Search

Simple Summary: Plastic pollution has become one of the main emerging ecological problems that has gained growing public and scientific interest in recent years. In this work, we detected the presence of plastics and other synthetic debris in a less studied ecosystem: inland wetlands. There, we confirmed the presence of anthropogenic materials in the nests of two bird species, the gull-billed tern (Gelochelidon nilotica) and the black-winged stilt (Himantopus himantopus), in a biosphere reserve. The detected debris probably originated from human activities (agriculture and domestic waste) and was probably dispersed by wind and water. Although no damage to the studied species was detected, the situation requires monitoring, which must extend to other wetland points and other species. Our paper records the spread of plastic pollution through wetland ecosystems and its interaction with unexpected wildlife. Despite more studies being carried out to know the impacts associated with plastic debris and much effort being spent on marine ecosystems, the impacts of plastics on terrestrial and freshwater species remain largely unknown. Here, we explored the presence of anthropogenic materials in nests of two wader species, the gull-billed tern (Gelochelidon nilotica) and the black-winged stilt (Himantopus himantopus), breeding on the inland salt lakes in the "La Mancha Húmeda" Biosphere Reserve, Central Spain. We revealed the presence of anthropogenic debris, mainly macroplastics (>5 mm), in 2.4% and 12.5% of the sampled nests of the gull-billed tern and the black-winged stilt, respectively. The fragments found in nests ranged from 8 mm to 257 mm for the gull-billed tern and from 7 mm to 19 mm for the black-winged stilt. This debris showed no clear pattern of color or size and probably originated both in the agricultural activities in the surroundings and domestic refuse. Although we did not detect any pernicious impacts on adults or chicks (e.g., entangled, injured, or dead individuals), the presence of plastics and other human waste directly placed in nests located in a protected area should warn us about the ubiquity of these pollutants, and the endocrine and immunological effects, among others, that may reduce the recruitment of new animals to the population should be assessed. [ABSTRACT FROM AUTHOR]

Despite more studies being carried out to know the impacts associated with plastic debris and much effort being spent on marine ecosystems, the impacts of plastics on terrestrial and freshwater species remain largely unknown. Here, we explored the presence of anthropogenic materials in nests of two wader species, the gull-billed tern (Gelochelidon nilotica) and the black-winged stilt (Himantopus himantopus), breeding on the inland salt lakes in the “La Mancha Húmeda” Biosphere Reserve, Central Spain. We revealed the presence of anthropogenic debris, mainly macroplastics (>5 mm), in 2.4% and 12.5% of the sampled nests of the gull-billed tern and the black-winged stilt, respectively. The fragments found in nests ranged from 8 mm to 257 mm for the gull-billed tern and from 7 mm to 19 mm for the black-winged stilt. This debris showed no clear pattern of color or size and probably originated both in the agricultural activities in the surroundings and domestic refuse. Although we did not detect any pernicious impacts on adults or chicks (e.g., entangled, injured, or dead individuals), the presence of plastics and other human waste directly placed in nests located in a protected area should warn us about the ubiquity of these pollutants, and the endocrine and immunological effects, among others, that may reduce the recruitment of new animals to the population should be assessed.

Background Coastal saltpans are a common supratidal human-modified wetland habitat found within many coastal landscape mosaics. Commercial salt production and aquaculture practices often result in the creation of exposed coastal substrates that could provide suitable breeding habitat for waterbird populations; however, few studies have quantified waterbird breeding success in these artificial wetlands. Methods Here we examine the nesting behavior of the Gull-billed tern (Gelochelidon nilotica) breeding in the Nanpu coastal saltpans of Bohai Bay, Yellow Sea, China over three consecutive nesting seasons (2017–2019) by using nest survival model in Program MARK. Results The results revealed that nest survival of Gull-billed terns in coastal saltpans (0.697) was higher than previously published estimates from other regions, with an estimated daily survival rate (DSR) of 0.982 ± 0.001 (±95% CI). High nest survival was mainly attributed to low levels of human disturbances and low predation rates, while exposure to strong winds, flooding and silting were the main factors causing nest failure. Model-averaged estimates revealed that eggs laid in nests located on ‘habitat islands’ with feather or clam shell substrates were most likely to hatch. Initiation date, nest age, clutch size and quadratic effects of nearest-neighbor distance, nearest distance to road and nearest distance to water were all significant predictors of nest success, but the nest survival declined overall from 2017 to 2019 due to the degradation and loss of breeding habitat anthropogenically caused by rising water levels. Discussion Coastal saltpans represent an alternative breeding habitat for the Gull-billed tern populations in Bohai Bay, but conservation management should prioritize flood prevention to improve the extent and quality of breeding habitat, concurrent with efforts to create further ‘habitat islands’ with suitable nesting substrate.

North American populations of Gull-billed Terns (Gelochelidon nilotica) are thought to winter in low numbers throughout Central America, with highest single-site concentrations of up to 200 individuals known from the Panama Canal zone. This paper presents information on a previously unknown stopover and wintering site in southern Honduras, where up to 1,640 individuals, approximately 20% of the entire North American metapopulation, are present during the non-breeding season. This site may be of key importance to full cycle conservation of declining North American populations. Information on habitat use in the eastern Gulf of Fonseca is also included. [ABSTRACT FROM AUTHOR]

Gull-billed Terns (Gelochelidon nilotica) have historically demonstrated variability in nest-site selection and reproductive success throughout their breeding range. However, few studies have investigated the breeding parameters of Gull-billed Tern populations on barrier islands in the northern Gulf of Mexico, USA. The main objective of this study was to investigate annual variability of breeding population size, hatching success, and causes of nest failure during eight breeding seasons (2009-2016). Annual variation was observed in colony sizes (Range = 1-68 nests), colony locations (among five islands), and hatching success (0-93%). Mean hatching success was 56% and flooding was the main cause of failure, accounting for 64% of all failed nests. Additionally, nest site habitat characteristics were compared between successful and unsuccessful Gull-billed Tern nests. Nest substrate composition differed between successful and failed nests, and successful nests were also associated with higher elevation, greater distance from die high tide line, and less vegetative cover. There was considerable variation in Gull-billed Tern breeding population size and hatching success, which may be attributable to the dynamic nature of barrier island habitats. Long-term monitoring is required to better understand the breeding dynamics of Gull-billed Terns, but conservation efforts should consider maintaining island habitats that are protected from flooding and have adequate nesting substrate, minimal vegetation, and limited disturbance from humans and predators. [ABSTRACT FROM AUTHOR]

From 12 May 2013 to 29 May 2013, the Gull-billed Tern (Gelochelidon nilotica) colony at the San Diego Bay National Wildlife Refuge, California, US, experienced a mass die-off of at least 92 adults, representing 71–92% of the breeding population on the US west coast. Cause of death was determined to be peritonitis due to perforations of the intestine by a large quantity of acanthocephala (Profilicollis [=Polymorphus] altmani). This is a unique report of P. altmani infecting G. nilotica, and a report of a great impact to a tern population in southern California. Mole crabs (Emerita analoga), the intermediate host for P. altmani and a major component of the Gull-billed Tern diet in San Diego, were found in the stomachs of necropsied terns along with cystacanths, and are the presumed source of the parasite infection. The tern’s dietary reliance upon mole crabs likely amplified parasite transmission and infection. We suggest additional research to determine factors that influence parasite infection of intermediate and definitive hosts, particularly mole crabs, given that they are a vital resource for migrating birds within the coastal zone. [ABSTRACT FROM AUTHOR]

Here we report the first documented records of the Gull-billed Tern, Gelochelidon nilotica (Gmelin, 1789), from Rio de Janeiro state, on the coast of southeastern Brazil. The species was recorded in Sepetiba Bay, in Rio de Janeiro municipality, in August and September 2014 and September 2015. In all cases, the birds had full nuptial plumage, which suggests breeding in the austral spring and summer. This is inconsistent with the possibility of a migrant from the Northern Hemisphere. The regular monitoring of the coastal environments of this region should provide more conclusive insights into seasonal patterns and the migration routes of this species. [ABSTRACT FROM AUTHOR]

The article reports on bird sightings in Connecticut from June 1 to July 31, 2015. Topics covered include the presence of White-winged Scoter at the Wethersfield Cove, the appearance of Red-throated Loon at Milford Point, and the sight of a Black Scoter at Harkness Memorial State Park. Also presented are images of a Cattle Egret, Gull-billed Tern, and the Great Northern Loon.

