Seabird Nests Research Articles

Frequency and composition of anthropogenic debris in the nests of sooty gulls Larus (Adelarus) hemprichii Bruch, 1853 from Sir Bu Na’ir Island, United Arab Emirates.

The proliferation and dispersion of marine debris results with various, often harmful, interactions with marine fauna. One such interaction, that is poorly investigated, is the incorporation of marine debris into the nests of seabirds, which at times results in hatchling entanglement. The objective of this study is to investigate the qualitative and quantitative aspects of marine debris used in the construction of the nests of sooty gulls Larus (Adelarus) hemprichii (Bruch, 1853) from Sir Bu Na’ir Island, United Arab Emirates. The numeric and gravimetric proportions of debris were documented following classification of type, color and presumed source. The results show that 11.2% of the 258 active nests examined contained debris. On average, nests included 2.0 ± 0.4 items of 6.1 ± 1.9 g mass. Non-plastic rubbish, particularly metals and glass, were the predominant debris utilized. The results reflect that sooty gulls frequently use anthropogenic debris as nesting materials in Sir Bu Na’ir Island.

Trophic interactions between the Kelp Gull (Larus dominicanus) and Royal and Cayenne terns (Thalasseus maximus maximusandThalasseus sandvicensis eurygnathus, respectively) in a human-modified environment

Many closely related seabirds nest in mixed colonies, and this association may result in interspecific interactions such as competition for common resources and kleptoparasitism. Trophic interactions were evaluated between the Kelp Gull (Larus dominicanus Lichtenstein, 1823) and Royal and Cayenne terns (Thalasseus maximus maximus (Boddaert, 1783) and Thalasseus sandvicensis eurygnathus (Saunders, 1876), respectively) nesting at a mixed-species colony in an area with high availability of recreational fishery waste for the opportunistic Kelp Gull. Diet analyses were based on gull chick stomach content samples and direct observations of food delivered to tern chicks in 2013 and 2014, complemented in 2014 with carbon and nitrogen stable isotope analysis of chick whole-blood samples. Main prey species of Kelp Gull chicks were Cynoscion guatucupa (Cuvier, 1830), a demersal species obtained from recreational fishery waste, Argentine anchovies (Engraulis anchoita Hubbs and Marini, 1935), and insects. Engraulis anchoita and Odontesthes spp. were the main prey of both tern species. Trophic niche and isotopic niche overlap between the Kelp Gull and Royal and Cayenne terns was low. Kelp Gull kleptoparasitism on Royal and Cayenne terns was ≤2.5% and <0.6%, respectively. The use of anthropogenic food subsidies by Kelp Gulls may be mediating the trophic relationships among species, favouring their use of predictable and abundant fishery waste over a more unpredictable pelagic schooling fish such as E. anchoita.

Anthropogenic debris accumulated in nests of seabirds in an uninhabited island in West Africa

Anthropogenic debris is rapidly spreading in marine environments and poses major problems to biodiversity and humans. However, mitigation strategies are limited by the lack of information on the accumulation patterns of these pollutants both at sea and in marine wildlife. Using observations from an uninhabited island in Delta du Saloum National Park, Senegal, we investigate here the prevalence and abundance of debris in nests of two sympatric seabird species, Caspian terns Hydroprogne caspia and great cormorants Phalacrocorax carbo, and its potential as an indicator of ocean pollution. We recorded debris in 15% of the Caspian terns' nests, and 40% of the great cormorants' nests. Plastics accounted for >95% of items recorded in the nests of both species. Caspian terns collected a diverse array of debris, both in terms of types and colours, with a preference for hard plastics and white items. The great cormorants accumulated in nests mainly greenish fishing gears resembling the vegetation typically used as nest materials. Nests of both bird species contained soft plastic in proportions lower than those observed in the environment. Our results suggest that nests of Caspian terns and great cormorants are not useful indicators of pollution by anthropogenic debris in the surrounding waters of the Delta du Saloum National Park. Nests of great cormorants, however, have the potential to indicate areas vulnerable to plastic pollution associated to fishery. The high amount of debris in nests of this species demonstrates the need for a better implementation of waste management strategies in Senegal.

Marine litter detection and correlation with the seabird nest content

A 3 year monitoring programme, realized in a citizen science context, from 2014 until 2016, allowed us to gather information on the prevalent quantities and qualities of anthropogenic waste in five Mediterranean coastal areas within the Pelagos Sanctuary, three of them located in Liguria, near La Spezia Gulf, and the other two in Tuscany. Here, we present results concerning the Polymeric Articles’ abundances registered during the survey. Moreover, we show the results of the first study devoted to describe and quantify the anthropogenic content of the nest of a pair of Northern Gannets (Morus bassanus), a pelagic bird that, starting from some years, has been reproducing regularly in La Spezia Gulf. This breeding is atypical for this species, as is associated with artificial structures such as piers, floating docks, or boats; the material used in the construction of the nest reflects the “anthropogenic” link with the chosen location and objects of polymeric origin in particular abound. We detect the existence of a correlation between the most abundant types of Anthropogenic Marine Debris found in the Northern Gannet’ nest (fragments of polypropylene nets) and one of the productive activities of the zones.

The Impact of Penguins on the Content of Trace Elements and Nutrients in Coastal Soils of North Western Chile and the Antarctic Peninsula Area

In isolated areas without direct human impact where several species of seabirds nest, transformations affecting the soil come mainly from natural processes, such as chemical enrichment caused by seabirds. Penguins constitute an important bird biomass in the Southern Hemisphere, where they breed in colonies on different sites from 100 to thousands of individuals. The accumulation of trace elements and nutrients in soils within two perennial colonies of Humboldt penguins (Spheniscus humboldti) located in north western Chile and three colonies of Adelie penguins (Pygoscelis adeliae) in the Antarctic Peninsula area were investigated here. Surface soil samples were collected directly from nesting sites. Control samples were taken outside the colonies within sites adjacent to the nesting areas, but not affected by bird excrement. The contents of Cd, Co, Cr, Cu, Mo, Ni, Sr, V and Zn were determined by inductively coupled plasma optical emission spectrometry. Ammonium (NH4) and nitrate (NO3) ions were determined colorimetrically. Extractable potassium (K) was determined by flame emission spectrometry, and available phosphorus (Olsen-P) was determined by spectrophotometry. The highest concentrations of trace metals (Cd, Co, Cr, Cu, Mo, V and Zn) and macronutrients (available N, K and P), along with an increase in salinity and acidity levels, were found directly below the seabird colony, a situation occurring in northern Chile as well as in the Antarctic Peninsula area, highlighting the role that penguins have as bio-vectors on generating geochemical changes in different ecosystems. Some terrestrial plants and animals that live near those penguin colonies might be affected at a greater level than the organisms that live in sites similar but distant from colonies of birds. New data about the role of these species of seabirds as bio-vectors of chemical contaminants are added.

Investigating brown rat Rattus norvegicus egg predation using experimental nests and camera traps

Introduced rat species have been implicated in the decline and local extirpation of numerous seabird species from islands across the globe, leading to widespread eradications as a conservation tool. However, little conclusive evidence has been established to determine the direct mechanisms in which rat and seabird species interact. This study aimed to quantify rates of egg predation by brown rats Rattus norvegicus using automated trail cameras at seabird nests baited with domestic quail and hen eggs to represent different-sized seabird eggs. The trail cameras were in situ for a total of 915 days during June and July 2011. Evidence for rats visiting the experimental nests was only observed at one location, where 19 visits were recorded, and no evidence of rat predation on hen or quail eggs was observed. Low levels of rat activity were observed during the study; therefore, it is not possible to conclude that rats never predate seabird eggs as predation may be more likely when rat densities are higher and pressure on food resources greater. This study does however highlight that where rats occur at low densities, predation of eggs is unlikely. Measures aimed at maintaining low abundance of rats in and around vulnerable seabird colonies may therefore be useful where complete eradication is not feasible, although potential for predation of chicks should also be considered.

Nests of the brown booby (Sula leucogaster) as a potential indicator of tropical ocean pollution by marine debris

Seabirds collect debris primarily nearby breeding sites, and thus they may be used to monitor these pollutants in the ocean. This study aimed to investigate the prevalence of marine debris used as nesting materials by the brown booby (Sula leucogaster) and to test the species selectivity to debris type and color in two coastal islands of Brazil. We found marine debris in 61% of the brown booby nests on both islands. Fishing gear and hard plastic were the most frequent types of debris. Higher prevalence of fishing gear was found on the island with greater fishery activity. Similarly, hard plastic was the most frequent type of debris in nests and adjacent beach environment. The frequency of debris in brown booby nests can be a potential indicator of the abundance of specific items in surrounding marine waters. Monitoring debris in brown booby nests in a long-term may provide a better understanding of the species⿿ selectivity for specific debris. Furthermore, the impacts of debris in seabird nests at population level remain an overlooked threat that may reduce the quality of nesting habitats. We showed that brown booby nests are widely impacted by marine debris and that these organisms are exposed to this form of pollution from the beginning of their life.

Molecular, morphological and ultrastructural characteristics of Prasiola crispa (Lightfoot) Kützing (Chlorophyta) from Spitsbergen (Arctic)

It is commonly known that seabirds, along with cyanobacteria, play a key role in the enrichment of nutrient-poor polar terrestrial ecosystems. In habitats particularly enriched with nitrogen and phosphate ions, ornithogenic vegetation with Prasiola crispa and unique species composition develops. However, no studies have examined the potentially different impacts associated with seabirds on the morphological, ultrastructural and molecular diversity of P. crispa. For that purpose, the present study analyzed four populations from the Hornsund Fjord area (West Spitsbergen) collected in the vicinity of planktivorous or piscivorous colonies and individual nests of seabirds. The morphological variability of P. crispa was studied using fresh samples, and it was documented with light microscopy as well as transmission and scanning electron microscopy. Populations were investigated by molecular analyses based on rbcL and 18S rRNA sequences. The differences in features measured were subjected to statistical analysis. This study provides new data concerning the macro- and submicroscopic structure and molecular diversity of P. crispa with regard to differences in humidity and the quantity of biogenic nutrients deposited by seabirds. Molecular research provided the first data about P. crispa from Spitsbergen. Birds’ diet is relevant for the quantity and quality of the provided nutrients, especially nitrogen compounds (planktivorous species) and phosphorus (piscivorous birds). Climate changes influence the quantitative structure of the colony, clearly favoring piscivorous birds. This, in turn, causes changes in the environment and vegetation. The obtained data on the P. crispa population may be compared with potential changes in the future.

Predictive Modelling to Identify Near-Shore, Fine-Scale Seabird Distributions during the Breeding Season.

During the breeding season seabirds are constrained to coastal areas and are restricted in their movements, spending much of their time in near-shore waters either loafing or foraging. However, in using these areas they may be threatened by anthropogenic activities such as fishing, watersports and coastal developments including marine renewable energy installations. Although many studies describe large scale interactions between seabirds and the environment, the drivers behind near-shore, fine-scale distributions are not well understood. For example, Alderney is an important breeding ground for many species of seabird and has a diversity of human uses of the marine environment, thus providing an ideal location to investigate the near-shore fine-scale interactions between seabirds and the environment. We used vantage point observations of seabird distribution, collected during the 2013 breeding season in order to identify and quantify some of the environmental variables affecting the near-shore, fine-scale distribution of seabirds in Alderney’s coastal waters. We validate the models with observation data collected in 2014 and show that water depth, distance to the intertidal zone, and distance to the nearest seabird nest are key predictors in the distribution of Alderney’s seabirds. AUC values for each species suggest that these models perform well, although the model for shags performed better than those for auks and gulls. While further unexplained underlying localised variation in the environmental conditions will undoubtedly effect the fine-scale distribution of seabirds in near-shore waters we demonstrate the potential of this approach in marine planning and decision making.

MODEL-BASED GEOMORPHOLOGY OF MALPELO ISLAND AND SPATIAL DISTRIBUTION OF BREEDING SEABIRDS

The spatial distribution of seabird nests present on Malpelo Island, the main characteristics of the islandʼs topography, and the types of substratum available for nesting were addressed using a Digital Elevation Model (DEM). The model is based on data from remote sensors (satellite images, aerial photography and panoramic photography), and from field data processed through a geographical information system. The nests of Sula granti prevail on the surfaces of Malpelo Island and neighboring islets, while those of the remaining species (S. sula, Creagrus furcatus, Anous stolidus, A. minutus and Gygis alba) are spatially restricted to the cliff margins and to crevices or caverns at different heights. The presence of terrestrial predators and predatory birds (Fregata spp.) seems to mainly explain the marginal distribution of other breeding species. The cartographic data presented here differ significantly from past and current representations, especially those concerning the islandʼs emerged surface and other geomorphologic features. This new cartographical information will support future studies on the terrestrial fauna and flora of Malpelo Island and its islets.

Intraspecific variation in opportunistic use of trophic resources by the lizard Ameiva corax (Squamata: Teiidae)

Ameiva coraxis restricted to a small island (<2 ha), off the coast Anguilla. We present information on intraspecific variation in its diet, based on observations of 190 marked individuals. Larger individual were more likely to attempt to enter active seabird nests and only large males were observed to successfully enter a nest and break open an egg. Flower eating was commonly observed and its occurrence was not related to lizard size or sex. More than half the population was observed visiting areas where fisherman mixed their bait, a foraging strategy also unrelated to lizard size or sex.Ameiva coraxis known to socially feed at large food items such as seabird eggs. The individuals that can initially access these food items may occupy key roles in the social network.

