Is earlier spring migration of Tatarstan warblers expected under climate warming?

We analysed data on the arrival dates of four species of leaf warbler (genus Phylloscopus) collected in Tatarstan between 1957 and 2004. There was no evidence over the whole period that the warblers returned to their breeding sites significantly earlier, mainly because local temperatures for April and May, months when the majority of birds arrived from their wintering grounds, did not increase significantly. However, arrival dates of two species (Chiffchaff P. collybita and Willow warbler P.trochilus) were strongly related to local temperature in April, and that of Greenish warbler P. trochiloides to that in May. As expected, arrival dates for the three species wintering in Africa (Chiffchaff, Willow and Wood warblers P. sibilatrix) correlated positively with one another (P < 0.01 in all cases), but were not correlated with arrival dates of Greenish warbler (P > 0.5 in all cases), a species wintering in the Indian sub-continent.     

Sex‐specific winter distribution in a sexually dimorphic shorebird is explained by resource partitioning

Sexual size dimorphism (SSD) implies correlated differences in energetic requirements and feeding opportunities, such that sexes will face different trade‐offs in habitat selection. In seasonal migrants, this could result in a differential spatial distribution across the wintering range. To identify the ecological causes of sexual spatial segregation, we studied a sexually dimorphic shorebird, the bar‐tailed godwit Limosa lapponica, in which females have a larger body and a longer bill than males. With respect to the trade‐offs that these migratory shorebirds experience in their choice of wintering area, northern and colder wintering sites have the benefit of being closer to the Arctic breeding grounds. According to Bergmann's rule, the larger females should incur lower energetic costs per unit of body mass over males, helping them to winter in the cold. However, as the sexes have rather different bill lengths, differences in sex‐specific wintering sites could also be due to the vertical distribution of their buried prey, that is, resource partitioning. Here, in a comparison between six main intertidal wintering areas across the entire winter range of the lapponica subspecies in northwest Europe, we show that the percentage of females between sites was not correlated with the cost of wintering, but was positively correlated with the biomass in the bottom layer and negatively with the biomass in the top layer. We conclude that resource partitioning, rather than relative expenditure advantages, best explains the differential spatial distribution of male and female bar‐tailed godwits across northwest Europe.     

The invasive predator <Emphasis Type="Italic">Bythotrephes</Emphasis> induces changes in the vertical distribution of native copepods in Lake Michigan

Invasive predators can have large negative effects on native prey populations. The susceptibility of native prey to invasive predators may depend on their ability to respond behaviorally to the presence of these non-native predators. In a field survey conducted in Lake Michigan over several years, we found that high densities of the invasive predatory cladoceran Bythotrephes were correlated with lower vertical distributions of some species and age classes of native copepods; moving from inhabiting primarily the epiliminion at low Bythotrephes density to primarily the hypolimnion at high Bythotrephes density. Five groups showed this pattern; diaptomid copepodites, adult cyclopoids, Diacyclops thomasi, and the adult diaptomids Leptodiaptomus ashlandi and L. minutus. In contrast, Bythotrephes density was not correlated with the vertical distribution of copepod nauplii and adult L. sicilis. Laboratory experiments suggest that the changes in the vertical distribution in the field at high Bythothrephes are due to an inducible, plastic response to predation threat from Bythotrephes signaled by water-borne cues. Species that were lower in the field at high Bythotrephes densities responded behaviorally to water-borne cues from Bythotrephes by moving to lower levels of experimental water columns. These species included D. thomasi and L. minutus, with L. ashlandi displaying a non-significant trend in the same direction. In contrast, L. sicilis, which was not correlated with Bythotrephes density in the field, was unaffected by the water-borne cues. Differences in vertical distribution shifts among these native copepod species and life-history stages are likely due to species-specific differences in spatial overlap with Bythotrephes and their relative ability to migrate large distances or employ alternative avoidance strategies. The varied responses exhibited among the copepod groups likely alter their interactions with each other, their resources and other predators, thus revealing the complex effects Bythotrephes can have on invaded communities.     

