular cooperative-breeding species.

Journal ArticleDOI
TL;DR: Both sexes make trade-offs between predator avoidance and behaviours associated with mating, and Females, however, seem to take higher risks during the courtship phase in order to find a partner compared to males.
Abstract: The effects of predation risk on the reproductive behaviour of male and female sand gobies, Pomatoschistus minutus, were investigated in two separate aquarium studies In the presence of a predator (cod, Gadus morhua), males decreased their courtship activity while females did not alter their level of activity In the second study, there was no difference between treatments (with and without predator) in the time from when a female was presented to a male with a nest until spawning took place or in the amount of eggs laid However, pre-spawning behaviour differed between the two treatments When the cod was in sight, both males and females burrowed in the sand more often In the absence of a predator, pairs spent longer together in the nest before spawning started, and females also inspected the nest alone, which never happened during predator presence Hence, both sexes make trade-offs between predator avoidance and behaviours associated with mating Females, however, seem to take higher risks during the courtship phase in order to find a partner compared to males

Journal ArticleDOI
Seiichi Mori1
TL;DR: Three-spined stickleback males in a small stream of the Tsuya River, Gifu Prefecture, Central Japan, was studied with reference to timing of nesting initiation, use of space for nesting and social interactions and reproductive success.
Abstract: 1) The breeding succes of three-spined stickleback (Gasterosteus aculeatus L., forma leiura) males in a small stream of the Tsuya River, Gifu Prefecture, Central Japan, was studied with reference to timing of nesting initiation, use of space for nesting and social interactions. The observations were made almost daily during March to early July 1988 along the shore at a distance of 1-2 m from the fish and nests. 2) All the males in an enclosed study pool were individually marked (99 males). Furthermore, a total of 67 females were marked and observed weekly. The males were individually observed and their agonistic, courtship and parental behaviour as well as their reproductive success were quantified. Reproductive success of individual male was measured as the number of nests built, the number of successful nests, the number of hatched fry per nest. Nest sites were categorized in six types (A-F) on the basis of the proportion of vegetation cover around the nest and distance from the shore. 3) Body size and environmental factors (water temperature, water depth, changes in water level) were not correlated with reproductive success. Flooding was not a major cause of unsuccessful nesting. The brightness of nuptial colouration at the onset of breeding correlated significantly with individual success. Individual variation in the development of secondary sexual characteristics such as a nuptial colouration may have an important consequence for the lifetime reproductive success of the individuals. There was no relationship between fish density and reproductive success. 4) All males that nested more than once had begun breeding early in the season. The sooner a male started nest-building, the more opportunities he had to complete breeding cycles. 5) After an unsuccessful nest, males were significantly more likely to move their nest sites than after a successful nest. The subsequent nesting cycle was not always successful. 6) There was variation in nest-sitc location. The spatial pattern of nest distribution was strongly related to the temporal pattern, because the first males which settled, more often built their nests at sites along the shore where the nest was covered on one or two sides by vegetation. The location of nest site was significantly correlated with reproductive success. When males nested in partly concealed places along the shore, they could sometimes obtain a high reproductive success irrespective of the date of breeding initiation. Thus, reproductive success was largely determined by the timing of nest-building and nest position.

