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Bordoibam-Bilmukh is a small wetland located at the boundary of the Dhemaji and Lakhimpur districts of Assam, India that provides shelter and breeding ground to many resident and migratory birds. A survey was conducted between October 2022 and March 2024 on the avian diversity of Bordoibam-Bilmukh Bird Sanctuary. A total of 47 bird species under 16 orders and 29 families were recorded during the survey. Order Passeriformes, recorded with the highest number of avian species (15). Among the families, the highest number of species (5) was recorded under Ardeidae. Out of all the species recorded, three species, viz., Brown Shrike, Citrine Wagtail, and White Wagtail were winter migratory; one species, the Lesser Kestrel, was summer migratory, and the remaining 43 were resident species. Besides, two species, viz., Lesser Adjutant and Greater Adjutant are listed as 'Near Threatened' species on the IUCN Red List. Comparing the avian diversity from 1997 to 2024, a decline in the number of avian species from 167 (as per the 1997 record) to 47 (as per the present study) has been observed in the sanctuary. Various anthropogenic activities such as habitat destruction and disturbance, hunting of birds, are the major causes of the decline of avian diversity. For future species diversity restoration in the sanctuary, these negative anthropogenic activities should be addressed immediately for conservation strategies. [ABSTRACT FROM AUTHOR]

The Vaal River catchment drains the largest and most populated industrial and mining region in Southern Africa. Heron, ibis, cormorant, egrets, and darter eggs, representing three habitats and four feeding guilds, were collected at four locations in 2009/10 to identify hotspots and hazards associated with persistent organic pollutants (POPs). The POPs included 21 organochlorine pesticides, five polybrominated diphenyl ether (PBDE) classes, 18 polychlorinated biphenyls (PCBs including six non-dioxin-like PCBs; NDL-PCB), and 12 dioxin-like PCBs (DL-PCBs), 17 polychlorinated dibenzo-p-dioxins and dibenzo-p-furans (PCDD/Fs), and perfluorooctane sulfonate (PFOS). Aquatic predators had higher PFOS and PCDD/F concentrations, while PCBs dominated in terrestrial eggs. Organochlorine pesticides, PBDEs, and PCBs were strongly associated with eggs from the industrial regions, while PCDD/F concentrations were evenly distributed. PCDD/F and PCB toxic equivalency quotient concentrations were low with no adverse effects expected. PFOS peaked at Bloemhof Dam with a maximum of 2300 ng/g wm in an African Darter egg, indicating an unexpected PFOS hotspot, the source of which is unknown. Despite order of differences in compound class concentrations, there was no association with egg size. To the best of our knowledge, this is the only study that analysed all 2010 POPs in bird eggs on a large geographic scale. This study highlighted the importance of multi-species studies sampling from multiple locations to assess the risk that POPs pose to avian populations as hotspots and species at risk may be missed by studies looking at one or few species. [ABSTRACT FROM AUTHOR]

ABSTRACT Herons (Ardeidae), an important group in wetland ecosystems, have a particularly strong relationship with humans. However, their predation on farmed fish and shrimp in aquafarms can lead to economic losses for local fish farmers. Consequently, notable conflicts arise between fish farmers and herons. Fish farmers adopt various measures to deter herons from “stealing” their fish; however, there is limited research on the behavioral responses of herons under such pressures of human disturbance. Flight initiation distance (FID) is an important manifestation of avian anti‐predation behavior and serves as an indicator of birds' tolerance to human disturbance. This study investigated the potential variations in tolerance to human disturbance between the little egret (Egretta garzetta) and the Chinese pond heron (Ardeola bacchus) in “stealing” environments (aquafarm environments) and non‐aquafarm environments in Hainan and Guangdong Provinces, south China, using FID as an indicator. Herons in aquafarm environments were less tolerant (having longer FIDs) to human disturbance compared to herons in non‐aquafarm environments. The main cause of this phenomenon could be the harsh deterrents used by humans to prevent herons from “stealing” fish. These deterrents increase the predation risk for herons when “stealing” in aquafarms, causing them to exhibit less tolerance to human disturbance. Our study increases understanding of the behavioral response patterns of herons in human–wildlife conflicts and provides valuable insights for more scientific and rational management and protection of Ardeidae species.

ABSTRACT Resource partitioning is crucial for the coexistence of colonial herons, as it allows multiple species to share the same habitat while minimising competition. This study took advantage of a natural experiment in 2006 and 2007 when Black‐crowned Night Herons were prevented from breeding at Lake Fetzara in the first year due to the presence of a feral cat. This event provided valuable insight into the spatial and temporal dynamics of nest site selection among coexisting heron species, which consisted of Cattle Egrets (Ardea ibis), Little Egrets (Egretta garzetta) and Squacco Herons (Ardeola ralloides). After the cat was removed, egg‐laying began in the core areas of the colony and gradually spread to the periphery. Species that initiated nesting early selected mid‐elevation sites near the tree trunk, which likely offered protection from both ground and aerial predators, while also providing some shielding from solar radiation and strong winds. These early selected sites featured larger branches, which conferred greater nest stability. Vertical stratification was evident among the heron species; however, contrary to long‐standing assumptions, it was not directly related to body size. Both vertical and horizontal stratification were observed, with nests progressively moving higher and further from the tree trunk as the breeding season advanced. The following year, Black‐crowned Night Herons displaced other species to lower heights and positions further from the trunk, highlighting the significant influence of interspecific interactions on nest site selection. This study underscores the complex interplay between nest site selection, biotic interactions and abiotic factors in heron colonies, emphasising the importance of resource partitioning in maintaining species coexistence in densely populated breeding sites.