The dispersal and distribution of polyphagous predatory Coleoptera in cereals

Observations were made on the phenology of the dispersal of polyphagous arthropod predators from their overwintering habitats in field boundaries into adjacent farmland in cereal fields in southern England from 1981 to 1984. Agonum dorsale, Bembidion lampros and Demetrias atricapillus dispersed from overwintering habitats into adjacent cereal crops by crawling. B. lampros was fully dispersed by early May and the other two species by late May. Tachyporus spp. were thought to disperse mainly by flight, T. hypnorum being fully dispersed by mid-May and T. chrysomelinus by late May. A small proportion of A. dorsale marked in field boundaries in April before dispersal began were later recaptured up to 200 m into adjacent crops later in the season. Areas of a crop, immediately adjacent to field boundaries in which high numbers of predators had overwintered, were found to have significantly (P<0.01) higher numbers of predators that disperse by walking (A. dorsale, B. lampros and D. atricapillus) moving through them towards the centres of fields. By mid-summer, the mid-crop density of D. atricapillus was correlated with its overwintering density in surrounding field boundaries the previous winter, but this was not so in the other species. Mid-crop, mid-summer densities of A. dorsale were significantly (P<0. 02) correlated with mean percentage weed cover in fields. The densities of the other species were not correlated with weed cover. Analysis of data collected over a 10-yr period on a Sussex study area in late June revealed that significantly more D. atricapillus were found in fields surrounded by hedgerows than fields surrounded by fence-post and wire boundaries.     

A quantitative study of mortality at emergence in the damselfly Pyrrhosoma nymphula (Sulzer) (Zygoptera: Coenagrionidae)

SUMMARY.

• 1 Emergence of the damselfly Pyrrhosoma nymphula was studied over three seasons in two ponds in northern England.
• 2 Numbers emerging were significantly negatively correlated with temperature and atmospheric pressure.
• 3 Overall mortality at emergence was 28%. of which predators (largely birds, ants and spiders) accounted for 22% and climatic factors 6%.
• 4 Daily mortality estimates were significantly positively correlated with precipitation.
• 5 There was no evidence of density dependent mortality at emergence.

     

Effects of non-lethal attacks by three phytoseiid species on subsequent development,fecundity and mortality of the two-spotted spider mite

The effects of attack by the three predaceous mite speciesPhytoseiulus persimilis Athias-Henriot,Phytoseius finitimus Ribaga andAmblyseius gossipi Elbadry on the development, reproduction and mortality of the two-spotted spider miteTetranyschus urticae Koch were evaluated after the prey larvae being exposed to attack by these predators for limited periods. Development of the surviving prey immatures was significantly prolonged; this influence was more distinctive when prey larvae were exposed to the predators for a longer period. The number of prey adults which died early was positively correlated with the length of the feeding period allowed to the predators. A substantial reduction in the number of eggs deposited by the prey females was noted, although the oviposition by the prey females was noted, although the oviposition period and adult longivity were not significantly affected.     

Use of ring recoveries to predict habitat suitability in small passerines

Aim Abundance of small passerines may be distributed over large wintering areas according to geographical patterns that are difficult to detect. This may prevent the identification and conservation of the most suitable sectors, or the detection of local and regional features affecting the species during winter. In this paper, we explore the usefulness of ring recoveries to predict bird distribution in wintering grounds by using Maxent, one of the presence‐only techniques available for modelling species distributions. We test whether suitability indices obtained in 2.5 × 2.5 km UTM squares from ring recoveries were positively correlated with the actual abundance of robins (Erithacus rubecula) and blackcaps (Sylvia atricapilla) inside the squares. Location Spain. Methods We used 686 and 1139 localities across the country in which blackcap and robin ring recoveries were recorded by the Spanish Office of Migratory Species to generate the suitability maps. In addition, we sampled bird abundance inside 70 control squares independent of ring recovery localities along a belt crossing mountains, highlands and lowlands of the Iberian Peninsula during January from 2006 to 2011. Results Suitability indices predicted by Maxent were positively correlated with robin (r = 0.42, n = 70, P < 0.001) and blackcap (r = 0.52, n = 70, P < 0.001) abundances in the 70 control squares along the belt crossing the Iberian Peninsula. Main conclusions These results suggest that the use of distribution models with ring recoveries may be used to describe the habitat suitability of the winter ranges of small, common passerines. This also means that the huge number of ring recoveries stored in national and transnational data banks could be used to explore the factors shaping bird ranges and to forecast the geographical distribution of suitable wintering areas of migratory birds in large, poorly known regions. This may be useful in biogeography and conservation.     

