Non-native Bird Species Research Articles

An Influx of Non-Native Bird Species into the Natural Environment Owing to the Accidental Release of Pet Birds in Japan.

The escape of pet birds into the wild raises concerns about the introduction of invasive avian species. This study investigated the impact of escaped pet birds on the introduction of non-native species in Japan. Data sourced from four lost-and-found pet websites between January 2018 and December 2021 revealed 12,125 recorded escapes exhibiting both daily occurrences and seasonal fluctuations. Statistical modeling identified the monthly average temperature (positively correlated) and maximum electricity demand (negatively correlated) as influential factors. Text analysis revealed "window" and "open" as frequently cited reasons for escapes. Budgerigars (Melopsittacus undulatus) and Cockatiels (Nymphicus hollandicus) accounted for 76% of the total escape, suggesting a low perceived risk of establishment in nonnative environments. Interestingly, two globally established invasive species, the Rose-ringed Parakeet (Psittacula krameri) and Monk Parakeet (Myiopsitta monachus), were among the escaped birds. While the Rose-ringed Parakeet is locally naturalized in Tokyo and its adjacent prefectures, the Monk Parakeet failed to establish itself in Japan. Despite the limited number of escaped Monk Parakeets, ongoing efforts are crucial for preventing the potential re-establishment of species with such capabilities.

The role of citizen science in management of invasive avian species: What people think, know, and do

In North America, nest site competition from invasive cavity-nesting birds can limit the opportunities for successful nesting by native birds. Managing invasive species is costly and complex, requiring input from biologists, decision makers, and the public. An informed and engaged public can play an important role in mitigating the negative effects of invasive avian species. However, little is known regarding the publics’ knowledge, attitudes, and behaviors toward non-native bird species. We examined the association between participating in a citizen science project and enjoyment, knowledge, and management of two non-native avian species in North America: European starlings (Sturnus vulgaris) and house sparrows (Passer domesticus). We administered a pre and post survey to 947 people who monitor nest boxes in the United States and Canada, 30% of whom were also reporting their observations to NestWatch, a citizen science project focused on nesting birds. We found that NestWatch participants were more likely to have negative views of non-native species, score higher on bird identification tasks, and manage for invasive species than non-participants. The most important predictor for undertaking management activities was respondents' perceptions of whether they believed non-native birds to be a problem at the continental scale, underscoring the important role of individual factors such as perception. Our study also highlights the important role citizen science may play in shaping attitudes and behaviors and increasing knowledge. We propose a conceptual model describing the mechanisms by which citizen science can be leveraged for management of invasive species.

Rapid morphological change of nonnative frugivores on the Hawaiian island of O'ahu.

Novel ecosystems have become widespread created, in part, by the global spread of species. The nonnative species in these environments can be under intense evolutionary pressures that cause rapid morphological change, which can then influence species interactions. In Hawaii, much of the native frugivore community is extinct, replaced by nonnative bird species. Here, we determined if the passerine species of the nonnative frugivore community on O'ahu have morphologically diverged from their native ranges. We compared a variety of traits, all important for frugivory, between museum specimens from the species' native ranges to wild individuals from O'ahu. All four species tested exhibited significant divergence ranging in magnitude from 2.3% to 13.0% difference in at least two traits. Using a method developed from quantitative genetics, we found evidence that a mixture of nonadaptive and adaptive processes worked in concert to create the observed patterns of divergence. Our results suggest that rapid morphological change is occurring and, based on the traits measured, that these changes may influence seed dispersal effectiveness. As these species are largely responsible for seed dispersal on the island, the rapid morphological change of these species can influence the stability and maintenance of plant communities on O'ahu.

The European trade ban on wild birds reduced invasion risks

AbstractInternational wildlife trade is a major source of current biological invasions. However, the power of trade regulations to reduce invasion risks at large, continental scales has not been empirically assessed. The European wild bird trade ban was implemented in 2005 to counter the spread of the avian flu. We tested whether the ban reduced invasion risk in two European countries, where 398 nonnative bird species were introduced into the wild from 1912 to 2015. The number of newly introduced species per year increased exponentially until 2005 (in parallel with the volume of wild bird importations), and then sharply decreased in subsequent years. Interestingly, a rapid trade shift from wild‐caught birds to captive‐bred birds, which have lower invasive potential than wild‐caught birds, allowed the maintenance of bird availability in markets. Our results demonstrate the effectiveness of a trade ban for preventing biological invasions without impacting the ability to meet societal demands.

