Larus Crassirostris Research Articles

Heavy metal contamination and metallothionein mRNA in blood and feathers of Black-tailed gulls (Larus crassirostris) from South Korea

The objectives of this study were to determine levels of heavy metal in the feathers and blood of Black-tailed gulls (Larus crassirostris), to evaluate metallothionein (MT) mRNA level in Black-tailed gulls on three independent islets, and to examine the correlation between heavy metal concentrations and MT mRNA expression. Eleven heavy metals (Al, Cd, Mn, Pb, Cr, Fe, Cu, Zn, Se, Hg, and As) were investigated in blood and feathers of 65 chicks from breeding colonies (Seomando, Hongdo, and Dokdo islet) of South Korea in 2010. Heavy metals were assayed by PerkinElmer NexION 300 inductively coupled plasma mass spectrometry. The mean concentrations of non-essential heavy metals were found to blood containing Cd (0.002 ~ 0.02ppm), Pb (0.06 ~ 0.18) ppm, Hg (0.03 ~ 0.05) ppm, and As (0.26 ~ 0.48ppm), and feather containing Cd (0.05 ~ 0.30ppm), Pb (2.47 ~ 10.80ppm), Hg (1.18 ~ 1.57ppm), and As (0.15 ~ 0.44ppm). Chicks on Seomando islet showed the highest levels of metals (Cd, Pb, Mn, Cr, Cu, and Se in blood; Al, As, Mn, Cr, Fe, Cu, and Se in feathers) among the colonies. Concentrations of Pb and Hg in feathers were the highest on Hongdo, and the levels of Cd and Zn in feathers were the highest on Dokdo islet. MT mRNA in the blood of Black-tailed gulls was relatively higher in gulls from Seomando than in gulls from Hongdo and Dokdo islet. MT mRNA level is thus positively correlated to heavy metal concentrations in Black-tailed gulls.

Climatic effects on breeding seabirds of the northern Japan Sea

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 454:183-196 (2012) - DOI: https://doi.org/10.3354/meps09627 Climatic effects on breeding seabirds of the northern Japan Sea Yutaka Watanuki1,*, Motohiro Ito1,2 1Graduate School of Fisheries Sciences, Hokkaido University, Minato-cho 3-1-1, Hakodate 041-8611, Japan 2Present address: National Institute of Polar Research, 10-3 Midoricho, Tachikawa, Tokyo 190-8518, Japan *Email: ywata@fish.hokudai.ac.jp ABSTRACT: Seabirds as marine top predators have been put forth as reliable indicators of ecosystem change. To understand climate−ecosystem change in the northern Japan Sea, we studied the timing of breeding, chick diets, and breeding success of 3 seabird species almost continuously over 26 yr on Teuri Island, 1984 through 2009. Key climate drivers in this region are: (1) westerly winter winds that cool the atmosphere and the ocean and (2) the northward flowing Tsushima Current (TC) that warms the ocean in late spring and summer. Chick diet showed decadal changes in coastal pelagic fish, with a switch from sardine Sardinops melanostictus to anchovy Engraulis japonicus in the late 1980s corresponding to intensification of the TC. There were no long-term trends in the timing of breeding or breeding success of rhinoceros auklet Cerorhinca monocerata and Japanese cormorant Phalacrocorax filamentosus, but these variables were affected by interannual variation in spring air and sea temperatures, as well as the timing of TC warm water intrusions within the foraging range (~60 km from the colony) of the birds. Effects include: (1) freezing of the breeding grounds by winter winds limiting access to nesting grounds and (2) availability of anchovy and sandlance Ammodytes personatus affecting chick diet, growth, and breeding success. We did not detect relationships between chlorophyll a concentrations and the availability of prey species. The timing and success of black-tailed gulls Larus crassirostris, which fed mainly on sandlance, however, could not be explained by these factors. Our study indicates potential links between the Pacific Decadal Oscillation index and the flow rate of the TC, and between the Arctic Oscillation index and local wind stress, and suggests that broad-scale atmospheric pressure fields influence local weather, oceanography, and seabirds indirectly through changes in prey availability. KEY WORDS: Auklet · Breeding performance · Chick diet · Cormorant · Gull · Prey availability · Regime shift · Timing of breeding Full text in pdf format PreviousNextCite this article as: Watanuki Y, Ito M (2012) Climatic effects on breeding seabirds of the northern Japan Sea. Mar Ecol Prog Ser 454:183-196. https://doi.org/10.3354/meps09627 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 454. Online publication date: May 21, 2012 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2012 Inter-Research.

