Invasive species offer ecologists the opportunity to study the factors governing species distributions and population growth. The Eurasian Collared-Dove (Streptopelia decaocto) serves as a model ...organism for invasive spread because of the wealth of abundance records and the recent development of the invasion. We tested whether a set of environmental variables were related to the carrying capacities and growth rates of individual populations by modeling the growth trajectories of individual populations of the Collared-Dove using Breeding Bird Survey (BBS) and Christmas Bird Count (CBC) data. Depending on the fit of our growth models, carrying capacity and growth rate parameters were extracted and modeled using historical, geographical, land cover and climatic predictors. Model averaging and individual variable importance weights were used to assess the strength of these predictors. The specific variables with the greatest support in our models differed between data sets, which may be the result of temporal and spatial differences between the BBS and CBC. However, our results indicate that both carrying capacity and population growth rates are related to developed land cover and temperature, while growth rates may also be influenced by dispersal patterns along the invasion front. Model averaged multivariate models explained 35-48% and 41-46% of the variation in carrying capacities and population growth rates, respectively. Our results suggest that widespread species invasions can be evaluated within a predictable population ecology framework. Land cover and climate both have important effects on population growth rates and carrying capacities of Collared-Dove populations. Efforts to model aspects of population growth of this invasive species were more successful than attempts to model static abundance patterns, pointing to a potentially fruitful avenue for the development of improved invasive distribution models.
Garden bird feeding constitutes a massive provision of food that can support bird communities, but there is a growing concern it might favour the establishment of exotic species that could be ...detrimental to others. How bird species compete with novel species for this anthropogenic food resources needs to be assessed.
Here, we investigated competition in wintering bird communities at garden birdfeeders. We evaluated whether – and how much – bird access to resources is hampered by the presence of putative superior competing species, among which the Rose-ringed parakeet, the most abundant introduced species across Europe.
Using the nation-wide citizen science scheme BirdLab, in which volunteers record in real-time bird attendance on a pair of birdfeeders during 5-minute sessions, we tested whether i) cumulative bird presence time and richness at birdfeeders, and ii) species probability of presence at birdfeeders, were influenced by three large species (the Eurasian magpie, the Eurasian collared-dove, and the Rose-ringed parakeet). Additionally, we assessed whether the Rose-ringed parakeet occupied resources significantly more than others.
Presence of the Rose-ringed parakeet or the Eurasian collared-dove similarly reduced community cumulative presence time at birdfeeders, but only the dove reduced community richness. Each of the three large species influenced the presence of at least one of the six smaller species that could be separately modelled, but effects varied in strength and direction. The Rose-ringed parakeet and the Eurasian collared-dove were among the three species monopolising birdfeeders the longest, substantially more than the Eurasian magpie.
Our findings confirm the competitive abilities of the large species studied, but do not suggest that garden bird feeding may alarmingly favour introduced species with detrimental effects on native species. Given the variability of large species' effects on small passerines, direct and indirect interactions among all species must be examined to fully understand the ecological net effects at stake.
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•Citizen scientists record birds at birdfeeders through a serious game.•Community effects of Rose-ringed parakeet were compared with two similar species.•Bird community use of feeding resources was hampered by two of three large species.•Each large species differently affected other species' use of birdfeeders.•Garden bird feeding may not greatly favour introduced over native bird species.