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TL;DR: Analysis of the social behaviour of wolves in and around the mating season at Burger's Zoo in Arnhem (the Netherlands) found that male competition was comparatively more context-related while female competition took the form of unprovoked hostility.
Abstract: [The social organization of wolves is characterised by strong pairbond associations. Groups may consist of a mating couple and their remaining offspring or of an association of potentially reproductive adults. When a pack consists of several adults, intrasexual mating competition and intersexual partner preference are expected to play an important role in the establishment of sexual relationships. Data from the wild show that as a rule only one female in a pack gives birth. Female suppression is assumed to prevent the other pack members from breeding. Our main interest was to elucidate the proximate behavioural mechanisms by which the socio-sexual relationships are structured in times of the mating season. Special attention was paid to the influence of differences in dominance status and sex on the competitive interactions between pack members. From 1977 to 1985 we studied the social behaviour of wolves in and around the mating season at Burger's Zoo in Arnhem (the Netherlands) by means of detailed observations on two wolf packs. Together with a general rise in frequency of (sexuo-affiliative) interactions we observed an increase in general aggression and in the frequency of interventions during the mating season. Our results reveal certain differences in male and female mating strategies. 1) Separative interventions were observed predominantly in males and were directed against male-female sexual interactions, while such interventions by females were less apparent. 2) Males showed a high frequency of intrasexual aggression but only during the mating season. By contrast, females showed less intrasexual aggression, and instead, showed a high level of intrasexual dominance display, especially the α-female, and they did so both in and outside the mating season. 3) Males tended to intervene in especially those intersexual contacts in which their own preferred female was involved, whereas the intolerance of the α-female was more general, i.e. it was shown with respect to all manifestations of other females. These patterns clearly explain why in free nature wolf social organization tends towards a multi-male uni-female system in which the non-dominant males have little chance of sexual contact, but are generally tolerated as helpers in brood care. In conclusion, male competition was comparatively more context-related while female competition took the form of unprovoked hostility., The social organization of wolves is characterised by strong pairbond associations. Groups may consist of a mating couple and their remaining offspring or of an association of potentially reproductive adults. When a pack consists of several adults, intrasexual mating competition and intersexual partner preference are expected to play an important role in the establishment of sexual relationships. Data from the wild show that as a rule only one female in a pack gives birth. Female suppression is assumed to prevent the other pack members from breeding. Our main interest was to elucidate the proximate behavioural mechanisms by which the socio-sexual relationships are structured in times of the mating season. Special attention was paid to the influence of differences in dominance status and sex on the competitive interactions between pack members. From 1977 to 1985 we studied the social behaviour of wolves in and around the mating season at Burger's Zoo in Arnhem (the Netherlands) by means of detailed observations on two wolf packs. Together with a general rise in frequency of (sexuo-affiliative) interactions we observed an increase in general aggression and in the frequency of interventions during the mating season. Our results reveal certain differences in male and female mating strategies. 1) Separative interventions were observed predominantly in males and were directed against male-female sexual interactions, while such interventions by females were less apparent. 2) Males showed a high frequency of intrasexual aggression but only during the mating season. By contrast, females showed less intrasexual aggression, and instead, showed a high level of intrasexual dominance display, especially the α-female, and they did so both in and outside the mating season. 3) Males tended to intervene in especially those intersexual contacts in which their own preferred female was involved, whereas the intolerance of the α-female was more general, i.e. it was shown with respect to all manifestations of other females. These patterns clearly explain why in free nature wolf social organization tends towards a multi-male uni-female system in which the non-dominant males have little chance of sexual contact, but are generally tolerated as helpers in brood care. In conclusion, male competition was comparatively more context-related while female competition took the form of unprovoked hostility.]

Journal ArticleDOI
TL;DR: Extended relaxed selection from rattlesnakes, but not gopher snakes, appears to have reduced the inhibition to harass large gopherSnake harassment by adults might protect pups by interfering with snake hunting activities.
Abstract: Nonvenomous Pacific gopher snakes (Pituophis melanoleucus catenifer) and venomous northern Pacific rattlesnakes (Crotalus viridis oreganus) have coexisted in a predator-prey relationship with California ground squirrels (Spermophilus beecheyi) for many thousands of generations. This long-term relationship has fostered in ground squirrels the evolution of antisnake defenses that consist of physiological resistance to rattlesnake venom and behavioral tactics of probing and harassing that might facilitate snake-species discrimination. Snake harassment by adults might also protect pups by interfering with snake hunting activities. Some ground squirrel populations have colonized habitats where rattlesnakes, but not gopher snakes, are rare or absent. Initial research indicates that squirrels experiencing relaxed selection from rattlesnakes are very aggressive toward their remaining nonvenomous snake predator, the gopher snake. Two experiments investigated the effects of relaxed selection from rattlesnakes by examining: 1) changes in level of venom resistance, 2) the reorganization of antisnake behaviors in lab-born pups and wild-caught adults from different sites, and 3) the role of natural experiences on the development of antisnake behavior in a rattlesnake-adapted population. Level of venom resistance was examined by an in vitro radioimmunoassay of serum-to-venom binding of two populations of Douglas ground squirrels (S. b. douglasii). The ancestors of one population are estimated to have experienced relaxed selection from rattlesnakes for about 9,000 years based on genetic distance and radiocarbon analyses. The antisnake behavior of 60-73 day-old lab-born pups from these two populations was video taped during presentations of a caged rattlesnake or gophcr snake for alternate 5-min trials in a seminatural laboratory setting. Two groups of wild-caught adult Beechey groundsquirrels (S. b. beecheyi) were studied using the same protocol for examining antisnake behavior. One group was obtained from a population that recently colonized a rattlesnake-rare site and exhibits moderate venom resistance. The second group came from a population that exhibits very low venom resistance and inhabits a rattlesnake-free site; relaxed selection from rattlesnakes for this population is estimated to span approximately 60,000 years. Comparisons of Douglas ground squirrels from rattlesnake-abundant and rettlesnakerare sites revealed that venom resistance declined approximately 59% after an estimated 9,000 years of relaxed selection from rattlesnakes. Lab-born Douglas pups from the same rattlesnake-rare site were more aggressive toward the gopher snake than toward the rattlesnake whereas pups from the population experiencing predation from both species of snake treated both snakes as similarly dangerous. Unlike pups, wild-caught adults from the rattesnake-adapted population harassed the rattlesnake more intensely than the gopher snake, a phenomenon that may reflect their experience with snakes in nature and larger body size that reduces their vulnerability to envenomation. Wild-caught Beechey ground squirrels that recently colonized a rattlesnake-rare site did not differentiate the rattlesnake and gopher snake whereas Beechey ground squirrels whose ancestors have experienced prolonged relaxed selection from rattlesnakes were more aggressive toward the gopher snake. Consistent with previous findings, prolonged relaxed selection from rattlesnakes, but not gopher snakes, appears to have reduced the inhibition to harass large gopher snakes. This microevolutionary shift in increased aggressiveness toward the gopher snake could result from the virtual absence of any risk in misidentifying rattlesnakes from gopher snakes.

