Winter Birds Research Articles

Montane forest birds in winter: do they regularly move to lower altitudes? Observations from the Eastern Cape, South Africa

Seasonal altitudinal migration to lower altitudes including the coast has been ascribed to a number of forest birds, of which 14 species occur at Fort Fordyce Reserve in the Eastern Cape, South Africa. Based on our observations and ringing at this site (2007–2017), as well as concurrent data from the South African Bird Atlas Project (SABAP2), we suggest that in this region only three species, the African Dusky Flycatcher Muscicapa adusta, White-starred Robin Pogonocichla stellata and Barratt's Warbler Bradypterus barratti, are regular altitudinal migrants. For two other species, the Grey Cuckooshrike Coracina caesia and Yellow-throated Woodland Warbler Phylloscopus ruficapilla, local movements apparently occur, but these may take place within the coastal zone rather than between the coast and inland forests.

Driving Through, and; Occupational Therapy

Driving Through, and; Occupational Therapy Emma Aprile (bio) DRIVING THROUGH safe car on safe road and highway switchbacksbaby girl with those gray wristbands onplastic pellet resting between tendonskeeping her stomach still or at least stiller than the black car and its sticky summer seatstight gridlines on the backs of our thighslittle white house peeking up at herfrom below the grey metal guardrails little creek smaller than the river she knowsplaying peekaboo with the swaying roadcarved strip in the mountain on the other sideshe knows the word logging thanks to Richard Scarry's overall'd cat-boybut maybe he's a girl like her who didn'tknow the dirt turns such a yellow-red colorwhen they take the trees away and string those wires along likea tree-lined set of hand-over-hand barsand it's still light out and they haven'tstopped for lunch and her brother wonders where the mountain's trees wentand wonders where all the houses' people arewhile his mom looks out the window andsays how beautiful it is along that road [End Page 90] and her voice sounds like a book's endthat he doesn't understand and he'd liketo play in the creek he keeps seeing butthey don't stop till the houses are gone when the bracelets stop workingbecause the road is just like his sister'sbelly and nothing like that stays stillwhen they have other places to go [End Page 91] OCCUPATIONAL THERAPY The morning's pain pill weighs her down. Unseen winter birds ask her to remember spring. She cannot recognize their calls. She postpones her pill as long as her coffee lasts. The pin inside her arm conducts weather to her bones, but she doesn't know why. Yesterday's paper unfolds across her table. A miniature blue motorcycle's plastic parts cover Jerusalem's riots, & paints smear over tax cuts, advertisements: reports on a world that's come & gone while she slept. Wool-blanket sky shrouds her bedroom. No one could tell the time with their sun buried in clouds. She has come to hate nature's moody reflections. Before the accident, her hours opened like highways, but today crumples, slices its light through thin shutters, obscures its own horizon. Instructions fold them-selves into an oragami bird, & she's confined to hidden routes insides its square stomach, along the creased & recreasedfolds of its triangular wings. Each pill's white circle cushions her in cotton, cradles her elbow's splintered bones insideits haze. The model's tiniest parts hop away across the news. Words she used to use—conflict, interior, accord—now difficult to define. Alone, she folds her scars into her chest. Cold, damp, easily torn: the model's instructions test dexterity. She stares at her loosened skin, waiting for her muscles, pink & striatedbehind their casings, to unfold, to open like a pair of wings—if only she could remember what for. [End Page 92] Emma Aprile Emma Aprile's poetry has appeared in online and print publications including, most recently, Shenandoah and Antiphon. She holds an MFA from George Mason University, and works as a copyeditor of literary fiction, nonfiction, and poetry for independent small presses. She lives in Louisville, Kentucky. Copyright © 2019 Berea College

Characteristics of fields used by birds in winter in New York

Populations of birds utilizing open fields have been declining for decades in North America. Research has primarily focused on these species during the breeding season, however, while wintering distribution and habitat selection are understudied. Research during the nonbreeding season may be especially important in northeastern North America where reforestation is reducing the amount of open-field habitat. In this study, we examined how the abundance of Snow Buntings (Plectrophenax nivalis) and Horned Larks (Eremophila alpestris) varied between agricultural fields of different cover types and sizes during the nonbreeding season. We conducted repeated transect surveys in 9 fields with different crop residues (stubble), a one-time rapid survey of 99 fields of varying sizes and agricultural uses, and an analysis of eBird data examining the presence or absence of our focal species across New York State. The repeated transect surveys revealed that both Snow Buntings and Horned Larks were more likely to be detected in corn stubble fields compared to pasture and hay fields. The rapid survey revealed no difference in the detection of Snow Buntings related to cover types or field size, although no buntings were detected in fields <8 acres (3.24 ha). More Horned Larks were detected in corn and soy fields than in all types of grass fields, and more were detected in larger fields than in smaller fields. The analysis of eBird data revealed that likelihood of occurrence for both species increases with the increasing percentage of open habitat in the surrounding landscape (500 m radius). This study highlights the importance large field complexes where corn and other agricultural stubbles provide habitat and presumably greater food resources for open-field birds in winter.

Grazing improves habitat suitability for many ground foraging birds in Mediterranean wooded grasslands

Wooded grasslands, usually grazed, cover vast areas in Southern Europe and Northern Africa. They host rich resident bird communities and, in winter, receive large numbers of migrants from Central and Northern European woodlands. Many species are partly or entirely dependent on ground foraging and, since in winter food is often the most limiting factor for birds, maintaining suitable ground habitat is crucial.To study how grazing influences suitability of winter ground habitat for birds, we carried out an experiment in a wooded grassland in Southern Iberia, whereby grazing was controlled in 12 purposely fenced two-hectare plots (4 × 15 sheep/ha, 4 × 3 sheep/ha and 4 × no grazing). We quantified ground habitat features, food abundance and intensity of use by ground-foraging birds in each of these 12 plots. In addition, we made focal observations of birds feeding on the ground and compared the habitat of 1m2 foraging patches with those of nearby control patches.We found that virtually all birds prefer to forage in patches with short ground vegetation and high food abundance. Measurements of these parameters in the experimental plots showed that while grazing shortens vegetation it decreases food availability, and thus has opposing effects on important determinants of habitat suitability. Nevertheless, the numbers of birds foraging in the plots indicate that, overall, grazing benefits the assemblage of ground-feeding birds, presumably because for most species the advantages of foraging in less cluttered habitats more than compensate the lower abundance of prey. However, arboreal bird species that make short foraging forays to the ground had lower numbers in grazed plots.Most bird species that forage on the ground benefited from grazing, and although they can forage under a broad range of grazing levels, some showed clear preferences along the gradient of grazing intensity. Such preferences should be taken into consideration by managers. In general, grazing should be maintained at a level sufficient to open up ground vegetation, increasing the area occupied by patches of short vegetation, in which almost all bird species prefer to forage. At moderate levels, grazing is thus a valuable management tool to promote winter bird habitat quality in Mediterranean wooded grasslands, while increasing the economic value of these threatened landscapes.

American Kestrel Nonbreeding Roost Use and Behavior in South Texas

Roost sites are likely an important component of the American Kestrel's (Falco sparverius), kestrel(s) hereafter, nonbreeding habitat, as quality roost structures can provide thermal cover and protection from predators. We studied winter roost-site use by kestrels in an agricultural landscape in South Texas, where the population is composed of a combination of territorial wintering birds and migrating individuals passing through. Through observations of color-marked and unmarked birds, we identified 50 roost sites during September–March, 2014–2017. Kestrels utilized foliated shrubs and trees as roosting sites (n = 24), as well as various human-made structures (n = 26) including buildings, petroleum and farm equipment, and electrical structures for roost sites. Roost sites varied greatly in the level of concealment and exposure, with seven kestrels roosting on electric structures that allowed high levels of exposure to weather and potential avian predators. We observed aggression between kestrels around roost sites, and we documented small communal kestrel roosts. Because we observed roosting in sites exposed to weather and predators, aggression around roost sites, and communal roosting, we speculate that roosting sites suitable for kestrels may be limited or poorly dispersed in this agricultural landscape.

From species to individuals: combining barcoding and microsatellite analyses from non-invasive samples in plant ecology studies

By means of DNA barcoding and microsatellite analyses, we studied the species and individuals of legitimate seed dispersers of the Mediterranean shrub Pistacia lentiscus, a keystone species that represents the main source of food in winter for frugivorous birds. We collected dropping of birds containing seeds, and after DNA extraction we amplified and sequenced a fragment of the mitochondrial COI gene. Through BLASTN queries of the sequenced fragments against registered sequences in the GenBank database we identified the bird species that are currently dispersing P. lentiscus seeds. Further, through the amplification of specific nuclear microsatellite loci we calculated standard genetic diversity parameters of the population of birds from the genus Sylvia (the blackcap and Sardinian warbler), the most important dispersers of P. lentiscus. Five bird species were identified as seed dispersers through their barcode match. Further, we found that S. melanocephala displayed slightly lower levels of genetic diversity than S. atricapilla. In this study we show how the genetic analyses of environmental faecal samples can be a useful and convenient tool for the study of plant-frugivore interactions through the ascertainment of the identity of the species involved and through the analyses of genetic variability of their populations.

Increasing photoperiod stimulates the initiation of spring migratory behaviour and physiology in a facultative migrant, the pine siskin.

The transition to a migratory state involves coordinated changes in physiology and behaviour. In species with regular, predictable (obligate) migrations, increasing day length triggers the expression of a spring migratory state and androgens play an important role in stimulating its development. By contrast, we know little about the environmental cues and endocrine mechanisms that regulate migration in species with less predictable (facultative) migrations. Here, we tested whether photoperiod stimulates a migratory state in a facultative nomadic migrant, the pine siskin (Spinus pinus). We exposed wintering birds to either a naturally increasing or short-day photoperiod and measured physiological and behavioural changes indicative of a migratory state. We also examined changes in circulating hormones that may play a role in the migratory transition. Natural-day, but not short-day, birds displayed physiological preparations for migration, including increases in fat deposition, and showed increased levels of migratory restlessness. We found no evidence for a role of corticosterone in the migratory transition, but testosterone may be important. This study is the first experimental test of the role of photoperiod in regulating facultative migration and demonstrates that the predictive cue used by many obligate migrants to time spring migration is also important in a facultative migrant.

The importance of nonnative Pacific oyster reefs as supplementary feeding areas for coastal birds on estuary mudflats

Abstract A combined empirical and modelling approach was used to investigate the value of a Pacific oyster reef to feeding shorebirds and to observe and predict the impact of reef clearance on bird populations in the Colne Estuary, a protected area in south‐east England. Macro‐invertebrate biomass and numbers of feeding birds were measured on a Pacific oyster reef, an adjacent uncolonized mudflat, and an area of mudflat that had been cleared of oysters 6 months previously. These data were used to parameterize an individual‐based model (MORPH) to predict the impact of clearance of the reef on winter bird survival. Feeding success and intake rates of Eurasian oystercatcher, Eurasian curlew, and Eurasian common redshank were also recorded during the course of a winter. The macro‐invertebrate diversity and biomass within both the oyster reef and the cleared area were significantly greater than the adjacent uncolonized mudflat. The density and biomass of large invertebrate prey in the mudflat were low, yet the Pacific oyster reef had much higher densities and biomass of large prey, especially annelids and shore crabs. The winter assemblage of feeding birds differed significantly between each of the areas. The mean total number of feeding birds was significantly greater on the uncolonized mudflat; however, mean peak counts, feeding success rate and prey intake rate of Eurasian oystercatcher were greater on the reef. Significantly greater intake rates and feeding success rates were also observed on the reef for Eurasian curlew, a species of conservation concern. Field data and model predictions show that Pacific oyster reefs can provide valuable supplementary feeding areas for some shorebirds, yet other species avoided the reef. However, as estuaries vary in available feeding resources, it is important that the value of reefs and their management is determined regionally.

Are common bird monitoring schemes and opportunistic observations appropriate for estimating raptor trends?