Studies on the distribution characteristics and environmental relevance of per- and polyfluoroalkyl substances (PFAS) in waterbird feathers are scarce. In the present study, the concentrations of twenty-three PFAS in the remiges, coverts, body, down, and tail feathers of three common species of Ardeidae (little egret, grey heron, and Chinese pond-heron) in Poyang Lake were investigated. The total PFAS concentrations in the pinna and scapus were 38 – 42 ng/g dry weight (dw) and 21 – 38 ng/g dw, respectively; long-chain C9–14 perfluorocarboxylic acids were abundant in all feathers. Most PFAS accumulated in the pinna; however, perfluorohexane sulfonic acid and perfluorooctane sulfonamide were predominant in the scapus. The PFAS concentrations were higher in the tail and flight feathers than in the cover and body feathers. Furthermore, the concentrations of PFAS in waterbird feathers were comparable with those in fish and higher than those in benthic invertebrates, all of which originated from Poyang Lake. The PFAS profiles in feathers were significantly and positively correlated with those in fish (r > 0.71) and benthos (r > 0.43). These results suggest that waterbird feather is a suitable biomonitor of PFAS contamination in regional freshwater ecosystems.

Heron colonies are dynamic components of wetlands. Therefore, their systematic monitoring is important for the management of both birds and wetlands. During the period 1988–2018, we counted breeding pairs of seven colonial breeding heron species at 65 colonies across 37 wetlands in Greece. We considered as annual variables of a population: (a) years since 1988, (b) Natura 2000 network inclusion, (c) protected area management authority overseeing, (d) wetland type (new or restored), and (e) new colonies (established after 2003). The Cattle Egret Bubulcus ibis and the Squacco Heron Ardeola ralloides had a positive breeding population trend. The Black-crowned Night Heron Nycticorax nycticorax, Little Egret Egretta garzetta, and Grey Heron Ardea cinerea had a negative trend, while the Purple Heron Ardea purpurea population was stable. The Great White Egret Ardea alba bred sporadically at only a few sites which precluded the evaluation of its population trend. The informative population variables differed among species, even of those at the same colony, which suggests trends are also affected by conditions at wintering grounds. The study highlights the need for the systematic monitoring of heron colonies and the protection of foraging/breeding areas in order to reverse the observed negative population trends.

Many marsh birds, like bitterns or rails, are endangered species inhabiting only natural habitats and dependent exclusively on different types of emergent vegetation. In a changing environment, some of these habitat specialists are becoming more flexible, shifting their preferences by colonizing man-made habitats. We studied habitat selection by Little Bitterns (Ixobrychus minutus minutus) breeding in a fishpond landscape in south-eastern Poland. Applying a large-scale research approach, we examined several habitat features in order to predict the presence of the Little Bittern from a direct comparison of areas with and without breeding birds. Partial least squares (PLS) regression identified two components of several variables that explained 53% of the variation in the presence of the Little Bittern in a fishpond habitat. The occurrence of the Little Bittern was limited to high-quality patches of emergent vegetation, the height, width and area of which were all significantly greater in the area with breeding birds than in unoccupied patches. Patches with a highly variable edge line in the form of fringes or indentations were less favoured. An optimal water level throughout the breeding season was crucial for nest-site selection and ensured access to food. The heterogeneity of the pond dykes and pond canals positively predicted the presence of the Little Bittern by creating potential nesting or foraging sites. Interestingly, the proportion of bulrushes (Typha spp.) in the emergent vegetation patches had a negative effect on the presence of the Little Bittern. The main threat to this habitat‐sensitive species was the cutting of perennial emergent vegetation, in particular the Common Reed (Phragmites australis). [ABSTRACT FROM AUTHOR]

Simple Summary: We studied the nesting population trends of the colonially nesting heron species in Greece from 1988 to 2018, aiming to identify drivers of these trends and thus inform colony/wetland conservation measures. Two species (Cattle Egret and Squacco Heron) had a positive trend, while three species (Black-crowned Night Heron, Little Egret and Grey Heron) had a negative trend. The Purple Heron presented a stable trend. Our results suggest that: (a) The Natura 2000 network and the operation of the protected areas Management Authorities have positively affected heron species nesting population trend or range expansion, (b) national wetland restoration efforts have facilitated the expansion of most heron species' breeding range via the establishment of new colonies, and (c) colonies located outside protected areas were—especially in the case of the Grey Heron—most likely to have a declining nesting population trend. The drivers behind the observed population trends differed among species, even among those sharing the same breeding sites. This suggests that the nesting population trends could be due to ecological changes at both the breeding and at the wintering sites. Our results emphasize the importance of continuing wetland restoration efforts, developing heron-friendly farming practices, and adopting a systematic nationwide survey of colonies. Heron colonies are dynamic components of wetlands. Therefore, their systematic monitoring is important for the management of both birds and wetlands. During the period 1988–2018, we counted breeding pairs of seven colonial breeding heron species at 65 colonies across 37 wetlands in Greece. We considered as annual variables of a population: (a) years since 1988, (b) Natura 2000 network inclusion, (c) protected area management authority overseeing, (d) wetland type (new or restored), and (e) new colonies (established after 2003). The Cattle Egret Bubulcus ibis and the Squacco Heron Ardeola ralloides had a positive breeding population trend. The Black-crowned Night Heron Nycticorax nycticorax, Little Egret Egretta garzetta, and Grey Heron Ardea cinerea had a negative trend, while the Purple Heron Ardea purpurea population was stable. The Great White Egret Ardea alba bred sporadically at only a few sites which precluded the evaluation of its population trend. The informative population variables differed among species, even of those at the same colony, which suggests trends are also affected by conditions at wintering grounds. The study highlights the need for the systematic monitoring of heron colonies and the protection of foraging/breeding areas in order to reverse the observed negative population trends. [ABSTRACT FROM AUTHOR]

In 2013-2023, in the Gizilaghaj Bay located on the South-Western coast of the Caspian Sea, the trophic relationships of the migratory and nesting bird populations belonging to the Ardeidae family (Botarus stellaris, Ixobrychus minutus, Nycticorax nycticorax, Ardeola ralloides, Bubulcus ibis, Egretta garzetta, Ardea alba, Ardea cinerea, Ardea purpurea) were evaluated with 100 points. It was evaluated 40-60 (sufficient) in 36 species, the main food objects of which are plants, in 9 species 60-80 (good). It was evaluated 40-60 (sufficient) in 12 species of birds, the main food objects of which are invertebrates, 60-80 (good) in the populations of 114 species and 80-100 (very good) in 10 bird species. It was evaluated 0-20 (very bad) in 14 species, the main food objects of which are vertebrates, 20-40 (bad) in 18 species, 40-60 (sufficient) in 56 species and 60-80 (good) in 10 species. [ABSTRACT FROM AUTHOR]

