Shorebirds Research Articles

Linking wading bird prey selection to number of nests

Establishing a link between food availability and productivity is often central to the recovery of declining populations; however, differences in prey selection may influence how populations are affected by changes in prey availability. We determined prey selection and prey availability for 3 wading bird species, and investigated the effects of prey availability on the number of nests initiated by 6 wading bird species in the Florida Everglades, USA. To determine prey selection, we compared food items recovered from tricolored heron (Egretta tricolor), snowy egret (Egretta thula), and little blue heron (Egretta caerulea) nestlings to aquatic prey availability from throw-traps across the Everglades landscape from 2012 to 2014. Tricolored heron and snowy egret prey composition was statistically similar across years, with the majority of prey biomass coming from relatively large (>1.9 cm) marsh fish. Little blue heron prey composition differed from the other wading bird species, and contained a higher percentage of grass shrimp (Palaemonetes paludosus) and exotic fish species. Numbers of small heron nests were positively influenced by the availability of large marsh fish across the landscape, whereas numbers of nests for other wading bird species (wood stork [Mycteria americana], great egret [Ardea alba], white ibis [Eudocimus albus]) were not. Our results suggest differences among wading bird species in their prey selection and availability. Although small heron foraging may seem restricted by their specialization on marsh fishes, their short nesting cycles allow for the phenological flexibility to delay nesting until foraging conditions are optimal. Conversely, wood storks with longer nesting cycles are more temporally constrained but have greater flexibility in prey items and foraging range. The annual number of small heron nests may be more robust to hydrological variability as a result of management action or global change than the number of wood stork nests. The temporal constraints of nesting by wood storks indicate that management of supporting wetland systems should provide continuous habitat availability during the nesting season. © 2016 The Wildlife Society.

Cessation? Intensification? Or maybe moderation? What is best for farmland waders?

Cessation? Intensification? Or maybe moderation? What is best for farmland waders?

Annual survival rates of migratory shore and upland game birds

ABSTRACTBand recoveries from hunted populations are widely used to estimate survival and harvest rates. We used long‐term (1950–2010) band‐recovery data from the United States and Canada to estimate average survival and recovery rates for juvenile and adult sandhill cranes (Grus canadensis), American coots (Fulica americana), clapper rails (Rallus longirostris), and Wilson's snipe (Gallinago delicata). Banding data were typically sparse and Brownie recovery rates ( f ) were <1% for most species and age classes, so we also utilized encounters from birds banded and recovered throughout the year, including nonhunting recoveries. Estimated juvenile and adult annual survival rates based on combined dead recoveries were 0.917 (SE = 0.080) and 0.884 (SE = 0.006) for sandhill cranes; 0.325 (SE = 0.025) and 0.583 (SE = 0.008) for American coots; 0.368 (SE = 0.070) and 0.500 (SE = 0.025) for clapper rails; and 0.372 (SE = 0.077) and 0.653 (SE = 0.020) for Wilson's snipe. American coots had sufficient band‐recovery data during 1951–1987 to estimate annual process variation in survival for juveniles ( = 0.017) and adults ( = 0.056). Based on average estimated juvenile and adult survival rates for each species, stable populations could be achieved with average annual recruitment rates (expressed as fledged young per adult in the preseason population) of 0.15 (SD = 0.02) for sandhill cranes, 1.26 (SD = 0.19) for American coots, 1.41 (SD = 0.31) for clapper rails, and 0.97 (SD = 0.23) for Wilson's snipe, with uncertainty reflecting measurement error in survival rates. Although band‐recovery models can be successfully applied to small data sets (e.g., 300–3,000 total recoveries in our analyses), juvenile survival estimates lacked precision and annual variation was inestimable for most species, leading to considerable uncertainty for population modeling efforts. © 2016 The Wildlife Society.

Sweet salvation.

A bar-tailed godwit, I thought, feeling rather smug. I was photographing wading birds at the nearby salt marshes, and was very pleased with myself, not only for recognising the creature, but for getting some reasonable pictures. I also saw a flock of migrant geese and some lapwings, so altogether it was a satisfying trip.