ABSTRACTCapsule: Transect-based common bird monitoring methods and opportunistic data from citizen scientists are not equal alternatives to mapping of raptors in study plots.Aims: To analyse the efficacy of common breeding and wintering bird monitoring schemes, as well as databases of casual bird observations, in providing population trends for raptors.Methods: We estimated trends for three raptor species using data from Estonian common bird monitoring schemes and a database of casual observations, and compared these with those resulting from special raptor monitoring programmes.Results: Significant trends for all three species were only detected using the specialized scheme Monitoring of Breeding Raptors in study plots, whereas Monitoring of Wintering Raptors showed some significant yearly fluctuations of the Common Buzzard Buteo buteo. However, Common Breeding and Wintering Bird Monitoring schemes provided uncertain trends, although results suggested a decline in the breeding Goshawk Accipiter gentilis population. Casual observations suggested recent declines in wintering populations of the Goshawk and Sparrowhawk Accipiter nisus, but data from more years are needed to validate this.Conclusion: Special monitoring schemes are most effective in monitoring raptor populations. Such schemes can be used to monitor trends of common and uncommon raptor species and provide additional information for their research and conservation.

Do bridge construction activities influence birds using the River Mersey, in northwest England?

ABSTRACTCapsule: Bridge construction works over a major river did not adversely impact the overall wintering and breeding bird assemblage, although contrasting species-specific trends in breeding number were noted.Aims: To determine whether the wintering water-bird and breeding bird assemblage using the River Mersey, in northwest England, was influenced by bridge construction works.Methods: Common bird census and wintering bird surveys were carried out before and during construction of the Mersey Gateway bridge. The species abundance and richness of wintering water-birds, assigned to a group (‘Waterfowl’, ‘Wader’, ‘Wetland species’ and ‘Gull’) and breeding birds, assigned to a group (‘Salt marsh species’, ‘Waterfowl species’, ‘Wader species’, ‘Warbler species’ and ‘Other passerine species’), were separately compared before and during the works.Results: We found little evidence that the bridge construction displaced wintering water-birds and instead found that for most bird groups, their assemblages were higher during the construction works, compared to before. Similarly, we found no evidence that the bridge construction reduced breeding density of any bird group. Contrasting species-specific trends were, however, noted, with some species only recorded breeding during the construction works, and other species recorded in higher breeding densities before the works.Conclusion: The inadvertent increase in the mud-flats around the bridge structure since the works resulted in more mud-flat being exposed for a greater amount of time, and thus increased the foraging opportunities for many birds. This may at least partly explain why overall wintering bird abundance and richness increased since the works began. Although most breeding birds either increased or remained stable, in number since the works, a small number reduced. This may have been a consequence of the removal of suitable nesting habitat. This study provides a preliminary assessment of the influence of bridge construction on birds.

Food preferences by birds using bird-feeders in winter: a large-scale experiment

BackgroundIntentional winter bird feeding in gardens is one of the most common interactions between birds and humans. Because feeding may have both desired effects (provisioning of nutritious food for under-nourished birds) and undesired effects (favouritism of competitively superior species, transmission of disease), management of supplementary sites should be optimized from an ecological and conservation perspective. Therefore, the main aim of this study was to experimentally test winter food preferences of birds, with underlying potential influence of habitat (rural vs. urban) on realised food preferences pattern.MethodsWe conducted an experimental analysis of food preferences of wintering birds by provided bird-feeders in urban and rural environments across Poland. Data were collected twice during winter 2013–2014 across Poland, in total with 80 experimental trials.ResultsSunflower seeds were the most preferred food supplement both in urban and rural habitats, significantly more exploited than any other food simultaneously available in feeders (animal fat, millet seed and dry fruits of rowanberry). However, no significant differences were recorded between urban and rural habitats in use of food.ConclusionsThe degree of use of a particular type of food at bird-feeders depended on the overall use of food in a bird-feeder—consumption of each of the four types of food was significantly positively correlated with that of the others, and it was positively correlated with the number of birds observed at the feeders.