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TL;DR: It is predicted that acute phase responses increase tadpole vulnerability to predation by influencing thermoregulatory behavior and their ability to detect, and avoid capture by, salamanders, and it is found that the sterotypical effects of the acute phase response can lead to increased predation.
Abstract: In this paper we propose the hypothesis that pathogen-induced host defense responses result in altered host behaviors and enhanced predation In particular we examine the effects of the acute phase response (whose effects include fever, reduced activity and malaise) on antipredatory behavior in bullfrog (Rana catesbeiana) tadpoles This host response is associated with the preliminary stages of infection with many pathogens yet its behavioral effects have received little attention Bullfrog tadpoles were injected with alcohol-killed bacteria to induce a response to infection and their ability to detect and avoid capture by predatory salamanders (Taricha granulosa) was explored We predicted that acute phase responses increase tadpole vulnerability to predation by influencing thermoregulatory behavior and their ability to detect, and avoid capture by, salamanders We found that the sterotypical effects of the acute phase response can lead to increased predation Malaise affected the refuge seeking behavior of the tadpoles in the presence of salamanders We suggest that for tadpoles provided with refuges, altered behaviors are a liability This endogenous response may afford some parasites a potential pathway to their next host

Journal ArticleDOI
TL;DR: The time budgets of all adult and yearling black-tailed prairie dogs in a wild population were measured between late April and mid-August 1989, finding that males were more vigilant and fed less than females did and non-fathers behaved more like females.
Abstract: The time budgets of all adult and yearling black-tailed prairie dogs in a wild population were measured in 14 separate samples between late April and mid-August 1989. In general, males were more vigilant and fed less than females did. This sex difference was due largely to the behavior of males that had sired offspring; non-fathers behaved more like females. As the summer progressed, prairie dogs spent more time feeding and less time vigilant. The lone exception to this pattern was mothers, who fed less and spent more time vigilant as the summer progressed. Other influences on time allocation produced similar effects for all sex/parental groups: animals were more vigilant while in tall vegetation and in the early morning as opposed to mid-day or evening. Environmental (e.g. weather) and social (e.g. number of other adults and pups present) effects on time allocation were analyzed via multiple regression. Of all potential influences, distance from the nearest burrow seemed to have the most consistent impact on time allocation for all individuals. These results point to strong effects of sex, parental status and environmental context in determining the particular pattern of time allocation observed in an individual prairie dog.

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TL;DR: In this article, the authors compared the attenuation and differential attenuation of pure tones, decreases in modal frequencies of computer simulated songs of American redstart (Setophaga ruticilla), and the decay of redstart songs and white noise at deciduous, coniferous and open forest sites.
Abstract: The environmental adaptation hypothesis (EAH) regarding birdsong dialects or ncighbourhoods states that song similarities between neighbouring individuals arise because of common influences on their songs exerted by the acoustic environment of their habitat. An assumption of the hypothesis is that sounds are distorted differently by different types of habitat. A prediction of the hypothesis is that some songs or parts of songs transmit better than others, depending on the habitat of their origin. We tested the assumption and prediction by comparing the attenuation and differential attenuation of pure tones, decreases in modal frequencies of computer simulated songs of American redstarts (Setophaga ruticilla), and the decay of redstart songs and white noise at deciduous, coniferous and open forest sites. The songs were representative of those used by redstarts living in thc three habitats. Results supported the assumption of acoustic differences between habitats but did not support the prediction that some songtypes transmit with less distortion in specific habitats than in others. The EAH also predicts that individuals which inhabit similar vegetation should share more song features than individuals which inhabitat dissimilar vegetation. To test this prediciton samples of songs were taken from the three habitats in different years. There were significant associations by habitat in both samples, but only one of several variables measured was significant and the discriminating variable was not the same for the two periods. Considering together the tests of the assumption and the two predictions, we conclude that for American redstarts evidence of the influence of the acoustic features of habitat on the formation of song dialects is mixed and not convincing.