Species Richness And Diversity of Sea Birds And Shore Birds of Red Sea Region In Massawa, Eritrea, North East Africa

Large number of birds are found in Red Sea region since there was no potential predators found in that region and hence the birds were selected it as a feeding and breeding ground for the sea and shore birds. The research site was around 0.05 sq.kms and it constitute about 50% of the island with mangrove cover and this also added for it for a nestling of their off-springs. The island with rich of Avicenna marina as a mangrove forests will cover most for shelter and breeding to these birds either migratory or resident birds and will act as symbiotic relationship with the birds. And from November to February during the survey 27 of sea and 11 of the shore birds were recorded. Shannon Wiener's index and Simpson's index for calculating the Diversity and Species Richness were used to represent the data. As per the results and the calculated data the richness and the diversity of the area of the birds were less than 1 and hence less diversity and abundance of the species.

Downwind Sedimentation and Habitat Development Following Ammophila arenaria Removal and Dune Erosion, Mason Bay, New Zealand

ABSTRACT Buckley, E.C.B.; Hilton, M.J., Konlechner, T.M., and Lord, J.M., 2016. Downwind sedimentation and habitat development following Ammophila arenaria removal and dune erosion, Mason Bay, New Zealand. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 268–272. Coconut Creek (Florida), ISSN 0749-0208. Since 2002 Ammophila arenaria has been progressively eradicated from a section of the transgressive dune system at Mason Bay, New Zealand to restore dune mobility. This study examines whether sand released from the treatment areas is accumulating in down-wind dune environments, particularly stony deflation surfaces. Deflation surfaces are nationally threatened habitats that contain at-risk native plants and are important flocking sites for endangered shore birds. Sand accumulation in the stonefield may cause a shift in texture and character from def...

ChemInform Abstract: Biomimetic Water‐Collecting Materials Inspired by Nature

AbstractReview: 176 refs.

Cocoi Heron (Ardea cocoi) Connects Estuarine, Coastal, Limnetic and Terrestrial Environments: an Assessment Based on Conventional Dietary and Stable Isotope Analysis

Wading birds are key components of wetlands, transporting matter, energy, contaminants and associated organisms among limnetic, estuarine, terrestrial and coastal ecosystems. The role of cocoi herons (Ardea cocoi) in connecting these ecosystems was studied in the only known estuarine and limnetic colonies in coastal plains of southern Brazil. Food obtained by parents around colonies when foraging for chicks and themselves was used to assess diet, by the analysis of 50 pellets, gastrointestinal contents and spontaneous regurgitated samples, as well as the analysis of stable isotopes (δ 13C and δ 15N) in the whole blood of 25 chicks. Cocoi herons were predominantly piscivorous in both environments, relying mainly on whitemouth croaker (Micropogonias furnieri) in the estuarine colony (47 % of samples and 36–56 % in the isotope mixing model), followed by Callinectes blue crabs and on trahira (Hoplias aff. malabaricus), in the limnetic colony (60 % of the dietary samples). However, for the limnetic colony, terrestrial and aquatic potential food sources contributed evenly to the isotopic mixing model. Furthermore, stable isotopes suggested that marine food sources, available on the coast 15 km away, were part of the diet of chicks in the limnetic colony. Complementary approaches used in the current study demonstrate that widely distributed, large-sized Ardea herons and other waterbirds are important for the connectivity of terrestrial and a range of aquatic environments. These birds contribute to the flow of matter and energy between wetlands and adjacent habitats and are key species for linking different food webs through complex and still poorly understood lateral subsides.

