The Eurasian collared dove Streptopelia decaocto (Frivaldszky, 1838) spread over the world in the last century. Its presence
in America started in the Caribbean islands in the 1970s due to an accidental escape, but the establishment of this non-native
species in Dominican Republic (La Hispaniola Island) remains unclear despite of the existence of recent records and its
presence in nearby countries since decades ago. We combined citizen science data (compiled in eBird) together with a largescale
survey conducted in 2017 (travelling approximately 2,150 kilometers across the main habitats of the island) to ascertain
the current invasion status of the species in Dominican Republic. Our results indicate that the species probably colonized -or
was introduced into- the island in 2002, being now well established in cities distant up to 270 km far from the city where it
was firstly recorded. The current spatial distribution and recent exponential increase in the number of individuals recorded
suggest that the spread to more cities and even natural habitats is likely to occur in the near future. Further research is needed
to assess its possible impacts on native biodiversity., Peer reviewed

[Background] Urbanization is one of the main causes of biodiversity loss worldwide. Wildlife responses to urbanization, however, are greatly variable and, paradoxically, some threatened species may achieve much larger populations in urban than in natural habitats. Urban conservation hotspots may therefore help some species avoid regional or even global extinctions, but not conserve their often overlooked ecological functions in the wild. We aim to draw attention to this issue using two species of globally threatened parrots occurring in the Dominican Republic: the Hispaniolan amazon (Amazona ventralis) and the Hispaniolan parakeet (Psittacara chloropterus)., [Methods] We conducted a large-scale roadside survey in June 2017 across the country to estimate the relative abundance of parrots in natural habitats, rural habitats, and cities. We combined this with informal interviews with local people to collect information on past and current human impacts on parrot populations. We also looked for foraging parrots to assess their potential role as seed dispersers, an ecological function that has been overlooked until very recently., [Results] Relative abundances of both parrot species were negligible in rural areas and very low in natural habitats. They were generally between one and two orders of magnitude lower than that of congeneric species inhabiting other Neotropical ecosystems. Relative abundances were six times higher in cities than in natural habitats in the case of the Hispaniolan parakeet and three times higher in the case of the Hispaniolan amazon. People indicated hunting for a source food and to mitigate crop damage as causes of parrot population declines, and a vigorous illegal trade for parrots (131 individuals recorded, 75% of them poached very recently), mostly obtained from protected areas where the last small wild populations remain. We observed parrots foraging on 19 plant species from 11 families, dispersing the fruits of 14 species by carrying them in their beaks and consuming them in distant perching trees. They discarded undamaged mature seeds, with the potential to germinate, in 99.5% of cases (n = 306), and minimum dispersal distances ranged from 8 to 155 m (median = 37 m)., [Discussion] The loss of ecological functions provided by some species when they disappear from natural habitats and only persist in cities may have long-term, unexpected effects on ecosystems. Our example demonstrates how two cities may soon be the last refuges for two endemic parrots if overharvesting continues, in which case their overlooked role as seed dispersers would be completely lost in nature. The functional extinction of these species could strongly affect vegetation communities in an island environment where seed-dispersal species are naturally scarce. While conservation plans must include urban populations of threatened species, greater efforts are needed to restore their populations in natural habitats to conserve ecological functions., This work was funded by project CGL2015-71378-P from MINECO (Spain). Álvaro Luna was supported by La Caixa-Severo Ochoa International PhD Program 2015 and the Severo Ochoa Program for Centres of Excellence in R+D+I (SEV-2012-0262)., Peer reviewed

