Bird Counts Research Articles

Making bird numbers count: Would Dutch farmers accept a result-based meadow bird conservation scheme?

Current management contracts under agri-environmental schemes (AES) are often action-based. This means that farmers are reimbursed for the costs incurred when implementing conservation measures but are not paid based on actual improvements in environmental outcomes. In theory, result-based schemes with payments for outcomes can improve the cost and ecological effectiveness of AES. This article analyses farmers' acceptance of a hypothetical meadow bird management scheme that includes payments for results. The tested scheme was developed together with a Dutch farmer collective and resulted in a hybrid scheme including both result-based and action-based elements. In a discrete choice experiment, farmers were offered (1) a bonus payment that depended on the collective's nature conservation success, and (2) an individual bonus payment that rewarded farmers implementing measures that are expected to contribute more to the success of conservation. Results show that the acceptance of the hypothetical hybrid scheme is high (75%). The collective bonus was evaluated positively when the collective bonus on offer was high (€ 1000/farmer), but a latent class analysis indicates that this does not apply uniformly to all farmers.

Bird Object Detection: Dataset Construction, Model Performance Evaluation, and Model Lightweighting.

The application of object detection technology has a positive auxiliary role in advancing the intelligence of bird recognition and enhancing the convenience of bird field surveys. However, challenges arise due to the absence of dedicated bird datasets and evaluation benchmarks. To address this, we have not only constructed the largest known bird object detection dataset, but also compared the performances of eight mainstream detection models on bird object detection tasks and proposed feasible approaches for model lightweighting in bird object detection. Our constructed bird detection dataset of GBDD1433-2023, includes 1433 globally common bird species and 148,000 manually annotated bird images. Based on this dataset, two-stage detection models like Faster R-CNN and Cascade R-CNN demonstrated superior performances, achieving a Mean Average Precision (mAP) of 73.7% compared to one-stage models. In addition, compared to one-stage object detection models, two-stage object detection models have a stronger robustness to variations in foreground image scaling and background interference in bird images. On bird counting tasks, the accuracy ranged between 60.8% to 77.2% for up to five birds in an image, but this decreased sharply beyond that count, suggesting limitations of object detection models in multi-bird counting tasks. Finally, we proposed an adaptive localization distillation method for one-stage lightweight object detection models that are suitable for offline deployment, which improved the performance of the relevant models. Overall, our work furnishes an enriched dataset and practice guidelines for selecting suitable bird detection models.

81st Annual Saskatchewan Christmas Bird Count - 2022

81st Annual Saskatchewan Christmas Bird Count - 2022

Structural complexity is a better predictor than single habitat attributes of understory bird densities in Andean temperate forests

Abstract The simplification of forest structural complexity, caused by anthropogenic land-use practices, is one of the main threats to understory specialist birds. We examined the association of both single structural attributes and structural complexity, with the density of 4 understory bird species in the Global Biodiversity Hotspot “Chilean Winter Rainfall-Valdivian Forests” of South America. Between 2011 and 2013, we surveyed habitat attributes and conducted bird point counts in 505 plots in Andean temperate ecosystems in Chile. In each habitat plot, we measured understory density, volume of coarse woody debris (CWD), number of snags, diameter at breast height (DBH) of trees, and leaf litter depth. With these attributes, we developed an index of stand structural complexity (ISC). On average, old-growth forests had higher values for understory density, CWD volume, DBH, and litter depth than secondary forests and open fields, and thus greater values of ISC. The density of understory birds was positively correlated with the ISC for the Rhinocryptidae Pteroptochos tarnii, Scelorchilus rubecula, and Scytalopus magellanicus. We also found a positive association between understory density and litter depth, with the density of the Furnariidae Sylviorthorhynchus desmursii. However, this latter species showed a negative association with the density of snags. Our results suggest the utility of using an index of structural complexity, rather than single or even additive habitat attributes, for determining the density of understory specialist birds. We recommend that management plans should promote the retention of habitat attributes that contribute to the structural complexity of temperate forests of South America and beyond.

