Spatial and taxonomic coverage of international migratory bird agreements

The Pliocene-Pleistocene transition had dual effects on North American migratory bird speciation

The coastal areas of Bangladesh are enriched with migratory avian species but the actual status of birds was unknown, particularly in the south-central coastal region of the country. A yearlong (June 2023 to May 2024) direct field observation-based study was conducted to unfold the present status of the migratory avifauna in three protected areas (Kuakata National Park, Tangragiri Wildlife Sanctuary, and Sonarchar Wildlife Sanctuary). In this study, a total of 85 migratory bird species were recorded under 10 orders and 22 families. Individuals of wetland dependent migratory birds were higher than other bird species. Sonarchar Wildlife Sanctuary (SWS) had the highest number of bird species and individuals (70 species; n = 3618 individuals) with the highest diversity index values (H’ = 3.135, Ds = 0.9257) compared to two other sites. Significant variations among migratory avian communities were found among the three study sites as indicated by the Analysis of Similarity (ANOSIM) test (R = 0.168, P < 0.001) in the non-metric multidimensional plot (NMDs). Among the migratory bird species, Charadrius dubius (14.75%), Anas crecca (14.33%), Threskiornis melanocephalus (11.69%), Actitis hypoleucos 8.47%), Vanellus cinereus (6.75%) were the most abundant. Population abundance was higher for the occurrence of the wetland dependent migratory bird species in the study area. Avian community composition of migratory species showed uneven distribution in the rank abundance curve. Across the three study sites, the majority of the migratory bird species exhibited clumped distribution patterns, followed by regular and random distribution patterns. A total of 37 (45.12%) species of migratory birds were found to use the coastline as their microhabitat. Unplanned fishing, tourism, expansion of agricultural land, hunting, and pollution were identified as major threats to the migratory bird species in the study area. This study suggests community-based conservation measures are essential for the proper conservation of the migratory birds. Dhaka Univ. J. Biol. Sci. 34(1): 155-173, 2025 (January)

Mangrove forests throughout the world are recognized as stopover sites by many migratory birds – including waders – as they contain ample food resources such as invertebrates, fruits, and flowers that are beneficial to most birds. In connection, the Talabong Mangrove Forest located in Bais, Negros Oriental, Philippines is recognized as a wildlife sanctuary, but no recent data on birds could supplement this. Thus, this study aims to assess the distribution patterns of migratory and resident birds in the said site during the southward migration which encompasses both wet and dry seasons. Also, the investigation determines whether Talabong mangrove could function as a stopover site for migratory birds. To examine the community structure, the populations of resident and migratory bird species were assessed for species composition, diversity, density, and abundance in three sampling periods: pre-migration, migration, and post-migration. The line transects and point-count methods were employed with four transect lines laid out on the study site. Each line stretched a kilometer long with a 250-m interval with five points for point-counting and was visited on each sampling period. Points were marked for a consistent sampling. For each sampling period, results showed that the birds’ abundance, diversity, and density remained consistently high throughout each sampling. Specifically, the species composition and the number of resident birds did not seem to alter and remained high as well. On the other hand, migrants had an abrupt increase during migration sampling and decreased towards the end. But similarity analyses suggest species composition remained approximately similar for the migrants. The results showed that Talabong mangrove forest contained some migratory species – making it a decent stopover site, although not as many migrants as in other protected mangroves and wetlands in the Philippines. The resident birds occupying the site may also have served as cues for the migrants.

The saga of migratory birds

Consequences of seasonal migration : How goose relocation strategies influence infection prevalence and pathogen dispersal

In April 2011, the British Ornithologist’s Union’s annual conference took place at the University of Leicester. The theme of this year’s conference was the ecology and conservation of migratory birds, and talks ranged from those focussed on either breeding, migration or wintering ecology, to those linking two or more of these and trying to build a more complete picture of the complex problems faced by long distance migrants. Talks also covered recent technological advances, which are increasingly allowing us intriguing new insights, particularly into the seasonal movements and wintering areas of some of the most declining species. Finally, talks examined the policy challenges associated with protecting migratory species and how best to tackle flyway-scale conservation of migratory birds.