The two-note call of the male common cuckoo (Cuculus canorus), the so-called “cu-coo”, is well known to people as a natural and cultural signal. However, the so-called “bubbling” call of the female ...cuckoo is almost unknown to most, and its function in the social organization of cuckoos remains understudied. We carried out a study of a possible intraspecific communication function of female bubbling calls, using playbacks to female cuckoos in their natural environment. Regarding vocal responses, both female and male cuckoos paid attention to the bubbling calls as they consistently responded acoustically by calling but did not so during control playbacks of collared dove (Streptopelia decaocto) calls. Accordingly, in about 63% of trials, females approached the loudspeaker closely and 81% uttered bubbling calls themselves during the experiment. These results are consistent with a function that the bubbling call plays a role in territorial signaling and defense among females. Male cuckoos also showed strong responses to playbacks of bubbling calls, as they approached the speaker and themselves called in 94% of playbacks; this is consistent with a scenario that they are interested in unfamiliar, new females in the area. Specifically, males approached the speaker repeatedly by flight, often flew around it and then perched on a tree, and uttered different call types beside the general “cu-coo” (e.g., quick “cu-cu-coo”, “gowk” call, and “guo” call). Our results represent an illustrative example that a simple female call may have multiple functions, as the cuckoo bubbling call advertises territory need for female cuckoos and attracts males.
Human-generated noise pollution now permeates natural habitats worldwide, presenting evolutionarily novel acoustic conditions unprecedented to most landscapes. These acoustics not only harm humans, ...but threaten wildlife, and especially birds, via changes to species densities, foraging behavior, reproductive success, and predator-prey interactions. Explanations for negative effects of noise on birds include disruption of acoustic communication through energetic masking, potentially forcing species that rely upon acoustic communication to abandon otherwise suitable areas. However, this hypothesis has not been adequately tested because confounding stimuli often co-vary with noise and are difficult to separate from noise exposure.
Using a natural experiment that controls for confounding stimuli, we evaluate whether species vocal features or urban-tolerance classifications explain their responses to noise measured through habitat use. Two data sets representing nesting and abundance responses reveal that noise filters bird communities nonrandomly. Signal duration and urban tolerance failed to explain species-specific responses, but birds with low-frequency signals that are more susceptible to masking from noise avoided noisy areas and birds with higher frequency vocalizations remained. Signal frequency was also negatively correlated with body mass, suggesting that larger birds may be more sensitive to noise due to the link between body size and vocal frequency.
Our findings suggest that acoustic masking by noise may be a strong selective force shaping the ecology of birds worldwide. Larger birds with lower frequency signals may be excluded from noisy areas, whereas smaller species persist via transmission of higher frequency signals. We discuss our findings as they relate to interspecific relationships among body size, vocal amplitude and frequency and suggest that they are immediately relevant to the global problem of increases in noise by providing critical insight as to which species traits influence tolerance of these novel acoustics.
Resumen La paloma de collar turca, el perico monje argentino, el estornino pinto y el mirlo dorso canela se registraron por primera vez hace una década en la ciudad de Querétaro. En otros países, las ...3 primeras especies son consideradas invasoras y causan problemas socioeconómicos y ecológicos. A fin de dar seguimiento a estas especies, en el presente estudio se analizó la abundancia y ocupación de las 4 especies mencionadas, su preferencia de hábitat y su coexistencia con aves locales en áreas verdes de la ciudad de Querétaro. Se hizo un muestreo estacional de la avifauna en 19 áreas verdes de la ciudad y se midieron 13 variables ambientales. Se encontró que la paloma de collar turca y el perico monje argentino han aumentado sus poblaciones y ocupación a 10 años de sus primeros registros, mientras que el mirlo dorso canela y el estornino pinto parecen tener poblaciones estables. Las principales características seleccionadas de las áreas verdes por estas especies son el tamaño, la diversidad de coberturas y la complejidad. Se presentó poca coexistencia con aves locales y no se registraron agresiones interespecíficas. Al encontrarse una importante cantidad de nidos de perico monje argentino en la ciudad, se sugiere controlar su crecimiento poblacional.