Gelochelidon nilotica and Sterna hirundo are two sympatric breeding species. The mitogenomes of G. nilotica and S. hirundo are 16,748 bp and 16,707 bp in size. Both two mitogenomes reveal the same gene order and genomic organization to that of typical avian mtDNA. The first conserved blocks with a interrupted poly-C are present in the two species control regions, but not existed in S. albifrons. Seventeen and 11 simple sequence repeats are found in G. nilotica and S. hirundo, respectively. Phylogenetic analysis indicated that Sternidae has the closest relationship with Laridae. We supported that Stercorariidea is a sister group to (Alcidae (Laridae, Sternidae)), G. nilotica is genetically most related to S. hirundo (all belonged to Black cap species), but distant with S. albifrons (White blaze species) in kinship, and suggested that the status of Larus vegae should be further investigated. [ABSTRACT FROM AUTHOR]

ABSTRACT Because of the variability in the types of human activities to which animals are exposed and the associated responses by different species, there is a lack of consensus on the effects of humans on wildlife behavior. We studied the effects of military air traffic, all-terrain vehicles, off-road vehicles, and pedestrians on the nesting behaviors of least terns ( Sternula antillarum), common terns ( Sterna hirundo), gull-billed terns ( Gelochelidon nilotica), and black skimmers ( Rynchops niger) at North Core Banks, Cape Lookout National Seashore (CALO), North Carolina. We deployed digital audio recorders and time-lapse cameras within 9 colonies from May to August 2010-2011 and sampled nesting behaviors before, during, and after human activities. There was no evidence that military or civilian aircraft adversely affected incubation behavior for any of the focal species. The mean incubation rate by least terns was less during pedestrian events than control periods (91% vs. 79%, S = −2.2, P = 0.04). The current patterns of aircraft operations are unlikely to affect colonial waterbird demographics. Current beach management policies restricting human activity to >50 m from colony boundaries mitigated adverse impacts to nesting colonial waterbirds. © 2015 The Wildlife Society. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Journal of Biology is the property of Instituto Internacional de Ecologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Blood levels of corticosterone have been traditionally analyzed to assess stress levels in birds; however, measuring steroid hormone metabolites in feces and droppings has gained much interest as a noninvasive technique successfully used for such purposed in vertebrates. Diet may affect these fecal metabolite levels (e.g., due to nutritional stress), however, this variable has not been taken into account in studies with chicks despite the great dietary flexibility of many avian species. In this study, we addressed for the first time this key issue and validated the technique in wild gull-billed tern chicks ( Gelochelidon nilotica ). Several enzyme immunoassays were used to determine the most appropriate test to measure the stress response. Subsequently, we performed an experiment in captivity to assess adrenocortical activity in gull-billed tern chicks fed with two diets: piscivorous vs. insectivorous. Finally, the relation between the chicks’ growth rate and excreted immunoreactive glucocorticoid metabolites (EGMs) was also evaluated. We found the immunoreactive cortisone metabolites to be a good index of stress (as being an index of adrenocortical reactivity) in chicks of this species. Fish-fed chicks had higher levels of cortisone metabolites when comparing both concentration and total daily excreted metabolites. Within each treatment diet, cortisone metabolite levels and growth rates were negatively correlated. These findings suggest that the diet should be considered when using this technique for comparative purposes and highlight the trade-off between stress levels and chicks growth rates. [ABSTRACT FROM AUTHOR]