When a species successfully colonizes an urban habitat it can be expected that its population rapidly adapts to the new environment but also experiences demographic perturbations. It is, therefore, essential to gain an understanding of the population structure and the demographic history of the urban and neighbouring rural populations before studying adaptation at the genome level. Here, we investigate populations of the burrowing owl (Athene cunicularia), a species that colonized South American cities just a few decades ago. We assembled a high-quality genome of the burrowing owl and re-sequenced 137 owls from three urban-rural population pairs at 17-fold median sequencing coverage per individual. Our data indicate that each city was independently colonized by a limited number of founders and that restricted gene flow occurred between neighbouring urban and rural populations, but not between urban populations of different cities. Using long-range linkage disequilibrium statistics in an approximate Bayesian computation approach, we estimated consistently lower population sizes in the recent past for the urban populations in comparison to the rural ones. The current urban populations all show reduced standing variation in rare single nucleotide polymorphisms (SNPs), but with different subsets of rare SNPs in different cities. This lowers the potential for local adaptation based on rare variants and makes it harder to detect consistent signals of selection in the genome., Peer Reviewed

Data are organized in two independent files:
(1) “Burrowing_Owl_Data.xlsx” records all the information of burrowing owls ringed during a monitoring program at Bahia Blanca (Argentina) during the breeding seasons 2005/2006 - 2017/2018. Each line corresponds to one individual. The dataset includes the year of birth and the year of first resight, the natal dispersal distance, the sex, the flight initiation distance (FID) and the breeding productivity both in the first breeding attempt and during the entire life for each individual. We also provide information about the habitat type, the conspecific density and the conspecific productivity both for their natal area and for their first breeding territory.--
(2) “dispnatalsurvival.inp” records the recaptures of each marked burrowing owls during a continuous monitoring program, grouped by sex and habitat. Each line corresponds to one individual. The first 11 columns represent the history of life of the individuals by years (with 0 = no resight and 1= resight). The following 4 columns are the groups (urban males, urban females, rural males, rural females), and the last column is the natal dispersal distance (log transformed) covered by each burrowing owl., Dataset (1) was used to analyze how different individual and social traits influence the natal dispersal distances of burrowing owls and how the variation in the dispersal distances can influence breeding productivity. Dataset (2) was used to study how dispersal distances can influence survival in male and females burrowing owls living in urban and rural habitats., The project was funded by Projects CGL2012-31888 and CGL2015-71378-P from MINECO (Spain) and Fundación Repsol. Antonio Palma and Álvaro Luna were supported by La Caixa-Severo Ochoa International PhD Program (2014 and 2015 respectively)., No

When a species colonizes an urban habitat, differences in the environment can create
novel selection pressures. Successful colonization will further lead to demographic
perturbations and genetic drift, which can interfere with selection. Here, we test
for consistent urban selection signals in multiple populations of the burrowing owl
(Athene cunicularia), a species that colonized South American cities just a few decades
ago. We sequenced 213 owls from three urban-rural population pairs and performed
a genome-wide comparison of urban against rural birds. We further studied genomewide
associations with flight initiation distance, a measure of harm avoidance in which
urban and rural birds are known to differ. Based on four samples taken over nine
years from one of the urban populations, we investigated temporal allele frequency
changes. The genomic data were also used to identify urban-specific signatures of
selective sweeps. Single genomic sites did not reach genome-wide significance for
any association. However, a gene-set analysis on the strongest signals from these
four selection scans suggests a significant enrichment of genes with known functions
related to synapses and neuron projections. We identified 98 genes predominantly
expressed in the brain, of which many may play a role in the modulation of brain connectivity
and consequently in cognitive function and motivational behaviour during
urbanization. Furthermore, polymorphisms in the promoter region of the synaptic
SERT gene – one of the two candidates known to correlate with urban colonization in
birds – associated with the habitat in which individuals lived (urban vs. rural)., Peer reviewed

