Strong evidence supporting a relationship between colour pattern and apparent survival in common crossbills

Carotenoid staining has been repeatedly shown to serve as a sexually selected individual quality signal. In different species, individuals that show brighter carotenoid-based signals have been found to have superior feeding abilities, recover faster from disease, and generally enjoy better body condition. In the common crossbill (Loxia curvirostra), the colour has also been related to the different populations, with northern and central European populations being described as redder than those in the Mediterranean region. A study in the Pyrenees showed that long-winged individuals had lower apparent survival, and the proportion of red individuals was higher in long-winged birds, concluding that they could be nomadic birds (that travel long distances). A priori, if the red crossbills are more mobile than the yellow and orange ones, their apparent survival will be lower. However, in our study, red males showed a greater survival than males of other colours and almost double than that of the yellow ones. These results suggest that red coloration is linked to higher quality individuals regardless of their mobility.Die Farbgebung durch Carotinoide hat sich schon oft als ein geschlechtsspezifisches Signal für individuelle Qualität herausgestellt. Für unterschiedliche Tierarten hat man festgestellt, dass Individuen, die hellere, auf Carotinoiden basierende Farb-Signale aussenden, eine bessere Nahrungsaufnahme haben, sich schneller von Krankheiten erholen und allgemein in besserer körperlichen Verfassung sind. Beim Fichtenkreuzschnabel (Loxia curvirostra) wurde die Farbgebung auch mit verschiedenen Populationen in Verbindung gebracht, wobei die nord- und mitteleuropäischen Populationen als rötlicher beschrieben wurden als die des Mittelmeerraums. Eine Untersuchung in den Pyrenäen zeigte, dass Tiere mit längeren Flügeln eine offenbar geringere Überlebensrate und einen höheren Anteil an rötlichen Individuen aufwiesen, woraus zu schließen wäre, dass es sich um nomadisierende Vögel handeln könnte (die weite Strecken zurücklegen). Wenn die roten Fichtenkreuzschnäbel mobiler als die gelben und orangefarbenen sind, könnte ihre Überlebensrate mutmaßlich geringer sein. Aber in unserer Untersuchung lebten rötliche Männchen länger als andersgefärbte und fast doppelt so lang wie die gelblichen Männchen. Diese Ergebnisse deuten darauf hin, dass die rote Färbung mit höherwertigen Individuen verbunden ist, unabhängig von deren Mobilität

Investment in the long-tail of biodiversity data: from local research to global knowledge

In business, the "long-tail economy" refers to a market strategy where the gravity center shifts from a few high-demand products to many, varied products focused on small niches. Commercialization of individually low-demand products can be profitable as long as their production cost is low and, all taken together, they aggregate into a big chunk of the market. Similarly, in the "business" of biodiversity data acquisition, we can find several mainstream products that produce zillions of bits of information every year and account for most of the budget allocated to increase our primary data-based knowledge about Earth's biological diversity. These products play a crucial role in biodiversity research. However, along with these large global projects, there is a constellation of small-scale institutions that work locally, but whose contribution to our understanding of natural processes should not be dismissed. These information datasets can be collectively referred to as the "long-tail biodiversity data"

Strong evidence supporting a relationship between colour pattern and apparent survival in common crossbills

Carotenoid staining has been repeatedly shown to serve as a sexually selected individual quality signal. In different species, individuals that show brighter carotenoid-based signals have been found to have superior feeding abilities, recover faster from disease, and generally enjoy better body condition. In the common crossbill (Loxia curvirostra), the colour has also been related to the different populations, with northern and central European populations being described as redder than those in the Mediterranean region. A study in the Pyrenees showed that long-winged individuals had lower apparent survival, and the proportion of red individuals was higher in long-winged birds, concluding that they could be nomadic birds (that travel long distances). A priori, if the red crossbills are more mobile than the yellow and orange ones, their apparent survival will be lower. However, in our study, red males showed a greater survival than males of other colours and almost double than that of the yellow ones. These results suggest that red coloration is linked to higher quality individuals regardless of their mobilit

