Bill color, not badge size, indicates testosterone-related information in house sparrows

The honesty of ornamental signals of quality is often argued to be enforced via costs associated with testosterone. It is still poorly understood, however, how seasonal variation of testosterone within individuals is related to the timing and extent of ornament development. Here, we studied inter- and intra-individual variability of plasma testosterone levels in a population of 150 captive male house sparrows (Passer domesticus) through the course of a full year. We further analyzed the relationship between plasma testosterone levels and two sexually dimorphic ornaments: badge size and bill coloration. Also, because of a known negative relation between molt and circulating testosterone levels, we analyzed the relationship between ornamentation and molt status during the fall. We found that testosterone levels increased towards the breeding season and decreased before the onset of annual molt. However, within individuals, relative testosterone titers demonstrated low repeatability between seasons. Plasma testosterone levels were not correlated with badge size in any season but were correlated strongly with bill coloration during all periods, except the breeding season when variation in bill color was low. Finally, we found that bill coloration strongly correlated with molt status during fall. Our results indicate that bill coloration, not badge size, is the best ornamental indicator of a “running average” of male testosterone in house sparrows and therefore the best potential indicator of qualities and/or behavioral strategies associated with testosterone

What’s new with numbers? Sociological approaches to the study of quantification

Calculation and quantification have been critical features of modern societies, closely linked to science, markets, and administration. In the past thirty years, the pace, purpose, and scope of quantification have greatly expanded, and there has been a corresponding increase in scholarship on quantification. We offer an assessment of the widely dispersed literature on quantification across four domains where quantification and quantification scholarship have particularly flourished: administration, democratic rule, economics, and personal life. In doing so, we seek to stimulate more cross-disciplinary debate and exchange. We caution against unifying accounts of quantification and highlight the importance of tracking quantification across different sites in order to appreciate its essential ambiguity and conduct more systematic investigations of interactions between different quantification regimes