Background:Land-use change is one of the main drivers of the global erosion of biodiversity.In that context,it is crucial to understand how landscape characteristics drive the presence of rare endangered species.Never...Background:Land-use change is one of the main drivers of the global erosion of biodiversity.In that context,it is crucial to understand how landscape characteristics drive the presence of rare endangered species.Nevertheless,it is also important to study common species in multiple habitats,because they represent a large proportion of biodiversity and are essential to maintain ecological functions.Interestingly,some habitats,as farmlands with permanent crops(e.g.vineyards),have been overlooked in the literature.Methods:In this study,we investigated the distribution of a widespread and common bird species,the Common Blackbird(Turdus merula),within and between the three main habitats of our study area(rural Western France).We specifically focused on(1)woodlands,(2)farmlands with a high vineyard coverage,and(3)moderately urbanized areas.Specifically,we aimed to assess the beneficial and detrimental effects of these habitats and their fine-scale composition on the presence of a common bird species,relying on a survey by point counts(nearly 100 locations).We studied the effects of habitats and gradients of fine-scale habitat composition on blackbird presence using logistic regression analyses.Results:Blackbirds were present in all studied habitats.However,their presence varied between habitats,being lower in vineyards than in woodlands and cities.In woodlands and cities,fine-scale analyses did not reveal any component driving the species'presence.However,we found that shrub and tree vegetation cover had a significant positive effect on blackbird presence in vineyards.Conclusions:Our results are in agreement with the definition of a generalist species.Interestingly,species distribution varied between habitats.The high presence of blackbirds in urban areas suggests that medium-sized cities,despite their artificialization,do not constrain the settlement of this former forest specialist and that green spaces may allow blackbirds to thrive in medium-sized cities.On the contrary,we found an impoverished presence of blackbirds in vineyards and a positive effect of vegetation on their presence in these landscapes.This suggests that permanent crops,and more generally farmlands,may impose important constraints to common species.Future studies should examine how to enhance biodiversity through agricultural management policies,especially in vineyards.展开更多
Background:Nests are composed of and built with different materials that are handled in specific ways. These mate?rials must initially have been used de novo before commonly being incorporated into nests. Plastic and ...Background:Nests are composed of and built with different materials that are handled in specific ways. These mate?rials must initially have been used de novo before commonly being incorporated into nests. Plastic and plastic bags were invented in the 1950s, and they are widely distributed in the environment. Birds started picking up plastic from plastic used to cover farm produce such as silage, potatoes, beets and other crops for use in their nests in the 1960s.Methods:I recorded the frequency of such plastic use by the Blackbird(Turdus merula) in nests in Denmark, starting in 1966, followed by a peak in use in the 1970s and a subsequent decline.Results:Nests with plastic were initially built earlier in the season than those without plastic, indicating an associa?tion between innovation and early reproduction. Plastic use was subsequently selected against because nests with plastic suffered from higher rates of predation than nests without plastic, probably because nests with plastic were easier to locate. However, the elevated risk of nest predation only applied to outdoor nests, but not to nests inside buildings, probably because visually searching nest predators such as corvids do not enter buildings.Conclusions:These findings show that the dynamics of nest material use depend on the benefits of innovation and the fitness costs of nest predation.展开更多
Hatching asynchrony in birds is considered an adaptation to facilitate brood reduction because under conditions of food scarcity, the smallest nestling usually dies soon after hatching, thereby minimizing parental eff...Hatching asynchrony in birds is considered an adaptation to facilitate brood reduction because under conditions of food scarcity, the smallest nestling usually dies soon after hatching, thereby minimizing parental effort. However, in species with extreme hatching asynchrony, the last hatchlings paradoxically experience a very low probability of survival and death can take so long that it can hardly be considered an adaptation. Here, we propose and experimentally tested a new adaptive hypothesis explaining the brood reduction paradox, namely the“Male Manipulation Hypothesis”. Our hypothesis suggests that by inducing asynchronous hatching,females increase the feeding requirements of the brood, which will induce males to increase provisioning effort. In addition, females may extend the period of male manipulation by feeding the smallest nestling just enough to sustain life. Our study showed that male common blackbirds(Turdus merula) increased their effort(i.e., number of food items per hour) in experimental asynchronous broods compared to synchronous broods, while females reduced their contribution, as predicted by the hypothesis.展开更多
Although there are some reports that have described primates eating animals,it is unknown whether predation on vertebrates exists in herbivorous leaf-eating primates.We have witnessed firsthand wild Sichuan snub-nosed...Although there are some reports that have described primates eating animals,it is unknown whether predation on vertebrates exists in herbivorous leaf-eating primates.We have witnessed firsthand wild Sichuan snub-nosed monkeys(Rhinopithecus roxellana)preying on and consuming Eurasian blackbirds(Turdus merula)in the Qinling Mountains of China.This event suggests that R.roxellana,which has previously been described as a herbivorous leaf-eating primate,may be partially carnivorous and the correct classification of this species would be omnivorous.Furthermore,food-share behavior among higher-ranked members occurs in a one-male unit when vertebrate prey is hunted by this species.展开更多