Vertical foraging shifts in Hawaiian forest birds in response to invasive rat removal.

Worldwide, native species increasingly contend with the interacting stressors of habitat fragmentation and invasive species, yet their combined effects have rarely been examined. Direct negative effects of invasive omnivores are well documented, but the indirect effects of resource competition or those caused by predator avoidance are unknown. Here we isolated and examined the independent and interactive effects of invasive omnivorous Black rats (Rattus rattus) and forest fragment size on the interactions between avian predators and their arthropod prey. Our study examines whether invasive omnivores and ecosystem fragment size impact: 1) the vertical distribution of arthropod species composition and abundance, and 2) the vertical profile of foraging behaviors of five native and two non-native bird species found in our study system. We predicted that the reduced edge effects and greater structural complexity and canopy height of larger fragments would limit the total and proportional habitat space frequented by rats and thus limit their impact on both arthropod biomass and birds’ foraging behavior. We experimentally removed invasive omnivorous Black rats across a 100-fold (0.1 to 12 ha) size gradient of forest fragments on Hawai‘i Island, and paired foraging observations of forest passerines with arthropod sampling in the 16 rat-removed and 18 control fragments. Rat removal was associated with shifts in the vertical distribution of arthropod biomass, irrespective of fragment size. Bird foraging behavior mirrored this shift, and the impact of rat removal was greater for birds that primarily eat fruit and insects compared with those that consume nectar. Evidence from this model study system indicates that invasive rats indirectly alter the feeding behavior of native birds, and consequently impact multiple trophic levels. This study suggests that native species can modify their foraging behavior in response to invasive species removal and presumably arrival through behavioral plasticity.

Can climate matching predict the current and future climatic suitability of the UK for the establishment of non-native birds?

ABSTRACTCapsule: Current UK distributions of non-native birds poorly match areas identified as being climatically suitable.Aims: Non-native species are spreading at unprecedented rates and though invasions are expected to increase under climate change, evidence for this is mixed. We assess climatic suitability throughout the UK based on the apparent match to the climate in species’ native ranges and investigate potential climatic limitation within the non-native range.Methods: Climate was characterized within polygons representing the native ranges of 167 potentially invasive species. Parts of the UK with current and future climate similar to that in the native range were deemed climatically suitable. The incidence of recent observations inside and outside suitable areas was used to test hypotheses about climatic limitation of non-native ranges.Results: Climate matching suggests that 69 of 167 non-native bird species could currently find climatically suitable areas for establishment in the UK. Future climate change would see this number increase by 14% by 2080. However, observed occurrences of non-native species in the UK were not significantly correlated to climatic suitability. Only 44 of the 69 species with suitable climate in the UK were present. Moreover, 85% of species observed in the UK had some UK occurrences in climatically unsuitable areas and for 57 species their entire UK range was in climatically unsuitable areas. Similar results were apparent for the subset of 12 species with established UK populations.Conclusions: Climate matching provides a relatively poor indication of the extent of current and future suitable areas because species can adapt to new climates or other factors constrain the native range and many climatically suitable areas are currently unoccupied. Improvements to climate matching techniques and ongoing surveillance are required to refine predictions to support effective management policies.

Surveillance Potential of Non-Native Hawaiian Birds for Detection of West Nile Virus.

