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There is insufficient data about the migratory duck Anas crecca, especially the beak and oropharyngeal cavity roof. This study aimed to characterize the beak and palatine adaptations and relate the morphological features with the species-specific feeding behavior of A. crecca collected near Lake Nasser (Egypt). Our study was carried out with the help of gross, scanning electron microscopy (SEM), and morphometric analysis. The lower median papillary teeth-like region corresponded to the lower papillary region in terms of food particle capture. The serrated gnathotheca surface exhibited transverse, wedge-like, cap-like, and serrated border-like processes. The lower mandibular space had four spaces: the rostral smooth, the middle folded, the long sublingual, and the caudal sublaryngeal space. The palate showed two major regions, the rostral long beak (beak nail, middle part, and the caudal papillary part) and the connecting region. The choana consists of the rostral narrow part, which has rostral non-papillated and caudal papillated parts, and the caudal papillated wide part, which has three papillary rows. The infundibular plate had numerous small papillae and sphenopterygoid salivary gland openings. Functionally, the beak plays an important role in the sieving filter feeding mechanism, and the palate is involved in the fixation of the captured food particles inside the oral cavity. Consequently, beak and palate structures exhibit anatomical adaptations for efficiently filtering feeding mechanisms. [ABSTRACT FROM AUTHOR]

The wetlands of southwestern Siberia (SWS) are a crossroads of bird migration routes, bringing avian influenza (AIV) strains that were previously isolated in different regions of the continent to Siberia. It is known that Anseriformes that breed in SWS migrate for the winter to central Hindustan or further west, while their migration routes to southeast Asia (SEA) remain unconfirmed. Here, we mapped the molting sites of the migrating Common Teals (Anas crecca) via analyzing stable hydrogen isotope content in feathers of hunters' prey and supplemented the analysis with the genetic structure of viruses isolated from teals in the same region. Post-breeding molt of autumn teals most likely occurred within the study region, whereas probable pre-breeding molting grounds of spring teals were in the south of Hindustan. This link was supported by viral phylogenetic analysis, which showed a close relationship between SWS isolates and viruses from south and southeast Asia. Most viral segments have the highest genetic similarity and the closest phylogenetic relationships with viruses from teal wintering areas in southeast Asian countries, including India and Korea. We assume that the winter molt of SWS breeding teals on the Hindustan coast suggests contacts with the local avifauna, including species migrating along the coast to SEA. Perhaps this is one of the vectors of AIV transmission within Eurasia. [ABSTRACT FROM AUTHOR]

The wetlands of southwestern Siberia (SWS) are a crossroads of bird migration routes, bringing avian influenza (AIV) strains that were previously isolated in different regions of the continent to Siberia. It is known that Anseriformes that breed in SWS migrate for the winter to central Hindustan or further west, while their migration routes to southeast Asia (SEA) remain unconfirmed. Here, we mapped the molting sites of the migrating Common Teals (Anas crecca) via analyzing stable hydrogen isotope content in feathers of hunters’ prey and supplemented the analysis with the genetic structure of viruses isolated from teals in the same region. Post-breeding molt of autumn teals most likely occurred within the study region, whereas probable pre-breeding molting grounds of spring teals were in the south of Hindustan. This link was supported by viral phylogenetic analysis, which showed a close relationship between SWS isolates and viruses from south and southeast Asia. Most viral segments have the highest genetic similarity and the closest phylogenetic relationships with viruses from teal wintering areas in southeast Asian countries, including India and Korea. We assume that the winter molt of SWS breeding teals on the Hindustan coast suggests contacts with the local avifauna, including species migrating along the coast to SEA. Perhaps this is one of the vectors of AIV transmission within Eurasia.

There is insufficient information about the migratory Eurasian teal, Anas crecca. The study provides the first anatomical description of lingual adaptations and their relationship with the species-specific feeding behavior of A. crecca collected near Egyptian Lake Nasser. Our investigation was applied with the help of gross, scanning electron microscopy (SEM), and morphometric analysis. The study focused on the feeding filtering apparatus that depends on eight lingual papillae. The spatula-shaped nail is adapted for food particle pecking, while the lingual combs, rostral border of the prominence, unique papillary crest, median groove, and papillary system aid in intra-oral transportation. The feeding apparatus is formed by the lateral and dorsal papillary systems. The lateral papillary system had conical papillae with numerous long filiform and hair-like filiform papillae to constitute the food filtration apparatus, while the dorsal papillary system had ridged-like and rod-like papillae in addition to the small papillae of the papillary crest and spinated border of the root to help in moving the food particles with water to the lateral sides of the prominence. The laryngeal region exhibited papillary (pre-glottic) and non-papillary (glottic) areas. The papillary area had two lateral papillary portions and a median smooth portion, while the non-papillary area had an ovoid laryngeal mound with a median glottic opening that was bordered by a papillary border. The papillary portion had three slightly oblique longitudinal papillary rows., (© 2024 Wiley Periodicals LLC.)