There is a growing need to understand how species respond to habitat changes and the potential key role played by natal dispersal in population dynamics, structure and gene flow. However, few studies have explored differences in this process between conspecifics living in natural habitats and those inhabiting landscapes highly transformed by humans, such as cities. Here, we investigate how individual traits and social characteristics can influence the natal dispersal decisions of burrowing owls (Athene cunicularia) living in urban and rural areas, as well as the consequences in terms of reproductive success and apparent survival. We found short dispersal movements among individuals, with differences between urban and rural birds (i.e., the former covering shorter distances than the latter), maybe because of the higher conspecific density of urban compared to rural areas. Moreover, we found that urban and rural females as well as bold individuals (i.e., individuals with shorter flight initiation distance) exhibited longer dispersal distances than their counterparts. These dispersal decisions have effects on individual fitness. Individuals traveling longer distances increased their reproductive prospects (productivity during the first breeding attempt, and long term productivity). However, the apparent survival of females decreased when they dispersed farther from their natal territory. Although further research is needed to properly understand the ecological and evolutionary consequences of dispersal patterns in transformed habitats, our results provide information about the drivers and the consequences of the restricted natal movements of this species, which may explain its population structuring through restricted gene flow between and within urban and rural areas.

Parrots stand out among birds because of their poor conservation status and the lack of available information on their population sizes and trends. Estimating parrot abundance is complicated by the high mobility, gregariousness, patchy distributions, and rarity of many species. Roadside car surveys can be useful to cover large areas and increase the probability of detecting spatially aggregated species or those occurring at very low densities. However, such surveys may be biased due to their inability to handle differences in detectability among species and habitats. We conducted 98 roadside surveys, covering > 57,000 km across 20 countries and the main world biomes, recording ca. 120,000 parrots from 137 species. We found that larger and more gregarious species are more easily visually detected and at greater distances, with variations among biomes.
However, raw estimates of relative parrot abundances (individuals/km) were strongly correlated (r = 0.86–0.93) with parrot densities (individuals/km2) estimated through distance sampling (DS) models, showing that variability in abundances among species (>40 orders of magnitude) overcomes any potential detectability bias. While both methods provide similar results, DS cannot be used to study parrot communities or monitor the population trends of all parrot species as it requires a minimum of encounters that are not reached for most species (64% in our case), mainly the rarest and more threatened. However, DS may be the most suitable choice for some species-specific studies of common species. We summarize the strengths and weaknesses of both methods to guide researchers in choosing the best–fitting option for their particular research hypotheses, characteristics of the species studied, and logistical constraints., This research was funded by Fundación Biodiversidad (Spanish Ministerio de Medio
Ambiente, project 52I.CA2109), Fundación Repsol, Spanish Ministerio de Ciencia e Innovación (Project CGL2015-71378-P), and mostly by Loro Parque Fundación (Project SEJI/2018/024)., Peer reviewed

12 pages, 3 figures, 2 tables, supplementary information https://doi.org/10.1038/s41598-023-37026-y.-- Data availability: The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request, Urbanization has reshaped ecosystems and changed natural processes, driving an intense transformation of biomes, biotic community composition and diversity. Despite the growing interest in studying urban ecology over the last decades, the consequences of these changes on species occupying these ecosystems are not yet fully understood. Trophic generalism and tolerance to human disturbance have been proposed as two key traits in the colonization of urban environments. However, most studies focused on species’ average traits, paying less attention to the potential role of inter-individual variability. Here, we examined diet specialization in urban and rural breeding pairs, as well as its relationship with individual behaviour and intraspecific competition, using the burrowing owl as a study model. Our results show that both urban and rural breeding pairs behaved as trophic specialists. The diet of burrowing owl breeding pairs followed a gradient from coleopteran- to micromammal-dominated, which is related to individual behaviour (bolder individuals consuming more coleopterans than shyer ones). Besides, pairs distant from others showed a more diverse diet than those experiencing higher levels of intraspecific competition. Models fitted separately for each habitat showed that the proportion of micromammals in the diet of urban breeding pairs was related to their behavior, while the diet of rural pairs was not affected by individual behavior but by intraspecific competition. However, despite the strong selection of tame and more explorative individuals in urban environments and the higher density they reach in this habitat type, they did not differ in their degree of diet specialization from rural conspecifics. Although it would be necessary to evaluate prey availability on a small scale, our results suggest that burrowing owl breeding pairs behave as specialists, despite the generalist character of the species, and that this specialization is not affected by the occupation of urban environments but to individual behaviour and intraspecific competition, The project was funded by Projects CGL2015-71378-P MINECO/FEDER, UE and CGL2012-31888 (Spain) and Fundación Repsol, With the institutional support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), Peer reviewed

