Publications per Biogeographic realm, ranked by decreasing number of publications per species.

<p>Four extinct species had an unknown biogeographic realm and are thus not included here. The low number of species in Europe, Central Asia, Middle-East, Antarctica and Central America is due to the fact that most species from these areas occupy several geographic areas, and were thus included in the category “several”.</p

Relationship between research effort and species traits (panels c and f: mean ± se).

<p>Relationship between research effort and species traits (panels c and f: mean ± se).</p

Figure 2

<p>a) Relationship between the total number of publications per order and the number of species per order. b) Relationship between the average number of publications per species within each order, and the number of species per order. Orders with low species numbers and low publication number per species are identified for information (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0089955#pone-0089955-t002" target="_blank">Table 2</a> for details on each order).</p

Intra-class Coefficients (ICC) for the different taxonomic levels and for the 3 levels together.

<p>Intra-class Coefficients (ICC) for the different taxonomic levels and for the 3 levels together.</p

Research effort and species number in the different orders, ranked in alphabetic order.

<p>Research effort and species number in the different orders, ranked in alphabetic order.</p

Correlations between research effort and species traits, ranked by decreasing correlation coefficient. n = species number.

<p>Correlations between research effort and species traits, ranked by decreasing correlation coefficient. n = species number.</p

Patterns of Research Effort in Birds

<div><p>Between species differences in research effort can lead to biases in our global view of evolution, ecology and conservation. The increase in meta-taxonomic comparative analyses on birds underlines the need to better address how research effort is distributed in this class. Methods have been developed to choose which species should be studied to obtain unbiased comparative data sets, but a precise and global knowledge of research effort is required to be able to properly apply them. We address this issue by providing a data set of research effort (number of papers from 1978 to 2008 in the Zoological Record database) estimates for the 10 064 species of birds. We then test whether research effort is associated with phylogeny, geography and eleven different life history and ecological traits. We show that phylogeny accounts for a large proportion of the variance, while geographic range and all the tested traits are also significant contributors to research effort variance. We identify avian taxa that are under- and overstudied and address the importance of research effort biases in evaluating vulnerability to extinction, with non-threatened species studied twice as much as threatened ones. Our research effort data set covering the entire class Aves provides a tool for researchers to incorporate this potential confounding variable in comparative analyses.</p></div

Number of reviews, comparative analyses and meta-analyses referenced on the Web of Science in ecology, evolution and conservation between 1995 and 2012 in birds, mammals and herptiles (amphibians and reptiles).

<p>The three slopes are significantly different from 0 (p<0.006 in the 3 cases), and the increase in the number of review papers across time is significantly smaller in amphibians and reptiles than it is in birds (p = 0.009) or mammals (p<0.001), but does not significantly differ between birds and mammals (p = 0.332).</p

Phylogenetic Mixed Model explaining research effort as a function of 7 life history traits.

<p>Models were run with 10 different phylogenies, and posterior means (pm), CI (Confidence Interval) and p-values were averaged over the 10 models with 10 different phylogenetic trees (see text for details). n = species number. n = species number.</p

Bajan Birds Pull Strings: Two Wild Antillean Species Enter the Select Club of String-Pullers

<div><p>String-pulling is one of the most popular tests in animal cognition because of its apparent complexity, and of its potential to be applied to very different taxa. In birds, the basic procedure involves a food reward, suspended from a perch by a string, which can be reached by a series of coordinated pulling actions with the beak and holding actions of the pulled lengths of string with the foot. The taxonomic distribution of species that pass the test includes several corvids, parrots and parids, but in other families, data are much spottier and the number of individuals per species that succeed is often low. To date, the association between string-pulling ability and other cognitive traits was never tested. It is generally assumed that string-pulling is a complex form of problem-solving, suggesting that performance on string-pulling and other problem-solving tasks should be correlated. Here, we show that individuals of two innovative species from Barbados, the bullfinch <i>Loxigilla barbadensis</i> and the Carib grackle <i>Quiscalus lugubris fortirostris</i>, pass the string-pulling test. Eighteen of the 42 bullfinches tested succeeded, allowing us to correlate performance on this test to that on several other behavioral measurements. Surprisingly, string-pulling in bullfinches was unrelated to shyness, neophobia, problem-solving, discrimination and reversal learning performance. Only two of 31 grackles tested succeeded, precluding correlational analyses with other measures but still, the two successful birds largely differed in their other behavioral traits.</p></div