Habitat complexity modifies the impact of piscivores on a coral reef fish population

Patterns in juvenile mortality rates can have a profound affect on the distribution and abundance of adult individuals, and may be the result of a number of interacting factors. Field observations at Lizard Island (Great Barrier Reef, Australia) showed that for a coral reef damselfish, Pomacentrus moluccensis, juvenile mortality (over 1 year) varied between 20 and almost 100% among sites. Correlative data showed that juvenile mortality increased as a function of initial densities (recruitment), predator densities and the availability of preferred coral substrata. A multiple regression showed that these three variables together did not explain significantly more variation in mortality than the single factor showing the strongest relationship. This appeared to be because recruitment, predator densities and preferred coral substrata were all highly correlated, suggesting that one, two or all of these factors may be influencing juvenile mortality rates. One hypothesis was that density-dependent mortality in juveniles was the result of an interaction between predators (which appear to aggregate at high-recruitment sites) and the availability of preferred substrata (predator refuges). We tested this hypothesis by using both laboratory and field experiments to see whether fish predation could significantly alter survivorship of this damselfish, and whether this impact was dependent upon the coral substratum. The laboratory experiment was designed to test the effects of three common predators (Pseudochromis fuscus, Cephalopholis boenak and Thalassoma lunare) and three different coral substrata that varied in their complexity (Pocillopora damicornis, Acropora nasuta and A. nobilis) on the survival of juvenile Pomacentrus moluccensis. There was a significant interaction between predator species and microhabitat in determining survival. Pseudochromis fuscus and C. boenak were both significantly better at capturing juvenile damselfish than T. lunare. Juvenile survivorship was significantly better when they were given the more complex corals, Pocillopora damicornis and A. nasuta, compared with those given the open-structured species A. nobilis. This pattern reflects habitat selection in the field. Predators differed in their strike rates and the proportion of strikes that were successful, but all exhibited greater success at prey capture where A. nobilis was provided as shelter. The interaction between the effect of predator species and microhabitat structure on damselfish survival was tested in the field for a cohort of juvenile Pomacentrus moluccensis. We examined juvenile survival in the presence and absence of two predators that co-occur on natural patch reefs (C. boenak and Pseudochromis fuscus). The experimental patch reefs we used for this purpose were constructed from both high complexity (Pocillopora damicornis) and low complexity (A. nobilis) coral substrata. Both juveniles and predators were translocated to reefs at natural densities. The effects of predation were clearly dependent upon the microhabitat. Reefs of the high-complexity coral with predators supported the same high numbers of Pomacentrus moluccensis as the reefs with no resident predators. However, damselfish abundance was significantly lower on low-complexity reefs with resident predators, relative to the other treatments. Background rates of loss were high, even on preferred coral in the absence of the manipulated predator, suggesting that transient predators may be even more important than the residents. We suggest that adult abundances in this species were strongly influenced by the densities of different predators and the availability of preferred refuges. Received: 3 April 1997 / Accepted: 26 August 1997     

The role of nutrition in regulation of predator-induced crests of Daphnia carinata

1. The effects of food level on the development of crests by Daphnia carinata in the presence of Anisops grains (Notonectidae) were investigated in two laboratory experiments and in the field. 2. In the laboratory experiments D. carinata were grown at different food levels either in the presence of A. gratus or in predator-free water. In the field study the effects of six variables (temperature, food level, density of Daphnia, density of Anisops, brood size and maternal nutrition) on development of crests in the next generation of Daphnia were investigated over a 12-month period at a single field site. 3. In the laboratory food level had a small but significant effect on relative crest height of D. carinata. In the presence of notonectid predators the rate of crest growth relative to body length was higher than for control D. carinata only during embryogenesis and/or the first two neonatal instars. Beyond this age the rate of crest growth was similar in both morphs. 4. In the field study, crest height was negatively correlated with density of Daphnia and positively correlated with density of Anisops and maternal nutrition (maternal nutrition was defined as the somatic weight of a female with a body length of 2.5 mm, calculated from the length-dry weight regression based on a sample of the population). However, these data were biased by a short period when no Anisops were present in the pond. When these data were excluded, the only factor which significantly correlated with crest height was maternal nutrition. This finding indicated that relative crest height of the next generation was determined primarily during embryogenesis on the basis of maternal feeding success and possibly on food availability during the first two instars.     

