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We report the use of stable isotope and crop content analyses to quantify the use of saguaro (Carnegiea gigantea) nectar and fruit by migratory desert white-winged doves (Zenaida asiatica mearsnii). Saguaro resources had characteristically13C-enriched CAM values (δ13C=-12.8±0.7‰ SD VPDB and -13.1±0.5‰ SD VPDB for nectar and fruit, respectively) relative to other food plants used by doves ($\\delta {}^{13}\\text{C}{}_{\\text{C}3}$=-24.9±3.3‰ SD VPDB). The water contained in saguaro nectar and fruit was deuterium enriched (δD=19.6±2.0‰ SD VSMOW and 48.4±1.6‰ SD VSMOW for nectar and fruit, respectively) relative to other water sources (ranging from -41 to -19‰ VSMOW). During the fruiting season, there was a positive correlation between δ13C in dove liver tissues and percent of saguaro in crop contents. A two-point mixing model indicated that during the peak of saguaro fruit use, most of the carbon incorporated in dove tissues was from saguaro. Desert white-winged doves appear to be saguaro specialists. Averaged over the period when doves were resident, saguaro comprised about 60% of the total carbon incorporated into dove tissues. Tissue δ13C and δD of body water showed a significant positive correlation, indicating that doves were using saguaro as a source of both nutrients and water. However, at the peak of saguaro utilization, the doves' body-water δD was more positive (by about 20‰) than saguaro fruit water. We hypothesize that this enrichment is due to fractionated evaporative water losses by doves. Using dove carbon isotope data and a two end-point mixing model we estimate that, on average, doves consume the equivalent of 128 saguaro fruits per season; each fruit contains on average 26.0±14.8 g SD of pulp (wet mass) of which 19.4 g is water. Stable isotopes have been used to produce qualitative re-constructions of animal diets. Our study shows that they can be used to provide quantitative estimates of the flow of nutrients from resources into consumers as well.

AbstractIn regions of intensive agriculture, such as the Yaqui Valley in Sonora, Mexico, unsustainable farming practices such as monoculture, excessive agrochemical use, and removal of native vegetation are prevalent. However, the impact of these practices on biodiversity is not well understood. In this study, we determine the diversity, abundance, and landscape affinities of the bird community in the Yaqui Valley. Between the fall of 2018 and the summer of 2019, we detected 16,775 individuals of 110 species grouped in 37 families along 15 routes. The species with the highest abundance were white-winged dove (Zenaida asiatica), Eurasian collared dove (Streptopelia decaocto), mourning dove (Zenaida macroura), rock pigeon (Columba livia), yellow-headed blackbird (Xanthocephalus xanthocephalus), red-winged blackbird (Agelaius phoeniceus), cliff swallow (Petrochelidon pyrrhonota), and Mexican duck (Anas diazi). The spring season had the highest biodiversity index, with more insectivorous species, followed by fall (carnivore species) and summer (piscivorous species). Of the recorded birds, 51 species were reproductive, 35 terrestrial, and 16 aquatic. They used abandoned fields (Gambel's quail, Callipepla gambelii), farms (Eurasian collared dove), aquatic vegetation (fulvous whistling duck, Dendrocygna bicolor; killdeer Charadrius vociferus), edge herbaceous vegetation (rufous-winged sparrow, Peucaea carpalis; song sparrow, Melospiza melodia; western meadowlark, Sturnella neglecta; common yellowthroat, Geothlypis trichas; yellow-breasted chat, Icteria virens), high arboreal layers (black-bellied whistling duck, Dendrocygna autumnalis), terrestrial vegetation (curve-billed thrasher, Toxostoma curvirostre), irrigation network (black-necked stilt, Himantopus mexicanus; burrowing owls, Athene cunicularia), and aquatic and terrestrial habitats (Mexican duck). Of the 110 species detected, 41 species (37%) are included in at least one conservation instrument, and the vulnerability increases with time. Regarding crop features, harvested_wheat combined with corn and various_crops had the highest bird biodiversity index. In contrast, immature_wheat, one of the most common landscapes in the Yaqui Valley, had the highest abundance of only a few species of birds.