Off peak

The major source of several influenza viruses in other species are aquatic birds. Long distances travel is carried out by many migratory bird species between their breeding grounds and non-breeding areas. These migratory birds as well as wild birds are considered as reservoirs of majority of influenza A viruses. The geospatial analysis of the pathways of migratory birds present in different geographical locations will throw further light on their role in influenza virus epidemiology. The influenza virus dynamics among migratory wild birds and mammals including humans are closely linked as is evident from H1N1 spread. It is important to note that the migratory water fowls play a negative role as far as the economic benefit out of poultry industry is concerned and imposes threat to lives of human as well, because of their capability to transmit the highly pathogenic avian influenza (HPAI) virus across the continents. Interestingly, several species of familiar songbirds or perching birds act as bridge species and has a possible role in transmitting the H5N1 AI to or from wild habitat. Surveillance and tracking of migratory and resident wild birds, utilisation of ornithological expertise, and analysis of the H5N1 ecology are needed for increasing our knowledge about strain- or host-specific pathogenecity, degree of shedding of virus and the routes of transmission between wild birds. In this aspect, it is quiet noteworthy that 13 membered International Scientific Task Force including UN bodies, wildlife treaties and specialist intergovernmental as well as non-governmental organizations have been created on the ground of various scientific studies concerning the role of migratory birds as potential transmitter of H5N1 subtype of Highly Pathogenic Avian Influenza (HPAI) virus.

BackgroundCampylobacter species (spp.) are one of the most important zoonotic bacteria possessing potential hazards for animal and human health worldwide. Migratory birds are implicated as significant carriers for microbes and a play very important role in the dissemination of Campylobacter to broiler chickens and their environment. The purpose of this investigation was to detect the prevalence, antibiotic resistant patterns, virulence and diversity of pathogenic Campylobacter spp. in 7 migratory bird species (Northern shoveler, Common pochard, Common teal, Northern pintail, Eared Grebe, Great Crested Grebe and Garganey) and broiler chickens that were collected from broiler poultry farms and live bird markets.ResultsThe prevalence of Campylobacter was 12.5% (25/200), of which 15% (15/100) was recovered from 5 migratory bird species only and 10% (10/100) from broiler chickens. At the level of migratory birds, eight isolates (53.3%) were Campylobacter jejuni (C. jejuni) and 7 isolates (46.7%) were Campylobacter coli (C. coli) meanwhile, in broiler chickens C. jejuni and C. coli were 50% (5/10) for each. All isolated strains had phenotypic resistance to doxycycline, while all of the isolates were susceptible to amikacin. The multidrug resistance to three, four or five antimicrobial classes was found in 72% (18/25) of the isolated strains. The multiantibiotic resistance index between the examined isolates was 0.22–0.77, with 10 antibiotic resistance patterns. The virulence of isolated Campylobacter strains (from both migratory birds and broiler chicken birds) was detected by targeting the VirB11, ciaB and iam genes which were recorded at 16%, 52% and 100%, respectively. Additionally, 100% and 84% of the antibiotic resistance genes were identified as tetA and BlaOXA-61, respectively.ConclusionsThe results of this study revealed the diversity between all the isolated strains from migratory birds and their similarity to broiler chicken isolates. The findings of the present study highlight the impact of migratory birds visiting Egypt and other countries on pathogenic Campylobacter spp. carrying pathogenic virulence and resistance genes, necessitating the application of biosecurity measures to prevent migratory birds from entering farms during their migration period.

AimWe compared the parasite assemblages of over‐wintering migratory birds and permanent residents on the wintering grounds. We determined whether parasite sharing between migratory and resident birds is influenced by host phylogenetic relatedness. We then inferred whether migratory birds transport haemosporidian parasite lineages between the breeding and wintering grounds.LocationSierra de Bahoruco National Park, Dominican Republic, Hispaniola.TaxaMigratory and resident birds (primarily Aves: Passeriformes) and their haemosporidian parasites (order Haemosporida, Plasmodium, Haemoproteus and Parahaemoproteus).MethodsWe used mist nets to capture birds in thorn scrub, broadleaf dry forests and pine forests during midwinter. We used molecular methods to recognize haemosporidian parasites in blood samples, and genotyped infections based on the nucleotide differences in a region of the parasite cytochrome b gene.Results and Main ConclusionWe identified 505 infections by 32 haemosporidian parasite lineages in 1,780 blood samples from 37 resident species, and in 901 blood samples from 14 overwintering migratory species, over five years at the same sites. Infection prevalence varied among migratory species from zero to 13%, whereas infection prevalence among resident species ranged up to 77%. Host relatedness did not predict parasite assemblage similarity. We discuss four hypotheses for the rarity of haemosporidian infections in migratory birds during winter, and for the infrequency of parasite sharing between migratory and resident birds: (a) relative abundance and host preferences of dipteran vectors lower parasite transmission to migratory birds; (b) parasite lineages adapted to infect endemic Caribbean hosts are unable to infect migratory species; (c) the physiology of migratory birds after migration and during winter reduces parasite survival; and (d) infected individuals suffer more pronounced mortality rates during migration. We highlight the link between host–parasite coevolution and the physiological adaptations associated with avian seasonal migration.