To See, Hear and Speak: How Counts of Birds in Individual Trees Help Address the Environmental Causes of the Sahel

To See, Hear and Speak: How Counts of Birds in Individual Trees Help Address the Environmental Causes of the Sahel

Comparing bird sightings between grassland and marsh habitats at a rehabilitated wetland in Gauteng Province, South Africa

Abstract. Botha J, Haussmann NS. 2023. Comparing bird sightings between grassland and marsh habitats at a rehabilitated wetland in Gauteng Province, South Africa. Biodiversitas 24: 3536-3542. Wetlands, including rehabilitated wetlands, form important feeding and nesting sites for a large range of bird species. The restoration of degraded wetlands is therefore important from a bird biodiversity perspective and bird surveys are needed in such systems. However, bird counts typically differ both spatially (e.g., between different habitats within the wetland) and temporally (e.g., between different seasons or times of the day). This study compared bird sightings at a rehabilitated wetland in the Gauteng Province of South Africa between marsh and grassland sections of the wetland and between morning and afternoon sessions. A total of 47 bird species were sighted at the wetland, including a number of species that have been listed as declining. Whereas more species were sighted in the marsh habitats of the wetland than the grassland habitats, differences in the number of sightings between habitats depended on the time of day. Thus, although there were no differences in the number of sightings between morning and afternoon sessions at the marshes, the number of sightings was higher in the afternoons than in the mornings at the grasslands. We therefore, first caution against comparing bird counts, in general, between studies conducted at different times of the day. More importantly, however, our results highlight the importance of not only conserving natural, pristine wetlands but also rehabilitated wetlands to create habitats for declining bird populations in transformed environments such as urban settings.

Impact of wildfires on ecosystems and bird communities on designated areas of blanket bog and heath

ABSTRACT Capsule Wildfires on moorland reduced bird species richness and abundance, along with the seedbank and abundance of ground beetles and spiders. The effects were detectable three years after the fires took place. Aims To describe the effects of wildfires during the breeding season on moorland birds, their habitat and ecosystem characteristics, by comparing burnt with adjacent unburnt areas in six designated sites up to three years post-fire. Methods Point counts of birds, vegetation height and cover, soil seedbank and pitfall traps were used to examine differences between areas burnt by wildfires and unburnt areas. Results One year after wildfire, bird species richness was 50% lower and abundance 32% lower on burnt compared to adjacent unburnt areas. Wildfire burnt areas had 80% of the species richness and 94% of the abundance of unburnt areas three years after wildfire. Bird species associated with upland moorland, including European Stonechat Saxicola rubicola, Common Redshank Tringa tetanus and Hen Harrier Circus cyaneus, were recorded exclusively in unburnt areas. Wildfire burnt areas were characterized by habitat generalist species and community composition in burnt areas remained distinct from unburnt areas three years after burning. Heather Calluna vulgaris and Erica spp. regenerated to 59% of the height of heather on unburnt areas three years after burning. Compared to unburnt areas, burnt areas had a reduced seedbank (22% lower), and reduced ground beetle (15% lower) and spider abundance (31% lower). Conclusion The immediate impacts of wildfire may differ from managed fires due to their indiscriminate character, where they occur, extent, duration and temperature. Wildfire incidence is likely to increase in cool temperate areas due to climate change and likely to undermine the characteristic features of designated areas. Research should focus on preventing wildfires, reducing their impact and accelerating the recovery of burnt moorland.

Результаты орнитологических наблюдений в ходе береговых экспедиций ММБИ РАН в 2021–2022 годах

The work presents the results of route counts of marine and near-water birds in different parts of the northern coast of the Murmansk region. The seasonal dynamics of the population of the common eider and herring gull in the area of Teriberka were shown, as well as the index of species diversity for some areas of the Kola Inlet. According to the results of observations, changes in the avifauna of some areas of the Pechenga and Kola inlets were noted.

Status and Diversity of Ornithofauna in Joggers Park, Lucknow, Uttar Pradesh, India

The present study was done to account for the status and diversity of ornithofauna of Joggers Park, Lucknow, U.P., India. The field explorations were carried out from September 2021 to August 2022. During the period of study, a total of 62 species of ornithofauna were identified which belonged to 13 orders and 32 families. The order Passeriformes had a maximum number of bird count (34 species) belonging to 16 families. The least number of bird species was recorded in orders Strigiformes, Charadriiformes, Apodiformes, and Galliformes each containing 1 species. All the 62 avian species reported in Joggers Park come under the least concerned category of IUCN. Out of the total species, 49 species were resident and 13 Residents were Migratory (RM).

Structural organization and ecology of birds of the High-Mountinous Dagestan

This paper analyzes the data of bird counts conducted in 1998–2021 in the province High-Mountainous Dagestan. For the first time, information was obtained on the modern average abundance of birds, their conservation status, residence status, species and faunistic composition. Of the 117 bird species recorded in the High-Mountain province of Dagestan, European, widespread, Mediterranean and Tibetan representatives of faunal complexes dominate in its humid northwestern and central parts, which is due to the prevalence of forests and shrubby subalpine meadows with large-scale rocky outcrops. In the southeastern, more aridized and treeless part of the highlands, where subalpine and alpine meadows with local rock inclusions dominate, representatives of the widespread, Mediterranean and Mongolian types of fauna are already taking the leading positions. Studies have shown that in mountains with a blurred altitudinal-belt gradient associated with the inversion of vegetation belts, the avifauna is subdivided not according to altitudinal differences, but according to habitats with corresponding ecological bird communities. Using the original ecological classification, the ecological structure of the avifauna of the study area was determined, including 11 ornithocomplexes differentiated according to the same type of habitats with an indication of their total abundance. Each habitat with the corresponding ornithocomplex was characterized according to ecological specifics, indicating with the indication of the first 5 species leading in terms of abundance. It has been established, that the specific appearance of the avifauna of the High-Mountinous Dagestan is given not only by the resident communities of typically mountain birds, but also by the adapted populations of migratory birds of the plains nesting in the highlands. The empirical data obtained make it possible to use them for spatial indication of bird communities for research purposes, for monitoring the state of the avifauna and its protection, as well as for organizing the rational use of hunting and commercial resources.

Vegetation structure from LiDAR explains the local richness of birds across Denmark.

Classic ecological research into the determinants of biodiversity patterns emphasised the important role of three-dimensional (3D) vegetation heterogeneity. Yet, measuring vegetation structure across large areas has historically been difficult. A growing focus on large-scale research questions has caused local vegetation heterogeneity to be overlooked compared with more readily accessible habitat metrics from, for example, land cover maps. Using newly available 3D vegetation data, we investigated the relative importance of habitat and vegetation heterogeneity for explaining patterns of bird species richness and composition across Denmark (42,394 km2 ). We used standardised, repeated point counts of birds conducted by volunteers across Denmark alongside metrics of habitat availability from land-cover maps and vegetation structure from rasterised LiDAR data (10 m resolution). We used random forest models to relate species richness to environmental features and considered trait-specific responses by grouping species by nesting behaviour, habitat preference and primary lifestyle. Finally, we evaluated the role of habitat and vegetation heterogeneity metrics in explaining local bird assemblage composition. Overall, vegetation structure was equally as important as habitat availability for explaining bird richness patterns. However, we did not find a consistent positive relationship between species richness and habitat or vegetation heterogeneity; instead, functional groups displayed individual responses to habitat features. Meanwhile, habitat availability had the strongest correlation with the patterns of bird assemblage composition. Our results show how LiDAR and land cover data complement one another to provide insights into different facets of biodiversity patterns and demonstrate the potential of combining remote sensing and structured citizen science programmes for biodiversity research. With the growing coverage of LiDAR surveys, we are witnessing a revolution of highly detailed 3D data that will allow us to integrate vegetation heterogeneity into studies at large spatial extents and advance our understanding of species' physical niches.

81st Annual Saskatchewan Christmas Bird Count - 2022

81st Annual Saskatchewan Christmas Bird Count - 2022

Winter range shifts and their associations with species traits are heterogeneous in eastern North American birds