Consistent individual variations in aggressiveness and a behavioral syndrome across breeding contexts in different environments in the Black-tailed Gull

Individual behaviors of animals do not evolve separately; they do so in association with other behaviors caused by single shared genetic or physiological constraints and/or favored by selection. Thus, measuring behavioral syndromes—suites of correlated behaviors across different contexts—leads to a better understanding of the adaptive significance of variations in behaviors. However, relatively few studies have examined behavioral syndromes in wild animal populations in changing environments. We investigated a potential behavioral syndrome across antipredator nest defense, territorial defense, chick provisioning, and mating behaviors of male Black-tailed Gulls Larus crassirostris in two successive years under different conspecific territorial intrusion risks and food conditions. Males that presented high levels of antipredator nest defense (aggressive antipredator defenders) against a crow decoy (crows are egg predators) defended their territories against conspecific intruders more frequently than did other males (nonaggressive antipredator defenders), independent of the risk of intrusion. Aggressive antipredator defenders also fed their chicks more frequently than nonaggressive males, but only in a year of low food availability. Taken together, this indicates that males show consistent aggressiveness regardless of breeding context (antipredator and territorial defense), but can regulate food provisioning according to food availability.

自動車のヘッドライトで攪乱されたサヨリ<i>Hyporhamphus sajori</i> のウミネコ<i>Larus crassirostris</i> による空中採餌

北海道函館市小安漁港で，ウミネコLarus crassirostris によるサヨリHyporhamphus sajori の夜間採餌を観察した。サヨリは自動車のヘッドライトに照らされた海面から飛び出したところを，ウミネコに空中で捕食されていた。本報告は，人工光が餌生物を攪乱するというユニークな方法で，海鳥に夜間採餌の機会を与えることを示した。

Factors affecting individual variation in nest-defense intensity in colonially breeding Black-tailed Gulls (Larus crassirostris)

The physiological state of parent birds combined with the value of their clutch may affect the intensity of their nest defense. In colonially breeding birds, nest-defense intensity may also be affected by the behavior of neighbors. We investigated individual variation in the nest-defense intensity among colonial Black-tailed Gulls ( Larus crassirostris Vieillot, 1818) over 2 years. Only 30%–40% of males attacked a decoy of an egg predator (Large-billed Crow ( Corvus macrorhynchos Wagler, 1827)), and the other males and females rarely attacked. Males attacking the decoy had higher levels of plasma testosterone than males that did not attack. Each male’s, but not female’s, nest-defense intensity was consistent throughout the incubation period and also across years. The intensity was not related to egg-laying date, clutch size, or age of offspring. The intensity was likely to be higher when individuals had one or more neighbors, representing higher nest-defense intensity in the year where gulls had larger number of adjacent neighboring nests (5.23 nests), but this trend was not observed in the year where they had smaller number of the neighboring nests (3.73 nests). Thus, in addition to testosterone levels, behavior of neighbors also influences the nest-defense intensity.

Characteristics of Bird Community in Yeongsan Lake

A total of 4,045 individuals of 47 species were observed in the Yeongsan Lake region of Yeongsan River between January and December of 2009. Dominant species, in decreasing order, included the Fulica atra (24.72%, 1,000 individuals), followed by the Larus ridibundus (17.31%, 700 individuals), Larus crassirostris (13.84%, 560 individuals), Mergus merganser (7.29%, 295 individuals), Passer montanus (6.18%, 250 individuals) and the Aythya fuligula (5.34%, 216 individuals). In terms of the total number of species observed per month, November showed the highest number at 23 species and September showed the lowest figure at 9 species. Furthermore, February showed the highest number of individuals at 2,382, and May showed the lowest number at 114 individuals. In relation to species diversity, May, despite being the month with the lowest bird count, showed the highest number of species as well as the highest level of species diversity (H') at 2.37 and species abundance at (Da) 4.22. Conversely, September, which recorded the lowest number of species observed, showed lowest levels of species diversity (H') at 0.37 and species abundance at (Da) 1.26. In terms of the seasons, summer (between July and September) showed the lowest species diversity, while spring and fall, which are migratory periods for migratory birds, showed high level of species diversity. This study observed 3 government protected species.

Within- and Among-Clutch Variation in Maternal Yolk Testosterone Level in the Black-Tailed GullsLarus crassirostris

Abstract Mother birds can enhance growth and/or survival of chicks by supplying energetic and hormonal resources to the egg yolk (i.e. maternal effect). In several bird species, mothers supply higher level of testosterone to the eggs laid later within the clutch and enhance the growth of the chick to compensate for the disadvantage of the later hatching. As same as this within-clutch mechanism, mothers breeding later in the season can be expected to supply higher level of testosterone to the clutch. However, among-clutch seasonal variation in yolk testosterone levels has been rarely described. Here, we investigated among-clutch seasonal variation in the yolk testosterone level in Black-tailed Gulls Larus crassirostris, as well as within-clutch variation. Mean yolk testosterone level of eggs laid later within the clutch (“b-eggs”) was significantly higher than that of eggs laid earlier (“a-eggs”). The yolk testosterone levels of both a- and b-eggs of later breeders were significantly higher than those of e...

Testosterone and Breeding Behavior in Male Black-Tailed Gulls: An Implant Experiment

Testosterone affects male sexual-, aggressive-, and parental-behaviors in bird species. To understand the breadth of the proximate contribution of testosterone to breeding behaviors in male Black-tailed Gulls Larus crassirostris, sexual behaviors, aggressive behaviors against egg-predators and conspecifics, and chick-provisioning behavior of five testosterone-implanted males (T-males) were observed and compared with those of three control males (placebo-implanted; C-males). T-males showed significantly higher levels of courtship and copulation behaviors than C-males. The levels of aggressiveness against egg-predators and against conspecifics, and the rate of feeding of chicks did not differ between T- and C-males. These results suggest that sexual and mating behaviors in male Black-tailed Gulls may be affected by testosterone, while aggressive- and feeding-behaviors are affected by certain ecological factors, such as individual age, or a necessity for high levels of feeding by males, rather than by testosterone.

Differential response of two Pinus spp. to avian nitrogen input as revealed by nitrogen isotope analysis for tree rings

Temporal variations in N concentration and δ15N value of annual tree rings (1 year of time resolution) of two Japanese Black Pine (Pinus thunbergii) and three Japanese Red Pine (Pinus densiflora) trees under current breeding activity of the Great Cormorant (Pharacrocorax carbo) and the Black-tailed Gull (Larus crassirostris), respectively, in central and northeastern Japan were studied. Both species from control sites where no avian input occurs show negative values (δ15N = around−4 ‰ to−2 ‰) which are common among higher plants growing under high rainfall regimes. The δ15N values of P. densiflora show uniformly positive values several years before and after the breeding event, indicating N translocation that moved the absorbed N of a given growth year to tree rings of the previous year while a clear historical value of soil N dynamics was kept intact in the annual rings of P. thunbergii. Long-term N trends inferred from tree rings must take into account tree species with limited translocation rates that can retain actual N annual acquisition.

A Study on the Community Characteristics and Habitat use of Birds in Goseong-gun, Gangwon-do, Korea

This study was conducted to clarify the community characteristics of birds in Goseong-gun, Gangwon-do, Korea at June and September of 2010. The result observed a total of 6,557 birds of 98 species. Dominant species included, in decreasing order, Larus crassirostris 3,319 counts (50.62%), Passer montanus 664 counts (10.13%), Sterna hirundo 208 counts (3.17%), Paradoxornis webbianus and Egretta alba modesta 178 counts (2.71%). In terms of the families, the herons showed a total of 7 species at 303 counts, the ducks showed 4 species of 185 counts, the raptors showed 6 species of 26 counts, the waders showed 13 species of 114 counts, the gulls showed 8 species of 3,585 counts, the passerine birds showed 56 species of 2,323 counts and others (Grebe, Cormorant, Pheasant, Moorhen) showed only 4 species of 26 counts. In terms of the number of species’ habitat usage, the forest area showed the highest level of species at 52 species, and human inhabited areas showed the lowest level at 14 species.

How Do Black-Tailed Gulls Respond to Long-Call Displays of Other Individuals?

Abstract Displays of animals do not always elicit equivalent responses from other conspecifics. Considerable variation exists among the responses, but the mechanism causing the variety remains unclear. We investigated how Black-tailed Gulls Larus crassirostris respond to long-call displays of other individuals. Results show that the response varies depending on the context. Territorial birds often respond to the long-calls of non-territorial birds by attacking. However, non-territorial birds typically respond to the long-calls of territorial birds by avoiding them. Nevertheless, they usually respond to the long-calls of their partners by using the same long-call. These results are explained well by the motivational conflict hypothesis.

Temporal changes in tree-ring nitrogen of Pinus thunbergii trees exposed to Black-tailed Gull (Larus crassirostris) breeding colonies

Abstract Natural abundances of 15N/14N ratios (commonly designated by δ15N notation) of annual rings from Pinus thunbergii trees were determined after transplantation from a nursery to breeding colonies of Black-tailed Gull (Larus crassirostris) in Miyagi and Aomori and a control site in Yamagata, in northeastern Japan. Tree-rings were collected in July/August/September, 2009. Transplanting was conducted in the year 2000 in the Miyagi site, whereas there is no information about transplanting data in the Aomori and Yamagata sites. Soils associated with piscivorous (fish eating) avian colonies receive large seasonal input of organic N in the form of feces. The organic N is microbiologically transformed into inorganic N in soils, from which P. thunbergii derives its N. The resulting NH 4 - and NO 3 - N are characterized by distinctly heavy δ15N ratios, due to coupled processes of mineralization, volatilization, nitrification and denitrification of feces. In general, total N concentration along with δ15N values stored in the annual rings of P. thunbergii increased steadily after transplanting from the nursery to locations under continued avian N input. Tree-ring N content and isotopic ratios provided a reliable record of past annual available soil N caused by changes in the Black-tailed Gull population, and thus can serve as an environmental tool to estimate past avian population dynamics.

The Avifauna in Ulleungdo

The avian fauna of Ulleungdo (Is.) was studied between June of 2006 and July of 2010, and the results gathered over 10 study session included a total of 18,046 individuals of 92 species. Dominant species included, in decreasing order, black-tailed gull (Larus crassirostris) at 13,188 individuals (73.1%), russet sparrow (Passer rutilans) at 1,278 individuals (7.08%), and white-rumped swift (Apus pacificus) at 900 individuals (4.99%). In terms of the time of the year, the highest numbers of species were detected in May of 2007 at 50 species and the highest numbers of birds were detected in February of 2009 at 4,137 individuals. In relation to endangered species designated by the Ministry of Environment, the peregrine falcon (Falco peregrinus) and Eurasian buzzard (Buteo buteo) were detected, and natural monument species designated by the Cultural Heritage Administration including the Japanese wood pigeon (Columba janthina), grey frog hawk (Accipiter soloensis), common kestrel (Falco tinnunculus), peregrine falcon, oriental scops owl (Otus scops), mandarin duck (Aix galericulata) and the little cuckoo(Cuculus poliocephalus) were detected. Compared to previous studies, a total of 33 new species, including the red-throated diver (Gavia stellata) and the Swinhoe's fork-tailed petrel (Oceanodroma monorhis), were observed.

Hemosporidian blood parasites in seabirds—a comparative genetic study of species from Antarctic to tropical habitats

Whereas some bird species are heavily affected by blood parasites in the wild, others reportedly are not. Seabirds, in particular, are often free from blood parasites, even in the presence of potential vectors. By means of polymerase chain reaction, we amplified a DNA fragment from the cytochrome b gene to detect parasites of the genera Plasmodium, Leucocytozoon, and Haemoproteus in 14 seabird species, ranging from Antarctica to the tropical Indian Ocean. We did not detect parasites in 11 of these species, including one Antarctic, four subantarctic, two temperate, and four tropical species. On the other hand, two subantarctic species, thin-billed prions Pachyptila belcheri and dolphin gulls Larus scoresbii, were found infected. One of 28 thin-billed prions had a Plasmodium infection whose DNA sequence was identical to lineage P22 of Plasmodium relictum, and one of 20 dolphin gulls was infected with a Haemoproteus lineage which appears phylogenetically clustered with parasites species isolated from passeriform birds such as Haemoproteus lanii, Haemoproteus magnus, Haemoproteus fringillae, Haemoproteus sylvae, Haemoproteus payevskyi, and Haemoproteus belopolskyi. In addition, we found a high parasite prevalence in a single tropical species, the Christmas Island frigatebird Fregata andrewsi, where 56% of sampled adults were infected with Haemoproteus. The latter formed a monophyletic group that includes a Haemoproteus line from Eastern Asian black-tailed gulls Larus crassirostris. Our results are in agreement with those showing that (a) seabirds are poor in hemosporidians and (b) latitude could be a determining factor to predict the presence of hemosporidians in birds. However, further studies should explore the relative importance of extrinsic and intrinsic factors on parasite prevalence, in particular using phylogenetically controlled comparative analyses, systematic sampling and screening of vectors, and within-species comparisons.

Experimental Study of the Effect of Clutch Size on Nest Defense Intensity in Black-Tailed Gulls

Since parent birds are hypothesized to adjust the level of their nest defense against predators so as to enhance the survival of their offspring, parental nest defense is expected to increase in intensity in relation to increasing clutch size. Empirical studies of bird species, in which clutch sizes have been manipulated artificially, however, have produced results contradicting such expectations, partly, it is thought, because of various errors in experimental design, such as a lack of nesting habitat control, or providing too short a time for parents to assess the value of the manipulated clutch, Hence, further evidence needed to be gathered to clarify whether the basic hypothesis is adequately supported. We manipulated the clutch size of Blacktailed Gulls Larus crassirostris and observed the responses of male parents to a crow decoy in controlled nesting habitats. The intensity of defense was not affected by the clutch size. Opportunities for future reproduction, or constant individual levels of aggressiveness of seem to best explain the observed intensity of nest defense in these long-lived Black-tailed Gulls, rather than the value of the current clutch.

Egg survival is related to the colour matching of eggs to nest background in Black-tailed Gulls

A long-standing hypothesis posits that, for species with exposed nests, a close match between the colour of the eggs and that of the nest in which they are laid should enhance egg survival, but this has rarely been tested in a rigorous manner. Here, we demonstrate the effects of egg–nest colour matching on egg survival in Black-tailed Gulls (Larus crassirostris) on Hongdo Island, Korea. We quantified the ground colour of eggshells and that of the nest background using a digital camera and computerized RGB and greyscale colour systems. We show that a close match of eggshell ground colour and nest background colour was associated with increased chances of eggs surviving through to hatching. In particular, there were strong survival advantages for eggs matching the nest colour in sites with poor concealment, whereas there was no effect of eggshell ground colour in nests that were more concealed by vegetation. Our findings support the hypothesis that egg colour functions to make eggs cryptic and that egg colouration may be a significant factor affecting egg loss.