AimDuring the Plio‐Pleistocene, glacial cycles shaped Northern Hemisphere species' distributions causing range contractions followed by interglacial expansions. In migratory bird species, climatic changes could result in a rapid reshaping of their ranges and/or migratory behaviour, given their dispersal capacity. In this context, it has been suggested that long‐distance North American migratory species could have lost their migratory condition during cold glacial periods, regaining it later in warmer periods. Here, we explored this hypothesis for extant Eurasian‐African migratory bird species.LocationEurasia and Africa.TaxonMigratory birds.MethodsWe used Species Distribution Models (SDMs) to infer the present and Last Glacial Maximum (LGM) potential distribution of 81 Trans‐Saharan migratory bird species, and reviewed the available bird fossil record for the Plio‐Pleistocene covering Eurasia and Africa.ResultsSDMs predicted a reduction of the northern edges of the breeding ranges during the LGM compared to the present. However, the current wintering ranges were somewhat similar in the Pleistocene, with the Saharan desert belt gap being always present through time, not overlapping with their breeding ranges. The fossil record also supports the persistence of migration during the Pleistocene.Main conclusionsThe palaeo‐distributions and absence of medullary bone in Pleistocene fossils from wintering Euro‐African migratory species confirm that they were migratory, providing independent support for our models. The hypothesis of the loss of migratory behaviour in these species during the Pleistocene is not supported. Furthermore, the differences in migratory species from Eurasia‐Africa and the Americas can be influenced by geographical differences, the persistence of the Mediterranean basin as climatically suitable area during glaciations and the existence of the Saharan belt.

BackgroundThe range of vertebrate hosts on which species of mosquito blood-feed is an important parameter for identifying potential vectors and in assessing the risk of incursion and establishment of vector-borne pathogens. In the United Kingdom, studies of mosquito host range have collected relatively few specimens and used techniques that could only broadly identify host species. This study conducted intensive collection and analysis of mosquitoes from a grazing marsh environment in southeast England. This site provides extensive wetland habitat for resident and migratory birds and has abundant human nuisance biting mosquitoes. The aim was to identify the blood-feeding patterns of mosquito species present at the site which could contribute to the transmission of pathogens.MethodsTwice-weekly collections of mosquitoes were made from Elmley Nature Reserve, Kent, between June and October 2014. Mosquitoes were collected using resting boxes, by aspiration from man-made structures and using a Mosquito Magnet Pro baited with 1-octen-3-ol. Blood-fed specimens were classified according to the degree of blood meal digestion using the Sella scale and vertebrate origin determined using sequencing of a fragment of the mitochondrial cytochrome C oxidase subunit I gene. Mosquitoes that were morphologically cryptic were identified to species level using multiplex PCR and sequencing methods.ResultsA total of 20,666 mosquitoes of 11 species were collected, and 2,159 (10.4%) were blood-fed (Sella scale II-VI); of these 1,341 blood-fed specimens were selected for blood meal analysis. Vertebrate origin was successfully identified in 964 specimens (72%). Collections of blood-fed individuals were dominated by Anopheles maculipennis complex (73.5%), Culiseta annulata (21.2%) and Culex pipiens form pipiens (10.4%). Nineteen vertebrate hosts comprising five mammals and 14 birds were identified as hosts for mosquitoes, including two migratory bird species. Feeding on birds by Culex modestus and Anopheles atroparvus populations in England was demonstrated.ConclusionsThis study expands the vertebrate host range of mosquitoes in the Thames estuary region of the UK. Feeding on both resident and migratory bird species by potential arbovirus vectors including Cx. pipiens f. pipiens and Cx. modestus indicates the potential for enzootic transmission of an introduced arbovirus between migratory and local bird species by native mosquito species.

An estimated 19% of the world's 9,856 extant bird species are migratory, including some 1,600 species of land- and waterbirds. In 2008, 11% of migratory land- and waterbirds were classed by BirdLife International as threatened or near-threatened on the IUCN Red List. Red List indices show that these migrants have become more threatened since 1988, with 33 species deteriorating and just six improving in status. There is also increasing evidence of regional declines. Population trend data show that more Nearctic–Neotropical migrants have declined than increased in North America since the 1980s, and more Palearctic–Afrotropical migrants breeding in Europe declined than increased during 1970–2000. Reviews of the status of migratory raptors show unfavourable conservation status for 51% of species in the African–Eurasian region (in 2005), and 33% of species in Central, South and East Asia (in 2007). Land-use change owing to agriculture is the most frequently cited threat affecting nearly 80% of all threatened and near-threatened species. However, while agricultural intensification on the breeding grounds is often proposed as the major driver of declines in Palearctic–Afrotropical migrants, some species appear to be limited by the quantity and quality of available habitat in non-breeding areas, notably the drylands of tropical Africa. Forest fragmentation in breeding areas has contributed to the declines of Nearctic–Neotropical migrants with deforestation in non-breeding areas another possible factor. Infrastructure development including wind turbines, cables, towers and masts can also be a threat. Over-harvesting and persecution remain serious threats, particularly at key migration locations. Climate change is affecting birds already, is expected to exacerbate all these pressures, and may also increase competition between migratory and non-migratory species. The conservation of migratory birds thus requires a multitude of approaches. Many migratory birds require effective management of their critical sites, and Important Bird Areas (IBAs) provide an important foundation for such action; however to function effectively in conserving migratory species, IBAs need to be protected and the coherence of the network requires regular review. Since many migratory species (c. 55%) are widely dispersed across their breeding or non-breeding ranges, it is essential to address the human-induced changes at the wider landscape scale, a very considerable challenge. Efforts to conserve migratory birds in one part of the range are less effective if unaddressed threats are reducing these species' populations and habitats elsewhere. International collaboration and coordinated action along migration flyways as a whole are thus key elements in any strategy for the conservation of migratory birds.

BackgroundWest Nile virus (WNV) and Usutu virus (USUV), both belonging to the genus Flavivirus, are emerging in Italy as important human and animal pathogens. Migratory birds are involved in the spread of Flaviviruses over long distances, particularly from Africa to Europe. Once introduced, these viruses can be further be dispersed by short-distance migratory and resident bird species. Thus far, there is still a considerable knowledge gap on the role played by different bird species in the ecology and transmission mechanisms of these viruses. The Region of Trentino-Alto Adige (north-eastern Italy) is located on the migratory route of many of the short- and long-distance migratory birds that cross the Alps, connecting northern Europe and western Asia with southern Europe and Africa. Until now, only a silent circulation of WNV and USUV within the territory of the Province of Trento has been confirmed by serological screening, whilst no cases of infected humans or animals have so far been reported. However, continuous spillover events of both viruses have been reported in neighbouring Regions. The aim of this study was to monitor the circulation of WNV and USUV in Trentino-Alto Adige, in order to detect if active virus shedding occurs in migratory birds captured during their seasonal movements and to evaluate the role that different bird species could play in the spreading of these viruses.MethodsWe carried out a biomolecular survey on oral and cloacal swabs collected from migratory birds during seasonal migrations. Birds belonging to 18 transaharian and 21 intrapaleartic species were examined during spring (n = 176) and autumn (n = 146), and were tested using a generic nested-PCR.ResultsAll samples tested negative for Flaviviruses. The possible causes of unapparent shedding, along with ecological and epidemiological implications are discussed.ConclusionsThe lack of detection of active virus shedding in these bird species does not exclude the circulation of these viruses within the Trentino-Alto Adige region, as reported in previous studies. The possible ecological implications are discussed.

The climate on earth is changing drastically. Some birds adapt to changing climate patterns while others are on the verge of extinction. Migratory birds provide food to other wildlife and help in controlling pests and pollinating birds. The climate change and global warming we are experiencing is human induced, which makes it difficult to cope up for the birds. Other than global warming, pollution, increasing population, depletion of natural resources, sea level shifts, lower water tables, higher draught frequency, all collectively impact habitat destruction which affect migration of birds. Short distance migratory birds are less affected by changing climate patterns, while long distance birds are struggling to keep up with their migration rhythm. During migration, birds need to refuel to continue their long journey. Habitat loss because of increasing temperatures causes flooding, drought, or desertification. Change in topography of landscape can affect migration route and food resources and can make bird feel exhausted at the end of the journey. Extreme weathers and intense storms can kill birds during migration due to thermals, and water and food scarcity. Migratory birds use coastal wetlands as resting area and for foraging. Climate change in Sahel region is an example of loss of habitat and resulted in desertification and depletion of resources. This also affected rainfall and made the climate worse for migratory birds. Similarly, Sahara expansion and habitat loss has made it difficult for African Eurasian migratory birds to cross Sahara region because of no possibility of resting. Climate change is also affecting vegetation structure of Siberian region. The rise in temperature has caused forest expansion in the region to Tundra. Researchers have reported that forest expansion in Siberian region has caused loss of breeding habitat for more than 90% species of arctic goose. The climate change is disturbing ecological balance. Some migratory birds cancel their journey and prefer to stay in their breeding places because of inhospitable stop over sites or changed weather pattern. This also affects food web for other animals and insects. Actions should be taken for successful breeding and survival of these birds. To fight climate change, more awareness should be given to reduce pollution and carbon emissions. Government should also take important steps to reduce the energy use and develop more sustainable future to conserve migratory birds and their habitat. Bird conservation programs should establish and protect migratory areas for birds. Migratory bird species and all other species on planet earth should be protected. This is the only they will perish.