Variations in physico-chemical parameters of water as abiotic factors affect the spatio-temporal distributions of the organisms that live in it. The present study aims to determine the influence of physico-chemical properties on Ardeidae spatiotemporal variations in the wetland of Ramsar site 1018 in Benin. To reach this goal, transect enumeration techniques and stationary counts lasting 15-30 min were used to count Ardeidae species once a month at different sites such as Nokoué Lake, Sô River, Porto-Novo Lagoon, Ouémé River and ancient Lagoons from January 2015 to December 2016. Water physico-chemical parameters were measured at three stations per site during the bird counts. Five of the 12 species recorded monthly were significantly influenced (p< 0.05) by water physico-chemical parameters. It was then revealed that pH influenced Ardeidae spatial variation. Such information is relevant to the management of Ramsar Site 1018, which hosts migratory waterbird species from Palearctic (Eurasia) every year. [ABSTRACT FROM AUTHOR]

A study conducted at Goalpara College in Assam, India, examined the habitat utilization and feeding patterns of birds on the campus. The study recorded and studied 44 bird species from 30 families, categorizing them into seven groups based on their food type. Insectivorous birds were found to be the most dominant. The study also analyzed the habitat selection of the birds, with the H-1 habitat type being the most species-rich. The findings highlight the importance of modified habitats in maintaining urban biodiversity and provide valuable information for the management of avifauna habitats. [Extracted from the article]

Polymorphism has been described in many avian taxa including Ardeidae. This study investigated the spatio-temporal distribution of color polymorphic forms (with regard to the color of the unfeathered parts (legs/lores)) of the Great White Egret Ardea alba alba in internet images from Europe. In total, 140 images of presumed polymorphs from 16 countries (from 2006 to 2021) have been collected and examined. Eight coloration schemes of visible unfeathered parts were distinguished. Since some polymorphs may represent the subspecies Eastern Great Egret Ardea alba modesta, the ratio of beak length to total head length was compared among individuals representing the nominal and Eastern Great Egret subspecies. The ratio distributions were similar in all compared groups; thus, polymorph egrets may represent both of these subspecies. Most polymorph images originate from the Netherlands and the southwestern Norwegian coast. This may have resulted from specific local diets and contact with hormone-disrupting compounds. Nevertheless, some observation biases, such as the presence of local breeding population or high numbers of nature photographers, could have affected our observation pattern. Some analyzed features also followed temporal patterns. Most polymorphs were observed during the breeding season, suggesting disruptions of sex hormones as a possible cause. Studies of spatio-temporal patterns of polymorph occurrence may allow us to obtain insights into the causes of large variation in coloration schemes in polymorphic species. [ABSTRACT FROM AUTHOR]

From a few strongholds in the 19th century, herons and egrets spread across the Algerian coastal strip of North Africa and colonised the Algerian Hauts Plateaux in the second half of the 20th century. Here we report the first breeding of Squacco Heron Ardeola ralloides and Black-crowned Night-Heron Nycticorax nycticorax in a mixed colony at Kef Doukhane, an artificial wetland near Ghardaïa in the northern Sahara. We recorded nine Squacco Heron nests with 37 eggs, with clutch sizes ranging from 1 to 5 eggs (mean = 4.1 + 1.3; N = 9), and three Black-crowned Night-Heron clutches with 3 eggs each. After the first three Squacco Heron clutches hatched, all other nests were wantonly plundered by children in search of eggs and the entire colony was abandoned. The expansion of artificial wetlands in the Sahara and possibly climate change have facilitated the successful colonisation of the Sahara Desert by herons and egrets, but human disturbance and vandalism due to economic hardship and lack of environmental education are currently the major obstacles to range expansion. [ABSTRACT FROM AUTHOR]

Herons typically reproduce colonially, either monospecific or mixed, over waterbodies, high in trees or shrubs, mangroves, and islands. Information from neotropical mangroves is lacking concerning heron breeding areas, reproductive biology, and functional relationships with mangroves. Here we compared the reproductive biology of Cattle Egret (Bubulcus ibis), Little Blue Heron (Egretta caerulea), and Snowy Egret (E. thula), with emphasis on breeding season, nesting materials, nest height, clutch size, breeding success, and nest failure in a mangrove ecosystem in ​​Sepetiba Bay, southeastern Brazil. The breeding season lasted from November to mid-February (195 nests). Nests were built mostly with twigs, but also with grasses (17 nests, 9%) and nylon lines and ropes (Cattle Egrets: 16 nests, 28%; Snowy Egrets: 4 nests, 14%). Little Blue Herons nested higher (2.25 ± 0.1 m) than Cattle Egrets (1.97 ± 0.06 m) and Snowy Egrets (1.80 ± 0.1 m). The modal clutch size differed among species, with two eggs in Cattle Egrets (1–7 range) and Little Blue Herons (1–4 range) and three eggs in Snowy Egrets (2–4 range). Breeding success was high both in Cattle Egrets (90%) and Snowy Egrets (89%) but was low in Little Blue Herons (41%). Higher nest failure in Little Blue Herons occurred due to localized predation events in all clumped nests built isolated at the colony edge. Therefore, these predation events suggest that interspecific nest aggregation was important to diminish nest failure. The remaining nests were quite successful, even though brood reduction (common in herons) occurred in most nests. [ABSTRACT FROM AUTHOR]

In this study, a 2600-ha Ramsar site, Lac Tonga, in northeastern Algeria, was fortnightly surveillance, for seven months, from December 2021 to June 2022. The aim was to monitor and determine the spatio-temporal distribution of Ardeidae. A total of seven species were inventoried, including the Western Cattle egret Ardea ibis (1701 individuals) and the Little egret Egretta garzetta (265 individuals). The other species were the Squacco heron Ardeola ralloides, Grey heron Ardea cinerea, Purple heron Ardea purpurea, Black-crowned Night heron Nycticorax nycticorax and Great egret Ardea alba, with 69, 56, 54, 51 and 35 individuals respectively. During the study period, maximum abundance was observed during May (A=582 individuals), and species richness generally varied between 3 and 5 species. The highest diversity and equitability indices values were noted during June (H'=1.4 bits and E=0.88), indicating the presence of a balanced population. The monitoring of Ardeidae’ spatial distribution shows that they exploit mainly the western and northeastern parts of the lake with an important occupation during the study period. [ABSTRACT FROM AUTHOR]

The water–air interface is a globally widespread habitat for interactions between prey and predators. We experimentally manipulated water surface conditions (flat, smooth waves, three levels of current-induced turbulence) and digitally quantified the visual integrity of above-surface models from a subsurface perspective. Progressive fragmentation was present in each of the models (upright heron, crouched heron, vertical block, horizontal block) with increased departure from flat surface conditions. Smooth directional waves produced multiple horizontal bands (shadows) that moved across the models while surface currents distorted the profile, including progressive disintegration of the models appearance into multiple fragments of different sizes. This fragmentation is caused by scattered surface irregularities interacting with waves and is accentuated at the broken periphery of the optical window, reducing recognition of the models. Unexpectedly, we found that bands and fragments emerging from different surface conditions resemble common frontal plumage patterns on some Ardeidae and shorebirds (Charadriiformes). While these natural plumages are widely recognized to reflect a diversity of adaptations, including camouflage in terrestrial habitats, we suggest that their resemblance to water surface-induced fragmentation might also reflect foraging adaptations of predators though the water–air interface. [ABSTRACT FROM AUTHOR]

Investigations on the parasites that infect migrating birds worldwide are ongoing. To identify the parasite species that infect ardeids, morphological and morphometric characteristics were used. A total of 20 Bubulcus ibis (Ardeidae) specimens were collected from the agricultural lands belonging to the Faculty of Agricultural at Cairo University, which were then examined for nematode parasites. Only one acuariid species, belonging to the Acuariidae family, has been identified, with a prevalence rate of 50 % (10/20) among infected egrets. The Desportesius species isolated from the gizzard of the egret host is morphologically and morphometrically compatible with Desportesius invaginatus, which was previously identified from several Ciconiiformes hosts of Bubulcus ibis (Egypt, India, and Taiwan), Egretta garzetta (France), and Egretta rufescens (USA). Additionally, utilizing the partial small subunit ribosomal RNA (18S rRNA) gene sequence, maximum parsimony based on the Tamura-Nei model was used to infer the phylogeny of the recovered Desportesius species. The query sequences revealed 99.37 % identity for the 18S (MW358651.1) of the previously mentioned D. invaginatus. In addition to clarifying several morphological features of D. invaginatus, this study also provided new DNA data for this species.

Ardeidae tend to exhibit low sexual dimorphism, both in size and plumage coloration, making sex attribution in the field challenging for both birdwatchers and ringers. Here, we assessed whether biometrics and plumage patterns are a good proxy for sex assignment in the Purple Heron (Ardea purpurea). We based our work on 27 molecularly-sexed free-living adults captured in Italy and Romania during the breeding season from 2018 to 2021. We found significant sexual size dimorphism in the beak, which resulted longer in males, but not in weight, wing, tarsus or sternum length. Birds with darker plumages, stronger contrast between reddish ornamental feathers and blackish mantle were classified as males, allowing for correct sex attribution in 70% of the males and 73 % of the females. On the one hand, we concluded that molecular sexing is the most reliable approach for sex attribution in this species. On the other hand, we also found that trained ringers or expert observers may achieve satisfactory sex attribution rates either based on biometrics or accurate plumage observation, possibly even from a distance. [ABSTRACT FROM AUTHOR]

Wetlands are among the most threatened ecosystems on the planet, largely due to their conversion to agricultural or dry land. L'Albufera de Vàlencia is characterized by a large expanse of rice fields (c. 14,000 ha), which hosts the most important colony of Grey Heron Ardea cinerea on the Mediterranean coast of Spain. The colony was visited every 10 days during February-April of 2016 to 2018 and during May-July of 2015 to 2017. The reproductive parameters were estimated for each year and season. We also monitored the available habitat and habitat use of the species in the rice fields from February 2016 to June 2017. The condition of the rice field was related to reproductive parameters. The breeding period was divided into two stages per year. In 2016 all reproductive parameters were lower values, coinciding with a larger area of dry fields in winter and low rainfall in summer. Breeding success was found to be positively associated with the muddy/semi-flooded fields and negatively associated with the sown fields. Like Grey Heron, other waterbirds species nesting in L'Albufera de Valencia could depend on the condition of the rice fields for breeding success. Their reproductive requirements should be considered in rice cultivation management. [ABSTRACT FROM AUTHOR]

The pathogenicity of the H5 subtype high pathogenicity avian influenza viruses (HPAIVs) in Ardeidae bird species has not been investigated yet, despite the increasing infections reported. Therefore, the present study aimed to examine the susceptibility of the Ardeidae species, which had already been reported to be susceptible to HPAIVs, to a clade 2.3.2.1 H5N1 HPAIV. Juvenile herons (four grey herons, one intermediate egret, two little egrets, and three black-crowned night herons) were intranasally inoculated with 106 50% egg infectious dose of the virus and observed for 10 days. Two of the four grey herons showed lethargy and conjunctivitis; among them, one died at 6 days post-inoculation (dpi). The viruses were transmitted to the other two cohoused naïve grey herons. Some little egrets and black-crowned night herons showing neurological disorders died at 4–5 dpi; these birds mainly shed the virus via the oral route. The viruses predominantly replicated in the brains of birds that died of infection. Seroconversion was observed in most surviving birds, except some black-crowned night herons. These results demonstrate that most Ardeidae species are susceptible to H5 HPAIVs, sometimes with lethal effects. Herons are mostly colonial and often share habitats with Anseriformes, natural hosts of influenza A viruses; therefore, the risks of cluster infection and contribution to viral dissemination should be continuously evaluated. Clade 2.3.2.1 H5N1 HPAIV causes lethal infections in Ardeidae sp. Viruses are transmitted among grey herons. Some herons with HPAIV showed conjunctivitis or neurological symptoms. HPAIV systemically replicated in herons tissues. [ABSTRACT FROM AUTHOR]