Individual differences in nest defense in the colonial breeding Black-tailed Gulls

Often in colonial seabirds, all colony members are believed to defend against nest predators and experience equal nest predation risk. However, the variation of defense behavior among members and its reproductive consequences are largely unknown. We investigated (1) individual variation in the nest defense of breeding Black-tailed Gulls Larus crassirostris against a natural egg predator, the Jungle Crow Corvus macrorhynchos and (2) how this behavioral variation affects an individual’s own nest predation risk and that of their neighbors. Results were compared between 2 years where crow attack levels were manipulated to average 5 and 22 times normal rates (“low” and “high” predation risk years, respectively) by the placement of varying numbers of artificial nests containing unguarded eggs at the perimeter of the gull colony. In both years, 23–38% of parents, mostly males, showed “aggressive” defense behavior (strikes or chases) against crows and decoys. Other “non-aggressive” gulls showed no defense. In the year of low predation risk, intrusion rates by crows (landing within 0.5 m of an individual gull’s nest) were similar for aggressive and non-aggressive gulls. In the year of high predation risk, however, the rates of intrusion for aggressive gulls (4%) and for non-aggressive gulls with an aggressive neighbor (37%) were significantly lower than for non-aggressive gulls without an aggressive neighbor (76%). These results indicate that aggressive individuals reduce nest predation risk for themselves and conspecific neighbors in a colonially breeding species.

Avifauna of Southern Coast of Ganghwado, Seokmodo and Gyodongdo

In June and September of 2009, a total of 11,590 individuals (sum of maximum individuals by each species) of 68 species of 31 families and 12 orders were found in the southern coast of Ganghwado (island), Seokmodo (island) and Gyodongdo (island). Dominant species included, in decreasing order of, Larus crassirostris (29.18%, 3,382 individuals), Larus saundersi (10.52%, 1,219 individuals), Egretta garzetta (9.19%, 1,065 individuals), Egretta alba modesta (9.01%, 1,044 individuals) and Numenius madagascariensis (8.57%, 993 individuals). In June of 2009 (1st survey), the study recorded a total of 4,915 individuals of 50 species, and in September of 2009 (2nd survey), a total of 8,246 individuals of 45 species were recorded. The number of birds was relatively low in the 1st survey, but its species diversity (H′) of 2.35 and species richness (Da) of 4.76 were higher than those of the 2nd survey, with the H’ of 2.22 and Da of 4.87. Furthermore, depending on the region, Seokmodo (island) recorded the highest species diversity (37 species) in the 1st survey, with H’ of 2.57 and Da of 5.59, and in the 2nd survey, Gyodongdo (island) recorded the highest species diversity of 36 species, at H’ of 2.46 and Da of 4.79. In this study, Egretta eulophote and Platalea minor, natural mouments numbers 361 and 205-1, as well as 1st grade endangered species, along with 13 government protected species, were found.

青森県蕪島におけるウミネコ成鳥の殺傷死体の発見

青森県蕪島におけるウミネコ成鳥の殺傷死体の発見

Dynamics of the abundance of seagulls (Charadriiformes: Laridae) in the northern Tatar Strait

Field observations on colonies of seagulls (Laridae) were carried out annually on islands of the northern Tatar Strait during 2001–2008. A general tendency towards a reduction in the number of nesting birds was observed on all islands surveyed. The anxiety factor and direct destruction of bird eggs and fledglings caused the whole or the greater part of colony to migrate to “quieter” sites on islands or the continental coast. The replacement of Larus crassirostris by L. schistisagus was observed in sites where the two species nest in neighborhood. Nesting specimens of L. schistisagus were found on islands of Lake Bolshoe Kizi, suggesting that the birds are in search of alternative nesting places that are less accessible to humans and predators.