Egretta Garzetta Research Articles

Morphological and molecular approaches of the nematode parasite Desportesius invaginatus (Acuariidae) infecting the cattle egret Bubulcus ibis (Ardeidae)

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.

Genomic insight into the nocturnal adaptation of the black-crowned night heron (Nycticorax nycticorax)

BackgroundThe black-crowned night heron (Nycticorax nycticorax) is an ardeid bird successfully adapted to the nocturnal environment. Previous studies had indicated that the eyes of the night herons have evolved several specialized morphological traits favoring nocturnal vision. However, the molecular mechanisms of the nocturnal vision adaptation of night herons remained inattentions. In this study, the whole genome of N. nycticorax was sequenced and comparative analyses were performed on the vision-related and olfactory receptor (OR) genes to understand the molecular mechanisms of the visual and olfactory adaptation of night herons.ResultsThe results indicated that a number of vision genes were under positive or relaxed selection in N. nycticorax, whereas a number of other vision genes were under relaxed or intensified selection in the boat-billed heron (Cochlearius cochlearius), which suggested that the two species adapt to nocturnality with different genetic mechanisms. The different selections acting on vision genes are probably associated with the enlargement of eye size and the enhancement of visual sensitivity in night herons. The analyses on olfactory receptor (OR) genes indicated that the total number of OR genes in the genomes of N. nycticorax and C. cochlearius were about half those in the little egret (Egretta garzetta), whereas the diversity of their OR genes was not remarkably different. Additionally, the number of expressed OR genes in the transcriptomes of N. nycticorax was also fewer than that in E. garzetta. These results suggest a reduced olfactory capability in night herons compared with E. garzetta.ConclusionsOur results provided evidence that several vision genes of the night herons were subjected to different natural selections, which can contribute to a better understanding of the genetic mechanisms of visual adaptions of the night heron. In addition, the finding of the reduced number of total and expressed OR genes in night herons may reflect a trade-off between olfaction and vision.

High risk of predation suppresses behavioural differences among bold and shy social prey individuals

Abstract Prey animals must attempt to optimize foraging success while reducing the probability of being captured. Within social prey groups, intrinsic differences in bold-shy personality among individuals influence their respective risk-taking tendencies. We examined the foraging and refuge use behaviour of mixed groups of goldfish (Carassius auratus) containing half bold individuals and half shy individuals under variable levels of predation risk from a live avian predator (Egretta garzetta). At the group level, the fish groups significantly decreased their foraging time by spending more time under the refuge when the predator spent more time at the focal pool. As expected, the bold fish tended to be the first to leave the refuge, and foraged outside the refuge more often than shy fish under control conditions and at lower risk levels. However, the behavioural differences between bold and shy fish disappeared under higher risk conditions. In terms of mortality, the predator captured significantly more bold fish than shy fish. Our study illustrates how bold individuals in social groups often take greater risks to achieve foraging success, but demonstrates that innate differences in boldness can be diminished in times of elevated predation risk.

Diversity and abundance of water birds in the mangrove area of south coast of Bangkalan, Madura Island, Indonesia

Abstract. Ramadhani A, Ambarwati R, Gumilang RS. 2022. Diversity and abundance of water birds in the mangrove area of south coast of Bangkalan, Madura Island, Indonesia. Biodiversitas 23: 3277-3284. The southern coastal mangrove area of ??Bangkalan, Madura Island, Indonesia, is an important bird habitat, especially for water birds. This study aimed to analyze the diversity and abundance of water birds in the southern coastal mangrove area of ??Bangkalan, Indonesia, as well as the environmental carrying capacity of this area as their habitat. Sampling was carried out using a birdwatching approach at four research stations. The diversity of water birds was analyzed using the Shannon-Wiener diversity index, while the abundance of water birds was calculated based on the abundance index. Environmental carrying capacity was analyzed descriptive-quantitatively based on the habitat profile. The results indicated that there were 15 species of water birds in the mangrove area belonging to five families in four orders, namely Charadriiformes, Ciconiiformes, Pelecaniformes, and Suliformes, with a diversity index of 1.547. There were three abundant species of water birds, namely the little egret (Egretta garzetta), Javan Pond-heron (Ardeola speciosa), and Great Egret (Ardea alba). In addition to water birds, there were nine species of arboreal birds in this area. The areas with dense mangroves provide better habitat carrying capacity for water birds compared to other coastal areas.