Rice fields have traditionally been considered key feeding grounds for many waterbird species, including herons. Studies show that field management and flooding cycles influence the reproductive parameters of these birds. L'Albufera de València, on the east coast of the Iberian Peninsula, has large areas of rice fields and is home to the third largest breeding colony of herons in Spain. Changes in water and rice field management that have occurred since the colony was last assessed (1990) may have affected the colony's reproductive performance. Clutch and brood size, and hatching, nesting and breeding success were estimated for Grey Heron Ardea cinerea, Purple Heron Ardea purpurea, Cattle Egret Bubulcus ibis, Little Egret Egretta garzetta, Squacco Heron Ardeola ralloides (Ardeidae) and Glossy Ibis Plegadis falcinellus (Threskiornithidae) in 2015–2017. The extent of flooding and cultivation of rice fields was assessed from February 2016 to June 2017. Reproductive parameters were related to the state of the rice fields. All reproductive output parameters were lower than those reported in the literature. In 2016, laying started earlier (at the end of April), when the fields were still dry and hatching started from May, after flooding. In 2017, peak hatching occurred in June, when the fields were sown. A significant relationship was found between breeding success and the area of sown fields, except for the Squacco Heron. We found that birds that initiated egg laying closer to the date of flooding had a relatively higher breeding success for the Little Egret, Glossy Ibis, Cattle Egret and Purple Heron. The success of nesting populations in this type of artificial wetland requires water management plans that synchronize flooding regimes and maintenance of flooded areas with the biological requirements of these species. [ABSTRACT FROM AUTHOR]

We discuss the possible mechanisms explaining the potential brood parasitism between Little Bittern and Common Moorhen by reporting the first case worldwide of a Little Bittern Ixobrychus minutus laying on a nest of Common Moorhen Gallinula chloropus recorded at Boussedra Pond (Algeria, Northern Africa). In this regard we review the cases of possible brood parasitism between Little Bittern and Common Moorhen. [ABSTRACT FROM AUTHOR]

Adults of the genus Posthodiplostomum , Dubois, 1936 are parasites of fish-eating birds, mainly of the family Ardeidae, and are globally distributed. The genus currently comprises 35 species, although recent molecular evidence has shown that the diversity of the genus is underestimated since several candidate species have been recognized. In the Neotropical region of Mexico, at least 6 Posthodiplostomum lineages have been detected with metacercaria stages recovered from unrelated fish hosts. Here, we obtained adult specimens of Posthodiplostomum from 6 fish-eating birds representing 2 families ( Butorides virescens , Ardea herodias , Nycticorax nycticorax , Tigrisoma mexicanum – Ardeidae, and Rynchops niger and Leucophaeus atricilla – Lariidae) from 4 localities in southern Mexico. Specimens were sequenced for 2 nuclear (28S and ITS1–5.8S–ITS2) and 1 mitochondrial ( cox1 ) molecular marker. Phylogenetic analyses allowed us to link metacercariae and adult specimens and recognized a lineage, which was described morphologically. The new species can be distinguished from its congeners by its prosoma morphology and body size; this is the first described species in the Neotropical region of Mexico. Additionally, new host and locality records for P. macrocotyle and P. pricei are presented, expanding their geographical distribution range in the Americas.

Toll-like receptor (TLR) genes have recently been used to assess the adaptive genetic diversity under natural selection. Here, we newly developed a set of primer pairs for amplifying TLR genes (TLR1LB, TLR2A, TLR3, TLR4, TLR5, TLR7 and TLR15) in the vulnerable Chinese egret (Egretta eulophotes). The PCR products, ranged between 407 and 988 bp (an average of 762 bp), were successfully amplified by using this primer set. Sequence analyses of all these TLR genes indicated that there were 22–75 variable sites and 20–77 single nucleotide polymorphisms. This primer set was also confirmed useful for nine other ardeid species, including four members in ardeinae and five in botaurinae. The versatility of this primer set will provide a useful groundwork for the further studies on the TLR conservation genetics of this vulnerable egret and other ardeid birds. [ABSTRACT FROM AUTHOR]

After more than a decade of regular occurrence, the first confirmed breeding of the Sacred Ibis Threskiornis aethiopicus in the lagoon of Venice (Italy) was observed in 2020, in three sites. The ibises nested in colonies with of one or more species of Ardeidae and Phalacrocoracidae. The colonies were on islets < 2 ha in size, covered with thick vegetation. Nests were placed on the top of bushes or trees, at a height of 1.5-5 m. The colony sites seemed not occupied by adults until the end of February - half of March; laying took place from early May, with hatchings occurring from the end of that month until July. Overall, 22-24 pairs nested in 2020. Birds were observed feeding at saltmarshes, freshwater wetlands and arable fields; a public garbage collection site was also used regularly. Given the high number of suitable nesting and feeding sites, a rapid growth of the Sacred Ibis population is expected in the next years. [ABSTRACT FROM AUTHOR]

This paper reports the occurrence of Clinostomum heluans Braun 1901 (Digenea: Clinostomidae) in a specimen of Botaurus pinnatus (Wager, 1829) (Ave: Ardeidae) found in southeastern Brazil. Although this parasite has been reported in other birds in Brazil, Cuba, the Czech Republic and Venezuela, this is the first report of B. pinnatus as a host for this parasite.