West Nile virus (WNV) was first detected in North America in 1999. Alaska and Hawaii (HI) remain the only U.S. states in which transmission of WNV has not been detected. Dead bird surveillance has played an important role in the detection of the virus geographically, as well as temporally. In North America, corvids have played a major role in WNV surveillance; however, the only corvid in HI is the endangered Hawaiian crow that exists only in captivity, thus precluding the use of this species for WNV surveillance in HI. To evaluate the suitability of alternate avian species for WNV surveillance, we experimentally challenged seven abundant non-native bird species present in HI with WNV and compared mortality, viremia, oral shedding of virus, and seroconversion. For detection of WNV in oral swabs, we compared viral culture, reverse-transcriptase polymerase chain reaction, and the RAMP(®) test. For detection of antibodies to WNV, we compared an indirect and a competitive enzyme-linked immunoassay. We found four species (house sparrow, house finch, Japanese white-eye, and Java sparrow) that may be useful in dead bird surveillance for WNV; while common myna, zebra dove, and spotted dove survived infection and may be useful in serosurveillance.

Espécies de aves não nativas no Brasil

Many non-native species of birds have been introduced beyond the limits of their natural geographic ranges, where they may subsequently establish viable populations and perhaps become invasive. Much attention in the literature has been devoted to the study of bird introductions, but relatively little of that attention has been focused on introductions to the continental tropics. Here, we compile published data on records of non-native bird species introduced to the wild in Brazil, with the aim of organizing and standardizing available information to facilitate future studies in this context. A total of 59 bird species were classified as introduced in Brazil, with one further species believed to be a recent natural colonist. Published information implies that 14 species have established or probably established non-native populations in Brazil, while a further 10 species have possibly established non-native populations. In this context, we map the non-native distributions of non-native species of birds in Brazil. Additional research is needed to confirm the status of these species, as well as to establish practical measures to combat and control introductions.Key words: alien birds, biological invasions, exotic species.

Plasmodium infections of red-billed gulls (Larus scopulinus) show associations with host condition but not reproductive performance

High prevalence of Plasmodium infection in some non-native bird species in New Zealand, coupled with distributional expansion of the introduced mosquito vector Culex quinquefasciatus, has raised concerns that immunologically naïve native species might be increasingly at risk from malarial parasites. We combined polymerase chain reaction (PCR) screening of archived blood samples with long-term field data of red-billed gulls (Larus scopulinus) at Kaikoura Peninsula to estimate the prevalence of malarial infection and its effect upon host condition and breeding success. Plasmodium prevalence assessed with PCR was 7.8±3.4%, 10-fold greater than estimates from microscopic analysis of blood smears (c. 0.7%, Tompkins et al. 2010). Phylogenetic analysis of parasite cytochrome b sequences isolated from red-billed gulls indicates that lineage RBG1 falls within a clade containing P. cathemerium morphospecies, whereas RBG2, isolated from a single individual, clusters with P. elongatum. We show that red-billed gulls infected with Plasmodium have bred at Kaikoura dating back to at least 1992, that chronic infections of lineage RBG1 are maintained over several years in some individuals, and that infection is associated with decreased body condition in breeding individuals of both sexes. There is currently no evidence that Plasmodium infection is associated with reduced breeding performance. However, further study involving the ecological context and temporal dynamics of infection is needed to assess cumulative effects on lifetime reproductive success.

Resource Use by Non-Native Ring-Necked Parakeets (Psittacula krameri) and Native Starlings (Sturnus vulgaris) in Central Europe

In general, non-native bird species may competitively exclude native species from nest sites. The potential resource conflict between a native and an introduced bird species, the native European Starling (Sturnus vulgaris) and the introduced Asian Ring-necked Parakeet (Psittacula krameri), was inferred from hole occupancy in parks of the German Upper Rhine Valley (Wiesbaden, Mannheim, Schwetzingen, Edingen-Neckarhausen), where Ring-necked Parakeets have been known to occur for 15 to 35 years. Only 2.2 % of trees (n = 3487) had cavities with an entrance diameter ≥4 cm. The number of unoccupied tree holes was high, representing 71 % of 639 recorded cavities. A niche separation corresponding to tree size and tree species preferred by both bird species could be detected. Starling preferred trees with a diameter of 0.75 ± 0.30 m, whereas Ring-necked Parakeet favoured ones with 1.16 ± 0.36 m in diameter. Both bird species were the most abundant hole-nesters in the examined cavities. Ring-necked Parakeets preferred Platanus x hispanica, which hosted 57 % of all broods for the parakeet, but did not use Acer pseudoplatanus. Starling favoured Quercus robur with 25 % of all broods, followed by A. pseudoplatanus with 19 %. P. x hispanica showed the highest numbers of cavities with 227 in total and a median of 3 holes per tree, partially produced by Ring-necked Parakeet. The largest colony-in-one-tree in this study was 9 for P. krameri and 5 for S. vulgaris. In this study, Starlings took over two nests from Ring-necked Parakeets, with one case vice versa, and Honeybees took over one active Ring-necked Parakeet nest.

