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Experienced Males (experience + male)
Selected AbstractsInfluence of Age and Prior Experience on Territorial Behavior and the Costs of Defense in Male Collared LizardsETHOLOGY, Issue 1 2007Andrew M. Schwartz In polygynous species where males maintain strong interseasonal philopatry to the same breeding territories, older individuals have prior experience defending their areas, whereas younger individuals are defending a territory for the first time. Theoretical and empirical studies predict that under such conditions the cumulative costs of defense may be lower for older experienced males as a consequence of familiarity with environmental and/or social conditions in their particular local habitats. We used quantitative data from focal observational studies and introduction experiments to test the hypothesis that older collared lizard males (Crotaphytus collaris) with prior territorial experience (3 yr+ males) acquire larger territories allowing them to court more, different females, with greater frequency without incurring higher defense costs. Consistent with this hypothesis, 3 yr+ males controlled significantly larger territories and courted more females, without having significantly higher rates of territory patrol, frequencies of advertisement display, or aggressive interactions with same-sex competitors. Moreover, the intensity of responses to size- and age/experience-matched tethered intruders by 3 yr+ males was lower than that by 2 yr males in their first season of territory defense. Our results support the hypothesis that age/prior occupancy of territories lowers defense costs allowing males to defend larger areas and increase opportunities to court females, perhaps increasing mating opportunities. By contrast, 2 yr males may need to respond more aggressively to intruders because their ownership of territories is tenuous as a consequence of shorter territory occupancy. [source] Achromatic Plumage Reflectance, Social Dominance and Female Mate Preference in Black-Capped Chickadees (Poecile atricapillus)ETHOLOGY, Issue 10 2005Elisabeth A. Woodcock Individual variation in achromatic plumage reflectance of male Black-capped Chickadees (Poecile atricapillus) is correlated with social rank and reproductive success, suggesting it may play an important role in sexual signaling. We asked whether female chickadees could assess male quality based on plumage, in the absence of information about relative social dominance. Sexually mature but inexperienced females captured during the pair formation period in late fall and early winter were presented with a choice of two unfamiliar, sexually experienced males in separate compartments of an outdoor mate choice arena. Following each preference trial, we released the males into a single compartment and scored their pairwise dominance interactions. In 10 of 11 trials, females spent significantly more time with the male subsequently identified as dominant, despite not witnessing the males interact. Spectral analysis of male plumage reflectance revealed that UV-chroma of dark body regions (bib, cap and mantle) was significantly greater in dominant, preferred males and that dominant, preferred males had significantly brighter white cheek patches. There were no differences in vocalization rates of preferred and non-preferred males. These results show that female chickadees can rapidly assess unfamiliar males based on visual cues, and suggest that variation in achromatic plumage functions in sexual signaling. [source] Site-dependent population dynamics: the influence of spatial habitat heterogeneity on individual fitness in the sedge warbler Acrocephalus schoenobaenusJOURNAL OF AVIAN BIOLOGY, Issue 2 2008Tadeusz Zaj During nine years of study, we detected a mechanism corresponding to site dependence operating in a population of the sedge warbler Acrocephalus schoenobaenus inhabiting a natural wetland of high within-habitat heterogeneity. Sites with a larger share of cover by tall wetland vegetation were preempted during spring settlement; they were occupied in more breeding seasons and by more experienced males. The fitness of males occupying these sites was higher in terms of local recruit production. The total area occupied by the population expanded or contracted depending on its population size. This mechanism increased or decreased the mean site quality, influencing local recruitment of young, although mainly by changing the share of unproductive sites in the total pool of occupied sites. The results indicate that population demographic rates may depend on the spatial heterogeneity of resources at the level of individuals. [source] Gender Earnings and Part-Time Pay in Australia, 1990,1998BRITISH JOURNAL OF INDUSTRIAL RELATIONS, Issue 3 2003Alison Preston This paper studies the effects of enterprise bargaining on the pay position of women and other target equity groups. Contrary to a priori expectations the paper shows a convergence in full-time and part-time gross gender pay gaps following the adoption of decentralized wage bargaining. Convergence in the latter reflects compositional (human capital) effects: the entry of less qualified and less experienced males into part-time employment. Overall the results show a deterioration in the pay position of men employed full-time relative to women and part-timers (men and women) brought about by slower wage growth amongst men in full-time employment. [source] | ||||||||||