Molecular characterization of the Gyrovirus galga 1 strain detected in various zoo animals: the first report from China

Since 2011, the Gyrovirus galga 1 (GyVg1, previously recognized as avian gyrovirus 2) strain has extensively been detected worldwide. The virus has been identified in several species, including chickens, humans, domestic cats, and snakes, especially in China. Therefore, in this study, the presence of GyVg1 was investigated in various zoo animals to determine whether it exists in various species in Nanyang, China. A total of 63 whole blood samples (1 sample from each animal) from 24 animal species were collected from the Nanyang Zoo. Eight different GyVg1 strains were identified in eight types of animals using polymerase chain reaction, and the full genome of each strain was sequenced. The whole genome of four GyVg1 strains, namely, HN2019-H1, HN2019-T1, HN2019-SD1, and HN2019-L1 identified in hippopotamus (Hippopotamus amphibius), tiger (Panthera tigris), sika deer (Cervus nippon), and lion (Panthera leo), respectively, comprised 2375 nucleotides (nt). The whole genome of the other strains, namely, HN2019-E1, HN2019-S1, HN2019-PF1, and HN2019-P1 identified in egret (Egretta garzetta), silver pheasant (Lophura nycthemera), peafowl (Pavonini), and common pheasants (Phasianus colchicus), respectively, comprised 2376 nt. Subsequently, a phylogenetic tree was constructed based on the 8 whole-genome sequence strains and 29 reference strains. These 37 strains were grouped into two major branches, group A and group B, and the 8 strains identified in this study were placed in group A. An analysis of the amino acids encoded by three open reading frames revealed some mutation sites unique to these eight strains. The substitution occurred at site 110 of viral protein 2 of HN2019-PF1, which is located in the highly conserved phosphatase motif WX7HX3CXCX5H (95-115aa). Recombination analysis revealed that, all these viral sequences were obtained as a result of recombination among the three GyVg1 strains (JL1511 and GS1512 from chickens and 17CC0810 from cat) from China and two strains (G17 from ferret of Hungary and RS-BR-15-2S from chicken of Brazil) from other countries. These findings indicate the complex evolution of GyVg1. Nevertheless, its transmission across the hosts is worth exploring.

Comparative chromosome maps between the stone curlew and three ciconiiform species (the grey heron, little egret and crested ibis)

BackgroundPrevious cytogenetic studies show that the karyotypes of species in Ciconiiformes vary considerably, from 2n = 52 to 78. Their karyotypes include different numbers of small to minute bi-armed chromosomes that have evolved probably by fusions of two ancestral microchromosomes, besides macrochromosomes and dot-like microchromosomes. However, it is impossible to define the inter-species homologies of such small-sized bi-armed chromosomes based on chromosome morphology and banding characteristics. Although painting probes from the chicken (Gallus gallus, GGA) chromosomes 1–9 and Z have been widely used to investigate avian chromosome homologies, GGA microchromosome probes are rarely used in these studies because most GGA microchromosome probes generated by flow sorting often contain multiple GGA microchromosomes. In contrast, the stone curlew (Burhinus oedicnemus, BOE, Charadriiformes) has an atypical low diploid chromosome number (42) karyotype and only 4 pairs of dot-like microchromosomes; a set of chromosome-specific painting probes that cover all BOE chromosomes has been generated. To get a genome-wide view of evolutionary chromosomal rearrangements in different lineages of Ciconiiformes, we used BOE painting probes instead of GGA painting probes to analyze the karyotypes of three ciconiiform species belonging to two different families: the eastern grey heron (Ardea cinerea, ACI, 2n = 64, Ardeidae), the little egret (Egretta garzetta, EGA, 2n = 64, Ardeidae) and the crested ibis (Nipponia nippon, NNI, 2n = 68, Threskiornithidae).ResultsBOE painting probes display the same hybridization pattern on chromosomes of ACI and EGA, while a different hybridization pattern is observed on chromosomes of NNI. BOE autosome probes detected 21 conserved homologous segments and 5 fusions on the sixteen pairs of recognizable chromosomes of ACI and EGA, while 16 conserved homologous segments and 4 fusions were found on the twelve pairs of recognizable chromosomes of NNI. Only a portion of smaller bi-armed chromosomes in the karyotypes of the ciconiiform species could have evolved from fusions of ancestral microchromosomes. In particular BOE 5, which is the result of a fusion between two segments homologous to GGA 7 and 8 respectively, was retained also as either a single chromosome in ACI (ACI 5) and EGA (EGA 5) or had fused with a part of the BOE 10 equivalent in NNI (NNI 5).ConclusionOur painting results indicate that different chromosome rearrangements occur in different ciconiiform lineages. Some of the small-sized bi-armed chromosomes in ACI, EGA and NNI are derived from the fusions of two microchromosomes, indicating that microchromosome fusions play an important role in ciconiiform chromosome evolution. The fusion segment homologous to GGA 7 and 8 is a potential cytogenetic signature that unites Ardeidae and Threskiornithidae.

ASPECTS OF THE BIRD FAUNA FROM CIRIC VALLEY’S (IAȘI)

The Ciric Valley, which is located in the northeastern region of Iași, integrates a considerable variety of habitats. Wetlands are dominant, being partially covered with compact reed beds. The other habitats are the deciduous forest, and meadows located in the northern part of the studied area. These allow the settlement of a diverse bird fauna in the area. Using the method of transects, the fixed-point observation, and sound identification, we identified 84 bird species between March 2020 and February 2021. Most species belong to the order Passeriformes (53 species), the rest of the orders having a significantly lower diversity. With the exception of the 20 sedentary species, Ciric’s avifauna consisted mostly of migratory species (39 summer visitors, 8 winter visitors, 13 vagrant species), and 5 partial migrant species during the research period. Among the identified bird species are 58 breeding species and 5 possible breeding species, representing 75% of the total number of the observed bird species. During the study, we identified 2 vulnerable species (Nycticorax nycticorax - black-crowned night-heron and Streptopelia turtur - european turtle-dove), 2 endangered species (Egretta garzetta - small egret and Ardea alba – great white egret) included in The Red Book of Vertebrates in Romania, and 13 species that require special conservation measures according to the Annex 1 of the Birds’ Directive.

First successful nesting of the Little Egret Egretta garzetta in Ghardaïa (Algerian Sahara)

We report on the first successful breeding of the Little Egret, Egretta garzetta, in the Sahara, Algeria. We conducted a study on the nesting of this species at Kef Doukhane, an artificial wetland in Northern Sahara that has become an increasingly important nesting site for waterbirds. The number of individuals was monitored between April and October 2021 and the greatest abundance with 470 individuals was recorded in October. However, during breeding, the colony decreased to about 50 birds that built seven nests. Egg-laying started at the beginning of July and at least 34 eggs were laid. Clutches varied between 5 and 6 eggs, and 28 nestlings fledged, yielding a breeding success of 82.4%.

Effects of Rice Field Phenology on Breeding Parameters of Heron Colonies in the East of the Iberian Peninsula

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.

Diversity of waterbirds in mudflat and fishpond habitats in coastal Wetlands of East Lampung, Indonesia

Coastal wetlands provide habitat for waterbirds. However, changes in land use in coastal wetlands in East Lampung, Lampung Province, might affect the use of habitats by waterbirds. The study objective was to identify waterbird species using wetland habitat in coastal areas of East Lampung. Field surveys were conducted in November 2020 in two habitat types, i.e., mudflats and fishponds, employing a concentration method from several vantage points, then calculating Shannon-Wienner diversity indices (H’). A total of 23 species from 9 families of waterbirds were recorded. Mudflat had a higher diversity (H’½2.21) than fishpond (H’=1.74). Sixteen species were found on mudflats, dominated by shorebirds from the families of Scolopacidae and Charadriidae, which are primarily migratory species. Fishponds were used by 12 species, dominated by the Little Egret (Egretta garzetta) and Glossy Ibis (Plegadis falcinellus). Two endangered species, i.e., Far Eastern Curlew (Numenius madagascariensis) and Milky Stork (Mycteria cinerea), and one vulnerable species, Lesser Adjutant (Leptoptilos javanicus), were observed using mudflats. This study showed that mudflat in coastal wetlands of East Lampung provides essential habitats for conserving threatened waterbirds and migratory shorebirds.

Population and distribution of some herons in Babakan Rancabayawak, Bandung City, Indonesia

Abstract. Megantara EN, Husodo T, Iskandar J, Nurjaman D, Suroso, Aminuddin SF, Atsaury ZIA, Wulandari I, Shanida SS. 2021. Population and distribution of some herons in Babakan Rancabayawak, Bandung City, Indonesia. Biodiversitas 22: 5389-5396. The Cinambo River flood control channel in the Rancabayawak impacts the decline in the habitat quality of some herons, such as cattle egret [Bubulcus ibis (Linnaeus, 1758)], little egret [Egretta garzetta (Linnaeus, 1766)], and Javan pond-heron [Ardeola speciosa (Horsfield, 1821)]. Besides, many built-up areas due to the urbanization in peri-urban areas also impact habitat quality, such as the loss of plants commonly used as perching and nesting sites. Along with the development of Rancabayawak as a built-up area, it is essential to study the management of those birds. This study aims to reveal: 1) plants used as perching and nesting sites, 2) population size and distribution, and management efforts on B. ibis, E. garzetta, and A. speciosa in Babakan Rancabayawak Hamlet, Gedebage Subdistrict, Bandung, West Java, Indonesia. A mixed-methods approach was applied in this study by calculating the estimated population and bird nests, plant inventory survey, and the installation of the A8 mini GPS. Bambusa vulgaris, Leucaena leucocephala, and Mimosa pigra are plants that are used as perching and nesting sites by B. ibis, E. garzetta, and A. speciosa. The estimated population mean of those birds was 630 individuals, 92 individuals, and 43 individuals, respectively, with the population average of those birds, is 1680 individuals. Three hundred twenty-nine nests (329) were found during the study. Based on distribution mapping, birds moved east and south, covering paddy fields in Rancaekek, Solokanjeruk, and Majalaya within a radius of 12 km. Management efforts can be conducted by not cutting down the plants that become nesting and perching sites and maintaining the wetlands in their habitats.

ĐA DẠNG THÀNH PHẦN LOÀI CHIM Ở VƯỜN CHIM ĐÀO MỸ, HUYỆN LẠNG GIANG, TỈNH BẮC GIANG

The study on Dao My Stork Garden with an area of 3 hectares located in Tan Phuc village, Dao My commune, Lang Giang district, Bac Giang province during 2017 - 2018 has identified 32 bird species belonging to 29 genera, 18 families, 7 orders, including 21 resident species, 11 winter migratory species. There is one species listed in the Vietnam Red Data Book (2007) which is Anastomus oscitans. There are 6 species of water birds living and colony nesting in the stork garden: Little Egret (Egretta garzetta), Chineses pond Heron (Ardeola bacchus), Egret Cattle (Bubulcus coromandus), Black-crowned Night Heron (Nycticorax nycticorax), Intermediate Egret (Egretta intermedia) and Asian Openbill (Anastomus oscitans). The water bird species with the highest number of population in breeding season is the Little Egret. There is a stratification of the habitat and nesting areas of water birds according to the vegetation in the stork garden. Birds mainly nest and live on eucalyptus and bamboo trees. Since this stork garden formed on the land is owned by the household, in order to preserve the stork garden for sustainablity, it is necessary to support from the local government and organizations to invest in the restoration of trees in the garden and protecting the stork garden from illegal bird hunting.

