Structural effects of reedbed grazing and its cessation on reed-nesting songbird densities

Reedbeds are crucial breeding habitats for vulnerable songbird species.Irrespective of their protection status,these habitats may be threatened by organic matter accumulation,progressively leading to structural homoge-nization and habitat succession towards woodland.Managers prevent excessive litter build-up with various in-terventions opening-up the reedbeds,such as grazing,which may be detrimental or suitable for some reed bird species.We assessed the effects of extensive grazing by horses and its cessation in the medium and long terms on reedbed structure,and the consequences on reed-nesting songbird densities in Estagnol Nature Reserve,a pro-tected wetland near the French Mediterranean coast.We compared reedbed structural features between grazed,newly ungrazed and old-ungrazed plots.During nine years,we censused four songbird species in spring and collected water level data in the same survey plots.Grazing reduced reedbed extent,rejuvenated the vegetation with more short green stems on a thinner litter,and produced higher structural heterogeneity and discontinuity compared to long-lasting non grazing.Newly ungrazed plot showed intermediate effects.All surveyed songbird total densities were similar among plots while species numbers and densities differed.Grazed reedbed was more attractive to Moustached Warblers(Acrocephalus melanopogon)and Great Reed Warblers(Acrocephalus arundi-naceus),likely due to the large edges and the high vegetation structural heterogeneity.However,Moustached Warblers were more negatively affected by higher water level in grazed reedbed,presumably because flooding prevents litter foraging.The newly ungrazed reedbed was not preferred by any species.All warbler species were found under low density in the old-ungrazed reedbed,where Reed Buntings(Emberiza schoeniclus)were exclu-sively found.Food availability related to thick litter layer may explain this predilection.Common Reed Warblers(Acrocephalus scirpaceus)were found everywhere in similar densities.We conclude that reedbed management by extensive horse grazing and also its long-term cessation may benefit several songbird species.Within a context of wetland degradation and disappearance,both management strategies are useful to establish and maintain suitable habitats for reed-nesting songbird communities.

Insights on the molecular mechanism of neuroprotection exerted by edible bird’s nest and its bioactive constituents

Neurodegenerative diseases are often associated with the accumulation of oxidative stress and neuroinflammation.Edible bird’s nest(EBN)is a glycoprotein(sialylated mucin glycopeptides)found to be beneficial against neurodegenerative diseases.Antioxidative,anti-inflammatory,and anti-apoptotic properties of EBN in preserving neuronal cells were widely researched using in vitro and in vivo models.Functional effects of EBN are often linked to its great number of antioxidants and anti-inflammatory glycopeptides.Bioactive compounds in EBN,especially sialic acid,add value to neurotrophic potential of EBN and contribute to neuronal repair and protection.Various studies reporting the neuroprotective effects of EBN,their molecular mechanisms,and neuroactive composition were gathered in this review to provide better insights on the neuroprotective effects of EBN.

Negative effects of artiffcial nest boxes on birds:A review

Artificial nest boxes are placed to attract birds to nest and breed in a specific location,and they are widely used in avian ecology research and in the attraction of insectivorous birds.There is evidence that artificial nest boxes can adversely affect breeding fitness but no great focus has been placed on this issue by researchers.Therefore,we retrieved 321 research papers regarding artificial nest boxes published from 2003 to 2022 and used the'Biblioshiny'program to extract and integrate keywords;we then summarized the adverse effects of artificial nest boxes on avian breeding success.The studies highlighted many drawbacks and misuses in the designing and placement of nest boxes;furthermore,bird attraction was decreased by their inappropriate selection,thus reducing breeding success.Regarding nest box production,there were shortcomings in the construction material,color,smell,and structural design of the boxes used.Nest boxes were also placed at inappropriate densities,locations,orientations,heights,and managed incorrectly.Finally,we propose suggestions for more efficient and safer artificial nest boxes for future use in avian ecology research and bird conservation.