Abstract During this one year study, blood and fecal samples of doves (Zenaida asiatica), ducks (Anas platyrhynchos), pigeons (Columba livia), partridges (Alectoris chukar), turkeys (Meleagris gallopavo) and goose (Chen caerulescens) were collected to assess the parasitic prevalence in these birds. The birds were kept at Avian Conservation and Research Center, Department of Wildlife and Ecology, University of Veterinary and Animal Sciences, Lahore. All these avian species were kept in separate cages and their entire body was inspected on regularly basis to record external parasites. For internal parasites, 100 blood and 100 fecal samples for each species were analyzed. During present study, two species of ectoparasites i.e. fowl ticks (Args persicus) and mite (Dermanyssus gallinae) while 17 species of endoparasites; three from blood and 14 from fecal samples were identified. Prevalence of blood parasites was Plasmodium juxtanucleare 29.3%, Aegyptinella pullorum 15% and Leucoctoyzoon simond 13%. Parasitic species recorded from fecal samples included 6 species of nematodes viz. Syngamus trachea with parasitic prevalence of 50%, Capillaria anatis 40%, Capillaria annulata 37.5%, Heterakis gallinarum 28.3%, Ascardia galli 24% and Allodpa suctoria 2%. Similarly, two species of trematodes viz. Prosthogonimus ovatus having parasitic prevalence of 12.1% and Prosthogonimus macrorchis 9.1% were also recorded from fecal samples of the birds. Single cestode species Raillietina echinobothrida having parasitic prevalence of 27% and 3 protozoan species i.e. Eimeria maxima having prevalence 20.1%, Histomonas meleagridis 8% and Giardia lamblia 5.3% were recorded. In our recommendation, proper medication and sanitation of the bird’s houses and cages is recommended to avoid parasites. Resumo Durante este estudo de um ano, amostras de sangue e fezes de pombos (Zenaida asiatica), patos (Anas platyrhynchos), pombos (Columba livia), perdizes (Alectoris chukar), perus (Meleagris gallopavo) e ganso (Chen caerulescens) foram coletados para avaliar a prevalência de parasitas nessas aves. As aves foram mantidas no Centro de Conservação e Pesquisa de Aves, Departamento de Vida Selvagem e Ecologia, Universidade de Veterinária e Ciências Animais, Lahore. Todas essas espécies de aves foram mantidas em gaiolas separadas e todo o seu corpo foi inspecionado regularmente para registrar parasitas externos. Para parasitas internos, foram analisadas 100 amostras de sangue e 100 amostras fecais de cada espécie. Durante o presente estudo, duas espécies de ectoparasitas, ou seja, carrapatos de aves (Args persicus) e ácaros (Dermanyssus gallinae), enquanto 17 espécies de endoparasitas, três de sangue e 14 de amostras fecais, foram identificadas. Os parasitas sanguíneos prevalentes foram Plasmodium juxtanucleare, 29,3%, Aegyptinella pullorum, 15%, e Leucoctoyzoon simond, 13%. As espécies parasitas registradas em amostras fecais incluíram 6 espécies de nematoides viz. Syngamus traqueia com prevalência parasitária de 50%, Capillaria anatis, 40%, Capillaria annulata, 37,5%, Heterakis gallinarum, 28,3%, Ascardia galli, 24% e Allodpa suctoria, 2%. Da mesma forma, duas espécies de trematódeos viz. Prosthogonimus ovatus com prevalência parasitária de 12,1% e Prosthogonimus macrorchis, 9,1%, também foram registrados nas amostras fecais das aves. Espécies de cestoide único Raillietina echinobothrida com prevalência parasitária de 27% e 3 espécies de protozoários, ou seja, Eimeria maxima tendo prevalência de 20,1%, Histomonas meleagridis, 8%, e Giardia lamblia, 5,3%, foram registradas. Em nossa recomendação, são indicados medicação adequada e saneamento das casas e gaiolas dos pássaros para evitar parasitas.