Fall vegetative cover and summer precipitation predict abundance of wintering grassland birds across the Chihuahuan desert

Local winter abundance of grassland passerines is highly variable throughout the Chihuahuan Desert among years. The objective of this study is to determine if plant biomass in grasslands and precipitation are predictors of bird abundance in space and time through Chihuahuan Desert. We conducted avian surveys in 17 Grassland Priority Conservation Areas (GPCA) in northern Mexico and southwestern United States in the winters of 2007–2011. We used distance sampling on line transects to estimate annual winter bird density in all GPCAs. We used a hierarchical model of distance sampling to estimate the effect of summer precipitation and vegetative cover during the fall on bird density for 10 grassland species. We used the MODIS NDVI at a pixel resolution of 231.5 m as a measure of plant biomass. Grasshopper Sparrow, Baird's Sparrow, Savannah Sparrow, Vesper Sparrow, and Eastern Meadowlark showed a strict positive response to NDVI, while Horned Lark, Sprague's Pipit, Chestnut-collared Longspur and Lark Bunting did not show a strictly-positive response to NDVI. Our results provide a valuable tool for the conservation of declining migratory birds on their wintering grounds by identifying a wildlife-habitat relationship using a remotely-sensed and readily available index of vegetative growth.

Implications of transformation to irregular silviculture for woodland birds: A stand wise comparison in an English broadleaf woodland

Woodland birds in Britain have undergone significant long term declines since the late 1960s, associated in particular with changes in woodland structure in general, and loss of early successional vegetation. Irregular, continuous canopy broadleaf management is a form of selective logging, very recently adopted in UK that produces woodlands with open canopies and substantial mid- and understorey growth. We examined spring and late winter bird densities, estimated using distance sampling, at 310 points in irregular, transitional (that being managed towards irregular), limited intervention, and coppice stands within a large working broad-leaf woodland in lowland southern Britain. Almost all understorey and canopy vegetation measures differed significantly across stand types. Ten of 20 species had highest spring abundance in irregular woodland, five in coppice, three in transitional, and just two in limited intervention. In winter, 5–6 species preferred each of limited intervention, irregular and transitional, while no species preferred coppice. Densities differed little across seasons except in Paridae where abundances increased in late winter during which limited intervention stands were used more by this group. Birds generally occupied similar niche positions and had similar niche breadths across seasons. Compared to under-managed woodlands, irregular silviculture in UK’s broadleaf woodlands is likely to enhance habitat quality for woodland birds, including several species of conservation concern e.g. marsh tit Poecile palustris which was twice as abundant in irregular stands as in any other stand type.

The potential virtue of garden bird feeders: More birds in citizen backyards close to intensive agricultural landscapes

Farmland bird abundances have been declining for decades, an erosion associated with agricultural changes. Main drivers have already been identified: intensification of practices, modification of landscapes, leading to impoverished summer and winter food availability. In parallel, winter bird feeding in private gardens became a common practice. Such a food supplementation may represent a bonanza for seed-deprived bird communities. Using data collected by citizen providing food to wintering birds in >1100 backyards, we analyzed the temporal and spatial trends in abundance of 30 species at feeders during four core winters periods and along a gradient of local agriculture intensification. Garden feeders located within intensively cultivated landscapes attracted more birds, the relationship being strongest for farmland species. We further found a temporal trend which strengthens this pattern as the winter progresses. These results confirm that supplying winter food to garden birds has not only a recreational value, but can also improve bird numbers hence probably winter survival rates, chiefly in intensive agricultural landscapes.

Environmental Factors Influencing Wintering Birds in Metropolitan Riparian Area and its Surroundings.

Environmental Factors Influencing Wintering Birds in Metropolitan Riparian Area and its Surroundings.

Recent climate change has increased forest winter bird densities in East Europe

AbstractRecent studies on climate change have reported serious impacts on winter forest birds in Western Europe. However, in areas where climate change has caused milder winters and more stable conditions in summer, one would expect resident bird populations to increase, rather than to decrease in winter. The aim of this study was to investigate the impact of climate change on the population dynamics of ten species of Passeriformes in the Tartarstan Republic, Russia. Ravkin's transect method was used to census fixed randomly selected plots spread over a large geographic area at least once every month for the past 26 years. Observers remained the same over the whole period. The abundance of nine species in the first half of the winter and four species in the second half of the winter showed significant increases during the study period. Unlike studies from countries in Western Europe, there were no significant decreases in these species. Significant changes in winter conditions, as well as during the breeding season, and an overall increase in annual temperatures are likely reasons for a significant increase in the number of birds in winter. Greater winter survival, an increase in the survival rate of fledglings and juveniles during the summer, and later onset of winter, are very important determinants of the winter population. Our findings show that numbers of birds in late winter are related to the severity of winter conditions. Our data do not support conclusions that the populations of forest bird species have decreased due to climate change.