Stakeholder-led science: engaging resource managers to identify science needs for long-term management of floodplain conservation lands

Floodplains pose challenges to managers of conservation lands because of constantly changing interactions with their rivers. Although scientific knowledge and understanding of the dynamics and drivers of river-floodplain systems can provide guidance to floodplain managers, the scientific process often occurs in isolation from management. Further, communication barriers between scientists and managers can be obstacles to appropriate application of scientific knowledge. With the coproduction of science in mind, our objectives were the following: (1) to document management priorities of floodplain conservation lands, and (2) identify science needs required to better manage the identified management priorities under nonstationary conditions, i.e., climate change, through stakeholder queries and interactions. We conducted an online survey with 80 resource managers of floodplain conservation lands along the Upper and Middle Mississippi River and Lower Missouri River, USA, to evaluate management priority, management intensity, and available scientific information for management objectives and conservation targets. Management objectives with the least information available relative to priority included controlling invasive species, maintaining respectful relationships with neighbors, and managing native, nongame species. Conservation targets with the least information available to manage relative to management priority included pollinators, marsh birds, reptiles, and shore birds. A follow-up workshop and survey focused on clarifying science needs to achieve management objectives under nonstationary conditions. Managers agreed that metrics of inundation, including depth and extent of inundation, and frequency, duration, and timing of inundation would be the most useful metrics for management of floodplain conservation lands with multiple objectives. This assessment provides guidance for developing relevant and accessible science products to inform management of highly dynamic floodplain environments. Although the problems facing managers of these lands are complex, products focused on a small suite of inundation metrics were determined to be the most useful to guide the decision making process.

Biomimetic water-collecting materials inspired by nature.

Nowadays, water shortage is a severe issue all over the world, especially in some arid and undeveloped areas. Interestingly, a variety of natural creatures can collect water from fog, which can provide a source of inspiration to develop novel and functional water-collecting materials. Recently, as an increasingly hot research topic, bioinspired materials with the water collection ability have captured vast scientific attention in both practical applications and fundamental research studies. In this review, we summarize the mechanisms of water collection in various natural creatures and present the fabrications, functions, applications, and new developments of bioinspired materials in recent years. The theoretical basis related to the phenomenon of water collection containing wetting behaviors and water droplet transportations is described in the beginning, i.e., the Young's equation, Wenzel model, Cassie model, surface energy gradient model and Laplace pressure equation. Then, the water collection mechanisms of three typical and widely researched natural animals and plants are discussed and their corresponding bioinspired materials are simultaneously detailed, which are cactus, spider, and desert beetles, respectively. This is followed by introducing another eight animals and plants (butterfly, shore birds, wheat awns, green bristlegrass, the Cotula fallax plant, Namib grass, green tree frogs and Australian desert lizards) that are rarely reported, exhibiting water collection properties or similar water droplet transportation. Finally, conclusions and outlook concerning the future development of bioinspired fog-collecting materials are presented.

Three Observations of Colour Banded Shorebirds

Three Observations of Colour Banded Shorebirds

Genome Sequence of a Urease-Positive Campylobacter lari Strain.

Campylobacter lari is frequently isolated from shore birds and can cause illness in humans. Here, we report the draft whole-genome sequence of a urease-positive strain of C. lari that was isolated in estuarial water on the coast of Delaware, USA.

First report of Oligocene vertebrate footprints from Iran

Mammalian and avian footprints documented from the Oligocene of the Khaf area, northeastern Iran, represent the first reported Oligocene vertebrates in the country. Avian and mammalian footprints are located on the upper bedding plane of two successive, medium-bedded, brownish litharenite sandstone layers. Layer one has more than 97 concave epirelief avian footprints that are arranged in 29 straight or curved trackways. Layer two contains dispersed mammalian footprints. The avian footprints include four slender digits with sharp tips, three oriented forward (II–IV), and one of them oriented backward (I). Metapodium imprints are visible in some footprints as isolated circular concavities. The avian footprints are attributed to Gruipeda intermedia. In order to establish this identification, we re-affirm the diagnostic features of Gruipeda, Iranipeda and Charadriipeda, and also re-evaluate the ichnospecies assigned to these ichnogenera. The mammalian footprints from the Khaf locality include Khafipus khadari nov. igen and nov. isp., which are large plantigrade footprints that have five dispersed digit imprints in the pes or manus and heel or digit imprints that are enclosed by circular ridges, which are disconnected from each other. Palaeotheriipus isp. is a tridactyl mammalian footprint that is large in the heel with forward oriented toe imprints. Platykopus isp. includes one footprint as a broad plantigrade impression with imprints of five connected digits. Avian footprints are attributed to anisodactyl shore birds and mammalian footprints are those of perissodactyls and large mammals such as ursid carnivores. The footprints from the Oligocene of Iran documented here add to a growing, but much understudied global record of Cenozoic tetrapod footprints and suggest a broad paleogeographic distribution of various, particularly avian, ichnogenera.