Despite the importance of green‐winged teal (Anas crecca) as a harvested species in North America, recent information on variation in vital rates among regions is lacking. We used band recovery data and hierarchical autoregressive models to examine temporal and age‐sex‐class variation in survival, hunting mortality, and nonhunting mortality probabilities of green‐winged teal banded at Kgun Lake on the Yukon‐Kuskokwim Delta, Alaska, USA, from 1997–2019. We used data from 10,554 adult and juvenile green‐winged teal of known sex and age banded and released at Kgun Lake, and 1,245 hunter recoveries. Estimates of annual survival probability for adult females and males ranged from 0.44 (95% CI = 0.29–0.54) to 0.49 (95% CI = 0.37–0.68) and 0.56 (95% CI = 0.50–0.61) to 0.58 (95% CI = 0.50–0.64), respectively, during our study period. Estimates of annual survival probability for juvenile females and males ranged from 0.36 (95% CI = 0.18–0.56) to 0.46 (95% CI = 0.31–0.71) and 0.51 (95% CI = 0.38–0.61) to 0.56 (95% CI = 0.44–0.71), respectively. Hunting mortality probability was greatest for juvenile males and least for adult females. Hunting mortality probability of juvenile males increased from 0.09 (95% CI = 0.05–0.13) in 1997 to 0.14 (95% CI = 0.11–0.18) in 2015. Nonhunting mortality probability was greater and more variable than hunting mortality probability for all age‐sex classes, indicating nonhunting mortality contributed most to total mortality of green‐winged teal banded at Kgun Lake during our study. Additionally, survival probability of female green‐winged teal banded at Kgun Lake is less than published estimates for green‐winged teal banded in the boreal forest of Alaska. We recommend continuing consistent banding operations for green‐winged teal on the Yukon‐Kuskokwim Delta and other important breeding areas to further understand factors influencing nonhunting mortality and how they may vary seasonally and geographically. [ABSTRACT FROM AUTHOR]

The Drugeon Basin is a Ramsar and Natura 2000 area (Ramsar and Natura 2000) where hunting generates a "Landscape of Fear" for waterbirds. Bird counts carried out for six successive years along the river show that several game species (Eurasian Teal Anas crecca, Mallard Anas platyrhynchos, Tufted Duck Aythya fuligula, Common Moorhen Gallinula chloropus and Eurasian Coot Fulica atra) and two protected species (Mute Swan Cygnus olor and Little Grebe Tachybaptus ruficollis) have much higher densities in villages and non-huntable areas than in areas where hunting is allowed. In contrast, the distribution along the watercourse of three protected species (Grey Heron Ardea cinerea, Great Egret Ardea alba and Common Kingfisher Alcedo atthis) and one game species (Water Rail Rallus aquaticus) is not impacted by hunting. In addition, monitoring for 14 years on two transects in the downstream part of the valley shows that the numbers of six game species (Eurasian Teal, Mallard, Tufted Duck, Common Moorhen, Eurasian Coot and Common Snipe Gallinago gallinago) and two protected species (Grey Heron and Little Grebe) decrease in the hunting season when they are expected to increase due to their migration phenology and that Eurasian Teals, Mallards, Northern Shovelers Spatula clypeata, Tufted Ducks, Little Grebes, Common Moorhens, Eurasian Coots and Common Snipe that frequent these transects change their spatial distribution after the opening of the hunt so as to avoid areas where they risk being killed. During the first half of September, on the two transects, the numbers of huntable birds during the hunting season are respectively 48% and 31% of the numbers observed when the hunt is closed. On the other hand, during this same fortnight, the number of waterbirds protected is not significantly different during the hunting season from that observed during the non-hunting period. [ABSTRACT FROM AUTHOR]