Levels and profiles of perfluorinated alkyl acids in liver tissues of birds with different habitat types and trophic levels from an urbanized coastal region of South Korea

Contamination status and characteristics of perfluorinated alkyl acids (PFAAs) including perfluorinated carboxylic acids (PFCAs) and perfluorinated sulfonic acids (PFSAs) was examined using liver tissue of birds - black-tailed gulls (Larus crassirostris), domestic pigeons (Columba livia var. domestica), pacific loons (Gavia pacifica), herons (Ardea cinerea), and egrets (Egretta garzetta and Ardea alba) - with different trophic levels, habitat types and migratory behaviors from an industrialized coastal region of South Korea. A wide range of PFAAs (1.09 ng/g to 1060 ng/g; median = 52.6 ng/g) were detected in bird livers from the Korean coasts with high detection frequency. Accumulation features of PFAAs in birds indicated that primarily trophic position and secondly habitat type influence the levels and composition of PFAAs, e.g., relatively high PFAA levels and high composition of odd-numbered long carbon chain PFCAs (perfluoroundecanoic acid (PFUnDA) and perfluorotridecanoic acid (PFTriDA)) and PFOS in higher trophic and marine birds. The prevalence of long carbon chain (≥14) PFCAs likely implies a wide use of fluorotelomer-based substances in Korea. Interspecies comparison in the accumulation profile of persistent organic pollutants (including polychlorinated biphenyls (PCBs), organochlorine pesticides, polybrominated diphenylethers (PBDEs), and PFAAs) reveals relatively high load of PFAAs in inland (pigeons) and estuarine (egrets/herons) species compared to marine bird species, indicating wide use of PFAAs in the terrestrial environment.

Waterbird Foraging Habitat Selection in Balikpapan Bay: Water Depth and Patch Area as Important Factors

Balikpapan Bay is one of the wetlands providing potential foraging habitat for waterbirds in Indonesia. Potential habitat loss due to oil industry expansion, recent waterbird occurrence, and co-occurrence of two closely related species with similar foraging characteristics led to habitat selection. Habitat selection could be affected by food as an intrinsic factor and extrinsic factor, for example, accessibility to the physical and biological components of the habitat. This study aimed to measure the foraging habitat selection, identify significant habitat quality parameters for the habitat selection and predict the foraging habitat selection model. We used one-zero sampling for collecting foraging habitat selection data, corer sampling for prey data, and collecting the abiotic environment, and Generalized Linear Modelling (GLM) to build the model. We identified four species as the migrant Little Egret (Egretta garzetta), Great Egret (Ardea alba), Purple Heron (Ardea purpurea), and Lesser Adjutant (Leptoptilos javanicus). All species, except Purple Heron, selected foraging habitats. A simple mathematic model of foraging habitat selection was significantly affected by two factors: water depth and patch area. A large patch area may provide primary prey abundance for waterbirds, while a low water depth level may give easy access to the prey.

Health risk assessment by toxic metals in little egrets (Egretta garzetta) and food chain contaminations.

This study analysed heavy metals from little egret (Egretta garzetta). Egret’s Eggs, egg shells, food (fish and insects), blood, meat samples (thigh, liver, and chest), water, soil and sediments samples were collected from the two selected sites of the study area. Samples were analysed on flame atomic absorption spectrometer after acid digestion. Detected metals were found almost inline of concentrations when compared with the both sites. Among detected metals Mn was found higher in concentration (µg/g) i.e. 18.509 followed by Zn i.e. 9.383, Ni, Cu, Pb and Cd. Sediment exhibited higher levels (µg/g) of metals (25.061) followed by the meat (19.044) egrets food (18.825), excreta (16.26), blood serums (4.577), eggs (3.626) and water samples (2.432).The level of metals in sediments of the study are showed environmental concerns. Health risks were also investigated that were compared to guidelines of WHO and FAO threshold limits. It was found a marginal health risk to life through detected metals. This study revealed that little egret are good bio-indicator for the screening and investigation of contaminates presence in the environment.