Abstract Many species’ distributions are shifting in response to climate change. Many distributional shifts are predictably poleward or higher in elevation, but heterogeneity in the rate and direction of shifts both within and between species appears to be common. We found high heterogeneity in the trajectory of winter range shifts for 65 species of birds across eastern North America and in the different traits and trait interactions associated with these shifts across the spatial scales we examined. We used data from the Christmas Bird Count to quantify the trajectory of winter latitudinal center of abundance range shifts over 4 decades (1980–2019) for 65 species of songbirds and woodpeckers in North America, both across eastern North America (ENA) as a whole and for the Atlantic (ATL) and Mississippi (MISS) flyways separately. We then used linear models and Akaike’s Information Criterion with small-sample size correction (AICc) model selection to test whether species traits could explain variation in range shifts or flyway discrepancies. Across ENA, most species showed northward latitudinal range shifts, but some showed no latitudinal shift while others shifted southwards. Amongst ATL and MISS, we documented both within- and between-species differences in the rate and direction of latitudinal shifts, complicating the results from across ENA. No single trait emerged as a dominant driver of range shift differences at the ENA and flyway scales. Migration strategy interacted with insectivory to explain variation at the largest spatial scale (ENA), whereas frugivory and mean winter latitude explained much of the variation in ATL and MISS, respectively. Exploring heterogeneity in range shifts within and between species, and in the associations between range shifts and life history traits, will help us better understand the mechanisms that mediate differing responses to environmental change and predict which species will be better able to adapt to those changes.

Trends in butterfly populations in UK gardens—New evidence from citizen science monitoring

Abstract Private gardens are recognised as potentially important refugia for butterflies. Yet little is known about how gardens might be contributing to butterfly conservation, as their restricted accessibility has meant that garden habitats are not well‐represented in traditional monitoring schemes. Garden BirdWatch (GBW) is the UK's largest structured bird survey, comprising over 25 years of weekly bird counts from more than 14,000 gardens, predominantly occupying suburban and rural locations. Since 2007, a subset of GBW participants have additionally recorded the weekly abundances of butterflies. Using data for 14 seasons (2007–2020) from 7971 gardens with consistent butterfly monitoring, we present the first garden‐specific, national trends for 22 widespread butterfly species (37% of all UK butterflies). Half of the species investigated increased significantly in abundance in gardens between 2007 and 2020. Conversely, only one species, Wall (Lasiommata megera), showed a marginal reduction, though this change was not statistically significant. A strong, positive association between these new, habitat‐focused trends and those for UK butterflies more broadly, previously reported by the UK Butterfly Monitoring Scheme (UKBMS), indicates that patterns of abundance in gardens are largely a reflection of the changes that are occurring nationally. However, butterflies do appear to be faring better in gardens compared to the wider landscape. Averaging trends across non‐migratory species revealed that GBW recorded significantly greater increases over time than UKBMS. Effective monitoring of butterflies in gardens can produce reliable and informative population trends, and it provides important evidence of the significant role gardens play in sustaining butterfly populations.

Bird population dynamics during the regenerative succession of mossy pine woodland in southwestern Belarus

Disturbed forest ecosystems are characterized by significant spatial and temporal changes. As a part of the study on bird communities, changes in bird abundance during the secondary succession of a cleared mossy pine woodland in southwestern Belarus were investigated. The purpose of the work was to determine the inter-annual dynamics of bird species abundance and to assess the variability of individual species abundance during the secondary succession of the mossy pine woodland. The material was collected in 2000–2019. Line transects were set to conduct bird counts in ecosystems at different stages of succession. For the data processing, generally accepted methods of statistical analysis were used. The species diversity of birds was found to increase from 8 to 42 species, the overall abundance from 171.7 to 587.1 birds/km2 during the succession (6 stages, from 1 to 90 years in age). The abundance of species (birds/km2) and inter-annual variability during 11 seasons were determined. The coefficient of variation (CV) was the highest (71.00–82.50%) for species whose abundance did not exceed 1.0 birds/km2. The average abundance of species varied considerably, e.g., among passerines at the 80–90-year old stage from 1.1 birds/km2 (Little Flycatcher) to 153.7 birds/km2 (Chaffinch). Bird populations with high abundance turned out to be the most stable, for example at the last two successional stages the CV of the Chaffinch is 6.02 and 7.16%. For species with average abundance the variability is found to be low or medium (varies from 11.90 to 36.20%), for species with low abundance the CV varies from 17.68 to 82.50%. All six stages of succession were dominated by nesting migratory birds, which account for 75.0% of the species in the first stage of succession to 52.4% in the fifth and sixth stages. Near and distant migrants form the basis of the bird community at all stages. Populations of sedentary species and distant migrants are more stable than those of near migrants.