Modeling flight activity and population dynamics of the pine engraver, Ips pini, in the Great Lakes region: effects of weather and predators over short time scales

Ascertaining the relative effects of factors such as weather and predation on population dynamics, and determining the time scales on which they operate, is important to our understanding of basic ecology and pest management. In this study, we sampled the pine engraver Ips pini (Say) (Coleoptera: Scolytidae) and its predominant predators Thanasimus dubius (F.) (Coleoptera: Cleridae) and Platysoma cylindrica (Paykull) (Coleoptera: Histeridae) in red pine plantations in Wisconsin, USA, over 2 years. We sampled both the prey and predators using flight traps baited with the synthetic aggregation pheromone of I. pini. Flight models were constructed using weather variables (temperature and precipitation), counts of bark beetles and their predators, and temporal variables to incorporate possible effects of seasonality. The number of I. pini per weekly collection period was temperature dependent and decreased with the number of predators, specifically T. dubius in 2001 and P. cylindrica in 2002. The number of predators captured each week was also weather dependent. The predators had similar seasonal phenologies, and the number of each predator species was positively correlated with the other. Including a term for the number of prey did not improve the model fits for either predator for either year. Our results suggest that exogenous weather factors strongly affect the flight activity of I. pini, but that its abundance is also affected by direct density-dependent processes acting over weekly time scales. Adult predation during both colonization and dispersal are likely processes yielding these dynamics.     

鄱阳湖区灰鹤越冬种群数量与分布动态及其影响因素

1998—2011年,采用地面同步调查法开展了鄱阳湖越冬灰鹤种群监测,并整合1984—2011年鄱阳湖国家级自然保护区历年的越冬灰鹤最大种群数量,分析了鄱阳湖灰鹤越冬种群动态以及影响其数量变化与空间分布的环境因素。结果表明,近13年来鄱阳湖区越冬灰鹤种群平均数量为(2 335±651)只,种群数量呈增长趋势,2011年冬季记录到最大种群数量7 640只。灰鹤越冬种群数量与10月平均最低气温以及10月平均气温存在显著正相关,与10月平均最大风速存在显著负相关,与各月的平均水位没有显著的相关性。每年冬季灰鹤在鄱阳湖呈聚集型分布。大湖池、大莲子湖、三湖、汉池湖、企湖、珠湖、南湖(共青)、大汊湖等8个湖泊是灰鹤的重点活动区,(74.9±5.6)%的越冬灰鹤分布在保护区之外。灰鹤的空间分布与滩地面积存在显著的正相关,与农田面积、人口密度、村庄数量、8月份初级生产力、11月份初级生产力等环境因子存在显著负相关。滩地面积是影响灰鹤空间分布的重要因子,对灰鹤利用频次空间变化的解释率为15.0%,与11月份初级生产力共同解释了灰鹤年平均群体数量空间变化的24.6%。如竞争、小生境结构、干扰等局地尺度的环境要素对灰鹤空间分布的影响研究将有助于更全面地认识鄱阳湖越冬灰鹤种群动态的影响机制。     

Does climate at different scales influence the phenology and phenotype of the River Warbler <Emphasis Type="Italic">Locustella fluviatilis</Emphasis>?

Weather and climatic conditions may impact on the phenology and morphology of birds, and thereby affect their survival rate and population dynamics. We examined the North Atlantic Oscillation (NAO), precipitation in the Sahel zone, temperatures in the wintering grounds, on the migration route, and in the breeding area in relation to arrival dates and six morphological measures (wing, tarsus, bill, and tail lengths, body mass, body condition) in a Slovak population of the River Warbler Locustella fluviatilis. Arrival dates did not change significantly over the study period, but were significantly positively correlated with NAO, although not with temperatures in wintering areas, migration route or breeding area, nor with Sahel precipitation. Four of the six morphological traits changed during the study period and part of the change in condition index can be attributed to climatic variables. We suggest changes in birds phenotype vary with food availability, which fluctuate according to climate events.     

The influence of host plant species on parasitism of pollen beetles (Meligethes spp.) by Phradis morionellus

We investigated the response of the specialist insect predator Oligota kashmirica benefica (Coleoptera: Staphylinidae) to volatiles from lima bean leaves infested with the spider mite Tetranychus urticae (Acari: Tetranychidae), both in a Y-tube olfactometer and in a field in Kyoto, Japan. Adult male and female predators were significantly more attracted to T. urticae-infested leaves than to clean air. Adult male and female predators were not more attracted to uninfested leaves, artificially damaged leaves, or the spider mites and their visible products when compared to clean air. In a field trap experiment, 12 adult predators were caught in three traps containing T. urticae-infested lima bean plants over 13 days, whereas no adult predators were trapped in three traps containing uninfested lima bean plants during the same period. These results showed that O. kashmirica benefica adults responded to herbivore-induced plant volatiles from T. urticae-infested lima bean leaves under both laboratory and field conditions.     