The number of wetlands in Europe decreased by more than 60% by the 1990s compared with the beginning of the twentieth century. Man-made wetlands may be an effective way to compensate for the loss and degradation of freshwater ecosystems. This loss impacts the populations of declining duck species, partly due to a lack of suitable breeding opportunities. In this study, we evaluated duck productivity and invertebrate abundance in 13 man-made Finnish wetlands that were created for waterbirds. Our findings revealed that man-made wetlands have higher duck production than average natural boreal lakes. High invertebrate levels were a key factor that positively correlated with duck pair density, brood density, duckling density of the common teal (Anas crecca), and duck density during the post-breeding period. Our results suggest that man-made wetlands are a useful tool for increasing duck productivity. For upholding this status in the long term, appropriate management should involve maintaining sufficient invertebrate levels. [ABSTRACT FROM AUTHOR]

Understanding the dynamics of migrant birds' gut microbial communities is essential for evaluating their ecological interactions, since these birds act as vectors for zoonotic viruses and their gut microbiome may have exceptional relationship with zoonotic viral infection. The Eurasian teal duck Anas crecca traverses continents during migration, combining and providing intercontinental links for avian influenza viruses (AIV) of different origins. The present study aimed to investigate how the AIV infection affects gut microbial composition and evaluate the consequent physiological stress and constitutive immunity of teal birds. Samples were collected from 2 flocks during their migratory stopover in northern Egypt. An important shift in gut microbiota of AIV-infected individuals has been detected by RT-PCR. In healthy teal, firmicutes dominated followed by proteobacteria, while the structure was reversed in infected birds. Infection with AIV significantly increased the stress hormone corticosterone, accompanied by a significant increase in both oxidative stress markers and antioxidants. Constitutive immunity, measured by plasma bactericidal effect against E. coli , the nonspecific natural antibodies, and the mediated complement activation, was reduced in AIV-infected teal birds. Constitutive immunity parameters were proportionally correlated to the firmicutes and inversely to the proteobacteria abundances, but not to the viral positivity. In conclusion, the present study provides initial evidence of the alteration of the gut microbiome in the Eurasian teal Anas crecca by AIV infection and demonstrates that the AIV-induced reduction in constitutive immunity is a consequence of the shift in microbiome composition rather than the virus infection itself or its induced stress. [Display omitted] • Avian influenza virus infection alters gut microbiota in migratory teal birds. • Microbiome shifts towards increased proteobacteria and decreased firmicutes. • AIV-induced reduction in constitutive activity was also observed in teal birds. • Constitutive immunity correlated proportionally to firmicutes and inversely to proteobacteria. • Alteration of constitutive immunity can be attributed to changed microbiome rather than virus infection. [ABSTRACT FROM AUTHOR]

Stopover sites provide crucial habitat for waterfowl to rest and refuel during migration. Knowledge of which land-cover types are of greatest importance to migrating waterfowl and how the surrounding landscape influences their use can inform management decisions and conservation plans to adequately meet resource requirements. Specifically, spring migration habitat is essential for waterfowl preparing for breeding yet is an understudied period of the life cycle. We placed radio-transmitters on Mallards (Anas platyrhynchos) and Green-winged Teal (Anas crecca) between January and April 2016–2017 in the Wabash River Valley of Illinois and Indiana to assess habitat use and movement patterns. Both Mallards and Green-winged Teal primarily used emergent and woody wetlands, with 89% of use points in these land-cover types even though they made up <5% of the study area. Use of both dry and flooded row crops was minimal. While habitat selection of Mallards was similar for diurnal vs. nocturnal periods, Green-winged Teal used emergent wetlands at a higher rate during the day and shifted to woody wetlands at night. In general, sites surrounded by greater amounts of open water, upland forest, and upland herbaceous/grassland cover were more likely to be used than areas surrounded by row-crop agriculture. Additionally, private and public lands enrolled in conservation easement programs (such as the Wetlands Reserve Program) were frequently used by migrating waterfowl compared to other protected or public lands. These findings highlight the importance of a landscape-level approach to conservation, specifically focusing on wetland restoration while minimizing reliance on agricultural fields to fulfill habitat needs during spring migration in the Midwest. [ABSTRACT FROM AUTHOR]