The nesting success and nestling growth were studied in a Gull-billed TernGelochelidon niloticaGmelin, 1789 colony located in western Iran, during the 2008 breeding season. The nesting success was modelled in order to assess the effects of various nest-site parameters and nest initiation date. Nestling growth rate, described as body mass, head-bill and tarsus growth per day during the first 10 days of age, was analyzed in relation to brood size and the hatching position of nestlings. Mean daily growth rate of nestlings’ mass (7.82 ± 0.35 g/day) varied in broods of different size but remained independent of nestlings’ hatch order within the brood. Similarly, the growth rate of head-bill length was influenced only by brood size while neither brood size nor hatching position had a significant effect on the wing length growth rate. Nest initiation dates and plant cover around the nests were the most important factors predicting nesting success. As time of breeding period progressed, the rate of nesting success increased. Higher plant cover around the nest also increased the nesting success, probably by hiding the eggs and providing shelter for nestlings thus decreasing predation and mortality rate. [ABSTRACT FROM AUTHOR]

The article presents a study on the genetic structure, diversity and subspecies status of Gull-billed Terns or Gelochelidon nilotica from the U.S. Nuclear microsatellite markers and mitochondrial DNA sequences were used in the study to examine the genetic diversity and differentiation patterns among Gull-billed Tern populations from Virginia, Texas, and California. Texas is considered an important habitat for large populations because it has the highest genetic diversity.

There is a growing body of evidence that maternal antibodies transferred to offspring have potential implications in the evolutionary ecology of birds. This transfer of maternal antibodies is a potentially flexible mechanism of non-genetic inheritance by which mothers could favour some offspring over others and/or increase offspring survival, but this is a phenomenon that remains poorly understood. We examined sex-specific deposition of maternal antibodies and its effects on early (5 d) and fledging (17 d) survival in semiprecocial chicks of the gull-billed tern Gelochelidon nilotica, a long-distance migratory bird. Mothers transferred a significantly greater amount of maternal antibodies to sons than to daughters. We found evidence for positive associations between maternal antibody levels at hatching and early offspring survival. This association might be sex-specific, which can be understood as a mechanism of parental favouritism for the most sensitive sex. [ABSTRACT FROM AUTHOR]

Nest-site characteristics and hatching success were studied at a mixed-species colony of Black-winged Stilts Himantopus himantopus and Gull-billed Tern Gelochelidon nilotica in AghGol wetland, Hamedan Province, Iran during the 2008 breeding season. Species-specific preferences and a possible correlation between hatching success and nest location were analysed. Black-winged stilts select significantly closer points to the water edge than random points while the distance to the water edge did not vary between preferred and non-preferred locations for Gull-billed Terns. Plant density was significantly higher in Gull-billed Terns than Black-winged Stilt nest-sites, which also preferred areas of lower plant density. Hatched Gull-billed Tern nests had significantly higher plant density around the nest than failed nests. Overall, hatching success of Gull-billed Tern was higher than that of Black-winged Stilt; mainly because of disturbances resulting from a decrease in the water level. [ABSTRACT FROM AUTHOR]

Abstract: Bird growth rates are usually derived from nonlinear relationships between age and some morphological structure, but this procedure may be limited by several factors. To date, nothing is known about the capacity of plasma metabolite profiling to predict chick growth rates. Based on laboratory-trials, we here develop predictive logistic models of body mass, and tarsus and wing length growth rates in Gull-billed Tern Gelochelidon nilotica chicks from measurements of plasma metabolite levels at different developmental stages. The predictive model obtained during the fastest growth period (at the age of 12days) explained 65–68% of the chicks'' growth rates, with fasting triglyceride level explaining most of the variation in growth rate. At the end of pre-fledging period, β-hydroxybutyrate level was also a good predictor of growth rates. Finally, we carried out a field test to check the predictive capacity of the models in two colonies of wild Gull-billed Tern, comparing field-measured and model-predicted growth rates between groups. Both, measured and predicted growth rates, matched statistically. Plasma metabolite levels can thus be applied in comparative studies of chick growth rates when semi-precocial birds can be captured only once. [Copyright &y& Elsevier]

The article highlights the impact of the diet on semi-percocial Gull-billed Terns Gelochelidon chicks. In the study carried out by the authors, they found that chicks with high fish intake has higher energy and macronutrient compared from the rest of the group. The study also disclosed that lipid assimilation efficiency was the only standard that did change with the last phase of growth of the bird. The authors conclude that diet quality and growth requirements are the factors that dictates the growth of a chick.