An opportunistic predation by Great Blue Heron (Ardea herodias) on Eastern cottontail rabbit (Sylvilagus floridanus) was observed in south Texas on 31 Oct 2019. The Great Blue Heron had already captured the Eastern cottontail rabbit at the first observation but the maneuvering process, killing, and ingestion were recorded photographically, which make this observation unique even though this might constitute the second report on Great Blue Heron eating Eastern cottontail rabbits. [ABSTRACT FROM AUTHOR]

Six species of wading birds collected from wildlife centers throughout South Florida were dissected for parasites. Twenty-six species of parasites represent new host records and five parasite species represent new geographic range extensions. [ABSTRACT FROM AUTHOR]

Due to the ability of birds to travel long distances in the air, the potential feeding area of each individual is much larger than that of typical terrestrial animals. This makes birds a convenient indicator of environmental lead (Pb) pollution over large areas, in particular areas of inland and coastal waters. The aim of this study was to assess the concentrations of Pb in various organs of water birds from a variety of locations. The focus was on ducks, geese and swans (Anatidae); herons and egrets (Ardeidae); terns (Sternidae); and gulls (Laridae). This article describes the level of lead in the most commonly studied tissue types: feathers, bones and the liver. The study also presents data concerning the concentration of lead in the eggs of water birds. The highest levels of lead pollution can be observed in China and Korea, related to their high level of industrialization. In Iran too, environmental lead pollution is high, likely due to the developed petrochemical industry. Lead pollution in Japan, as well as in Western European countries (Spain, France, Italy), seems to be much lower than in China, India or Iran. Nevertheless, the level of pollution in Europe is higher than satisfactory, despite the introduction of a number of bans related to, for example, the use of leaded petrol or lead-containing paints. Finally, the USA and Canada appear to be the areas with the lowest lead pollution, possibly due to their low population densities. [ABSTRACT FROM AUTHOR]

Background: Understanding the movement and displacement of individuals within avian species is important for conservation. Herons, Storks and Egrets are especially important as they are migratory species and are potential indicator species. It is therefore valuable to set life history baselines to understand survival. Objectives: To establish baseline longevity and displacement values for the avian families Ardeidae, Threskiornithidae and Ciconiidae using the South African Bird Ringing Scheme (SAFRING) data for Africa and to highlight gaps in the SAFRING database for these families. Method: We used data archives of ringed and subsequently reported individuals to determine maximum displacement and longevities from the past seven decades for each species within these three families. Displacement was estimated by the straight-line distance between subsequent records for the same individual. Longevity is the measure of time elapsed in records for the same individual. Results: Displacement and longevity data were available for 17 of the 24 species in the focus families. Individuals of most of the species were ringed as nestlings so displacement records may represent dispersal. Displacement ranged from a maximum of 10 114 km for a White Stork (Ciconia ciconia) to 2.5 km for a Little Bittern (Ixobrychus minutus). Several species are poorly sampled, resulting in longevity records of just a few days. Despite that, longevity values were 5 years for 16 species, and the highest value was 25.3 years for a White Stork. Conclusion: It was possible to determine longevity values for most of the species within the three families investigated. Based on the displacement profiles for species with sufficient records, there are large differences in movement between species. Certain common species such as Purple Heron (Ardea purpurea) have very few ringing records, which indicate a need for further species-specific research as the longevity values are not representative. This could greatly benefit studies aiming to use these species as ecosystem health indicators as well as identify which species are at risk.

Se registró la reproducción de las garzas Egretta thula, Bubulcus ibis y Cochlearius cochlearius en el estero Boca Negra, Jalisco, México. El período reproductivo se presento al inició de la estación de secas (finales de marzo) y terminó a la mitad de la temporada de lluvias (finales de agosto). Se dio seguimiento a nueve nidos de E. thula, nueve de B. ibis y dos de C. cochlearius. Para las tres especies se registraron diversos componentes de éxito reproductivo.

We revisit the holotype of Calcardea junnei Gingerich, 1987 from the latest Paleocene (Clarkforkian) of the Willwood Formation (Wyoming, USA). The species is based on a partial skeleton and was originally assigned to the Ardeidae (herons). As we show, this classification cannot be upheld and Calcardea Gingerich, 1987 more closely resembles the taxon Vastanavis Mayr et al., 2007 (Vastanavidae), a parrot-like bird from the early Eocene of India. Even though C. junnei is a large bird, its long wings and short tarsometatarsus argue against a predominantly terrestrial way of living, and the morphology of the tarsometatarsus and pedal phalanges instead suggest strong grasping feet. We conclude that an assignment of Calcardea to the landbird clade (Telluraves) is better supported than its classification into the waterbird clade (Aequornithes), which includes Ardeidae and other 'ciconiiform' and 'pelecaniform' taxa. Calcardea junnei is one of the oldest known representatives of Telluraves and its morphology shows plesiomorphic features, which contributed to its previous misidentification as a heron. Calcardea exhibits a distinctive osteology and affords a glimpse of a previously unknown late Paleocene avian morphotype. [ABSTRACT FROM AUTHOR]

As heron and egret colonies are sometimes abandoned due to human activity and subsequently newly established at nearby locations, colony locations per se cannot represent colony fates. Here, "colony lineages" were traced by connecting short-distance location shifts between colony sites in consecutive years to quantify the site fidelity of heron colonies themselves rather than the breeding-site fidelity of individuals. Site fidelity of 61 colony lineages recorded from 1963 to 2013 in and around Ibaraki Prefecture, Japan, was evaluated by persistence periods with survival analysis and shapes of historical trajectories by applying the correlated random walk analysis. While 36% (n = 22) of colony lineages did not show site fidelity and lasted only 1 year or indicated untangled shapes of historical trajectories, 64% (n = 39) of colony lineages exhibited site fidelity by reusing the same locations for multiple years or by staying within a small area with entangled shapes of historical trajectories. Even though suitable breeding sites were abundant in the study area and site fidelity of colony members was low, a high rate of site fidelity in colony lineages may be achieved when a few faithful pioneer herons and egrets are followed by many others. [ABSTRACT FROM AUTHOR]