Impacts of Great Cormorant and Cattle Egret Nesting on Other Waterbirds in a Shared Breeding Site in Piedmont (NW Italy)

Some waterbird species are believed to have an impact on other waterbird species as they are able to usurp a limited habitat and destroy vegetation. In this study, we have analysed the nesting dynamics of five waterbird species: Grey Heron Ardea cinerea, Great Cormorant Phalacrocorax carbo, Little Egret Egretta garzetta, Black-crowned Night Heron Nycticorax nycticorax and Cattle Egret Bubulcus ibis, that had settled in a colony in the Royal Castle Park of Racconigi (Cuneo, NW Italy) over a 17-year period (2000 to 2017). The Great Cormorant and the Cattle Egret settled in the colony in 2008 and 2012, respectively. We analysed the relationships between the number of breeding pairs of the five species. In addition, we used the time series forecasting method to study the nesting dynamics and the impact of the new settlements on the pre-existing colony. The number of nests of the Great Cormorant and the Cattle Egret increased annually, and these species significantly affected the nesting trends of the other pre-existing species: Grey Heron, Black-crowned Night Heron and Little Egret. The Grey Heron mainly suffered from the occupation of its old nests by the Great Cormorant from 2008 to 2013. However, since 2014, the Grey Heron has been able to react, by displacing its breeding site to the tops of trees adjacent to the old heronry, and this has resulted in an even greater number of nests than before 2008. The Black-crowned Night Heron and the Little Egret suffered more from the settlement of the new species than the Grey Heron did, and started to suddenly or gradually abandon the breeding site. The colony has been modified profoundly by the settlement of the Great Cormorant and the Cattle Egret, and it is still subject to dynamics that could transform it in the coming years.

The bigger the better? Predation and prey size choice in a patchy environment

Prey individuals vary in their body size even within groups and are often scattered heterogeneously in patchy environments. A foraging predator has to evaluate and select the patches where it can maximize its energetic gains. We studied the foraging behavior of a predator (little egret, Egretta garzetta) hunting prey groups (goldfish, Carassius auratus) that differed in body size and composition across three different patches (one large, one mixed, and one small). We quantified predator’s stay time, return time and size-specific kills of the prey. The egret spent a similar amount of total time foraging in the three patches; however, it spent more time per-visit in pools containing large-bodied fish and also returned to those pools soonest after leaving to forage elsewhere, suggesting that the predators employ a time management strategy to maximize energetic returns. Furthermore, the egret preferentially killed larger individuals. Such size-selective predation can shift the prey size structure in the landscape and influence the dynamics of species interactions and eventually the structure of the communities.

Comparative Analysis of Heavy Metal Accumulation Pattern and Genotoxicity in Water Fowl

Waterfowl spend their lives mostly on water bodies include ducks, geese, and swans, also include birds such as coots, grebes, moorhens, shorebirds and seabirds etc. Wetlands in Pakistan offer habitat to a variety of migratory birds. Bird’s diversity facing problems due to loss of natural habitat and hunting causing serious issues to bird’s territories. Objective: To investigate bioaccumulation of heavy metals and genotoxicity in waterfowl. Methods: This study investigated bioaccumulation of heavy metals and genotoxic effects that could result from exposure of waterfowl to heavy metals in the Chenab River, Punjab, Pakistan. The three different species, common teal (Anas crecca), little egret (Egretta garzetta) and mallard (Anas platyrhynchos) were obtained from head Marala, River Chenab. The liver, kidneys, heart, muscle, blood, and feathers of birds were collected for the purpose of determining the presence of heavy metals. The study investigated the most common heavy metals Pb, Cd, Ni, and Cr indicating higher concentrations of heavy metals in blood and feathers from the study site. At study sites Pb Cr, Ni concentrations were high (P ≤ 0.05). Results: The results in the current study revealed metals concentration in different species trend as Anas crecca > Egretta garzetta > Anas platyrhynchos. The deposition of heavy metals in organ trends as Pb>Cr>Ni>Cd. The level of metals in blood trends as Pb>Cr>Ni>Cd. Metal concentrations in feathers trend as Pb>Cr>Ni>Cd. Conclusions: Expression analysis of anti-apoptosis Bcl-2 made for Egretta garzetta and genotoxicity results showed that the effect of metals in study groups found negative for the expression of the Bcl2 gene.

