The competition for power in a complex social world is hypothesized to be a driving force in the evolution of intelligence. More specifically, power may be obtained not only by brute force but also by social strategies resembling human politics. Most empirical evidence comes from primate studies that report unprovoked aggression by dominants to maintain power by spreading fear and third-party i...

Common ravens (Corvus corax) are a major predator on the threatened desert tortoise (Gopherus [= Xerobates] agassizii). Large numbers of juvenile tortoise shells have been found beneath known raven nests and perches; many shells that show evidence consistent with raven predation have been found sporadically throughout the range of the tortoise; significant proportional decreases in juvenile siz...

Complex social behavior builds on the mutual judgment of individuals as cooperation partners and competitors [1]. Play can be used for assessing the others' dispositions in humans and nonhuman mammals [2], whereas little is known about birds. Recently, food-caching corvids have been found to rival primates in their ability to judge the behaviors and intentions of others in competition for hidde...

BIRKHEAD, T. R. 1974. Utilization of guillemot (Uria aalge) colonies by jackdaws (Corvus monedula). Ornis Scand. 5:71-8 1. CULLEN, E. 1957. Adaptations in the kittiwake to cliff-nesting. Ibis 99:275-302. HAGGBLOM, L., AND V. M. MENDENHALL. 1990. Chapter 5: Cape Peirce. In V. M. Mendenhall [ed.], Monitoring of populations and productivity of seabirds at St. George Island, Cape Peirce, and Bluff,...

U Siebert, G Sroczynski, S Rossol, J Wasem, U Ravens-Sieberer, B M Kurth, M P Manns, J G McHutchison, J B Wong, German Hepatitis C Model (GEHMO) Group, International Hepatitis Interventional Therapy (IHIT) Group . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ....

Parents face a trade-off when allocating limited resources to reproduction and self-maintenance, this can result in differential investment individual offspring rearing multiple simultaneously. In birds with biparental care, it is not well understood how each parent allocates its different chicks of the same brood. Theory suggests that parental depends on quality brood size, but empirical quant...

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1. Introduction What is true and what is not depends upon how the world is: that there are no white ravens is true because there are no white ravens. That much, Trenton Merricks accepts. But he denies that principles about truthmaking can do any heavy lifting in metaphysics, and he provides powerful, sophisticated arguments for this denial. The hunt for individual truthmakers for specific truth...