Correction: Frontiers in Zoology 17, 13 (2020) https://doi.org/10.1186/s12983-020-00360-2
Following publication of the original article [1], the authors reported that the funding information has to be updated.
The correct funding information should read:
This study was supported by project CGL2015-71378-P MINECO/FEDER, UE, the Severo Ochoa Program (SVP-2014-068732) and Action COST ES1304 (ParrotNet). Logistical and technical support for fieldwork was provided by Doñana ICTS-RBD.

The original article [1] has been updated., Peer reviewed

Parrots are among the most diverse and widely distributed groups of birds and one of the most threatened bird orders mainly due to habitat loss and illegal poaching. Most parrots are obligate cavity nesters, so the logging of mature trees and the transformation of natural cliffs represent important threats to their conservation. Here, we report novel observations of Neotropical parrots nesting in previously unrecorded substrates. We show the first documented case of the cliff-nesting burrowing parrots trying to breed at ground level in an abandoned burrowing owl cavity. Additionally, we provide the first documented observations of this species attempting to nest in building cavities in three urbanized areas of Argentina. Moreover, we report data from four countries of 148 pairs of eight species typically breeding in tree cavity using palm tree bracts as nest sites. Behavioral plasticity in nest sites may allow parrots to maximize their nesting success by exploiting alternative breeding substrates. Moreover, these novelties could contribute to cope with habitat loss and further transformation.
However, further research is needed to assess the consequences of these nesting innovations in terms of individual fitness and population dynamics as well as potential factors promoting their appearance., This work was supported by Loro Parque Fundacion (Project SEJI/2018/024) and by project CGL2015-71378-P from Ministerio de Economía, Industria y Competitividad (Spain). Álvaro Luna was supported by La Caixa-Severo Ochoa International PhD Program 2015 and the Severo Ochoa Program for Centres of Excellence in
R + D + I (SEV-2012-0262), Peer reviewed

We analyzed the ectoparasite community of a monomorphic and non-social bird, the burrowing owl, Athene cunicularia, breeding in rural and urban habitats. Such community was composed by two lice, one mite and one flea species. Rural individuals had more fleas and less mites than urban ones. Adult birds harbored less ectoparasites than young ones and females harbored more lice than males. The presence of lice was positively related to the presence of fleas. On the contrary, the presence of mites was negatively related to the presence of fleas and lice. The study of parasite communities in urban and rural populations of the same species can shed light on how urban stressor factors impact the physiology of wildlife inhabiting cities and, therefore, the host-parasite relationships. Urbanization creates new ecological conditions that can affect biodiversity at all levels, including the diversity and prevalence of parasites of species that may occupy these environments. However, few studies have compared bird-ectoparasite interactions between urban and rural individuals. Here, we analyze the ectoparasite community and co-infection patterns of urban and rural burrowing owls, Athene cunicularia, to assess the influence of host traits (i.e., sex, age, and weight), and environmental factors (i.e., number of conspecifics per nest, habitat type and aridity) on its composition. Ectoparasites of burrowing owls included two lice, one flea, and one mite. The overall prevalence for mites, lice and fleas was 1.75%, 8.76% and 3.50%, respectively. A clear pattern of co-infection was detected between mites and fleas and, to less extent, between mites and lice. Adult owls harbored fewer ectoparasites than nestlings, and adult females harbored more lice than males. Our results also show that mite and flea numbers were higher when more conspecifics cohabited the same burrow, while lice showed the opposite pattern. Rural individuals showed higher flea parasitism and lower mite parasitism than urban birds. Moreover, mite numbers were negatively correlated with aridity and host weight. Although the ectoparasitic load of burrowing owls appears to be influenced by individual age, sex, number of conspecifics per nest, and habitat characteristics, the pattern of co-infection found among ectoparasites could also be mediated by unexplored factors such as host immune response, which deserves further research.