نتایج جستجو برای: bellied malkoha
تعداد نتایج: 613 فیلتر نتایج به سال:
Plumage coloration has long been studied as a sexually selected character. The tawny-bellied seedeater, Sporophila hypoxantha, is a sexually dichromatic species, with adult males the more colorful sex and juvenile males indistinguishable from females. We did choice experiments to evaluate female preferences for males that differ in age or plumage coloration. Females were evaluated in three expe...
Most studies on similar coexisting species enumerate ecological differences which presumably reduce the demand for common resources and allow coexistence (MacArthur 1958, Root 1967, Stallcup 1968). As Schoener (1974) pointed out, however, these differences alone do not demonstrate the role of competition in structuring avian communities. Even if niches were arranged randomly with respect to one...
Batrachochytrium dendrobatidis is considered a main driver of the worldwide declines and extinctions of amphibian populations. Nonetheless, fundamental questions about its epidemiology, including whether it acts mainly as a "lone killer" or in conjunction with other factors, remain largely open. In this paper we analysed contemporary and historical samples of the endangered Apennine yellow-bell...
Cover photo: A vigilant yellow-bellied marmot (Marmota flaviventris) at the Rocky Mountain Biological Laboratory, Colorado, USA. Blumstein et al. (pp. 879–887) report that the time allocated to anti-predator vigilance in marmots is heritable and is weakly correlated with locomotor performance. Interestingly, faster marmots allocate more time to vigilance while slower marmots allocate less time....
Threatened species managers are often required to make swift decisions in the face of considerable uncertainty. We tested a structured approach for evaluating conservation options critically endangered orange-bellied parrot. The Orange-bellied Parrot Recovery Team provides advice government agencies inform allocation limited number captive-bred birds different release scenarios. Using expert el...
The social substructure and the distribution of genetic variation among colonies of yellow-bellied marmots, when analyzed as an evolutionary system, suggests that this substructure enhances the intercolony variance and retards the fixation of genetic variation. This result supports a traditional theory of gradual evolution rather than recent theories suggesting accelerated evolution in social m...
Ancient origins, profound ecological divergence, and extensive hybridization make the fire-bellied toads Bombina bombina and B. variegata (Anura: Bombinatoridae) an intriguing test case of ecological speciation. Previous modeling has proposed that the narrow Bombina hybrid zones represent strong barriers to neutral introgression. We test this prediction by inferring the rate of gene exchange be...
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