Three-dimensional niche partitioning between two colonially nesting ardeid species in central China

BackgroundInterspecific competition is known to be strongest between those species that are both closely related and sympatric. Egrets are colonially nesting wetland birds that often overlap and can therefore be expected to compete in roosting and nesting habitat as well as in diet. According to the niche partitioning hypothesis, it is to be expected that these similar species would show differentiation in at least one of the main niche dimensions to reduce competition. We tested niche partitioning between the colonially nesting Little Egret (Egretta garzetta) and Cattle Egret (Bubulcus ibis) in temporal, spatial and trophic dimensions.MethodsField study was conducted in three mixed egret colonies in Yangxian County, southwest Shaanxi Province, central China. For each nest colony we recorded its spatial location, the height of nesting trees and of nests, the height of roosting trees and of roosting individuals within the trees. We determined the first egg-laying and first hatching dates of the two species. Craw dissection of storm-killed egret nestlings was used to measure the diet. Six transects were surveyed to study foraging habitat selection.ResultsWe found that hatching time of Little Egrets peaked earlier (by about 1 month) than that of Cattle Egrets. Cattle Egrets nested and roosted higher than Little Egrets. The foraging habitats used by Little Egrets were dominated by river banks (73.49%), followed by paddy fields (13.25%) and reservoirs (10.84%), whereas Cattle Egret foraging sites were characterized by grasslands (44.44%), paddy fields (33.33%) and river banks (22.22%). Little Egrets consumed more fishes (65.66%) and Odonata larvae (13.69%) than Cattle Egrets, while Cattle Egrets were found feeding mainly on Coleoptera (29.69%) and Orthoptera (23.29%). Little Egrets preyed on larger mean biomasses of food items than Cattle Egrets.ConclusionsOur results confirm the niche partitioning hypothesis as a mechanism for coexistence among ecologically similar species. In two coexisting egret species, niche partitioning is multidimensional, such that the two coexistent species occupy differing ecological space based on all three temporal, spatial and trophic niche dimensions.

Abundance and behavior of little egrets (Egretta garzetta) near an onshore wind farm in Chongming Dongtan, China

Wind energy development has complex ecological consequences for many bird species. Previous environmental impact assessments (EIAs) for avian taxa mainly focused on the direct and indirect impacts of wind farm, such as collision mortality, flight changes, and habitat displacement. Their impact on waterbird behavior is less studied, especially foraging behaviors, which determine their energy budget and, thus, their reproduction and survival. In this study, we examined the effect of wind farms and the surrounding landscape on the abundance and energy budget-related behaviors of little egrets (Egretta garzetta), a dominant resident waterbird species near wind farms along the East China coast, from June to October 2019. Three egret behavioral categories were recorded, i.e., rest, locomotion, and foraging, and three foraging subcategories, i.e., stand-and-wait, walk slowly, and walk quickly. We also measured the distance to the wind farm and five landscape variables (aquaculture pond edge, ditch, marsh grassland, marsh open water, and river) within each quadrat. We found no significant effect of the distance to the wind farm on the abundance of little egrets, although their abundance was positively and negatively related to the aquaculture pond edge and marsh open water, respectively. The distance to the wind farm was positively correlated with stand-and-wait foraging. In addition, the river was negatively correlated with locomotion. Marsh open water was negatively correlated with walk slowly foraging. Therefore, the abundance of little egrets in Chongming Dongtan was not affected by the wind farm, although the wind farm resulted in changes to some of their behavior. Overall, the effect of this wind farm on little egrets was limited. We suggest aquaculture ponds mainly inhabited by egrets as alternatives for coastal wind farm development. We also highlight the behavioral evaluation of waterbirds as a complementary technique for EIAs of wind farm developments.