摘要:

(1) The analyses were based on the comparison of three wood-dwelling, medium sized raptor species with 366 nest-years in BuzzardsButeo buteo, 110 nest-years in GoshawksAccipiter gentilisand 34 nest-years in Honey BuzzardsPernis apivorus. (2) Field data from 52 different nesting-habitat plots of Buzzards, 25 plots of Goshawks and 28 plots of Honey Buzzards were evaluated by discriminantanalysis and revealed differences in nest-habitat selection between these species. (3) Nesting-habitat features (measured in these plots) which were found to be associated with habitat selection in a principal-component-analysis, were also related to reproductive success with some differences between the species. These differences were similar to the different habitat selection found in the discriminant- analysis. The gradient (from poor to good) in habitat selection is slightly different between the species considered. Goshawk and Buzzard were found to be more closely related in habitat use than either were to the Honey Buzzard. (4) None of the species used their nesting-territories at random from year to year. Therefore, certain places had nests more often than expected by chance at the population levels found and others less often. (5) This use was related to nest-success. On average, the most often used territories showed the greatest success in all species. (6) From both parts of my analyses (2 and 3 and 4 and 5) the same nesting- habitat features were associated with good breeding success: habitat-parameters which gave good correlations to breeding success were found to be overrepresented in the more frequently used territories.

ISSN:0394-9370    

DOI:10.1080/08927014.1996.9522931

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Models of sexual selection assume that there is genetic control of mating behaviour. A useful tool for studies of consistency in male display and female mate preference is repeatability, a quantitative genetics measure that sets an upper limit on heritability. In this study, repeatability of several parameters of courtship behaviour in Montandon’s newt,Triturus montandoni, were calculated. Only one characteristic of male display had repeatability significantly different from zero. Estimates of repeatability for absolute female preferences with respect to two male characteristics were near-zero. Other parameters of female mating behaviour were also inconsistent. The results may suggest that there is little additive genetic variation in mating behaviour.

ISSN:0394-9370    

DOI:10.1080/08927014.1996.9522932

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Interspecific differences in population variability (fluctuations or cycles) can be due to environmental variability, different trophic interactions or differences in movement behaviour under severe circumstances. To establish the most important factor, variations in numbers of small mammals and passerine birds were examined during 11 years along transect lines extending from mature coniferous forests out into cleared areas, thus providing the potential for recording temporal variation at least in suboptimal habitats. Coefficients of variation did not correlate with sample means and were considerably higher in mammals than in birds. Spatial variation was usually larger than temporal variation, except for two small mammal species. Tropical migrants among the passerines demonstrated especially low temporal variation. Correlations with extrinsic variables (variation in weather and food supply) were only observed in resident mammals and birds. The differences in variability between the two vertebrate classes could not be related to food habits or demography but probably to differences in mobility. The later observation calls for consideration and definition of species-specific scales when examining relations between population fluctuations and extrinsic or community factors.

ISSN:0394-9370    

DOI:10.1080/08927014.1996.9522933

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Groups ofO. mossambicuswere formed 10 days after the end of mouthbrooding and were observed at the onset of sexual maturity by focal sampling. The agonistic interactions were recorded and used to construct sociometric matrices. The dominant hierarchies were found to be linear (h = 0.94 ± 0.06) and semi-despotic (alpha individuals participated in more than half of the group interactions). Size and sex were important factors in determining the outcome of agonistic interactions. The alpha individuals were males and the largest members of their groups. Despite the fish being raised together for a long period, agonistic interactions involving high intensity aggression were common which indicates that at this stage frequent assessment of competitive ability is performed by the group members. Agonistic interactions are especially common among males and less frequent than expected among females and between males and females. Omega individuals participated in fewer agonistic encounters than expected. According to rank distance, hierarchical neighbours were involved in less interactions than expected except for symmetrical interactions that made up a low proportion of the total number of interactions. This finding is contrary to expectations, but maybe explained by the fact that aggression is initiated by dominants presumably to maintain their status against individuals that are clearly subordinates. It was found that a single dominance index (victories/victories + defeats) was a very good predictor (rs= 0.963, n = 45) of the rank order positions of the individuals within their groups. It is argued that in species where agonistic interactions are not controlled by processes involving complex cognitive operations this index may be a biologically realistic indicator of aggressive motivation.

ISSN:0394-9370    

DOI:10.1080/08927014.1996.9522934

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Ranging behaviour (home range size, core area size, activity levels) of four red foxes (Vulpes vulpes; three males and one female) was studied by radio-tracking in a rural area of Central Italy during the mating and breeding seasons (January to May). Home range size was equal or smaller than in other areas, ranging from 47 to 320 ha (kernel analysis) or from 57 to 394 ha (minimum convex polygon), with the exception of a yearling male, who ranged over a very large area (2307 ha). Core areas ranged from 11 to 29 ha. Foxes were most active between 19:00 and 00:00 hr, then activity decreased slowly until sunrise. Foxes used about 25% of their range each night, with individually different strategies: the two resident males greatly increased their range in the second half of female fertile period, whereas the nomadic male restricted his large range during the peak of matings. Barking bouts (indices of agonistic and contact behaviour) were most common after median ovulation date. The female decreased her range at the time of births. The range expansion by males during the mating season, also reported by previous studies, was limited to the second half of the females' fertile period. Males could therefore maximise individual reproductive success by roaming only after the oestrus of their mate. Because of the small number of foxes followed, these results should be verified in other studies.

ISSN:0394-9370    

DOI:10.1080/08927014.1996.9522935

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Time budgets for 17 behaviors were analyzed for cohort, day-period, season- period and interactions among the main effects for three colonies of yellowbellied marmots in the Upper East River Valley in western Colorado. These effects explained up to 79% of the variation in the behaviors. Marmots allocated more time (40-60%, 110-265 min daily) above-ground to sitting/lying than to any other activity. Foraging was the other major activity (12-23%, 37 to 94 min daily). Vigilance/alert varied from 1.1 to 14.5% and from 12.0 to 71.7 min daily. Social status affected the time budget, especially time allocated to vigilance/alert. All other behaviors averaged about 5% or less except for out-of-sight and enterburrow. The adult male cohort spent significantly more time above-ground than all other cohorts and reproductive females allocated significantly more time to foraging than the other cohorts. The amount of time spent above-ground decreased linearly from the down-river site to the up-river site. The proportion of time spent above-ground was significantly less at mid day than in the morning or afternoon. Above-ground activity was lowest during gestation, increased during lactation, remained high during early post-lactation, and declined during the final season-period. The following significant relationships common to the three colonies suggest species characteristics or common environmental influences: more time allocated to foraging and foraging-vigilance in the afternoon and more time allocated to foraging-alert, alert, and locomotion during gestation and lactation than during post-lactation. Marmots adjust their behaviors according to prevailing conditions. The remaining significant relationships can be attributed to specific age-sex cohorts or to habitat differences. Because marmots allocate so much time to sitting/lying, we suggest that energy budgets are not constrained by foraging time but by time required to process ingested food. Similarly, time spent vigilant/alert does not seem to constrain energy intake. Social behavior is not limited by time, but could easily be expanded by spending less time inactive. In general, there do not seem to be tradeoffs among activities. Among other species of ground-dwelling sciurids, social behavior occupies a small proportion of the time budget, but the amount of time allocated to foraging and sitting/lying varies widely.

ISSN:0394-9370    

DOI:10.1080/08927014.1996.9522936

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

ISSN:0394-9370    

DOI:10.1080/08927014.1996.9522937

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor