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Twenty eight cestodes were obtained from three little grebs, Podiceps rufficolis (Pallas) from Jhansi. Morphological studies of the cestodes revealed that they belonged to the genus, Variolepis Spasskii and Spasskaja, 1954 of the sub family Hymenolepidinae Perrier, 1897 family Hymenolepidae Ralliet and Henery, 1909 and regarded as n.sp Variolepis podicepsi.

Interspecific associations can arise when one species benefits from the presence or behavior of another, often during foraging. Here, we describe a previously undocumented behavioral interaction between pied‐billed grebes (Podilymbus podiceps) and an American alligator (Alligator mississippiensis) in a freshwater wetland in South Florida. Across a ~10‐min observation period, two grebes consistently followed behind an alligator, adjusting their speed and trajectory in concert with its movements and maintaining close spatial proximity. Although the grebes approached the alligator closely and repeatedly followed its trajectory, one bird exhibited a rapid escape response when the alligator turned and approached directly, indicating an active assessment of predation risk. This behavior aligns with nuclear follower foraging associations in other taxa, where follower species exploit prey flushed by a larger nuclear species. While grebes are not currently known to form such associations, this instance suggests that they may opportunistically do so, such as under favorable ecological conditions. The observation contributes to a growing body of work recognizing the ecological significance of facultative interspecific associations in shaping foraging behavior and predator–prey dynamics. We discuss possible explanations for the behavior and its placement within interspecific interaction frameworks.

Bycatch, the incidental capture of non-target species in fishing gear, has been recognised as the most significant global conservation threat affecting seabird species. Geographically, bycatch rates vary widely, depending on local fishing efforts, environmental features, and seabird community composition. Regional and local research is essential due to the complexity of accurately extrapolating general conclusions regarding the impacts of bycatch. Existing European bycatch research predominantly focuses on northern regions, leaving a significant knowledge gap regarding bycatch in the Mediterranean Sea. This work presents findings of wintering diving seabirds as bycatch of small-scale fisheries in a coastal area of the northern Adriatic Sea, based on data collected between 2021 and 2023. Seabird distribution varied along the depth profile. The bathymetric range between 3 m and 5 m was the most exploited by fishermen. Bycatch of seabirds was confirmed in the study area, with five species recorded, i.e. Black-necked Grebe Podiceps nigricollis, Red-throated Loon Gavia stellata, Black-throated Loon Gavia arctica, Mediterranean Shag Gulosus aristotelis desmarestii, and Great Crested Grebe Podiceps cristatus. Our results suggest that bathymetry likely plays a strong influence on bycatch occurrence. Incidental captures were not widespread but appeared concentrated in the shallowest depths <5 m and the range <2.5 m was identified as particularly susceptible due to the low associated fishing effort and the majority of bycatch events recorded. We estimate that between 46 and 108 birds were incidentally captured during the research period. This study identifies key factors shaping the areas of bycatch vulnerability and risk, proposing a spatial–temporal mitigation framework within Natura 2000 sites and highlighting the value of local stakeholders’ engagement.

Taolimiao‐Alashan Nur (T‐A Nur) is an important breeding site for the Relict Gulls (Larus relictus) and many other waterbirds. To understand the gut health status of rare bird species living there and to protect these bird species, this study analyzed the gut microbiota of four waterbird species, including Relict Gull (L. relictus), Black‐necked Grebe (Podiceps nigricollis), Greylag Goose (Anser anser), and Ruddy Shelduck (Tadorna ferruginea), using 16S rRNA high‐throughput sequencing. Results showed that the gut microbiota of Ruddy Shelduck had the highest α‐diversity, while Greylag Goose had the lowest. The composition of gut microbiota varied significantly among the bird species. The dominant bacterial phylum in the guts of Black‐necked Grebe, Greylag Goose, and Ruddy Shelduck was Firmicutes, while it was Pseudomonadota in Relict Gull. At the genus level, the dominant bacteria were Halomonas in Black‐necked Grebe, Escherichia‐Shigella in Relict Gull, Ligilactobacillus in Greylag Goose, and Enterococcus in Ruddy Shelduck. Correlation analysis revealed significant relationships among gut bacterial communities, suggesting that gut bacteria can regulate host metabolism and physiological state by their interactions. KEGG functional predictions indicated that gut microbiota were primarily involved in metabolism. The abundance of metabolism‐related microorganisms in Relict Gull was significantly lower than in Greylag Goose and Ruddy Shelduck, indicating that the gut microbiota of Greylag Goose and Ruddy Shelduck can provide stronger metabolic functions for the hosts. Additionally, microorganisms related to human diseases were more abundant in the gut of Relict Gull compared to Ruddy Shelduck and Black‐necked Grebe, and in Greylag Goose compared to Ruddy Shelduck. These findings suggested that the gut microbiota of birds in this area harbor some human pathogens, which warrants attention and preventive measures. This study analyzed the gut microbiota of four waterbird species including Relict Gull (Larus relictus), Black‐necked Grebe (Podiceps nigricollis), Greylag Goose (Anser anser), and Ruddy Shelduck (Tadorna ferruginea) using 16S rRNA high‐throughput sequencing in T‐A Nur in Erdos Relic Gull National Nature Reserve, Inner Mongolia, China to understand the survival status of rare bird species living there.