Oklahoma Winter Bird Atlas by Dan L. Reinking

Oklahoma Winter Bird Atlas by Dan L. Reinking

Результаты мониторинга гнездовой группировки стервятников на хребте Нарат-Тюбе и прослеживания с помощью GPS/GSM-трекеров несовершеннолетних стервятников из этой группировки (Республика Дагестан, Россия)

This article represents a data obtained during observing a breeding group of Egyptian Vultures ( Neophron percnopterus ) and GPS-tracking of 4 juvenile birds from the breeding group located on the Narat-Tyube ridge, State Nature Reserve “Dagestanskiy”, Dagestan, Russia. The population number of this breeding group remains stable during the last 7 years. The density of breeding pairs is 7.2/100 sq.km. A distance between neighboring pairs vary from 1.9 km to 4.1 km, the mean value (n=9) is 3.05±0.69 km. Only one out of 4 juvenile birds tagged with GPS/GSM tracker finished its migration successfully and spent winter in Yemen. The signal from another one was lost on the territory without coverage area, another bird was caught in Iraq and its fate remains unknown, and the last one crashed into powerline wires in Saudi Arabia and was taken to the rehabilitation center. Our data showed that Dagestan Egyptian Vultures use same migration routes that were already known for Transcaucasian birds. According to our data obtained from sole juvenile bird wintering area of Egyptian Vultures from this population also coincides with previously known wintering areas of the species in Yemen. The migration distance from breeding to wintering site obtained in our study is 3299 km and the length of migration route is 4155 km; the duration of autumn migration is 31 days; the individual wintering area (95% MCP) is 2256 sq.km, Kernel 50% – 38 sq.km or 1.7% from 95% MCP.

A preliminary investigation on supplemental food and predation by birds

Birds that are active in the winter must continually meet their metabolic needs to survive many months of cold temperatures. Overwintering insects inhabiting trees provide an important food source for these birds. The objective of this study was to test whether or not winter birds present in the deciduous forest surrounding the Saint Francis University campus would forage more on tree-dwelling insects if there was a supplemental food source provided in the area. We used frozen mealworms placed in trees as surrogate overwintering insects and measured the foraging success of birds on these insects during a three-week period in the winter of 2014. Mealworm predation was compared across three sites differing in supplemented food sources: sunflower seeds, suet, and no provided food (control). Each site had four mealworms placed in holes drilled in 16 surrounding trees for a total of 64 mealworms per site. The consumption of these mealworms was measured during the experiment to analyze whether provided food sources influence the foraging behavior of birds in the winter. Observations after three weeks indicated that the predation rates were 78%, 72% and 69% at the seed, control and suet sites, respectively. The bird counts reveal a greater number of birds visiting the suet site compared to the control and the seed site. Birds appear to prey on insects inhabiting trees independently of foraging on supplemental food sources, or perhaps different species of birds forage on tree insects compared to those that visit feeders.

Habitat quality affects stress responses and survival in a bird wintering under extremely low ambient temperatures.

Animals normally respond to stressful environmental stimuli by releasing glucocorticoid hormones. We investigated whether baseline corticosterone (CORT), handling-induced corticosterone concentration(s), and body condition indices of members of willow tit (Poecile montanus) groups differed while wintering in old growth forests and managed young forests in mild weather conditions and during cold spells. Willow tits spend the winter season in non-kin groups in which dominant individuals typically claim their priority to access resources, while subordinate individuals may experience greater levels of stress and higher mortality, especially during cold spells. We captured birds to measure baseline CORT and levels of handling-induced CORT secretion after 20min of capture. Willow tits in the young forests had higher baseline CORT and a smaller increase in CORT in response to capture than individuals in the old forests. Baseline CORT was higher in females and juvenile birds compared to adult males, whereas handling-induced CORT secretion did not differ between birds of different ages. During cold spells, baseline CORT of willow tits increased and handling-induced CORT secretion decreased, especially in birds in young forests. Willow tits' survival was higher in the old forests, with dominant individuals surviving better than subordinates. Our results show that changes in CORT secretion reflect responses to habitat quality and climate harshness, indicating young managed coniferous forests as a suboptimal habitat for the willow tit.