The Great Blue Heron (Ardea herodias) is a Species of Special Concern in the State of Maine, USA, due to declines along the Atlantic coast since the mid-1980s. To determine if this decline was statewide, an aerial survey was conducted from 1 May to 18 June 2015 to estimate the breeding population using a stratified dualframe design accounting for imperfect detection of colonies. The strata were based on habitat and known colony densities. The area frame consisted of 10-km x 10-km plots. Stratum samples were searched by air independently by front and rear observers for known and new colonies. The list frame consisted of plots containing known colonies, a sample of which was checked for nesting activity. The dual-frame design combined the strengths of both list- and area-only surveys. Flying directly to known colonies in the list frame was very efficient, and accounting for new colonies in the area frame, allowed unbiased, statistically valid estimation. Estimates were calculated for a Maine statewide total of active Great Blue Heron colonies (n = 243, 90% credible interval (CI) = 193–352), total nests (n = 2,019, CI = 1,778–2,434), and active nests (n = 1,593, CI = 1,416–1,872). Observer detection ranged from 25 to 99%. The percentage of list frame colony coverage in the dual-frame estimate was 63%, but varied by stratum. The percent CV of the dual-frame statewide total active nests was 8.9%, but also varied by stratum. By repeating these methods, strata and statewide population trends could be obtained. [ABSTRACT FROM AUTHOR]

Herons comprise a distinctive family of birds, the Ardeidae, adapted to living in aquatic environments. The history of herons in human culture dates back at least 4,000 years, continuing through successive cultures. Through the millennia, hunting herons for sport, food, or feathers has been one of the more enduring conservation issues for the group. Killing egrets for their feathers initiated the modern conservation era in the United States and Europe. Overall, protection of nesting sites and feeding habitats has been, and remains, a significant theme in heron conservation. Owing to their longevity, wetland dependence, and site specificity, herons have been proposed as potential indicators of environmental conditions and trends. It has been recognized that landscape and regional conservation action is the most effective conservation tool for most species, but several species and populations have been identified as being at risk and requiring special species- and population-level planning and action. To facilitate the conservation of herons, HeronConservation, the Heron Specialist Group of the International Union for Conservation of Nature, was founded in 1982 and has since led global engagement in heron conservation through communication, networking, technical syntheses, and action planning and facilitation. [ABSTRACT FROM AUTHOR]

At the 40th Annual Conference and General Meeting of the Waterbird Society, a symposium and workshop titled Herons of the World Symposium was convened to address the current world status of Ardeidae (herons). This paper introduces the origin of this symposium, demonstrates the geographical areas of study and proposes a framework for future world symposia on coastal and freshwater colonial waterbirds. In that way, it complements the coverage of pelagic colonial waterbirds by the World Seabird Union. The Herons of the World Symposium was held in New Bern, North Carolina, USA, during 21–23 September 2016. The purpose of this first symposium was to bring together heron researchers and enthusiasts from around the world to meet and discuss local, regional and international advances in their biology. In this Special Section, four papers from the symposium are presented. Additional papers and research summaries of participants can be found in the online Journal of Heron Biology and Conservation. [ABSTRACT FROM AUTHOR]

Abstract Ichthyophagous birds aggregate at cage fish farms attracted by caged and associated wild fish. Spatio-temporal variability of such birds was studied for a year through seasonal visual counts at eight farms in the western Mediterranean. Correlation with farm and location descriptors was assessed. Considerable spatio-temporal variability in fish-eating bird density and assemblage structure was observed among farms and seasons. Bird density increased from autumn to winter, with the great cormorant being the most abundant species, also accounting largely for differences among farms. Grey heron and little egret were also numerous at certain farms during the coldest seasons. Cattle egret was only observed at one farm. No shags were observed during winter. During spring and summer, bird density decreased markedly and only shags and little egrets were observed at only a few farms. Season and distance from farms to bird breeding/wintering grounds helped to explain some of the spatio-temporal variability. Highlights • Spatio-temporal variability of ichthyophagous birds was assessed at eight Mediterranean cage fish farms. • Great cormorant, shag, grey heron, little egret and cattle egret density at farms was studied. • Bird density showed a marked seasonal pattern: highest density occurred in autumn and winter. • Differences between farms were related to the proximity of natural breeding/wintering areas. [ABSTRACT FROM AUTHOR]

The functional roles of nesting heron species (Ardeidae) as top predators in regional wetland landscapes may be sensitive to variation in nesting abundances at subregional scales corresponding to available habitat for nesting and foraging within individual wetland subsystems. This study investigates the dynamics of annual nesting abundances of four ardeid species within 10 major wetland subsystems of the San Francisco Bay Area, California, USA, during 1991–2010. Interrupted time series analysis was used to measure impact and recovery rates related to sudden major declines in nesting abundance below selected thresholds of annual change. Year-to-year persistence of initial impacts was above 78% for Great Blue Herons (Ardea herodias) and Great Egrets (A. alba). Snowy Egrets (Egretta thula) recovered more quickly, with 63–66% annual carryover of initial impacts. The time required for 95% recovery averaged 18.8 years for Great Blue Heron, 13.0 years for Great Egret, 7.2 years for Snowy Egret, and 14.5 years for Black-crowned Night-Heron (Nycticorax nycticorax). Most of the major subregional declines in nest abundance were associated with impacts at a single colony site. The results highlight the significant effects of sudden major declines in nesting abundance on the status of ardeids within individual wetland systems across a larger regional wetland landscape. [ABSTRACT FROM AUTHOR]

Vivid plumage colors are some of the best examples of elaborate trait evolution resulting from sexual selection. Bird feathers often contain high concentrations of pigment or intricate microstructures for reflecting light at distal feather tips, in order to maximize color presentation to intended viewers (e.g., prospective mates, rivals). However, here we describe a rare form of “hidden” plumage coloration, whereby several species of heron (Pelecaniformes: Ardeidae) have powder down tracts liberally coated in yellow pigments that are hidden from view underneath contour feathers. We show using Raman spectroscopy and high-performance liquid chromatography that the yellow coloration is due to carotenoid pigmentation. We also show that fatty acids and carotenoids co-occur in samples and discuss the possible evidence and implications for the presence of esterified carotenoids in powder down. Our study of hidden feather coloration is in apparent contrast with the traditional view of carotenoid pigmentation in plumage, which holds that carotenoids are costly pigments that are displayed to advertise individual quality. We hypothesize that carotenoid pigments are transferred onto powder down as a consequence of the chemical affinity that these pigments have to lipoid secretions associated with subcutaneous fat. Further investigation may identify functions for carotenoid pigmentation in powder down (e.g., signaling, microbiological protection), but we cannot rule out the possibility that the powder down of herons may provide the first evidence for carotenoid coloration in feathers being a non-adaptive by-product of other processes. [ABSTRACT FROM AUTHOR]