4대강 사업 이전 낙동강 하구 철새 도래지의 주요 조류 현황

낙동강 하구의 생태적 역할과 서식하는 조류종을 바탕으로 한 체계적이고 지속가능한 하구 관리를 위해서는 이곳을 이용하는 조류현황에 대한 이해가 필요하다. 따라서 본 연구에서는 부산발전연구원 조류모니터링 자료(2003-2011)를 활용하여 4대강 사업 이전의 낙동강 하구의 조류 현황을 파악하고자 하였다. 낙동강 하구에서 관찰된 조류 중 겨울새의 비중이 종수에서는 38.36%, 개체수에서는 63.14%로 가장 많은 비율을 차지하여, 낙동강하구가 겨울철새의 도래지임을 보여주었다. 조사권역별로는 명지(208,651개체), 서낙동강(202,444개체), 을숙도(153,232개체), 백합 도요등(150,595개체) 순으로 누적개체수가 많았으며, 을숙도(171종), 서낙동강(141종), 일웅도(124종), 명지(123종), 삼락둔치(121종) 순으로 종수가 많은 것으로 나타났다. 낙동강하구에서 기록된 232종 중 청둥오리가 197,870개체, 전체의 17.71%로 가장 많이 관찰되었으며, 다음으로 흰뺨검둥오리(8.85%), 괭이갈매기(6.48%), 큰기러기(6.09%), 홍머리오리(5.16%), 민물도요(4.22%) 순으로 우점하고 있는 것으로 조사되었다. 혹부리오리류를 제외한 대부분의 분류군들이 연간 변동은 보였지만 조사 기간 중 점차 증가하는 추세를 보였다. 가마우지류, 고니류, 갈매기류 등은 다른 분류군의 조류 보다 조사 기간 동안의 연간 변동 폭이 큰 것으로 나타났는데, 특히 고니류의 경우 5차년도(2007-2008)와 7차년도(2009-2010)에 개체수가 전년도에 비해 크게 감소하였으며, 또한 8차년도(2010-2011)에는 도요 물떼새류, 갈매기류, 할미새류, 기타 새류에서 개체수의 감소가 관찰되어 이들 분류군의 서식에 영향을 줄 수 있는 환경변화가 있었던 것으로 보인다. 전체적으로는 서식지의 특성이 우점종의 분포와 연관성이 있는 것으로 조사되었다. Understanding bird status is essential for the systematic and sustainable management of the Nakdong River Estuary, taking into consideration the relationship between ecosystems and the bird species. In this study, bird status in the Nakdong River Estuary Bird Sanctuary prior to the Four Major Rivers Project was analyzed using the bird monitoring data (2003-2011) from surveys conducted by the Busan Development Institute. The high percentage of winter visitors in terms of both species diversity (38.36%) and individual bird numbers (63.14%) suggest that the Nakdong River Estuary is an important wintering site for migratory birds. Cumulative numbers of individual birds were higher in Myungji (208,601), West Nakdong River (202,444), Eulsukdo (153,232), and Baekhap Doyodeung (150,595). The total numbers of migratory species were higher in Eulsukdo (171), Ilungdo (124), Myungji (132), and Samrak (121). Among the 232 species found in the Nakdong River Estuary, Anas platyrhynchos (17.71%) was the most common species, followed by Anas poecilorhyncha (8.85%), Larus crassirostris (6.48%), Anser fabalis (6.09%), Anas penelope (5.16%), and Calidris alpina (4.22%). Most bird taxa, except shelducks, showed annual fluctuations in individual numbers, with increasing frequency during survey periods. Of these, cormorants, swans, and gulls showed higher fluctuations than other taxa. Swans decreased drastically in numbers in 2007-2008 and 2009-2010 compared to previous years. Shore birds, gulls, wagtails, and other forest birds were also less common in 2010-2011. These results suggest that there were some environmental changes that might have affected the birds in the Nakdong River Estuary. Overall, the results suggest that habitat types affect the distribution of dominant species.