Quiet in the nest:The nest environment attenuates song in a grassland songbird

The nest environment may limit the ability of nest-bound birds to hear sounds from the outside world.In vocal learning species,such as humans and songbirds,it is vital for young animals to hear the voices of conspecific animals early in life.In songbirds,nest structure varies considerably across species,and the resulting impact on sound transmission may have consequences for vocal learning in nestlings.In this study,we tested the hypothesis that the nest environment attenuates song of Savannah Sparrows(Passerculus sandwichensis),grassland songbirds that build nests on the ground under cover of dense vegetation.We recorded live Savannah Sparrows singing at variable distances from 21 nests.We recorded songs using one microphone inside the nest(the typical position of a nestling)and another placed 1 m directly above the nest(a typical position of an adult).We found a substantial reduction in signal-to-noise ratio,where songs recorded inside the nest were an average of 11 dB lower than songs recorded directly above the nest.We estimate that the attenuation imposed by the nest reduced the maximum acoustic environment from 117.7 m(for recordings above the nest),to 78.6 m(for recordings within the nest),which is analogous to listening from a position 39.1 m farther away from the singer.Previous research estimated that song transmits up to 100 m in this species,so any adult male within 100 m of a young bird was previously considered a potential vocal tutor.By reducing the nestling acoustic environment from 100 m to 78.6 m,the number of male tutors available to nestlings is reduced by an average of 27%.Given the growing evidence that song learning begins very early in life,future research on vocal development should account for how the structural properties of the natal environment affect the songs that nestlings hear.

Bird species composition and conservation challenges in the Gaoligong Mountains, one of the most diverse bird areas in the world

The Gaoligong Mountains(GLGM),located in southwestern China,extend north to south along the western border of the Hengduan Mountains,spanning approximately 600 km.In this study,we consolidated findings from 17 bird surveys conducted in the GLGM between 2010 and 2022.We found that the GLGM harbors tremendous bird diversity,with a total of 796 documented bird species in the region.Nearly a quarter(23.0%)of these species are listed as state key protected species or as Chinese and global threatened species.Analysis of species richness at the county level showed a decreasing trend with increasing latitude,with the greatest diversity in Yingjiang(661 species).Observations indicated that the GLGM belongs to the Oriental realm,primarily composed of bird species from southern and southwestern China.The GLGM plays an important role in avian conservation by sheltering exceptional bird diversity,providing corridors and flyways for bird migration and dispersal,and mitigating the effects of climate change.In response to the conservation needs of birds and other wildlife,the Chinese government has established numerous protected areas within the GLGM.Despite these efforts,avian conservation still faces considerable challenges in the GLGM due to limitations in the protected area network,transboundary nature of the regions,and existing gaps in monitoring and research.

Weather influenced nestling growth of an insectivorous but not a granivorous grassland passerine in Argentina

Nestling growth of birds can be affected by weather fluctuations.In general,it is expected that higher temper-atures favor growth by improving food availability and nestling metabolism,while rain hinders it by reducing foraging efficiency.However,most of these patterns have been described in insectivorous cavity-nesting birds in temperate forests.We tested these predictions in two neotropical grassland ground-nesting birds with contrasting nestling diets and therefore potentially different responses to weather.We measured nestlings of the Hellmayr’s Pipit(Anthus hellmayri,an insectivorous passerine)and the Grassland Yellow-Finch(Sicalis luteola,which feeds its nestlings exclusively with seeds)during three breeding seasons(2017-2020)in central-eastern Argentina.We took measurements of tarsus and body mass,modeled growth curves using nonlinear mixed-effects models,and evaluated the effects of minimum daily temperature and precipitation during the growth period and the 30 days prior to hatching.For pipits(60 nestlings from 21 nests),minimum temperatures during the growth period were positively associated with tarsus and body mass asymptotes.Also,there was a positive association between precipitation during the pre-hatching period and tarsus asymptote.Conversely,none of the weather variables analyzed had significant effects on nestling growth of finches(131 nestlings from 35 nests).Dietary contrast between species may explain the different results.Arthropod activity and abundance can be affected by weather variations within the span of a breeding season,whereas seeds may depend on conditions from previous years,making the effects harder to detect.Fledglings with reduced asymptotic size can have reduced chances of sur-vival.Hence,pipit populations could be impacted if they experience cold and dry conditions during their breeding season,which is of major relevance in the current context of climate change.