Will the Effects of Sea-Level Rise Create Ecological Traps for Pacific Island Seabirds?

More than 18 million seabirds nest on 58 Pacific islands protected within vast U.S. Marine National Monuments (1.9 million km2). However, most of these seabird colonies are on low-elevation islands and sea-level rise (SLR) and accompanying high-water perturbations are predicted to escalate with climate change. To understand how SLR may impact protected islands and insular biodiversity, we modeled inundation and wave-driven flooding of a globally important seabird rookery in the subtropical Pacific. We acquired new high-resolution Digital Elevation Models (DEMs) and used the Delft3D wave model and ArcGIS to model wave heights and inundation for a range of SLR scenarios (+0.5, +1.0, +1.5, and +2.0 m) at Midway Atoll. Next, we classified vegetation to delineate habitat exposure to inundation and identified how breeding phenology, colony synchrony, and life history traits affect species-specific sensitivity. We identified 3 of 13 species as highly vulnerable to SLR in the Hawaiian Islands and quantified their atoll-wide distribution (Laysan albatross, Phoebastria immutabilis; black-footed albatross, P. nigripes; and Bonin petrel, Pterodroma hypoleuca). Our models of wave-driven flooding forecast nest losses up to 10% greater than passive inundation models at +1.0 m SLR. At projections of + 2.0 m SLR, approximately 60% of albatross and 44% of Bonin petrel nests were overwashed displacing more than 616,400 breeding albatrosses and petrels. Habitat loss due to passive SLR may decrease the carrying capacity of some islands to support seabird colonies, while sudden high-water events directly reduce survival and reproduction. This is the first study to simulate wave-driven flooding and the combined impacts of SLR, groundwater rise, and storm waves on seabird colonies. Our results highlight the need for early climate change planning and restoration of higher elevation seabird refugia to prevent low-lying protected islands from becoming ecological traps in the face of rising sea levels.

Antioxidant Activity of the Sea Bird Nest (Eucheuma Cottonii) and Its Radical Scavenging Effect on Human Keratinocytes

Antioxidant Activity of the Sea Bird Nest (Eucheuma Cottonii) and Its Radical Scavenging Effect on Human Keratinocytes

Determinación del éxito reproductivo del alcatraz enmascarado (Sula dactylatra dactylatra, Pelecaniformes:Sulidae) en Cayo Middle, Banco de Pedro Jamaica

Received 17-X-2013 Corrected 13-III-2014 Accepted 24-III-2014 Abstract: The masked booby (Sula dactylatra dactylatra) colony at Middle Cay, Pedro Bank, 60 miles south of Jamaica, has been affected by challenges resulting from anthropogenic disturbances. Despite habitat degrada- tion, the colony displays resilience by remaining extant on the cay. Between June 2008 and June 2009 we inves- tigated the colony's health (mainly breeding success). Data were collected once per month for twelve months and included one day, seven day and 24 hour (day and night continuous observational) sojourns. Forty-four nests were marked and monitored using a novel method for marking seabird nests based on painted seashells. Data collected from the colony included: the presence/absence/number of egg(s)/chick(s) in nests, offspring maturity, adult attendance at nests and the time of data collection. An average of 227 adult birds constituted the colony. Using the Mayfield Method and the Naive Estimator for comparison, the colony's breeding success was determined to be 37.20% despite a hatching success of 40% and a fledgling success of 93%. This is less than the estimated 45.77% success typical of healthy colonies of sulids such as the masked booby elsewhere. Based on the breeding success calculations the long term survival of this colony is at risk and needs active conservation. Rev. Biol. Trop. 62 (Suppl. 3): 159-167. Epub 2014 September 01.

Complex Interrelationships Among Aboveground Biomass, Soil Chemical Properties, and Events Caused by Feral Goats and Their Eradication in a Grassland Ecosystem of an Island

This study examined the recovery, via biotic and abiotic pathways, of a grassland ecosystem after eradication of introduced exotic goats. We used path analyses to evaluate the relative strength of relationships among aboveground biomass, soil chemical properties (carbon, nitrogen, and phosphorus content; soil acidity), presence of nesting seabirds after goat eradication, extent of vegetation degraded by goats before their eradication, plant species composition after removal of goats, and topography. Models including the same variables with different paths were constructed using the Bayesian estimation method, and the best-fit models were constructed by comparing deviance information criterion values. Results of the path analyses demonstrated that vegetation degradation and soil erosion prior to goat eradication increased soil exchangeable acidity, which resulted in limitation of aboveground biomass. Seabird nesting after goat eradication increased the quantity of soil nutrients, possibly through inputs of feces, eggshells, and dead chicks or adults. The increase in nutrients was affected indirectly, via seabird nesting, by topography and vegetation type after goat eradication. The direct and indirect relationships demonstrated by our results suggest the existence of complex interrelationships during recovery of ecosystem function after eradication of exotic mammals.