Effects of vertebrate predation on freshwater gastropods: an exclosure experiment

A field experiment with predator exclosures was performed in a pond in Southern Sweden to evaluate the effects of vertebrate predators on the diversity, density and distribution of freshwater gastropods. Ten exclosures (1 × 1 × 1.5 m) were erected in the nearshore vegetation at a waterdepth of 0.5–0.7 m in early June 1983 so that they included different amounts and species of macrophytes. The exclosures and cageless controls were sampled for macrophytes and gastropods at the end of the summer. The density of gastropods in the controls, exposed to predators, was positively correlated to the abundance of macrophytes. No such correlation existed in the exclosures. Further, the density of gastropods was significantly higher in the exclosures than predicted by the regression between gastropods and macrophytes in the controls. There was no difference between species composition of gastropods between controls and exclosures, but the number of species and the density of gastropods were lower in the macrophyte stands dominated byScirpus lacustris than in the more complex stands dominated bySparganium erectum. These results indicate that vertebrate predation is a major structuring force of benthic freshwater gastropod communities.     

The impact of predation on the viburnum whitefly, (Aleurotrachelus jelinekii)

Summary In association with a detailed study of the population dynamics of the viburnum whitefly, Aleurotrachelus jelinekii, observations were made on the predators including spiders and five species of insect, notably the mirid Campyloneura virgula and the neuropteran Conwentzia psociformis. Although the species richness of the predator guild was positively correlated with prey population density, at the individual level there was little evidence over twelve years of a density dependent relationship. In these populations natural enemies do not seem to play an important role in the dynamics.     

Top‐down effects on pelagic heterotrophic nanoflagellates (HNF) in a large river (River Rhine): do losses to the benthos play a role?

1. The abundance, production and control of pelagic heterotrophic nanoflagellates (HNF) in the Lower River Rhine (Germany) were investigated. Field samples (live‐counting technique) were taken at least every 2 weeks at Cologne (km 685) over a period of 20 months. In addition, Lagrangian sampling was carried out 160 km downstream of Cologne (Kalkar–Grieth, km 845) over a period of 12 months. Potential HNF growth rates and loss rates caused by planktonic predators were estimated in the laboratory (size fractionation experiments) and compared with the changes in HNF‐density in a water parcel flowing downstream. 2. Mean abundance (±SD) ranged from 7 ± 6 to 4890 ± 560 individuals mL^–1 and was positively correlated with discharge. Heterotrophic nanoflagellates abundance increased up to 30‐fold during flood events, whereas there were only minor changes in the taxonomic composition. 3. HNF growth rate ranged from 0.16 ± 0.12 to 1.98 ± 0.10 day^–1. Between 0 and 95% (mean: 32%) of the gross production was lost to planktonic predators; a larger portion between 0 and 195% (mean: 64%) of the HNF gross production was lost by other means. 4. There may be an important role for benthic predators in the control of pelagic HNF. First, production of HNF was high and grazing losses to planktonic predators low at times when HNF abundance was low. Secondly, high in situ loss rates (not explicable by planktonic predators), which were positively related to temperature, indicate the importance of biotic interactions. Thirdly, the dependence of HNF abundance on discharge indicated a decrease grazing intensity with rising water levels (increase in water volume/colonised river bed ratio). 5. The impact of discharge on planktonic HNF mediated by the grazing impact of benthic predators was modelled, showing a good fit with the field data.     

EVIDENCE FOR BATESIAN MIMICRY IN A POLYMORPHIC HOVERFLY

Palatable Batesian mimics are avoided by predators because they resemble noxious or defended species. The striking resemblance of many hoverflies to noxious Hymenoptera is a “textbook” example of Batesian mimicry, but evidence that selection by predators has shaped the evolution of hoverfly patterns is weak. We looked for geographical and temporal trends in frequencies of morphs of the polymorphic hoverfly Volucella bombylans that would support the hypothesis that these morphs are Batesian mimics of different bumblebee species. The frequency of the black and yellow hoverfly morph was significantly positively related to the frequency of black and yellow bumblebees across 52 sites. Similarly, the frequency of the red‐tailed hoverfly morph was positively related to the frequency of red‐tailed bumblebees. However, the frequencies of hoverfly morphs were positively spatially autocorrelated, and after controlling for this, only one of the two common hoverfly morphs showed a significant positive relationship with its putative model. We conclude that the distribution of V. bombylans morphs probably reflects geographical variation in selection by predators resulting from differences in the frequencies of noxious bumblebee species.     