Strong evidence supporting a relationship between colour pattern and apparent survival in common crossbills

Carotenoid staining has been repeatedly shown to serve as a sexually selected individual quality signal. In different species, individuals that show brighter carotenoid-based signals have been found to have superior feeding abilities, recover faster from disease, and generally enjoy better body condition. In the common crossbill (Loxia curvirostra), the colour has also been related to the different populations, with northern and central European populations being described as redder than those in the Mediterranean region. A study in the Pyrenees showed that long-winged individuals had lower apparent survival, and the proportion of red individuals was higher in long-winged birds, concluding that they could be nomadic birds (that travel long distances). A priori, if the red crossbills are more mobile than the yellow and orange ones, their apparent survival will be lower. However, in our study, red males showed a greater survival than males of other colours and almost double than that of the yellow ones. These results suggest that red coloration is linked to higher quality individuals regardless of their mobility.Die Farbgebung durch Carotinoide hat sich schon oft als ein geschlechtsspezifisches Signal für individuelle Qualität herausgestellt. Für unterschiedliche Tierarten hat man festgestellt, dass Individuen, die hellere, auf Carotinoiden basierende Farb-Signale aussenden, eine bessere Nahrungsaufnahme haben, sich schneller von Krankheiten erholen und allgemein in besserer körperlichen Verfassung sind. Beim Fichtenkreuzschnabel (Loxia curvirostra) wurde die Farbgebung auch mit verschiedenen Populationen in Verbindung gebracht, wobei die nord- und mitteleuropäischen Populationen als rötlicher beschrieben wurden als die des Mittelmeerraums. Eine Untersuchung in den Pyrenäen zeigte, dass Tiere mit längeren Flügeln eine offenbar geringere Überlebensrate und einen höheren Anteil an rötlichen Individuen aufwiesen, woraus zu schließen wäre, dass es sich um nomadisierende Vögel handeln könnte (die weite Strecken zurücklegen). Wenn die roten Fichtenkreuzschnäbel mobiler als die gelben und orangefarbenen sind, könnte ihre Überlebensrate mutmaßlich geringer sein. Aber in unserer Untersuchung lebten rötliche Männchen länger als andersgefärbte und fast doppelt so lang wie die gelblichen Männchen. Diese Ergebnisse deuten darauf hin, dass die rote Färbung mit höherwertigen Individuen verbunden ist, unabhängig von deren Mobilität

Bigger or long-winged male common crossbills exhibit redder carotenoid-based plumage coloration

Carotenoid-based ornaments are often considered reliable (honest) individual condition signals because their expression implies physiological costs unaffordable for low-quality animals (handicap signals). Recently, it has been suggested that efficient cell respiration is mandatory for producing red ketocarotenoids from dietary yellow carotenoids. This implies that red colorations should be entirely unfalsifiable and independent of expression costs (index signals). In a precedent study, male common crossbills, Loxia curvirostra, showing a red plumage reported higher apparent survival than those showing yellowish-orange colors. The plumage redness in this species is due to ketocarotenoid accumulation in feathers. Here, we correlated the male plumage redness (a 4-level visual score: yellow, patchy, orange, and red) and the body morphology in more than 1,000 adult crossbills captured in 3 Iberian localities to infer the mechanisms responsible for color evolution. A principal component analysis summarized morphometry of 10 variables (beak, wing, tarsus length, etc.). The overall body size (PC1) and the length of flight feathers regarding body size (PC3) showed significant positive relationships with plumage redness. Plumage redness was barely correlated with bill shape measures, suggesting no constraint in acquiring carotenoids from pine cones. However, large body sizes or proportionally long flying feathers could help carotenoid acquisition via social competition or increased foraging ranges. Proportionally longer flight feathers might also be associated with a specific cell respiration profile that would simultaneously favor flying capacities and enzymatic transformations needed for ketocarotenoid synthesis. Such a phenotypic profile would agree with the hypothesis of ketocarotenoid-based colors acting as individual quality index signals