The Eurasian collared-dove (Streptopelia decaocto) has expanded its range into South Texas, bringing it into contact with native columbid species. We studied urban columbid breeding ecology at three study sites, representing five South Texas towns, in 2006 and 2007. Columbids began nesting in April and peaked in late spring, followed by a secondary nesting peak. A positive relationship occurred between nesting vegetation type and mean nest density of each columbid species but was inconsistent within and among study sites. Eurasian collared-doves also utilized human-constructed structures for nesting sites. Columbids were nonselective in choosing nest placement within trees except for Eurasian collared-doves nesting in Rio Grande ash (Fraxinus berlanderiana). White-winged doves (Zenaida asiatica) and Eurasian collared-doves tended to nest higher in trees than mourning doves (Zenaida macroura) or Inca doves (Columbina inca) where all four species co-occurred. Eurasian collared-dove, Inca dove, mourning dove, and white-winged dove productivity was 1.3 ± 0.1 (SE) fledged young/nest, 1.3 ± 0.2, 0.9 ± 0.1, and 1.1 ± <0.1, respectively. Overall, urban nesting columbids used a generalist habitat and nest site association strategy, which negated interspecific competition for available nest sites. We provide some of the first information on nesting ecology and productivity of the Eurasian collared-dove associated with native columbid species within North America. La paloma de collar turca (Streptopelia decaocto) ha expandido su área de distribución al sur de Texas, poniéndose en contacto con especies columbidas nativas. Estudiamos la ecología reproductiva de columbidae urbana en tres sitios de estudio, representando cinco ciudades del sur del estado de Texas en 2006 y 2007. Las palomas columbidae comenzaron a anidar en abril, alcanzando su pico máximo a fines de la primavera, seguido de un pico secundario de anidación. Se produjo una relación positiva entre el tipo de vegetación de anidación y la densidad media de nidos de cada especie columbina, pero fue inconsistente dentro de sitios individuales y entre ellos. Las palomas de collar turcas también utilizaron estructuras construidas por humanos para sitios de anidación. Las columbidae no fueron selectivas al elegir la ubicación de los nidos dentro de los árboles, excepto las palomas de collar turcas que anidan en los fresnos del río Grande (Fraxinus berlanderiana). Las palomas de alas blancas (Zenaida asiatica) y la paloma de collar turca solían anidar más alto en los árboles que la paloma huilota (Zenaida macroura) o la tortolita cola larga (Columbina inca) donde coexistían las cuatro especies. La productividad de la paloma de collar turca, la tortolita cola larga, la paloma huilota y la paloma de alas blancas fue de 1.3 ± 0.1 (ES) crías que salieron por nido, 1.3 ± 0.2, 0.9 ± 0.1, y 1.1 ± <0.1, respectivamente. En general, las columbidae de anidación urbana utilizaron una estrategia general de asociación de hábitat y sitios de anidación, lo que negó la competencia interespecífica por los sitios de anidación disponibles. Proporcionamos una parte de la primera información sobre la ecología de anidación y la productividad de la paloma de collar turca asociada con especies de columbidae nativas dentro de América del Norte.

Background and Research Aims Power lines are one of the main anthropogenic causes of bird mortality on a global scale, but research is scarce in some countries with a high diversity of birds, such as Mexico. In this study, we assessed the impact of bird collisions and electrocutions with power lines on avian communities at three wind farms located in three different states in Mexico. Methods Carcass searches were carried out at sites in Tamaulipas (4 months in 2021), Guanajuato (2 months in 2020, 4 months in 2021), and Oaxaca (55 months from 2014 to 2021). Results A total of 579 bird carcasses from 65 different species were recorded. The White-winged Dove (Zenaida asiatica) was the most frequently found species (282 records) across the three sites. When considering the number of species identified per family, Icteridae had the highest number of species at the Oaxaca site, Columbidae and Passerelidae at the Tamaulipas site, and Anatidae at the Guanajuato site. At the order level, Passeriformes had the highest number of species at the Tamaulipas and Oaxaca sites, and Anseriformes in Guanajuato. Of the total species recorded, 12 are within some category of risk according to Mexican legislation and the IUCN Red List, and 18 are migratory species. Conclusions Our results, together with evidence from previous studies, indicate that power lines represent one of the main causes of anthropogenic mortality in Mexico in terms of the number of affected bird species. Further research is urgently needed to explore the effect of power lines on bird populations in the country, particularly those at risk of extinction, and migratory species. Implications for Conservation The high diversity of species found to be affected in this study highlights the wide-ranging impact of these structures and the need to implement mitigation strategies at the three sites studied, particularly for the most affected species, the White-winged Dove (Zenaida asiatica).