Nest decoration:Black feathers prevent Crested Mynas from nest usurpation

Nests are important structures for birds to raise their offspring and for signaling.Many birds incorporate feathers into the nest,since feathers were traditionally thought to serve the function of insulation.Hypotheses in recent years have considered that some birds place feathers in conspicuous locations in the nest for decoration to trigger a fear response in the competitors.In this study,we investigated whether decorative feathers could deter nest usurpation by Crested Mynas(Acridotheres cristatellus)by manipulating nest box contents.The results revealed that Crested Mynas preferred black feathers to white feathers as decorations and occupied nest boxes decorated with black feathers significantly less than those decorated with white feathers,suggesting that black decorative feathers in the nest could be more effective in preventing nest usurpation by Crested Mynas and that white decorative feathers may have other functions.The black feathers in the nest are prominently placed at the edge of the nest to convey the message that“this nest is occupied”or“the owner of this nest has been preyed upon”to visitor Crested Mynas,thus effectively preventing them from usurping the nest at a later stage.

Birds’Diversity in Kalfou Forest Reserve and Its Peripheral Zone, Far North, Cameroon

The Far North Region of Cameroon is home to a great diversity of bird species, which unfortunately remains very little explored. This work was initiated to establish an inventory of birds and the factors affecting their diversity and distribution for sustainable management in the Kalfou Forest Reserve (KFR) and its periphery. Two methods were used for sampling, linear strip transects from which direct counts and indirect observations were made and the mist netting to complement the first. In total, 2525 birds were observed, including 149 species, belonging to 20 orders and 55 families. Accipitridae had the greatest number of species (11). The species richness was greater in the KFR (117 species) compared to the periphery (95 species). The specific richness was higher in wooded savannah compared to other habitats. Shannon index was significantly higher in the KFR (3.99) compared to that obtained in the periphery (3.80). The value of the Simpson index was higher on the outskirts of the KFR than on the periphery. The indices of species diversity were greater in the wooded savannah compared to other vegetation types. The seasons had no influence on bird diversity. Among the human activities encountered, the pressure indices were more important for grazing (7.3 contacts/km). Human activities have resulted in a significant decrease in specific richness. Six endangered species were encountered, four belonging to the Accipitridae family. The greater bird diversity in the reserve compared to the periphery shows that protected areas are a long-term solution for biodiversity conservation.

One bird,multiple stones:The race to find a gene of dominant negative effect in wheat

In the current issue of The Crop Journal,Chen et al.[1]reports map-based cloning of a wheat gene that showed temperaturedependent pleiotropic effects on multiple traits including plant height,leaf shape,spike and grain morphology,and accordingly was named WPA1 for Wheat Plant Architecture 1.The mutant was first observed among EMS-treated plants and repeatedly appeared in multiple occasions.

Use of evergreen and deciduous plants by nocturnal-roosting birds:A case study in Beijing

With continually increasing urbanization,the land cover in urban areas continues to change,resulting in the loss of biodiversity.Birds are highly sensitive to changes in habitat.Most forest birds perch on plants that provide increased safety to reduce the risk of predation,and small birds may also consider insulation when using roosting plants in winter because of cold weather.Landscaping plants thus shape the nocturnal roosting environment of urban birds,and proper planting is essential for the survival of birds at night.The use of roosting plants by urban birds should therefore be studied to provide a reference for landscaping.In the current study,we observed 1865 nocturnal roosting birds in Beijing from 2021 to 2022,with 23 species of birds from 12 families and 45 species of plants from 22 families recorded.Juniperus chinensis exhibited the highest bird rarity-weighted richness,followed by Fraxinus pennsylvanica,Phyllostachys propinqua,Pinus tabuliformis,and Ulmus pumila.The diameter at breast height,tree height,and crown width of plants used by birds was largest in summer and smallest in winter,and the perch height of birds was the highest in spring and summer and the lowest in winter.Birds used the highest proportion of deciduous plants in summer and the highest proportion of evergreen plants in winter.A significant seasonal difference in the use of evergreen and deciduous plants by small birds was noted,with a preference for deciduous plants in summer and evergreen plants in winter,while this preference was not found in large birds.These findings indicate that evergreen plants provide a vital nocturnal roosting environment for small birds in winter.To provide a better nocturnal roosting habitat for urban birds,we recommend paying attention to the combination of evergreen and deciduous plants when carrying out landscape construction.

