scholarly journals The Thrush Trudus celaenops, as an Avian Predator of Juvenile Eumeces okadae on Miyake-Jima, Izu Islands

1990 ◽  
Vol 13 (3) ◽  
pp. 65-69 ◽  
Author(s):  
MASAMI HASEGAWA
Keyword(s):  
Avian Predator ◽  
Izu Islands

Post-logging effects on nest predation and avian predator assemblages in a subtropical forest

2021 ◽  
pp. 119858
Author(s):  
Ever Tallei ◽  
Luis Rivera ◽  
Alejandro Schaaf ◽  
Maila Scheffer ◽  
Natalia Politi
Keyword(s):  
Nest Predation ◽  
Subtropical Forest ◽  
Avian Predator ◽  
Logging Effects

scholarly journals Interference competition pressure predicts the number of avian predators that shifted their timing of activity

2018 ◽  
Vol 285 (1880) ◽  
pp. 20180744 ◽  
Author(s):  
Yifan Pei ◽  
Mihai Valcu ◽  
Bart Kempenaers
Keyword(s):  
Species Richness ◽  
Body Size ◽  
Interference Competition ◽  
Relative Importance ◽  
Exploitation Competition ◽  
Predator Species ◽  
Avian Predator ◽  
Avian Predators ◽  
Time Partitioning ◽  
Competition Pressure

Being active at different times facilitates the coexistence of functionally similar species. Hence, time partitioning might be induced by competition. However, the relative importance of direct interference and indirect exploitation competition on time partitioning remains unclear. The aim of this study was to investigate the relative importance of these two forms of competition on the occurrence of time-shifting among avian predator species. As a measure of interference competition pressure, we used the species richness of day-active avian predator species or of night-active avian predator species (i.e. species of Accipitriformes, Falconiformes and Strigiformes) in a particular geographical area (assemblage). As an estimate of exploitation competition pressure, we used the total species richness of avian predators in each assemblage. Estimates of the intensity of interference competition robustly predicted the number of Accipitriformes species that became crepuscular and the number of Strigiformes species that became day-active or strictly crepuscular. Interference competition pressure may depend on body size and on the total duration of the typical active period (day or night length). Our results support—to some extent—that smaller species are more likely to become time-shifters. Day length did not have an effect on the number of time-shifter species in the Accipitriformes. Among the large Strigiformes, more time-shifter species occur in areas where nights are shorter (i.e. where less of the typical time resource is available). However, in the small Strigiformes, we found the opposite, counterintuitive effect: more time-shifters where nights are longer. Exploitation competition may have had an additional positive effect on the number of time-shifters, but only in Accipitriformes, and the effect was not as robust. Our results thus support the interference competition hypothesis, suggesting that animals may have shifted their time of activity, despite phylogenetic constraints on the ability to do so, to reduce the costs of direct interactions. Our findings also highlight the influence of body size as a surrogate of competitive ability during encounters on time partitioning, at least among avian predators.

An incubating northern giant petrel actively feeds on a Salvin's prion

2019 ◽  
Vol 31 (6) ◽  
pp. 317-318
Author(s):  
Christopher W. Jones ◽  
Michelle M. Risi ◽  
John Cooper
Keyword(s):  
Southern Ocean ◽  
Giant Petrel ◽  
Avian Predator ◽  
First Case

Pelagic seabirds often nest on islands that are far from productive foraging areas. The Procellariiformes (petrels, shearwaters and albatrosses) are among the longest-ranging seabirds; they have several adaptations that permit them to efficiently utilize distant foraging areas and fast for long periods during incubation (Phillips & Hamer 1999). Giant petrels (Macronectes spp.) are large surface-nesting procellariiforms. They feed both by direct predation and by scavenging carrion, and they are the largest avian predator-scavengers in the Southern Ocean. Among procellariiform seabirds, one partner forages while their mate remains on the nest to incubate their single egg (Warham 1990). Northern giant petrels (Macronectes halli) have incubation shifts lasting up to 17 days (Cooper et al. 2001). In general, incubating procellariiform seabirds do not feed during their shift (Warham 1990). We report the first case to our knowledge of a procellariiform seabird, a northern giant petrel, actively feeding at its nest whilst incubating.

Demography of an island population of the lizard,Eumeces okadae, on Miyake-jima, Izu Islands

1990 ◽  
Vol 32 (1) ◽  
pp. 119-133 ◽  
Author(s):  
Masami Hasegawa
Keyword(s):  
Island Population ◽  
Izu Islands

scholarly journals Pictorial 2 : Tephrochronological Study of Higashiyama Volcano at Hachijojima, Izu Islands

1998 ◽  
Vol 107 (3) ◽  
pp. Plate6-Plate8
Author(s):  
Shigeo SUGIHARA
Keyword(s):  
Izu Islands

Numerical Simulation and Optimization of a Wave Energy Converter for the Izu Islands Sea in Japan

2014 ◽  
Author(s):  
Takeshi Kamio ◽  
Makoto Iida ◽  
Chuichi Arakawa
Keyword(s):  
Numerical Simulation ◽  
Wave Energy ◽  
Power Output ◽  
Test Site ◽  
Wave Energy Converter ◽  
Complex Conjugate ◽  
Maximum Output ◽  
Energy Converter ◽  
Simulation And Optimization ◽  
Izu Islands

The purpose of this study is the numerical simulation and control optimization of a wave energy converter to estimate the power at a test site in the Izu Islands. In Japan, ocean energy is once again being seriously considered; however, since there are many inherent problems due to severe conditions such as the strong swells and large waves, estimations are important when designing such devices. The numerical simulation method in this study combines the wave interaction analysis software WAMIT and an in-house time-domain simulation code using the Newmark-β method, and introduces approximate complex-conjugate control into the code. The optimized parameters were assessed for a regular sine wave and an irregular wave with a typical wave spectrum. With the optimized parameters, average and maximum output power were estimated for the observed wave data at the test site. The results show a more than 100 kW average power output and a several times larger maximum power output.

Rediscovery and redescription of a sponge-associated axiid shrimp, Eiconaxius acutifrons Bate, 1888 (Crustacea: Decapoda: Axiidea)

Zootaxa ◽  
2012 ◽  
Vol 3393 (1) ◽  
pp. 27 ◽  
Author(s):  
TOMOYUKI KOMAI ◽  
SHINJI TSUCHIDA
Keyword(s):  
Deep Water ◽  
Type Species ◽  
Eastern Pacific ◽  
Congeneric Species ◽  
Type Specimens ◽  
Diagnostic Characters ◽  
Izu Islands

A poorly known deep-water axiid shrimp, Eiconaxius acutifrons Bate, 1888, the type species of the genus, is redescribedon the basis of the two type specimens (lectotype and paralectotype, designated herein) from the Banda Sea, Indonesia,and three recently collected specimens from the Myojin Knoll, Izu Islands, Japan. Diagnostic characters of this speciesare reassessed, and the comparison with closely allied congeneric species is made. Previous records referred to E.acutifrons are reviewed. It has been confirmed that none of the subsequent records under the name represent the true E.acutifrons. We found that Eiconaxius albatrossae Kensley, 1996 and E. faxoni Sakai, 2011 were based on the same seriesof material from the eastern Pacific, referred to E. acutifrons by Faxon (1895), but the Sakai’s (2011) taxon name is unavailable because of the lack of an explicit type fixation.

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