Background: The aim of the present study was to study pathological and parasitological characteristics of simultaneous capillariasis and hystrichiasis in a diseased Anas crecca captured in Mazandaran Province of Iran on Oct 2016. Methods: Parasitology and histopathology techniques were used to detect the parasites of the carcass of the captive common teal. Results: Macroscopically, severe chronic inflammatory reactions and nodular or granuloma formation and irregular thickening of the affected wall of the esophagus, crop, proventrculus and ventriculus were observed. Microscopically, apart from the chronic inflammatory reactions and granuloma formation, in the paraffin sections stained with Harris Hematoxyline and Eosin technique, the characteristics of the mature female and male Capillaria spp. and their barrel-shaped operculated embryonated eggs were found within the tunnels burrowed by the nematode in the hyperplastic stratified squamous epithelium of the inflamed crop and distal portion of the esophagus. The mature female Hystrichis spp. containing oval-shaped, embryonated non-operculated eggs and male parasite were found within the labyrinthus spaces formed in the submucosa granulomas of the ventriculus and proventriculus. Conclusion: Based on the parasitological and pathological studies, the species of the nematode parasites were identified as Capillaria (Thominx) contorta and Hystrichis. tricolor.

Background: The aim of the present study was to study pathological and parasitological characteristics of simultaneous capillariasis and hystrichiasis in a diseased Anas crecca captured in Mazandaran Province of Iran on Oct 2016. Methods: Parasitology and histopathology techniques were used to detect the parasites of the carcass of the captive common teal. Results: Macroscopically, severe chronic inflammatory reactions and nodular or granuloma formation and irregular thickening of the affected wall of the esophagus, crop, proventrculus and ventriculus were observed. Microscopically, apart from the chronic inflammatory reactions and granuloma formation, in the paraffin sections stained with Harris Hematoxyline and Eosin technique, the characteristics of the mature female and male Capillaria spp. and their barrel-shaped operculated embryonated eggs were found within the tunnels burrowed by the nematode in the hyperplastic stratified squamous epithelium of the inflamed crop and distal portion of the esophagus. The mature female Hystrichis spp. containing oval-shaped, embryonated non-operculated eggs and male parasite were found within the labyrinthus spaces formed in the submucosa granulomas of the ventriculus and proventriculus. Conclusion: Based on the parasitological and pathological studies, the species of the nematode parasites were identified as Capillaria (Thominx) contorta and Hystrichis. tricolor. [ABSTRACT FROM AUTHOR]

Avian species respond to ecological variability at a range of spatial scales and according to life history stage. Beaver dams create wetland systems for waterbirds that are utilized throughout different stages of the breeding season. We studied how beaver‐induced variability affected mobile pairs and more sedentary broods along with the production of Common Teal Anas crecca at the patch and landscape scale on their breeding grounds. Beavers Castor spp. are ecosystem engineers that enhance waterfowl habitats by impeding water flow and creating temporary flooding. Two landscapes in southern Finland with (Evo) and without (Nuuksio) American Beavers Castor canadensis were used in this study. To investigate the patch‐scale effect, pair and brood densities along with brood production were first compared at beaver‐occupied lakes and non‐beaver lakes in the beaver landscape. Annual pair and brood densities/km shoreline and brood production were compared between beaver and non‐beaver landscapes. Facilitative effects of beaver activity were manifest on brood density at both patch and landscape scales: these were over 90% and 60% higher in beaver patches and landscapes, respectively. An effect of beaver presence on pair density was only seen at the landscape level. Pair density did not strongly affect brood production, as shown earlier for relatively mildly density‐dependent Teal populations. Because the extent of beaver flooding was a crucial factor affecting annual Teal production in the study area, we infer beaver activity has consequences for the local Teal population. Ecosystem engineering by the beaver could therefore be considered a restoration tool in areas where waterfowl are in need of high‐quality habitats. [ABSTRACT FROM AUTHOR]

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A female Green-winged Teal Anas carolinensis, paired with a drake, was seen and photographed in Shetland in May 2018. This is perhaps the first confirmed record of a female for Britain & Ireland. The identification of this bird, and that of female Green-winged Teal in general, is discussed. [ABSTRACT FROM AUTHOR]