The increasing intensity of wetland stressors in the Upper Midwestern United States hastens the need to understand how matrix composition influences wetland bird occurrence and abundance. The optimal spatial scale for assessing species–habitat relationships is not always apparent, but may affect inference about wetland use and suitability. We developed occupancy and abundance models, accounting for imperfect detection, for 9 wetland bird species breeding in Minnesota. We evaluated land cover associations at 3 spatial scales (12.6 ha, 50.3 ha, and 4,000 ha), quantified speciesspecific sensitivity to wetland availability and matrix habitat composition (agricultural and developed land covers), and assessed ecoregional variation in occupancy and abundance. Amount of wetland cover was positively associated with occupancy of 89% of species and with abundance of 67% of species, but the spatial scale of support differed among species. American Bittern (Botaurus lentiginosus), Pied-billed Grebe (Podilymbus podiceps), and Wilson's Snipe (Gallinago delicata) in particular were negatively impacted by anthropogenic land uses within the surrounding matrix, indicating a need to shift wetland conservation planning from the site scale to the landscape scale to capture pertinent drivers of wetland bird habitat use. Mean expected occupancy across all species was greatest in the Prairie Pothole Region (PPR), suggesting that restoration efforts within this ecoregion are likely to maintain wetland bird diversity. However, given the minimal total wetland availability and predominantly agricultural matrix in the PPR, protecting wetlands and upland buffers in the Aspen Parklands or Boreal ecoregions may represent a better investment for agricultural-sensitive species such as American Bittern, Sandhill Crane (Antigone canadensis), and Wilson's Snipe. Our modeling approach provides a multi-species framework for identifying habitat management priorities; future applications at broader spatial extents can continue to improve wetland bird conservation in a region with high rates of wetland loss and degradation.

Secretive marsh birds (SMBs) are important indicator species of coastal wetlands but are difficult to detect and monitor. In coastal Louisiana, an important stronghold for these species, climate and hydrological models predict that freshwater and intermediate marshes will expand in the next 50 years, while brackish marshes will shrink. We used a multi-species Bayesian hierarchical occupancy model to estimate detection and occupancy probabilities for 11 SMB species in low and high saline marshes using data from automated recording units at 33 sites in southwestern Louisiana from February–June 2012. A quadratic effect of Julian date, but not minimum daily temperature nor precipitation affected detection of SMB species. King Rail ( Rallus elegans ), American Bittern ( Botaurus lentiginosus ), Common Gallinule ( Gallinula galeata ), and Pied-billed Grebe ( Podilymbus podiceps ) occupied mainly freshwater and intermediate marshes. Clapper Rail ( Rallus crepitans ), Seaside Sparrow ( Ammospiza maritima ), and Sora ( Porzana carolina ) predominantly occupied brackish and salt marshes. American Coot ( Fulica americana ), Purple Gallinule ( Porphyrio martinica ), Least Bittern ( Ixobrychus exilis ), and Marsh Wren ( Cistothorus palustris ) occupied both low and high saline marshes, showing flexibility that could maintain populations of these species as marsh salinities change in the future. If the current distribution of SMB species persists as marsh availability changes under future conditions, populations of the 4 species we found in low saline marshes may increase, whereas populations of at least 2 species found primarily in high saline marshes may decrease. Our modeling indicates that automatic recording units can produce comparable detection probabilities to other studies using traditional SMB sampling methods.

The stopovers provide food and habitat for migratory birds and therefore play an important role in facilitating the birds’ completion of their migration. The Hengduan Mountains, which have a complex topography, are located in a large corridor of the Central Asian migratory flyway, so the lakes along the Hengduan Mountains are important for waterbird migration. The existing research on lakes in the Hengduan Mountain area is mostly concentrated in the central and southern parts of the mountains, which proves that many lakes are wintering grounds for migrating birds. We wonder whether the ecological functions of lakes will change more with further elevation. With this question, we conducted four surveys for the seasonal bird survey in Mangcuo Lake, which is located in the northwest of the Hengduan Mountains, in Markam County of Qamdo City, between October 2019 and July 2020. We recorded a total of 6109 birds from 20 species of waterbirds, including 20 species of migratory waterbirds, accounting for 100% of all bird species. The diversity and richness of waterbirds in Mangtso Lake is shown as spring > autumn ≥, summer > winter, with no waterbirds in winter. The black-necked grebe (Podiceps nigricollis), great crested grebe (Podiceps cristatus), bar-headed goose (Anser indicus), and ruddy shelduck (Tadorna ferruginea) were the dominant species in the waterbird community. The highest number of waterbird species and total individuals were found in the transition zone between the marsh wetlands and lakes, and the number of waterbird species differed significantly among habitats (X2 = 14.405, p = 0.000), with habitat complexity being an important factor influencing waterfowl abundance and distribution. The IUCN Red-listed species recorded include the black-necked crane (Grus nigricollis), painted stork (Mycteria leucocephala), and common pochard (Aythya ferina). By comparing with other lakes in Hengduan Mountain, we found that the ecological functions of the plateau lakes in the Hengduan Mountains, to support the life histories of migrating waterbirds, are gradually transforming as the altitude rises, and can be divided into approximately three levels, with the first level of Qionghai, Chenghai, Erhai, and Jianhu at altitudes of 1500–2200 m being the most important ecological function in terms of providing wintering grounds for migrating birds. The second layer, at an altitude of 2400–3300 m, includes Lashihai, Lugu Lake, and Napahai, which are not only wintering wetlands for migratory birds but also important stopover sites. The third layer of Mangcuo Lake, which is above 4000 m above sea level, provides a breeding ground for some migratory waterbirds in summer and a migratory resting place for migratory waterbirds in spring and autumn. We advocate for the importance of Mangcuo Lake in the alpine region along the central Asian flyway, as well as emerging nature conservation action that was previously neglected.