Sex ratio is an important parameter influencing the demography of wildlife species. Sex ratios are categorized as primary (sex at fertilization), secondary (sex at birth through immaturity), tertiary (sex at adulthood), and quaternary (sex at post-reproductive age). Herein, we examined the secondary1 (hatchling), secondary2 (juvenile or subadult), and tertiary (adult) sex ratios of white-winged doves (Zenaida asiatica). Also, because white-winged doves typically hatch two eggs, we also evaluated the secondary sex ratio of co-occurring nestlings. Interestingly, secondary and juvenile sex ratios were significantly male biased, whereas tertiary sex ratios were not biased. Additionally, the ratio of same-sex nestlings was also male biased. The lack of bias at the tertiary level supports Fisher's principle that differential selection for sex ratios of 1:1 exist and lead to more stable populations. Therefore, we conclude that there is some selection mechanism present in this species that selects against males reaching adult status given our findings at the secondary and juvenile sex ratio levels. La proporción de sexos es un parámetro importante que influye en la demografía de las especies silvestres. Las proporciones de sexos se clasifican en primarias (sexo en la fecundación), secundarias (sexo al nacer/inmaduro), terciarias (sexo en la edad adulta) y cuaternarias (sexo en la edad pos reproductiva). Aquí, examinamos la secundaria1 (cría), secundaria2 (juveniles o subadultos) y terciarios (adultos) de las palomas aliblancas (Zenaida asiatica). Además, debido a que las palomas aliblancas suelen incubar dos huevos, también evaluamos la proporción de sexos secundarios de los polluelos coexistentes. Curiosamente, las proporciones de sexos secundarios y de juveniles fueron significativamente sesgadas por los machos, mientras que las proporciones de sexos en el terciario no lo fueron. Además, la proporción de polluelos del mismo sexo también estaba sesgada por los machos. La falta de sesgo en la proporción terciaria apoya al principio de Fisher, que existe la selección diferencial para la proporción de sexo de 1:1 y conducen a poblaciones más estables. Por lo tanto, llegamos a la conclusión de que existe algún mecanismo de selección presente en esta especie que selecciona para que los machos no alcancen el estado adulto, dados nuestros hallazgos en la proporción de sexos secundaria y de juveniles.

Aim: Range expansion across a heterogeneous landscape may depend on the habitat selected and used by the expanding species. If habitat selection influences range expansion then localities colonized by a species should contain a greater proportion of favoured habitat (and less non-habitat) than other nearby localities not colonized. White-winged doves (Zenaida asiatica) and Eurasian collared doves (Streptopelia decaocto) are two bird species that provide an excellent opportunity to test this hypothesis, because the geographic ranges of both species have been expanding in North America for more than two decades. Location: Continental USA. Methods: We used distribution data from the North American Breeding Bird Survey to test whether the landscapes occupied by each species contained a greater proportion of favoured habitat (urban land, grassland/pasture, shrub land and cropland) and a lower proportion of non-habitat (forest land) than landscapes where doves were not found. We tested each species separately in each of three broad expansion areas, namely East, Central and West. We also compared rates of spatial spread between expansion areas and between the two species. Results: As predicted, both species tended to occupy landscapes with greater proportions of urban land, shrub land and cropland but with less forest land compared with landscapes without doves, in all three expansion areas. Contrary to prediction, occupied landscapes tended to have slightly less grassland/pasture than unoccupied landscapes. Rates of spread differed between the two species and among expansion areas. Main conclusions: Range expansion and the extent to which a species fills or saturates its range are influenced by the habitat ecology of the expanding species. Species colonize localities based on the availability of suitable habitat. However, the role of habitat in a species' range expansion does depend somewhat on the greater geographical setting. Over large regional and geographical scales, range expansion (rate of spread and saturation) may proceed unevenly, suggesting that range expansion is a very dynamic and context-specific process.