Identifying an organism's migratory strategies and routes has important implications for conservation. For most species of European ducks, information on the general course of migration, revealed by ringing recoveries, is available, whereas tracking data on migratory movements are limited to the largest species. In the present paper, we report the results of a tracking study on 29 Eurasian Teals, the smallest European duck, captured during the wintering period at three Italian sites. The departure date of spring migration was determined for 21 individuals, and for 15 the entire spring migratory route was reconstructed. Most ducks departed from wintering grounds between mid‐February and March following straight and direct routes along the Black Sea‐Mediterranean flyway. The breeding sites, usually reached by May, were spread from central to north‐Eastern Europe to east of the Urals. The migratory speed was slow (approximately 36 km/day on average) because most birds stopped for several weeks at stopover sites, mainly in south‐eastern Europe, especially at the very beginning of migration. The active flight migration segments were covered at much higher speeds, up to 872 km/day. Stopover duration tended to be shorter when birds were closer to their breeding site. These results, based on the largest satellite tracking effort for this species, revealed for the first time the main features of the migratory strategies of individual Teals wintering in Europe, such as the migration timing and speed and stopover localization and duration. [ABSTRACT FROM AUTHOR]

The article provides information on the observation of birds such as falcon, phylloscopus and anas crecca. Topics include nesting of the arctic tern bird, increasing bird population by importing birds of various species and species ordered according tothe bird list of Switzerland such as gulls of larus subspecies.

Summary: This study presents the histomorphological features of tongue in Eurasian teal (Anas crecca); the smallest extant dabbling duck. Heads of four adult males and four adult females were used in this study. The results illustrate a tongue with three different parts; the apex with a lingual nail in ventral surface, the body with a lingual prominence in caudal part and some large and small conical papillae in lateral sides and the root, that was covered with many conical papillae in different sizes. Histological results revealed two types of keratinized and non‐keratinized epithelium covering parts of the tongue. The lingual salivary glands were observed in the lamina propria of the body and root of the tongue showed strongly periodic acid–Schiff (PAS)‐positive reaction. The yellow adipose tissue was located under the lamina propria on the body and root of the tongue. The filiform papillae between the conical papillae of the body were arranged densely. The sensory organs, which contain sensory receptors (Grandry and Herbst corpuscles), were located in the lamina propria of the body of the tongue. In conclusion, the anatomical and histological structure of the Eurasian teal’ tongue was generally similar to its family members such as domestic goose and duck but showed some differences that may be adoptions to the bird's habitat and mode of feeding. [ABSTRACT FROM AUTHOR]

Accurate flyway delineation is a prerequisite for effective conservation and management of migratory bird populations, yet such limits have so far mostly been set subjectively. We present a statistical method to infer population boundaries from the analysis of ring recoveries, using a Bayesian framework. The approach was applied to Eurasian teal Anas crecca ringed in Camargue, southern France, and Abberton Reservoir, Essex, eastern England. The results presented show the boundaries of the two teal flyways in western Europe, with a zone of overlap, broadly matching those previously defined. The percentage of teal switching flyways (abmigration rate) was 2.4-2.6%, greater in birds ringed as juveniles than as adults. Abmigrants ended up at sites within the other flyway where the density of local birds was lower than expected by chance, suggesting abmigration resulted from exploratory or aberrant behaviour. The methodology presented here can be used to infer flyway boundaries of any bird with an adequate ring-re-encounter dataset, which has crucial consequences for the evaluation of their trends in abundance and hence conservation status, and the management of sustainable harvests. [ABSTRACT FROM AUTHOR]

The complete mitochondrial genome of Anas crecca is 16,596 bp in length. It was predicted to contain 13 PCGs, 22 tRNA genes, and 2 rRNA genes, and a putative control region. All of the PCGs initiate with ATG, except for MT-CO1, MT-CO2, and MT-ND5, which began with GTG. Four types of termination codons were identified. Phylogenetic analysis shows that A. crecca clustered with Anas acuta, and the monophyly of the genera Anser, Cygnus, Aythya, and Anas was strongly supported. Moreover, our results also support a sister-group relationship between Anas and Aythya.