The article offers information on the reports from October to November 2015 on birds in Great Britain including cackling goose, black kite and gull-billed tern.

The article offers a study which gathers records of Gull-billed Tern nests on roofs in Florida from 1998 to 2007 and conducts surveys for roof-nesting birds in northwest Florida from 2004 to 2007. It aims to identify whether more Gull-billed Terns nested on roofs in subsequent years as expected. According to the article, records recommend that roof-nesting by Gull-billed Tern nests in the state will continue to grow, as long as suitable gravel roofs are available. However, it noted that the future significance of gravel roofs as nesting sites for Gull-billed Terns in the state is still uncertain provided that gravel-covered roofs are not used anymore and the mean success rate for Gull-billed Tern nests on roofs is unknown.

Presents a study that investigated the influence of gull-billed terns on nest site choice of black skimmers. Nest site characteristics; Methodology; Results of the study.

Investigates whether black skimmers gain an antipredator advantage by nesting with gull-billed terns. Natural predators encountered by the black skimmer colonies; Response of gull-billed terns to both natural and simulated predators; Perception of the black skimmers to the natural and simulated predators.

Looks at the colony-site dynamics of Gull-billed Terns, using a Markov process model, highlighting the analysis of the breeding numbers in this species from 1993 through 1996 along with Common Terns and Black Skimmers at colony sites along coastal Virginia. Examination of flooding events and renesting; Details on the development of the model; What the results of the examination revealed.

Background: Coastal saltpans are a common supratidal human-modified wetland habitat found within many coastal landscape mosaics. Commercial salt production and aquaculture practices often result in the creation of exposed coastal substrates that could provide suitable breeding habitat for waterbird populations; however, few studies have quantified waterbird breeding success in these artificial wetlands., Methods: Here we examine the nesting behavior of the Gull-billed tern ( Gelochelidon nilotica ) breeding in the Nanpu coastal saltpans of Bohai Bay, Yellow Sea, China over three consecutive nesting seasons (2017-2019) by using nest survival model in Program MARK., Results: The results revealed that nest survival of Gull-billed terns in coastal saltpans (0.697) was higher than previously published estimates from other regions, with an estimated daily survival rate (DSR) of 0.982 ± 0.001 (±95% CI). High nest survival was mainly attributed to low levels of human disturbances and low predation rates, while exposure to strong winds, flooding and silting were the main factors causing nest failure. Model-averaged estimates revealed that eggs laid in nests located on 'habitat islands' with feather or clam shell substrates were most likely to hatch. Initiation date, nest age, clutch size and quadratic effects of nearest-neighbor distance, nearest distance to road and nearest distance to water were all significant predictors of nest success, but the nest survival declined overall from 2017 to 2019 due to the degradation and loss of breeding habitat anthropogenically caused by rising water levels., Discussion: Coastal saltpans represent an alternative breeding habitat for the Gull-billed tern populations in Bohai Bay, but conservation management should prioritize flood prevention to improve the extent and quality of breeding habitat, concurrent with efforts to create further 'habitat islands' with suitable nesting substrate., Competing Interests: The authors declare there are no competing interests., (©2020 Wu et al.)

Around forty bird species habitually reproduce in the Northern Hemisphere during summer, and migrate to the Southern Hemisphere during northern winter. These migrating birds fly together in large or small groups until they have reached the Caribbean, Central American, or Brazilian shores. Charadrius semipalmatus, Bonaparte 1825, is one of these migrating species that uses resting and feeding areas along eastern and western coasts of North and South America, with several records for the Brazilian coast, and very few for the inland country. On November 24, 2011, an individual of this species was observed on the banks of one of the lakes that compose a complex of about 40 temporary lakes within the Karst of Lagoa Santa Environmental Protection Area. On October 29 and 30, 2012 a single individual of Gelochelidon nilotica, Gmelin 1789, was also observed in Sumidouro State Park. We suggest that these specimens have used the Atlantic Ocean migration route, following the São Francisco River Basin, until the karst area. Although highly impacted, the temporary lakes within the Karst of Lagoa Santa still harbor a significant number of bird species, and serve as resting and feeding places for migratory or errant species that are still eliciting new records.