AIM: The geographical expansion of white‐winged doves (Zenaida asiatica) in North America has attracted the attention of biologists and sportsmen because of their recreational and aesthetic value; however, data on factors driving the spatial spread of this species are lacking. We examined spatial and temporal patterns of range expansion for white‐winged doves along the northern edge of their geographical range from 1979 to 2007 and used a dynamic occupancy model to estimate when and where doves would be found along an expansion gradient. LOCATION: Southern half of the USA. METHODS: We modelled spatial variation in the range expansion of white‐winged doves from 1979 to 2007 using data from the North American Breeding Bird Surveys (BBS) and distance from initial population centre, area of urban land cover, and ecoregion. We used a robust design occupancy analysis to estimate species expansion rate based on a model set grounded in broad‐scale conditions likely to drive dove distribution. We evaluated our best fitting model (using Akaike's information criterion adjusted for small sample size) by comparing estimates to actual observations in 1993 and 2007 using area under the curve (AUC) metrics from receiver‐operating characteristic plots. RESULTS: Our spatial distribution model indicated that range expansion of white‐winged doves was primarily influenced by distance from the core population centre, with additive effects of ecoregion and land cover. In 1979, white‐winged doves were present in 12% of survey locations, whereas presence increased to 41% by 2007. Across all ecoregions, urban land cover was positively related to probability of occupancy. We evaluated our model for 1993 and 2007 by comparing derived occupancy estimates to sightings of white‐winged doves within our sample hexagons using BBS survey data. Based on high AUC statistics (> 0.85), we concluded that our model was useful for accurately predicting range expansion. MAIN CONCLUSIONS: Estimating occurrence and range expansion of white‐winged doves and other expanding/invasive avian species at large spatial scales can be effectively conducted using BBS data. Using these nationwide, long‐term survey data to relate expansion to a suite of conditions likely to drive population dynamics is an effective approach to developing predictive models of range expansion.

The white-winged dove (Zenaida asiatica) serves an important ecological role as a diurnal pollinator of the saguaro cactus in the Sonoran desert and an economic role as a highly sought after game bird in North America. White-winged doves are intimately linked to anthropogenic changes on the landscape and because of this, have experienced dramatic population fluctuations over the last 75 years in response, both positively and negatively, to anthropogenic changes on the landscape. To understand the factors driving population growth and decline of migratory species like the white-winged dove, it is imperative we study resource use on both their breeding and wintering grounds. To understand how populations are distributed on the wintering grounds, we tested an alternative to band recovery approaches by using stable isotope analysis. Before we could use isotope analysis to link breeding and wintering locations for this species, we first needed to determine if hydrogen (δ2H) and carbon (δ13C) stable isotopes in feather tissue (δ2Hf and δ13Cf, respectively) could differentiate among populations of white-winged doves across their breeding range in Texas, New Mexico, and Arizona. δ2Hf and δ13Cf not only differentiated between populations of white-winged doves that breed in the United States, but δ2Hf also provided further differentiation in white-winged doves that breed in native Sonoran Desert and agricultural habitats in the western portion of their range. Ecological processes associated with desert resources and anthropogenic influences, specifically saguaro cacti and irrigated crops, largely determined δ2Hf in some white-winged doves in Arizona whereas δ2H of precipitation (δ2Hp) largely determined δ2Hf of doves in New Mexico and Texas. This study highlights the usefulness of stable isotope analysis to differentiate populations of animals across the landscape and the insight isotopes can provide into habitat and resource use. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

We observed white-winged doves (Zenaida asiatica asiatica) feeding on Chinese tallow (Triadica sebifera) seeds in south Texas. We noted two types of foraging behavior from October through January during 2013–2015. We observed white-winged doves either plucking seeds directly from the branches or cooperatively feeding by one dove shaking a branch, allowing loose seeds to fall to the ground to be consumed by other doves. This is the first recorded occurrence of apparent collaborative foraging behavior between white-winged doves on the ground and individuals in the treetops.