After centuries of wetland modification, wetland-dependent wildlife are of high conservation concern. Particularly important are secretive marsh birds, a cryptic and understudied guild of wetland-dependent birds, many of which have experienced population declines concurrent with anthropogenic modification of wetlands. We used point-based sampling to investigate densities and habitat associations of secretive marsh birds at multiple spatial scales in the Prairie Pothole Region of North Dakota. We focused on five species for modeling. The most abundant species was Virginia Rail ( Rallus limicola ; 0.20 individual -ha SE = 0.04), followed by Sora ( Porzana carolina ; 0.13 individual -ha SE = 0.02), American Coot ( Fulica americana ; 0.08 individual -ha SE = 0.02), American Bittern ( Botaurus lentiginosis ; 0.07 individual -ha SE = 0.03), and Pied-billed Grebe ( Podilymbus podiceps ; 0.06 individual -ha SE = 0.01). Densities of all species were best explained by multi-scale models. Despite a few commonalities, secretive marsh birds have diverse habitat requirements and models suggest species-specific wetland complex management will likely be most effective. This information provides a baseline for species with previously unknown densities and informs conservation actions and policy for secretive marsh birds in the northern Great Plains.

Despite many decades of studies, our knowledge of skeletal development in birds is limited in many aspects. One of them is the development of the vertebral column. For many years it was widely believed that the column ossifies anteroposteriorly. However, later studies indicated that such a pattern is not universal in birds and in many groups the ossification starts in the thoracic rather than cervical region. Recent analyses suggest that two loci, located in the cervical and thoracic vertebrae, were ancestrally present in birds. However, the data on skeletal development are very scarce in the Neoaves, a clade that includes approximately 95% of extant species. We review the available information about the vertebral column development in birds and describe the ossification pattern in three neoavians, the domestic pigeon (Columba livia domestica), the great crested grebe (Podiceps cristatus) and the red-necked grebe (Podiceps grisegena). In P. cristatus, the vertebral column starts ossifying in the thoracic region. The second locus is present in the cervical vertebrae. In the pigeon, the cervical vertebrae ossify before the thoracics, but both the thoracic and cervical loci are present. Our ancestral state reconstructions confirm that both these loci were ancestrally present in birds, but the thoracic locus was later lost in psittacopasserans and at least some galloanserans.

Estuarine waterbodies typically support diverse and abundant waterbird communities. However, global environmental degradation as a result of anthropogenic activities is leading to species level changes in biodiversity, with top predators such as piscivorous waterbirds being particularly vulnerable to ecosystem changes. The study aimed to document long-term spatial and temporal patterns of abundance of piscivorous and scavenging waterbirds in the Wilderness Lakes Complex (WLC) in the Garden Route National Park, South Africa, and where possible identify potential causes for observed trends. The abundance of waterbirds on these wetlands was determined biannually from 1992 to 2019, with counts conducted from a boat following a standardised route. Historical waterbird abundance data from the 1980s were also used to describe long-term abundance changes. Eight of the species exhibited seasonal variability in abundance with most, excluding Common Tern Sterna hirundo, being more abundant in winter. Substantial changes occurred in the abundance of several species over the four-decade study period, notably increases in Cape Cormorant Phalacrocorax capensis and Great Crested Grebe Podiceps cristatus, and decreases in Common Tern and Black-necked Grebe Podiceps nigricollis. Long-term abundance trends indicate a combination of declining, increasing, and stable populations. Although some species have undergone contrasting abundance changes on different waterbodies in the WLC the dominant pattern was a similar direction of change on most or all waterbodies and in different seasons. Local reasons for changes probably include loss of sandbanks, changing prey availability, and the absence of recreational disturbance on some waterbodies.Conservation implicationsDrivers of changes in the abundances of piscivores are likely to be multifaceted, functioning on multiple spatial and temporal scales, and affecting different species in different ways. Recommended local corrective actions include managing emergent macrophyte encroachment on sandbanks, reducing recreational disturbance, managing processes affecting indigenous fish stocks, and protecting nesting sites.