Bird-Count: a multi-modality benchmark and system for bird population counting in the wild

Bird-Count: a multi-modality benchmark and system for bird population counting in the wild

Evidence of Continuing Downward Trends in American Kestrel Populations and Recommendations for Research into Causal Factors

ABSTRACT We analyzed long-term datasets from nest box programs, Breeding Bird Surveys run by the US Geological Survey, Christmas Bird Counts run by the National Audubon Society, and counts from two key fall migration watch sites, Hawk Mountain Sanctuary and Cape May Hawkwatch. We found that populations of American Kestrels (Falco sparverius) in North America are generally still declining, albeit with some caveats. Some populations are actually increasing, while others are remaining stable. Overall, the magnitude of annual change appears to be decreasing slightly during recent years. To understand potential causes of the decline, we recommend the following courses of action in no particular order: (1) determine whether the increase in Cooper's Hawk (Accipiter cooperii) populations is restricting kestrel distributions by the mere presence of the larger raptor; (2) study the effects of habitat loss and/or degradation on the falcon's wintering range; (3) further investigate on a broader spatial scale whether within-season habitat alterations are creating ecological traps for breeding kestrels; (4) determine the importance of arthropods in the diet of kestrels, especially the long-term population trends and timing of emergence of grasshoppers in relation to kestrel breeding chronology; (5) discover whether rodenticides pose a serious risk to American Kestrels across North America; (6) learn more about possible effects, both direct and indirect, that the use of neonicotinoids may have on kestrels; and (7) continue ongoing studies of the effect of climate change on these birds.

Poleward shifts and altered periodicity in boreal bird irruptions over six decades.

Range boundaries are long-term biogeographic features of species distributions and abundance. However, many species demonstrate dynamic range boundaries, reflecting strong seasonal and annual variability in migratory behaviour. As a form of facultative migration, irruptions involve the movement of many individuals outside of their resident range in response to climate variability, resource availability, and demographic processes. Many species have experienced range shifts and altered phenology in response to modern climate change, but spatiotemporal changes in irruption dynamics are less well known. We quantified changes in the geography and periodicity of boreal bird irruptions across eastern North America from 1960 to 2021. Using data from Audubon's Christmas Bird Count for nine finch species, including several exhibiting recent population declines, we evaluated latitudinal trends in southern range and irruption boundaries and characterized irruption periodicity using spectral wavelet analysis. Six boreal birds exhibited significant northward shifts in their southern range boundaries and three species displayed shifts in their southern irruption boundaries. Irruption periodicity across multiple species was consistent across the 1960s and 1970s, culminating in frequent and synchronized irruptions of multiple species (superflights) during earlier decades. Coherence between species dampened beginning in the early 1980s as superflight periodicity became increasingly unstructured, finally reforming in recent decades, after 2000. Boreal birds are considered important sentinels of the boreal forests, and northward shifts and altered periodicity of irruptions may indicate broad-scale changes in climate- and resource-associated drivers operating across the boreal forests.

Remote and local threats are associated with population change in Taiwanese migratory waterbirds

Although several countries along the East Asian-Australasian Flyway have recently begun reporting population trends and identifying threats to migratory waterbirds, there remains rather sparse geographical coverage of systematic waterbird monitoring, impeding our understanding of the flyway-wide status of waterbird populations. To fill this gap, we used the data from a nationwide citizen science project, the “Taiwan New Year Bird Count'' to examine recent population trends of 31 migratory waterbird species across Taiwan, and within three of its waterbird hotspot regions, between 2014 and 2021. Island-wide, the abundance of two species declined significantly while five species increased. However, there was substantial heterogeneity in population trends among regions, with nine species declining significantly in Yi-Lan, four species in Chang-Hua and one species in Chia-Nan. Conversely, 11 species increased significantly in Chia-Nan, one species in Chang-Hua, but no species increased in Yi-Lan. This suggests that a combination of local and remote factors is driving population change in Taiwanese migratory waterbirds. Moreover, species that use local rice paddies or are dependent on tidal flats around the Yellow Sea were more likely to show population declines, and those able to use aquacultural wetlands showed growth. These results suggest that recent rice paddy loss and habitat loss in the Yellow Sea have been contributing to migratory waterbird declines in Taiwanese wetlands. Our findings suggest that local land use planning policies within Taiwan as well as mitigation of Yellow Sea tidal flat loss are likely to be complementary in safeguarding the future of migratory waterbirds in Taiwan.

Report of Annual Challenge Bird Count – 2022

Report of Annual Challenge Bird Count – 2022