The complete genome sequence was determined for avian paramyxovirus (APMV-6) serotype 6 strain teal/Chany/455/2009, isolated from a teal ( Anas crecca) in Siberia. Siberia is crossed by four major migration flyways and represents the major breeding area for many wild bird species in the Palearctic. Strain teal/Chany/455/2009 is genetically closely related to Kazakh and Chinese strains and belongs to the genetic group of duck/Hong Kong/18/199/77-like APMV-6 viruses. We show that the virus has low pathogenic potential according to genetic markers and animal model experiments. [ABSTRACT FROM AUTHOR]

Blue-winged teal ( Anas discors) are abundant, small-bodied dabbling ducks that breed throughout the prairies of the northcentral USA and central Canada and that winter in the southern USA and northern Neotropics. Given the migratory tendencies of this species, it is plausible that blue-winged teal may disperse avian pathogens, such as parasites causing avian malaria, between spatially distant areas. To test the hypothesis that blue-winged teal play a role in the exchange of blood parasites between North America and areas further south, we collected information on migratory tendencies of this species and sampled birds at spatially distant areas during breeding and non-breeding periods to diagnose and genetically characterize parasitic infections. Using a combination of band recovery data, satellite telemetry, molecular diagnostics, and genetic analyses, we found evidence for (1) migratory connectivity of blue-winged teal between our sampling locations in the Canadian prairies and along the US Gulf Coast with areas throughout the northern Neotropics, (2) parasite acquisition at both breeding and non-breeding areas, (3) infection of blue-winged teal sampled in Canada and the USA with Plasmodium parasite lineages associated with the Neotropics, and (4) infection of blue-winged teal with parasites that were genetically related to those previously reported in waterfowl in both North America and South America. Collectively, our results suggest that blue-winged teal likely play a role in the dispersal of blood parasites between the Neotropics and North America, and therefore, the targeting of this species in surveillance programs for the early detection of Neotropical-origin avian pathogens in the USA may be informative. [ABSTRACT FROM AUTHOR]

Objective: To determine the helminth parasites of Anas crecca (A. crecca) in one of proper refuges of Iran, Fereydunkenar. Methods: A total number of one hundred thirty-six gastrointestinal tracts of green-winged teal (A. crecca) were collected from Fereydunkenar, Mazandaran province during September and October 2011. The gastrointestinal tracts were examined for helminth infection. Results: The total infection rate was 70.50% (96) that 68.96% (40) of males and 71.79% (56) of females shown helminthes infection. The examined A. crecca harbored one species of Nematoda, Cestoda and two species of Digenea which were as following: Contracaecum larvae (from stomach wall), Diorchis stefanskii (D. stefanskii) (from small intestine), Hypoderaeum conoideum (from small intestine) and Notocotylus attenuatus (N. attenuatus) (from caecum), respectively. There was no significant difference in the prevalence of infection between examined males and females ducks in Hypoderaeum conoideum, D. stefanskii and N. attenuatus (P>0.05) whereas a significant relationship was observed between males and females in Contracaecum larvae (P

A large body of research has accumulated on the impact of climate change on wildlife movements and distributions, especially for migratory birds. We used large ringing datasets for the Common Teal ( Anas crecca) from the Camargue, southern France, to compare historic (from 1956-1975) spatiotemporal patterns of teal recovery with those seen in modern (2002-2012) years and assess whether the migration phenology of these ringed birds and their use of the Camargue as winter quarters has changed. Because teal are short-distance migrants (i.e., they breed in northern Europe and winter north of the Sahara), they would be predicted to delay their autumn migration in response to climate change. Conversely, ring recoveries showed that teal are now arriving much earlier: a stable 80 % of the recoveries were made locally in the Camargue each week between mid-November and late January in the modern dataset, whereas this percentage was only 53 % on average in the older data, and the proportion of recoveries made locally in the Camargue gradually increased through the autumn and winter until late January. This suggests that Camargue habitats have changed markedly and become more attractive to teal compared to other potential wintering areas, consistent with known changes in local habitat management practices and improvements in the body condition of the birds. Despite the fact that global climate change will likely be one of the main drivers of wildlife distribution over the long term and at large spatial scales, local habitat management should not be overlooked, as it can increase habitat attractivity to migratory birds. [ABSTRACT FROM AUTHOR]