Seasonal increase in nest defense,but not egg rejection,in a cuckoo host

The interactions between avian brood parasites and their hosts provide an informative and easy-to-handle system for studying coevolution.Avian brood parasitism reduces the reproductive success of hosts,and thus,hosts have evolved anti-parasitic strategies,such as rejecting parasitic eggs and adopting aggressive nest defense strategies,to avoid the cost brought on by brood parasitism.To test whether host anti-parasitic strategies are adjusted with the risk of being parasitized when the breeding seasons of brood parasites and hosts are not synchronous,we conducted a field experiment assessing nest defense and egg recognition behaviors of the Isabelline Shrike(Lanius isabellinus),a host of the Common Cuckoo(Cuculus canorus).In the local area,the host Isabelline Shrike begins to breed in April,whereas the summer migratory Common Cuckoo migrates to the local area in May and begins to lay parasitic eggs.Results showed that nest defense behaviors of the Isabelline Shrike increases significantly after cuckoo arrival,showing higher aggressiveness to cuckoo dummies,with no significant difference in attack rates among cuckoo,sparrowhawk and dove dummies,but their egg rejection did not change significantly.These results imply that Isabelline Shrikes may adjust their nest defense behavior,but not egg rejection behavior,with seasonality.

Can urban forests provide acoustic refuges for birds?Investigating the influence of vegetation structure and anthropogenic noise on bird sound diversity

As a crucial component of terrestrial ecosystems,urban forests play a pivotal role in protecting urban biodiversity by providing suitable habitats for acoustic spaces.Previous studies note that vegetation structure is a key factor influencing bird sounds in urban forests;hence,adjusting the frequency composition may be a strategy for birds to avoid anthropogenic noise to mask their songs.However,it is unknown whether the response mechanisms of bird vocalizations to vegetation structure remain consistent despite being impacted by anthropogenic noise.It was hypothesized that anthropogenic noise in urban forests occupies the low-frequency space of bird songs,leading to a possible reshaping of the acoustic niches of forests,and the vegetation structure of urban forests is the critical factor that shapes the acoustic space for bird vocalization.Passive acoustic monitoring in various urban forests was used to monitor natural and anthropogenic noises,and sounds were classified into three acoustic scenes(bird sounds,human sounds,and bird-human sounds)to determine interconnections between bird sounds,anthropogenic noise,and vegetation structure.Anthropogenic noise altered the acoustic niche of urban forests by intruding into the low-frequency space used by birds,and vegetation structures related to volume(trunk volume and branch volume)and density(number of branches and leaf area index)significantly impact the diversity of bird sounds.Our findings indicate that the response to low and high frequency signals to vegetation structure is distinct.By clarifying this relationship,our results contribute to understanding of how vegetation structure influences bird sounds in urban forests impacted by anthropogenic noise.

Habitat preferences and nest site selection by sympatric populations of Middle Spotted Woodpecker(Dendrocoptes medius) and Syrian Woodpecker(Dendrocopos syriacus) in natural mountain forests of Southwest Iran

We examined habitat preferences and nesting requirements of sympatric populations of Middle Spotted Woodpecker(Dendrocoptes medius) and Syrian Woodpecker(Dendrocopos syriacus).We carried out our study in 2015–2018 in natural mountain forests of Southwest Iran.We compared selected features of nesting,territory,and outside territory tree stands of the studied woodpeckers.The Middle Spotted Woodpecker occupied only oak forests,but the Syrian Woodpecker inhabited heterogenic forests that included the preferred tree of this species,the Mount Atlas Mastic.We recorded that in the breeding territories of the Middle Spotted Woodpecker,a greater area covered by tree crowns,as well as a larger number of trees,and a larger trunk basal area were observed in comparison to the territories occupied by the more plastic Syrian Woodpecker.Different habitat preferences demonstrated by both species could be a result of the selection of tree stands that provide the necessary food resources for each woodpecker species.Adaptation of Syrian Woodpecker to use heterogenic forest stands including tree species that produce fruits and as Mount Atlas Mastic trees,which likely allowed this species to colonise in Asia and Europe non-forest tree stands as orchards or gardens.Our results showed that poor tree condition and large tree trunk dimensions had a positive impact on the selection of nesting sites by both species.The presence of trees with large trunk dimensions was associated with multiple years of use of woodpecker breeding sites in the studied forests.Maintaining habitats in suitable condition for both studied woodpeckers can be achieved by preserving natural forests in the mountain regions of Iran.