We characterized the morphological and anatomical adaptations of the lingual microstructures of the Eurasian collared dove and discussed their implications for its dietary niche. We analyzed tongues ...of nine S. decaocto using histological, histochemical, stereomicroscopic, and scanning electron microscopic techniques. Our findings showed that the tongue is relatively short with a tapered apex that carries a terminal lingual nail. However, the lingual body has median scales and is bordered laterally by filiform papillae. Further, the tongue body bears a distinctive papillary crest. The tongue root is nonpapillate and infiltered with orifices of the posterior salivary glands. The bulky laryngeal mound has a circular glottic fissure, carrying a single row of papillae at the rear edge. Concurrently, our histological and histochemical findings demonstrate that the tongue has taste buds, anterior and posterior salivary glands, along with an elongated entoglossum that extends from lingual apex to root. Besides, ovoid and globular mucous glands displayed intense alcianophilic reactions. More substantially, the palate is made up of three palatine ridges with a caudal choanal cleft that was bounded by two rows of palatine papillae. Our data indicate multiple and novel structural variations for the lingual and palatal sculptures coopted for their feeding style.
Diet differences between the sexes and ages have often been recorded for bird species. Many raptor species show extreme sexual size dimorphism, with females often considerably larger than the males ...and these differences may be reflected in their diets. Diet studies in raptors most frequently focus on analysing prey remains or pellets collected at nest‐sites. These methods are subsequently limited to breeding birds in the breeding season and are also restricted by their inability to distinguish prey items between the sexes. The use of web‐sourced photographs to examine raptor diet has the potential to overcome some limitations of more traditional methods used to assess diet. We used this approach for the Eurasian Sparrowhawk Accipiter nisus in the United Kingdom, exploring diet between the sexes and ages throughout the entire year. In total, we obtained 843 web‐sourced photographs of Sparrowhawks with their prey items. There were 12 key prey items that had a frequency ≥ 10 in the Sparrowhawk diet: Common Wood Pigeon Columba palumbus, Common Starling Sturnus vulgaris, Eurasian Collared Dove Streptopelia decaocto, Rock Dove Columba livia, Common Blackbird Turdus merula, House Sparrow Passer domesticus, unidentified ‘small’ and ‘medium’ birds, European Goldfinch Carduelis carduelis, European Greenfinch Chloris chloris, Eurasian Blue Tit Cyanistes caeruleus and Stock Dove Columba oenas. Several prey species were more often seen in the diet of one sex or age group. Overall, average prey weights of adult females were two and a half times heavier than for adult males and one and a half times heavier for juvenile females. However, this method may be slightly biased towards larger prey items, which should be considered in future studies. Despite this limitation, our method enabled dietary differences between the sexes and ages of this highly sexual size dimorphic raptor species to be explored throughout the year.
Context
Understanding the mechanisms governing the selection of habitats by urban expanding species to inform population control.
Objectives
We aimed to determine the effects of landscape ...composition, human disturbance, and spatial structuring on the occurrence of invasive
Streptopelia decaocto
(EUCD) and expanding
Columba palumbus
(EWP) in the city of Rabat, Morocco.
Methods
In 2021, presence-absence data of EUCD and EWP were collected at 666 point locations. Generalized linear mixed models (GLMM) were used to identify the factors associated with EUCD and EWP probability of occurrence, while variation partitioning (VP) analyses were performed to assess the importance of landscape composition, human disturbance, and spatial structure, on the occurrence.
Results
The GLMM showed that the probability of EWP occurrence increased with landscape cover of green villa zones, urban parks, and fruit orchards, and declined with average noise intensity and distance to the nearest urban area. The probability of EUCD occurrence exhibited a hump-shaped relationship with the cover of built-up areas and distance to the nearest urban area, a positive association with the extent of urban parks, and a negative correlation with the extent of cereals, distance to the nearest river, and average noise intensity. VP analyses demonstrated that the shared fraction explained by landscape composition and space is doubly more pronounced for the EWP (
R
2
= 0.30) than in EUCD (
R
2
= 0.15).
Conclusion
Taking into account landscape composition and spatial structure is essential when assessing the adaptation level of bird species in expansion in an urban environment.
