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Age, arrival date and reproductive success of male American Redstarts Setophaga ruticilla. -J. Avian Biol. 27: 164-170.We tested whether the age-related differences in reproductive success in male American Redstarts are caused by differences in date of arrival on the breeding grounds. By relating arrival date to three measures of reproductive success we determined what stage of the breeding cycle is affected by date of arrival. Adult male redstarts were more successful than subadults at obtaining mates. Adult males were also more likely than subadults to have nests built in their territories, and to fledge young. Among mated males, neither age class was significantly more likely to obtain nests. However, among males that nested, there were significant age-related differences in fledging success. Adult males arrived on the breeding grounds before subadults. Within both age classes, males that mated had arrived significantly earlier than those that did not mate. Similarly, males that nested had arrived significantly earlier than those that did not. There were no significant differences in arrival date between males that fledged young and those that did not. Finally, adult males were more likely to renest after nest failure. Therefore, we conclude that reproductive success in male redstarts is independently affected by both arrival date and age, and that the lower success of subadults may not be a consequence solely of their age and late arrival, but also of their lack of experience in selecting territories early in the breeding season.

Historically, papers have been physically bound to the journal in which they were published; but in the digital age papers are available individually, no longer tied to their respective journals. Hence, papers now can be read and cited based on their own merits, independently of the journal's physical availability, reputation, or impact factor (IF). We compare the strength of the relationship between journals' IFs and the actual citations received by their respective papers from 1902 to 2009. Throughout most of the 20th century, papers' citation rates were increasingly linked to their respective journals' IFs. However, since 1990, the advent of the digital age, the relation between IFs and paper citations has been weakening. This began first in physics, a field that was quick to make the transition into the electronic domain. Furthermore, since 1990 the overall proportion of highly cited papers coming from highly cited journals has been decreasing and, of these highly cited papers, the proportion not coming from highly cited journals has been increasing. Should this pattern continue, it might bring an end to the use of the IF as a way to evaluate the quality of journals, papers, and researchers.

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FORUM FORUM FORUM FORUM is intended for new ideas or new ways of interpreting existing information. It provides a chance for suggesting hypotheses and for challenging current thinking on ecological issues. A lighter prose, designed to attract readers, will be permitted. Formal research reports, albeit short, will not be accepted, and all contributions should be concise with a relatively short list of references. A summary is not required.