Deterministic processes drive turnover-dominated beta diversity of breeding birds along the central Himalayan elevation gradient

Beta diversity,the variation of community composition among sites,bridges alpha and gamma diversity and can reveal the mechanisms of community assembly through applying distance-decay models and/or partitioning beta diversity into turnover and nestedness components from functional and phylogenetic perspectives.Mountains as the most natural experiment system provide good opportunities for exploring beta diversity patterns and the underlying ecological processes.Here,we simultaneously consider distance-decay models and multiple di-mensions of beta diversity to examine spatial variations of bird communities,and to evaluate the relative importance of niche-based and neutral community assembly mechanisms along a 3600-m elevational gradient in the central Himalayas,China.Our results showed that species turnover dominates taxonomic,functional,and phylogenetic beta diversity.We observed strongest evidence of spatial distance decays in taxonomic similarities of birds,followed by its phylogenetic and functional analogues.Turnover component was highest in taxonomic beta diversity,while nestedness component was highest in functional beta diversity.Further,all correlations of assemblage similarity with climatic distance were higher than that with spatial distances.Standardized values of overall taxonomic,functional,and phylogenetic beta diversity and their turnover components increase with increasing elevational distance,while the standardized values of taxonomic and phylogenetic nestedness decreased with increasing elevational distance.Our results highlighted the niche-based deterministic processes in shaping elevational bird diversity patterns that were determined by the relative roles of decreasing trend of environmental filtering and increasing trend of limiting similarity along elevation distances.

Bird Habitats in Urban Environments: A Case from an Urban Landfill in and around Tayba Al Hasanab Landfill, Khartoum, Sudan

Managed open landfill sites can serve as crucial feeding grounds for birds. Studies have demonstrated that garbage dumps offer favorable feeding habitats for various trophic generalist species, including storks and scavenger raptors. This study aimed to assess bird diversity and abundance in and around Tayba Al Hasanab Landfill, Khartoum. A bird census was conducted using block counts in January 2021. A questionnaire complemented field observations, and interviews were conducted with landfill authorities and waste collectors to gather information on bird availability, numbers, and diversity. During the block counts, 23 bird species were recorded inside and around the landfill. These species directly relied on food resources available at and around the landfill, belonging to 8 orders and 11 families. The four most abundant species foraging at the landfill were Sparrow House (Passer domesticus) with 97 individuals, Black kite (Milvus migrans) with 67 individuals, cattle egret (Bubulcus ibis) with 42 individuals, and Laughing Dove (Spilopelia senegalensis) with 36 individuals. This suggests that these species are the primary exploiters of food resources at the landfill. The results indicate that all species are considered least concerned except the Egyptian Vulture (Neophron percnopterus), which is classified as endangered. Most of the interviewed individuals reported seeing birds in the study area. The study recorded instances of dead birds, such as a white stork colliding and being electrocuted with a transition line observed at different sites along transmission lines near the landfill. Surveys around Tayba landfill need to be conducted to identify deadly power lines for replacement or implement possible mitigation measures on power lines running parallel and close to the Tayba landfills. The avian community foraging at the landfill displayed fluctuations in abundance and interspecific interactions across seasons. Given that the substantial influx of birds to landfills can pose various environmental challenges in urban settings, this study underscores the significance of examining the seasonal dynamics of bird communities concerning the location and management of landfills.