Validation of a Mechanistic Model for Non-Invasive Study of Ecological Energetics in an Endangered Wading Bird with Counter-Current Heat Exchange in its Legs.

Mechanistic models provide a powerful, minimally invasive tool for gaining a deeper understanding of the ecology of animals across geographic space and time. In this paper, we modified and validated the accuracy of the mechanistic model Niche Mapper for simulating heat exchanges of animals with counter-current heat exchange mechanisms in their legs and animals that wade in water. We then used Niche Mapper to explore the effects of wading and counter-current heat exchange on the energy expenditures of Whooping Cranes, a long-legged wading bird. We validated model accuracy against the energy expenditure of two captive Whooping Cranes measured using the doubly-labeled water method and time energy budgets. Energy expenditure values modeled by Niche Mapper were similar to values measured by the doubly-labeled water method and values estimated from time-energy budgets. Future studies will be able to use Niche Mapper as a non-invasive tool to explore energy-based limits to the fundamental niche of Whooping Cranes and apply this knowledge to management decisions. Basic questions about the importance of counter-current exchange and wading to animal physiological tolerances can also now be explored with the model.

Linking Dynamic Habitat Selection with Wading Bird Foraging Distributions across Resource Gradients.

Species distribution models (SDM) link species occurrence with a suite of environmental predictors and provide an estimate of habitat quality when the variable set captures the biological requirements of the species. SDMs are inherently more complex when they include components of a species’ ecology such as conspecific attraction and behavioral flexibility to exploit resources that vary across time and space. Wading birds are highly mobile, demonstrate flexible habitat selection, and respond quickly to changes in habitat quality; thus serving as important indicator species for wetland systems. We developed a spatio-temporal, multi-SDM framework using Great Egret (Ardea alba), White Ibis (Eudocimus albus), and Wood Stork (Mycteria Americana) distributions over a decadal gradient of environmental conditions to predict species-specific abundance across space and locations used on the landscape over time. In models of temporal dynamics, species demonstrated conditional preferences for resources based on resource levels linked to differing temporal scales. Wading bird abundance was highest when prey production from optimal periods of inundation was concentrated in shallow depths. Similar responses were observed in models predicting locations used over time, accounting for spatial autocorrelation. Species clustered in response to differing habitat conditions, indicating that social attraction can co-vary with foraging strategy, water-level changes, and habitat quality. This modeling framework can be applied to evaluate the multi-annual resource pulses occurring in real-time, climate change scenarios, or restorative hydrological regimes by tracking changing seasonal and annual distribution and abundance of high quality foraging patches.

Fallen Nestlings and Regurgitant as Mechanisms of Nutrient Transfer from Nesting Wading Birds to Crocodilians