Fine-scale distribution of aboveground biomass of herbaceous vegetation and soil nutrients on an oceanic island after goat eradication are correlated with grazing damage and seabird nesting.

We tested whether vegetation recovery on an oceanic island after the eradication of feral goats is related to disturbances by goats and recovery of seabird nesting in an island. To test, we investigated relationships among the aboveground biomass of herbaceous vegetation, nutrient concentrations in the soil after goat eradication, and vegetation degradation before goat eradication and seabird nesting after the eradication. The investigation was conducted on the island of Nakoudojima, a subtropical island situated in the northwestern Pacific Ocean with consideration of fine-scale variation of topography and structure of current vegetation. The aboveground biomass of herbaceous vegetation was correlated with the presence of vegetation degradation before goat eradication but not with seabird nesting after eradication. Concentrations of carbon and nitrogen in the soil were correlated with both the presence of vegetation degradation and seabird nesting. The concentration of available phosphorus in the soil was correlated with nesting seabirds but not with vegetation degradation. The presence of nesting seabirds was correlated with differences in dominant species in the vegetation after goat eradication and with topography. Our results suggested that fine-scale heterogeneities of the aboveground biomass of herbaceous vegetation and the concentrations of nutrients in the soil after goat eradication in an island could be related to vegetation degradation and subsequent erosion of surface soil caused by goats and seabird nesting after the goat eradication.

2010–2013年の焼尻島における海鳥の巣数

During a 2010–2013 census of the number of seabird nests on Yagisihi Island the number of Japanese Cormorant Phalacrocorax capillatus nests fluctuated, whereas Slaty-backed Gull Larus schistisagus nests continuously increased. In 2013, Black-tailed Gulls L. crassirostris nested in Yagishiri Island for the first time. More than half of Slaty-backed Gull nests were located on artifacts at Yagishiri Port. Fluctuations in the number of Japanese Cormorant nests on Yagishiri Island generally corresponded with those occurring at Teuri Island.

Ayersacarus, an endemic mite genus from Zealandian seabird nest environments: revision, with four new species (Acari: Mesostigmata: Leptolaelapidae)

Four new species of Ayersacarus Hunter (Acari: Mesostigmata: Leptolaelapidae) are described: A. hurleyi sp. n. from Stephens I./Takapourewa (Cook Strait, New Zealand); A. forsteri sp. n. from Pitt I./Rangiauria, Chatham Is.; A. knoxi sp. n. from Snares Is./Tini Heke; and A. savilli sp. n. from Stewart I./Rakiura (New Zealand). Prestacarus gen. n. is proposed with Ayersacarus tilbrooki Hunter, 1967 from South Georgia as the type species. This restores Hunter's original 1964 conception of the genus and leaves Ayersacarus with nine species confined to Zealandia. A key to the females of all nine Ayersacarus species is included. All Ayersacarus and Prestacarus species are restricted to seabird nests and their immediate environs.

Identifying the origins of fishing gear ingested by seabirds: a novel multivariate approach

Abstract The global decline of albatrosses (Diomedidae: Procellariiformes) is thought to have occurred largely as a direct result of fishery‐related mortality. Albatrosses and other large petrels interact with fisheries in several ways, including scavenging used bait and discarded offal, which may contain hooks. Hooks that are ingested by breeding birds are often fed to chicks which subsequently regurgitate them shortly before fledging. In this study a series of mathematical (cladistic, cluster and principal components) analyses are applied to a sample of 241 items of fishing gear (hook, snood and hook/snood unit) collected from seabird nest sites on Bird Island, South Georgia, and 44 reference gear items provided by four South Atlantic regional fisheries. The five separate analyses failed to assign most gear to a particular fishery or to identify any consistent annual trends. The homogeneous nature of the material, which was largely derived from the same manufacturers, meant that gear origin could not be determined. This suggests that hooks found at seabird colonies in this, and potentially other regions, will be of limited use in identifying offending fisheries, unless operators are obliged to deploy gear with unique marks in the future. Nevertheless, it is suggested that this approach should work effectively where birds interact with a range of fisheries targeting different species using variable gear. This study therefore represents an innovative approach to the characterization of lost fishing gear with potentially widespread application. Copyright © 2010 John Wiley & Sons, Ltd.

Colony Site Dynamics and Habitat Use in Atlantic Coast Seabirds

Colony Site Dynamics and Habitat Use in Atlantic Coast Seabirds