Social structure and the defensive role of soldiers in a eusocial bamboo aphid,Pseudoregma bambucicola (Homoptera: Aphididae): A test of the defence-optimization hypothesis

A complete understanding of the evolution of sociality in aphids requires a detailed knowledge of the patterns of soldier investment in their ecology. The eusocial bamboo aphidPseudoregma bambucicola has a morphologically specialized first-instar soldier caste. The proportion of soldiers was positively correlated with colony size. Within a colony, soldiers were evenly distributed among subcolonies; within each subcolony, however, their distribution was biased toward peripheries which were exposed to many predators. Field experiments introducing natural enemies such asEupeodes confrater (Diptera: Syrphidae) andSynonycha grandis (Coleoptera: Coccinellidae) revealed that the survival rate of these predators was negatively correlated with the density of soldiers, suggesting that soldiers can more or less defend their colonies by killing or removing a range of natural enemies. Observations suggest that large mature colonies attract more predators than newly established small colonies and that, within a colony, the predators attack each subcolony regardless of its position on bamboo shoots. This implies the presence of a positive correlation between colony size and predation risk. Thus, the investment in soldiers seems to reflect the attacking pattern of predators within a colony. These results agree with the defence-optimization hypothesis in soldier investment ofP. bambucicola colonies.     

Spatial distribution of interacting insect predators: Possible roles of intraguild predation and the surrounding habitat

Predator foraging behaviour affects the outcome of enemy–enemy interactions. Using a combination of fieldwork and laboratory experiments, we show that intraguild predation may be important in the field distribution of generalist predators that share a common prey: the eggs (and larvae) of the leaf beetle Phratora vulgatissima, a major insect pest in coppicing willow plantations. We focused on a species from the hoverfly genus Parasyrphus (Syrphidae), which may exhibit large temporal and spatial variation in density. Predator and prey densities were quantified in 40 field plots in willow plantations. The likelihood of finding hoverfly eggs declined with increasing densities of two predatory mirids, Orthotylus marginalis and Closterotomus fulvomaculatus, which exhibit less mobile behaviour similar to that of hoverfly larvae. The density of a more mobile predatory bug species, the anthocorid Anthocoris nemorum, was not associated with hoverfly occurrence. These results corroborate the hypothesis that less mobile predators should be stronger intraguild predators than mobilepredators. Further partial support for this hypothesis was obtained in the laboratory study where individual predators were presented with clutches of P. vulgatissima eggs containing one hoverfly egg: the less mobile C. fulvomaculatus and O. marginalis tended to consume the hoverfly egg more readily than the more mobile A. nemorum. However, most individuals of all three bug species consumed the egg of the potential competitor – the syrphid – within 24 h. The field study also showed that hoverfly occurrence was positively associated with the density of their prey and with the presence of nearby forests. We conclude that intraguild predation, abundance of prey and the surrounding habitat affect the distribution of hoverflies in this system and should be considered when developing biological control methods.     

Potential use of weather radar to study movements of wintering waterfowl

To protect and restore wintering waterfowl habitat, managers require knowledge of routine wintering waterfowl movements and habitat use. During preliminary screening of Doppler weather radar data we observed biological movements consistent with routine foraging flights of wintering waterfowl known to occur near Lacassine National Wildlife Refuge (NWR), Louisiana. During the winters of 2004–2005 and 2005–2006, we conducted field surveys to identify the source of the radar echoes emanating from Lacassine NWR. We compared field data to weather radar reflectivity data. Spatial and temporal patterns consistent with foraging flight movements appeared in weather radar data on all dates of field surveys. Dabbling ducks were the dominant taxa flying within the radar beam during the foraging flight period. Using linear regression, we found a positive log-linear relationship between average radar reflectivity (Z) and number of birds detected over the study area (P < 0.001, r² = 0.62, n = 40). Ground observations and the statistically significant relationship between radar data and field data confirm that Doppler weather radar recorded the foraging flights of dabbling ducks. Weather radars may be effective tools for wintering waterfowl management because they provide broad-scale views of both diurnal and nocturnal movements. In addition, an extensive data archive enables the study of wintering waterfowl response to habitat loss, agricultural practices, wetland restoration, and other research questions that require multiple years of data. © 2011 The Wildlife Society.