Natural and anthropogenic Iberian wetlands in southern Europe are well known for supporting large numbers of migratory Palaearctic waterbirds each winter. However, information on the geographical origin of dabbling ducks overwintering in these wetlands is scarce and mostly limited to data from ringing recoveries. Here, we used intrinsic isotopic markers to determine the geographical origin of male and female Northern Pintails Anas acuta and Eurasian Teal Anas crecca in Extremadura, inland Iberia, a key site for overwintering dabbling ducks. Additionally, we fitted six Northern Pintails with GPS- GSM tags to complement the data derived from stable isotope analysis. Most (> 70%) first calendar-year Northern Pintails were assigned to regions above 55°N, flying 2600-5600 km from their main natal regions to Extremadura. Mean values of δ2Hf varied significantly between male and female Northern Pintails, suggesting that the sexes had different geographical origins. Data from tagged adult Northern Pintails supported the isotopic data, one male flying more than 5000 km to the coast of the Pechora Sea (Russia). Most (> 70%) first calendar-year Eurasian Teal were assigned to the region between 48° and 60°N, travelling 1500-4500 km to arrive in Extremadura. Male and female Eurasian Teal showed marginal differences in mean values of δ2Hf. In migratory dabbling ducks, pairing typically occurs on the wintering grounds, and ducks in their first winter can breed the following spring. For Northern Pintails, pair formation in Extremadura could occur between individuals with different geographical origins, which could contribute to the genetic variability of their offspring. [ABSTRACT FROM AUTHOR]

The growth rate of populations usually varies over time, often in a density-dependent manner. Despite the large amount of literature on density dependence, relatively little is known of the mechanisms underlying the density-dependent processes affecting populations, especially per capita natality. We performed a 20-year study on the density dependence of brood production in two duck species differing in the stability of habitat use. Our study was conducted in a boreal watershed in southern Finland. We predicted that a diving duck common goldeneye Bucephala clangula, with more stable habitat use, would show stronger density dependence than a dabbling duck common teal Anas crecca. We investigated reproductive output in relation to the duck pair density per se as well as in relation to per capita food availability. As predicted, the reproductive output of the goldeneye showed a more density-dependent pattern than that of the teal. The number of goldeneye broods per pair decreased when the pair density increased. This was not the case with the teal. However, when the breeding success was measured by taking into account per capita food availability, both species showed density dependence. Our results imply that the occurrence of density dependent processes may vary even in sympatric ducks breeding in the same, relatively stable landscape. Our analysis also emphasizes that it is important to take into account per capita resource availability when studying the density dependence of breeding success. Both findings have important implications for the management and conservation of species. [ABSTRACT FROM AUTHOR]

Boreal forest lakes are normally considered stable environments, but from a duck's point of view, both resource abundance and habitat quality in the lakes may differ from 1 year to another. Duck species differ in their flexibility to respond to variation in environmental factors, such as habitat quality, habitat variability and weather. Anas crecca, the common teal, has been suggested to be a species that can readily colonise newly formed habitat., We studied the effect of habitat quality (invertebrate food resources, amount of spring flood, beaver flood abundance, predation pressure), weather (temperature, precipitation, timing of ice break-up) and pair abundance on breeding success of teal at the landscape scale in Southern Finland. We used 20 years of data (1989-2008) from a study area consisting of 50 lakes. This is typical boreal breeding area for the teal, whose population size is markedly variable. We express breeding success as number of broods in two different age classes., The number of broods in both age classes was explained well by habitat quality, but different variables seem to operate during different phases of the breeding season. Increases in abundance of breeding pairs and of food led to increased production of younger broods. Habitat factors including food and flood abundance were the most important predictors for older broods, which are the more influential in terms of recruitment. These factors manifested in an age-specific manner, highlighting the importance of comprehensive breeding time surveys of boreal breeding ducks to understand variation in their recruitment., Our research underlines the importance of high-quality habitats for breeding teal populations in the boreal forest landscape. The existence of these habitats depends substantially on human actions, such as managing beaver populations and preserving seasonal pond habitats. [ABSTRACT FROM AUTHOR]

The Huajiang wetland is an important wintering site for a population of the migratory common teal, Anas crecca. Three habitat variables, slope, substratum elevation and distance to the nearest vegetation, were measured and used to construct habitat suitability index (HSI) models for the conservation of the wintering population and management of the wetland habitat. Two HSI models, the 'minimum function' and the 'regression', were developed. The results indicated that the common teal preferred localities with low slope (0.7 to 1.4 %), low substratum elevation (0.3 to 0.7 m above the mean sea-level) and close proximity to vegetation (distance to the nearest vegetation < 4 m). According to a validation dataset, only the 'regression' model accurately predicted the teal's habitat preference. Habitat suitability maps showed that the area classified as good or excellent (HSI values > 0.5) accounted for 84.8 % of the entire study site. This model suggested that substratum elevation was the most important variable affecting the quality of the common teal's habitat. Our findings provide a useful basis for determining potential habitats for the common teal and for restoring degraded habitats. Our study is also applicable to other waterfowl species in Taiwan and the wintering areas for common teal in other regions. [ABSTRACT FROM AUTHOR]