基金funded by the Agence Nationale de la Recherche(ANR project URBASTRESS,ANR-16-CE02-0004-01 to F.A.,and ANR project VITIBIRD to F.A.)by the Région Nouvelle-Aquitaine(MULTISTRESS project)+1 种基金by the Agence nationale de sécuritésanitaire de l’alimentation,de l’environnement et du travail(ANSES project Biodi Tox#2019/1/031)by the Centre National de la Recherche Scientifique。
文摘Background:Land-use change is one of the main drivers of the global erosion of biodiversity.In that context,it is crucial to understand how landscape characteristics drive the presence of rare endangered species.Nevertheless,it is also important to study common species in multiple habitats,because they represent a large proportion of biodiversity and are essential to maintain ecological functions.Interestingly,some habitats,as farmlands with permanent crops(e.g.vineyards),have been overlooked in the literature.Methods:In this study,we investigated the distribution of a widespread and common bird species,the Common Blackbird(Turdus merula),within and between the three main habitats of our study area(rural Western France).We specifically focused on(1)woodlands,(2)farmlands with a high vineyard coverage,and(3)moderately urbanized areas.Specifically,we aimed to assess the beneficial and detrimental effects of these habitats and their fine-scale composition on the presence of a common bird species,relying on a survey by point counts(nearly 100 locations).We studied the effects of habitats and gradients of fine-scale habitat composition on blackbird presence using logistic regression analyses.Results:Blackbirds were present in all studied habitats.However,their presence varied between habitats,being lower in vineyards than in woodlands and cities.In woodlands and cities,fine-scale analyses did not reveal any component driving the species'presence.However,we found that shrub and tree vegetation cover had a significant positive effect on blackbird presence in vineyards.Conclusions:Our results are in agreement with the definition of a generalist species.Interestingly,species distribution varied between habitats.The high presence of blackbirds in urban areas suggests that medium-sized cities,despite their artificialization,do not constrain the settlement of this former forest specialist and that green spaces may allow blackbirds to thrive in medium-sized cities.On the contrary,we found an impoverished presence of blackbirds in vineyards and a positive effect of vegetation on their presence in these landscapes.This suggests that permanent crops,and more generally farmlands,may impose important constraints to common species.Future studies should examine how to enhance biodiversity through agricultural management policies,especially in vineyards.
文摘Background:Nests are composed of and built with different materials that are handled in specific ways. These mate?rials must initially have been used de novo before commonly being incorporated into nests. Plastic and plastic bags were invented in the 1950s, and they are widely distributed in the environment. Birds started picking up plastic from plastic used to cover farm produce such as silage, potatoes, beets and other crops for use in their nests in the 1960s.Methods:I recorded the frequency of such plastic use by the Blackbird(Turdus merula) in nests in Denmark, starting in 1966, followed by a peak in use in the 1970s and a subsequent decline.Results:Nests with plastic were initially built earlier in the season than those without plastic, indicating an associa?tion between innovation and early reproduction. Plastic use was subsequently selected against because nests with plastic suffered from higher rates of predation than nests without plastic, probably because nests with plastic were easier to locate. However, the elevated risk of nest predation only applied to outdoor nests, but not to nests inside buildings, probably because visually searching nest predators such as corvids do not enter buildings.Conclusions:These findings show that the dynamics of nest material use depend on the benefits of innovation and the fitness costs of nest predation.
基金supported by the Consejeria de Economia, Innovacion, Ciencia y Empleo, Junta de Andalucia(research project CVI-6653 to M.S.)。
文摘Hatching asynchrony in birds is considered an adaptation to facilitate brood reduction because under conditions of food scarcity, the smallest nestling usually dies soon after hatching, thereby minimizing parental effort. However, in species with extreme hatching asynchrony, the last hatchlings paradoxically experience a very low probability of survival and death can take so long that it can hardly be considered an adaptation. Here, we propose and experimentally tested a new adaptive hypothesis explaining the brood reduction paradox, namely the“Male Manipulation Hypothesis”. Our hypothesis suggests that by inducing asynchronous hatching,females increase the feeding requirements of the brood, which will induce males to increase provisioning effort. In addition, females may extend the period of male manipulation by feeding the smallest nestling just enough to sustain life. Our study showed that male common blackbirds(Turdus merula) increased their effort(i.e., number of food items per hour) in experimental asynchronous broods compared to synchronous broods, while females reduced their contribution, as predicted by the hypothesis.
基金on-going operating grants from the Natural Science Foundation of China(No.30770375,No.30570312 and No.30630016)the Cosmo Oil Eco Card Fund of Japan(2005–2010).
文摘Although there are some reports that have described primates eating animals,it is unknown whether predation on vertebrates exists in herbivorous leaf-eating primates.We have witnessed firsthand wild Sichuan snub-nosed monkeys(Rhinopithecus roxellana)preying on and consuming Eurasian blackbirds(Turdus merula)in the Qinling Mountains of China.This event suggests that R.roxellana,which has previously been described as a herbivorous leaf-eating primate,may be partially carnivorous and the correct classification of this species would be omnivorous.Furthermore,food-share behavior among higher-ranked members occurs in a one-male unit when vertebrate prey is hunted by this species.