Invited article: The impacts of non‐native species: a review of the British Ornithologists’ Union's Autumn 2008 Scientific Meeting

Invited article: The impacts of non‐native species: a review of the British Ornithologists’ Union's Autumn 2008 Scientific Meeting

Inventory of alien birds and mammals in the Wallis and Futuna Archipelago

In November 2007 and November 2008, we conducted a bird and mammal survey on Wallis and Futuna. We found two non-native bird species on Wallis: the Common Myna (Acridotheres tristis) and the Chestnut-breasted Munia (Lonchura castaneothorax), and one on Futuna: the Jungle Myna (Acridotheres fuscus). We also recorded Black Rats (Rattus rattus) on Futuna, a recent introduction to this island. The introduction of 3 bird species and Black Rats in the last decade denotes a lack of preventive measures and demonstrates that the issue of invasive species has not received sufficient priority.

The role of species traits in the establishment success of exotic birds

AbstractThere is now abundant evidence that propagule pressure, a composite measure of the number of individuals released into the nonnative location that varies between introduction events, is the most consistent predictor of success in the establishment of exotic species. However, the reasons why we expect propagule pressure to be important – because larger propagules ameliorate the effects of demographic, environmental or genetic stochasticity, or of Allee effects – also predict an influence of species traits on success. Here, we use a quantitative meta‐analytical approach to assess the effect of three categories of species‐level traits in the successful establishment of nonnative bird species: traits relating to population growth rates, traits that predispose species to Allee effects, and traits that enable a species to cope with novel environments. Traits that predispose species to Allee effects tend to decrease introduction success, whereas traits that enable a species to cope with novel environments tend to increase success. The breadth of habitats a species uses has the strongest mean effect of all variables analysed here. Mean effects for traits relating to population growth rates conflict in sign: in general, success is greater for species with large body mass whereas clutch size is not consistently related to establishment success. These results suggest a likely influence of some species‐level traits on exotic bird establishment success, especially traits that enable a species to cope with novel environments. We suggest that considering such traits in terms of the small‐population paradigm from conservation biology may be a productive avenue for future research.

RELATIONSHIPS AMONG BREEDING BIRDS, HABITAT, AND RESIDENTIAL DEVELOPMENT IN GREATER TUCSON, ARIZONA

Bird abundance trends have been correlated with habitat changes in urban developed areas but have seldom been associated with specific patterns of urban-related habitat changes. We examined breeding bird–habitat relationships in 334 random plots ranging from undisturbed natural to highly developed land in Tucson, Arizona. In each plot we quantified 19 variables describing three land cover patterns (habitat physiognomy, floristics, and spatial relationships of native habitat fragments) and correlated them with abundances of 21 bird species. Abundances of 17 bird species were associated with variables describing land cover pattern. In addition, we correlated abundance, species richness, and evenness for three bird guilds (non-natives, natives, and a native indicator guild) with land cover variables. Housing density best explained the variation in species richness for both the non-native (r2 = 0.79) and the indicator guilds (r2 = −0.69), whereas area of Upland Sonoran vegetative cover (r2 = 0.56) and distance from undisturbed washes (r2 = −0.56) correlated most strongly with the native-bird group. Finally, we developed and tested regression models predicting species richness for each bird guild. The following variables loaded into the predictive models: house density; percentage cover of paved areas; exotic, Upland Sonoran, and undisturbed riparian vegetation; and distance from undisturbed washes. The models explained 71% of the variation in non-native bird species richness, 56% of the variation in native bird species richness, and 60% of the variation in species richness for the indicator guild of birds. The correlations and regression models can be used to predict species richness responses to future residential development in the Tucson area.