Positive interspecific interactions can shape fundamental wetland ecosystem dynamics, including energy transfer and spatial distribution of nutrients. Birds, by foraging in one location and nesting in another, commonly act as between-ecosystem nutrient vectors. However, the distribution of nutrients within nesting areas and mechanisms of transfer to other trophic levels are poorly understood. We report on measurements of available food transferred from nesting long-legged wading birds to American alligators (Alligator mississippiensis) in the Everglades of Florida, USA. Using throughfall traps, a historic dataset on nesting success and a literature-parameterized alligator energy budget, we estimated the potential food available to alligators via regurgitant and nestling carcasses, and compared that to alligator food requirements. Although dropped regurgitant is of little importance to scavenging alligators, we estimate that nestling carcasses throughout the ecosystem could support the energetic requirements of hundreds of alligators for periods of several months. This resource occurs during the dry season, when alligator thermoregulatory opportunities are relatively scarce and female alligators are mobilizing resources for egg-laying. Our results indicate that through fallen nestlings, wading bird nesting colonies have strong potential to benefit alligators. This facilitative exchange may be globally widespread, forming a keystone process in many tropical and subtropical wetlands.

Social Cues and Environmental Conditions Influence Foraging Flight Distances of Breeding Wood Storks (Mycteria americana)

Abstract. The influence of both environmental conditions and social cues on the distance flown to foraging sites was examined for breeding Wood Storks (Mycteria americana) in the Florida Everglades, USA. Adult Wood Storks (n= 73) were followed in a small plane from their nesting colony to their foraging locations during the time when adult Wood Storks were incubating and feeding chicks. On average, foraging sites were close to the nesting colony (mean = 9.6 km ± 1.1), and in shallow water (mean = 9.9 cm ± 0.7) that was receding at a moderate rate (-0.36 cm/day ± 0.13). Wood Storks landed at foraging sites already occupied by other white wading birds 99% of the time, with a mean flock size of 64 ± 14 birds. Model selection identified flock size and water recession rate as the most important variables that influenced Wood Stork foraging flight distances. Distances flown to foraging sites increased with increasing flock sizes and decreased with increasing recession rates (increasing by 39% and decreasing by ...

Top–down control by great blue herons Ardea herodias regulates seagrass‐associated epifauna

Top predators can influence the structure and function of plant and animal communities. In coastal marine systems, fish, shark and mammal population declines are major drivers of recent ecosystem‐level change. Cascading effects of predatory wading birds, however, are less understood, even though wading bird populations have declined in many regions. We quantified the effects of predation by the piscivorous great blue heron Ardea herodias fannini on fish, invertebrates and epiphytes living in eelgrass Zostera marina. We found that herons forage on benthic fish in seagrass meadows, and foraging intensity increased from late spring until midsummer. When we experimentally excluded herons, benthic fish abundance increased, and the invertebrate assemblage shifted to more shrimp‐dominated assemblages while grazing gammarid amphipod abundance declined. These shifts were associated with reduced epiphyte abundance when herons were excluded, reflecting a four‐level trophic cascade and mediated by shifts in the grazer assemblage. In summary, we found that a piscivorous wading bird species exerts top down control in a subtidal seagrass ecosystem. Losses and recovery of wading birds could have ecosystem‐level ecological consequences that may need to be considered in the context of concern for overfishing and predator recovery in marine coastal management.

Physiological condition of juvenile wading birds in relation to multiple landscape stressors in the Florida Everglades: effects of hydrology, prey availability, and mercury bioaccumulation.

The physiological condition of juvenile birds can be influenced by multiple ecological stressors, and few studies have concurrently considered the effects of environmental contaminants in combination with ecological attributes that can influence foraging conditions and prey availability. Using three temporally distinct indices of physiological condition, we compared the physiological response of nestling great egrets (Ardea alba) and white ibises (Eudocimus albus) to changing prey availability, hydrology (water depth, recession rate), and mercury exposure in the Florida Everglades. We found that the physiological response of chicks varied between species and among environmental variables. Chick body condition (short-term index) and fecal corticosterone levels (medium-term) were influenced by wetland water depth, prey availability, region, and age, but not by mercury contamination. However, mercury exposure did influence heat shock protein 70 (HSP70) in egret chicks, indicating a longer-term physiological response to contamination. Our results indicate that the physiological condition of egret and ibis chicks were influenced by several environmental stressors, and the time frame of the effect may depend on the specialized foraging behavior of the adults provisioning the chicks.