Kentish Plover(Charadrius alexandrinus) and Little Tern(Sternula albifrons) prefer shells for nesting:A field experiment

Shorebird populations are declining worldwide,mainly due to human disturbances and loss of coastal wetlands.However,supratidal habitats as saltpans could play a role in buffering human impact.Saltpans have shown to be important as feeding or breeding sites of some shorebird species.A potential conservation strategy to increase shorebird populations in saltpans is to manipulate the cues that birds use to select optimal breeding habitat.Here it is hypothesized that shorebirds are attracted to bivalve shells due to the advantages they offer.Following this hypothesis,we supplemented a restored saltpan in 2019 and 2021 with bivalve shells,expecting an increase in the number of breeding birds’ nests.More than 75% of Kentish Plover(Charadrius alexandrinus) and Little Tern(Sternula albifrons) nests were found in patches with shells in both years.The best model for both species indicates that the presence of shells is the factor that most correlates with the location of nests.The probability of choosing one place over another to settle their nest increases in areas with an abundance of shells,double in the case of the Kentish Plover and triple in the case of the Little Tern.The result of this study may constitute a valuable tool for attracting birds to restored saltpans and could contribute to the success of expensive restoration projects where time is usually a constraint.

Comprehensive Overview and Analytical Study on Automatic Bird Repellent Laser System for Crop Protection

Birds are a huge hazard to agriculture all around the world,causing harm to profitable field crops.Growers use a variety of techniques to keep them away,including visual,auditory,tactile,and olfactory deterrents. This study presents a comprehensive overview of current bird repellant approaches used in agricultural contexts,as well as potential new ways. The bird repellent techniques include Internet of Things technology,Deep Learning,Convolutional Neural Network,Unmanned Aerial Vehicles,Wireless Sensor Networks and Laser biotechnology. This study’s goal is to find and review about previous approach towards repellent of birds in the crop fields using various technologies.

Bird specimen number linked with species trait and climate niche breadth

Biological specimens are fundamental for taxonomy and flora/fauna research.More importantly,they also play crucial roles in recording environmental impacts on morphology and behavior,which is vital for biodiversity research and conservation.However,there are few systematic studies on the patterns and drivers of bird specimen number at regional scales.This study is the first attempt to examine the relationships between bird specimen number and species traits as well as climate niche breadth in China,aiming to answer two questions:1)how do species’temperature niche breadth and precipitation niche breadth influence specimen number?2)which trait is most associated with bird specimen number?The associations between bird specimen number and explanatory variables were examined using ordinary least squares,generalized linear models,phylogenetic generalized linear mixed models,and multiple comparisons.The results showed that Muscicapidae was the family with the highest specimen number,and Passeriformes was the order with the highest specimen number.Bird specimen number significantly increased with larger temperature niche breadth and precipitation niche breadth.Specimen number was also positively associated with geographic range size,habitat specificity,hunting vulnerability and clutch size,but negatively associated with body size.These findings suggest that future bird specimen collection should pay more attention to birds with limited ecological niches,large body sizes,and small clutch sizes.This research enhances the use of bird specimen data to study and preserve biodiversity.

Design and assembly of a nested imaging X-ray telescope for the Hot Universe Baryon Surveyor mission

The Hot Universe Baryon Surveyor (HUBS) mission will carry a nested X-ray telescope capable of observing an energy range from 0.5 keV to 2 keV to study hot baryon evolution. In this paper, we report the latest progress in the design and construction of nested X-ray telescopes which were designed to use a three-stage conic-approximation type assembly to simplify the manufacturing process. The mirror substrate is made using the thermal glass slumping method, with mirrors characterized by a root-mean-square roughness of 0.3 nm, with expected high reflectivity and good thermal stability. We also discuss methods of telescope construction and conduct a deformation analysis of the manufactured mirror. The in situ measurement system program is developed to guide the telescope assembly process.

Review of the Cretaceous avian diversity of Antarctica:a changing scenario for the evolution of early Neornithine birds

The worldwide record of Cretaceous Neornithes and Neornithine-like birds is both controversial and poorly understood.However,in recent years,the Antarctic continent has yielded a substantial number of Maastrichtian avian specimens,contributing significantly to our understanding of the early evolution of this group.Simultaneously,the keen interest and collaborative efforts of various paleornithologists have resulted in a wealth of knowledge,which we have thoroughly reviewed,updated,and discussed in the context of recent discoveries.