The present study emphasizes the diversity, richness and abundance of butterfly and bird species in Belgharia town situated in North 24 Parganas district in West Bengal during larger parts of 2017. 47 species of butterflies belonging 15 subfamilies and 5 families were recorded from the study area. Family Nymphalidae was the most prevalent among the five families of butterflies with 20 species followed by Lycaenidae, Pieridae and others. Regarding avian diversity, 56 bird species from 26 families and 10 orders were observed in Belgharia. The maximum number of bird species was recorded under family Ardeidae, followed by Picidae and Columbidae. The study indicates that though the town is a densely populated urban area, it has got a rich avian and butterfly fauna which needs active monitoring and protection. [ABSTRACT FROM AUTHOR]

El comportamiento de pesca con cebo activo ha sido registrado en especies de la familia Ardeidae. Para la Garza blanca (Ardea alba) sólo existe un registro previo en la literatura. Mediante este aporte se documenta el registro de pesca con cebo activo por la Garza blanca observado en un Parque urbano de Argentina.

The objective of this study was to develop tools for distinguishing between sexes of the two Black-crowned Night-Heron ( Nycticorax nycticorax) subspecies ( N. n. obscurus and N. n. hoactli) using discriminant function analysis. Significant differences were found in length of the culmen, length of the bill from the gape, and length of the wing chord between the sexes of each subspecies, with males being larger than females. The resulting discriminant functions were able to differentiate between the sexes of each studied subspecies and between subspecies after determining the sex of the individuals (with a correct classification of 77.8% for females and 97.8% for males). In females, all morphometrics were greater for N. n. obscurus than N. n. hoactli; this was also the case for males, except for bill width, which was greater in N. n. hoactli. Wing chord length was the most useful measurement for constructing the discriminant functions. External morphometrics are a valuable tool not only for discriminating between N. n. hoactli and N. n. obscurus but also for sexing these subspecies. [ABSTRACT FROM AUTHOR]

Habitat selection by herons, egrets and bitterns (Ardeidae) is influenced by the extent and quality of surrounding wetlands in natural landscapes. However, these relationships may be different in highly modified urban environments where inter- and intra-specific competition could be increased. To assess the relative effects of habitat and competition on habitat selection by ardeids in an urban landscape, all known colonies in the densely populated coastal region around Macao Special Administrative Region, China, were surveyed. The relationship among ardeid communities and patch-level habitat variables were investigated using multivariate and co-occurrence analyses. Ardeid species ( n = 12) were recorded during 2006-2009. Habitat patches were categorized into three types based on 10 habitat factors using redundancy analysis. The area of adjacent open land (r13= 0.772, P = 0.002) and patch area (r13= 0.670, P = 0.012) were the major indicators of species richness and abundance, respectively. However, the factor that influenced habitat selection the most was perimeter-area ratio (marginal effect: λ1 = 0.33). The lack of evidence for competition in the co-occurrence analysis suggested that the spatial pattern of the ardeid community in Macao Special Administrative Region, China, was primarily driven by variation in habitat features that satisfy species-specific requirements. [ABSTRACT FROM AUTHOR]

Wetlands are one of the most important ecosystems worldwide due to the great biologic diversity that they harbor and the resources and ecosystem services that they provide; however, their conservation is seriously threatened. Waterfowl are one of the most representative components of wetland biodiversity and the study of their communities is necessary to establish protection priorities appropriately. In this study, we describe the species richness and relative abundance of the waterfowl community of an artificial wetland in Mexico State which we visited from August 2010 to August 2011. We found 23 species, most of which belong to the Anatidae (ducks) and Ardeidae (herons) families and we recorded an accumulated abundance of 25,220 individuals. We performed an accumulation curve and we used Clench's model which estimated 24 species; thus, we observed 95% of the predicted species. The arrival of migratory species contributed substantially to the increase of the species richness and the abundance of individuals, especially from October to March. We consider that the species richness and the abundance that we recorded, including observations of rare species, species reproducing, and species under a conservation category, are indicative of the great ecological value of this wetland despite its limited size. Therefore, it is relevant to assess ecological features of natural and artificial wetlands, including waterfowl communities, in order to improve the conservation actions in this region. [ABSTRACT FROM AUTHOR]

The nesding diets of four heron species breeding on a small forestry islet in Anzali, Iran, were investigated to determine the dietary segregation among sympatric breeders. Regurgitated samples from Black-crowned Night-Herons (Nycticorax nycticorax), Litde Egrets (Egretta garzetta), Catde Egrets (Bubulcus ibis) and Squacco Herons (Ardeola ralloides) were collected during the breeding season from 23 May to 16 August 2016. A total of 1,606 prey items were identified representing 39 prey categories from nine different classes. Differences were detected among these four ardeid species for the percentage of each prey category. Fish dominated the regurgitates of the Blackcrowned Night-Heron (67%; n = 43 samples), Litde Egret (45%; n = 33 samples) and Squacco Heron (53%; n= 10 samples), whereas arachnids and insects combined (53% and 40%, respectively, based on total number of individuals) and insects (61.9% based on weight) were the most common prey items for the Catde Egret. Although fish items were dominant in Black-crowned Night-Herons, Litde Egrets and Squacco Herons, their weight (Χ²3,= 318, P< 0.001) and length (Χ²3= 225.2, P< 0.001) differed significantiy. There was some overlap in the diet of all four heron species, especially between Black-crowned Night-Herons and Squacco Herons, with a Pianka Overlap Index equaling 0.92. There was sufficient dietary segregation in terms of number, weight and length of prey items that could contribute to a reduction in competition for limited food resources. [ABSTRACT FROM AUTHOR]