Macroscopic Sarcocystis cysts were detected in the muscles of 28 Mallards ( Anas platyrhynchos), 1 Eurasian Wigeon ( Anas penelope), and 1 Common Teal ( Anas crecca) hunted in Lithuania and Finland. According to the sequences of the 18S rRNA gene, 28S rRNA gene, and ITS-1 region, the macrocysts examined from all 30 ducks belonged to Sarcocystis rileyi. This parasite was found in the Eurasian Wigeon and the Common Teal for the first time. All S. rileyi isolates examined were identical to each other and differed from 2 S. rileyi isolates previously reported from 2 Mallards from the United States only by 1 nucleotide substitution within the ITS-1 region. [ABSTRACT FROM AUTHOR]

ABSTRACT Wetlands are rich in biodiversity, but globally threatened. After a long period of regional extirpation, beavers have recently returned to many European areas and are now restoring wetlands. The beaver is remarkable regarding the large impacts it has not only on individual species but on entire communities and ecosystems. In fact, beavers are referred to as 'ecosystem engineers'., The facilitative effect of the beaver Castor canadensis on a waterbird community of seven species of waders and ducks in boreal ponds was studied by using the before-after control-impact method (BACI) and analysing the effect of the duration of flooding. The before-after setting could be used since beavers had caused disturbance by flooding several forest ponds during the course of this long-term study (1988-2009). The study took place in southern Finland, where waterbirds were surveyed four times during the breeding season., The number of waterbird species per pond per year was significantly higher during beaver inundation than before beaver activity, as was the waterbird abundance per survey. Changes were negligible in the controls. The numbers of all seven species increased during flooding, although the increase was significant in only three species. Common teal Anas crecca and green sandpiper Tringa ochropus showed the most positive numerical response to flooding. Mallard Anas platyrhynchos and wigeon Anas penelope were new species entering the duck guild in the flooded wetlands. The beneficial effect of the flood lasted the whole period of inundation, although the most substantial increase in species number appeared during the first two years of flooding., The beaver acted as a whole-community facilitator for waterbirds. It was inferred from previous studies that this was done by modifying the habitat to make it more productive and structurally favourable. It is concluded that favouring beavers is a worthwhile tool in restoring wetlands to promote waterbird communities., Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

ABSTRACT Commercial fisheries and waterbirds are often in competition for available resources and may affect each other through limiting available forage for birds or reducing harvest for commercial fisheries. Relatively little is known regarding the wintering population of waterfowl on the hypersaline Great Salt Lake (GSL), Utah, but mid-winter counts indicate waterfowl use the GSL during winter coinciding with a commercial harvest of brine shrimp ( Artemia franciscana) cysts (i.e., eggs). We surveyed previously unmonitored pelagic regions of GSL to estimate total wintering populations of waterfowl and collected northern shoveler ( Anas clypeata) and green-winged teal ( Anas crecca) during 3 nonbreeding seasons, 2009-2012, to examine patterns in diet and body mass of birds using the GSL and estimate the amount of cyst removal by ducks. Our results indicated >200,000 northern shovelers and >150,000 green-winged teal wintered in the GSL and their diets, based on esophageal contents, changed seasonally, likely because of food availability. Esophagi contained predominately wetland plant seeds in fall and spring, whereas GSL invertebrates (i.e., brine shrimp adults and cysts, brine fly [ Ephydra spp.] larvae) made up 75-100% aggregate wet weight during winter. Body mass of both species of ducks was greatest in fall and decreased through winter until a partial to full recovery of mass by spring. Though decreases in body mass were positively associated with decreases in GSL cyst abundance, cyst mass in duck diets peaked when cyst abundance was lowest in the GSL. Our results suggest current management of commercial cyst harvest leaves adequate cysts for waterfowl consumption during late winter. Furthermore, estimates of cyst removal from the GSL by ducks suggests they consume <1% of the yearly raw mass removed by ducks and commercial harvest combined, which implies ducks do not have an adverse impact on the commercial cyst harvest. We suggest managers begin incorporating pelagic areas in mid-winter waterfowl surveys to better monitor the relationship between cyst harvest and waterfowl abundance and distributions. © 2014 The Wildlife Society. [ABSTRACT FROM AUTHOR]