Global biodiversity is increasingly threatened by the spread of invasive species. Understanding the mechanisms influencing the initial colonization and persistence of invaders is therefore needed if ...conservation actions are to prevent new invasions or strive to slow their spread. The Eurasian Collared-Dove (Streptopelia decaocto, EUCO) is one of the most successful avian invasive species in North America; however, to our knowledge, no study has simultaneously examined the role that climate-matching, human activity, directional propagation, and local density have in this invasion process. Our research expands upon a cellular-automata-based hierarchical model developed to assess directional invasion dynamics to further quantify the impacts of climate, elevation, and land cover type on the spread of EUCO in North America. Our results suggest that EUCO's dispersal patterns can largely be explained by the effects of habitat, climate, and environmental conditions at different stages of the invasion process rather than some innate preferred north-westerly spread. Specifically, EUCO initially colonized warm and wet grassland habitats and tended to persist in urban areas. We also found that while EUCO were more likely to spread to the northeast of existing habitats, directional preference did not drive persistence and recolonization events. These findings highlight the importance of incorporating both neighborhood effects and environmental factors in the modelling of range-expanding species, adding to the toolset available to researchers to model invasive species spread. Further, our research demonstrates that historical records of invasive species occurrences can provide the data resources needed to disentangle the characteristics driving species invasion and enable predictions that are of critical importance to resource managers. The Eurasian Collared-Dove is an invasive species in North America. Starting from the Bahamas in 1974, it has colonized much of the U.S. and Canada. The Eurasian Collared-Dove tended to spread to the northwest, and previous studies suggested that this was due to an innate preference for this direction. However, these studies did not consider that this might also be explained by habitat selection. We studied the Eurasian Collared-Dove's range expansion using data from the Project Feeder Watch citizen science study. Our findings suggest that they prefer grasslands and thrive in areas with higher temperatures, more precipitation, and higher elevations, with little regard for direction. These results add to our understanding of the invasion process of the Eurasian Collared-Dove in North America, and broadly highlight the importance of historical records to disentangle the characteristics driving species invasion that are important to resource managers. The new methods can also be applied to understand the spread of other invasive species. La biodiversité mondiale est de plus en plus menacée par la propagation d'espèces envahissantes. Il est donc nécessaire de comprendre les mécanismes qui influencent la colonisation initiale et la persistance des envahisseurs si l'on veut que les mesures de conservation empêchent de nouveaux envahissements ou ralentissent leur propagation. Streptopelia decaocto est l'une des espèces aviaires envahissantes ayant le plus de succès en Amérique du Nord; toutefois, à notre connaissance, aucune étude n'a examiné simultanément le rôle de l'adaptation au climat, de l'activité humaine, de la propagation directionnelle et de la densité locale dans ce processus d'envahissement. Nos recherches s'appuient sur un modèle hiérarchique à base d'automates cellulaires développé pour évaluer la dynamique d'envahissement directionnel afin de quantifier les impacts du climat, de l'altitude et du type d'occupation du sol sur la propagation de S. decaocto en Amérique du Nord. Nos résultats suggèrent que les patrons de dispersion de S. decaocto peuvent être largement expliqués par les effets de l'habitat, du climat et des conditions environnementales à différents stades du processus d'envahissement plutôt que par une préférence innée pour une propagation vers le nord-ouest. Plus précisément, S. decaocto a d'abord colonisé des habitats de prairies chaudes et humides et a eu tendance à persister dans les zones urbaines. Nous avons également constaté que si S. decaocto était plus susceptible de se propager au nord-est des habitats existants, la préférence directionnelle ne déterminait pas les événements de persistance et de recolonisation. Ces résultats soulignent l'importance d'incorporer à la fois les effets de voisinage et les facteurs environnementaux dans la modélisation des espèces qui étendent leur aire de répartition, ajoutant ainsi à la panoplie d'outils disponibles dont disposent les chercheurs pour modéliser la propagation des espèces envahissantes. En outre, nos recherches démontrent que les mentions historiques de présence d'espèces envahissantes peuvent fournir les données nécessaires pour démêler les caractéristiques qui régissent l'envahissement des espèces et permettre des prédictions qui sont d'une importance critique pour les gestionnaires de ressources.
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