scholarly journals Heterospecific foraging associations between reef‐associated sharks: first evidence of kleptoparasitism in sharks

Ecology ◽  
2020 ◽  
Vol 101 (11) ◽  
Author(s):  
Pierre Labourgade ◽  
Laurent Ballesta ◽  
Charlie Huveneers ◽  
Yannis Papastamatiou ◽  
Johann Mourier
2000 ◽  
Vol 78 (5) ◽  
pp. 809-816 ◽  
Author(s):  
Amy A Yackel Adams ◽  
Susan K Skagen ◽  
Richard L Knight

We investigated the functions of perch relocations within a communal night roost of wintering bald eagles (Haliaeetus leucocephalus) along the Nooksack River, Washington, during two winters. We tested seven predictions of two nonexclusive hypotheses: (1) bald eagles relocate within roosts to assess foraging success of conspecifics and (2) bald eagles relocate to obtain thermoregulatory benefits from an improved microclimate. Additionally, we gathered descriptive information to allow refinement of further alternative hypotheses. We rejected the hypothesis that relocations are a means of assessing foraging success. Contrary to our expectations, immature eagles did not relocate to be closer to adults, and relocations were less frequent when food was less abundant. Our data support the hypothesis that eagles relocate within night roosts to obtain a favorable microclimate during winters when they are subjected to cold stress and food stress. In both winters, relocations were more frequent in the evening than in the morning. In both winters, most evening relocations were to the center of the roost rather than to its edge, and the frequency of relocation to the center was greater when temperatures were low. The microclimate hypothesis, however, explains only a limited number of relocations. Based on our findings, it is likely that relocation has multiple functions, including establishing and (or) maintaining foraging associations, establishing and (or) maintaining social-dominance hierarchies when food is less abundant, and nonsocial activities.


2006 ◽  
Vol 80 (4) ◽  
pp. 351-361 ◽  
Author(s):  
Cristina Sazima ◽  
João Paulo Krajewski ◽  
Roberta M. Bonaldo ◽  
Ivan Sazima

2011 ◽  
Vol 11 (4) ◽  
pp. 359-362 ◽  
Author(s):  
Domingos Garrone Neto ◽  
Lucélia Nobre Carvalho

During under and overwater observations were recorded nuclear-follower foraging associations among three species of characiform fishes - Chalceus epakros, Hemiodus semitaeniatus and Hemiodus unimaculatus - and a freshwater stingray species - Potamotrygon orbignyi - in the Teles Pires and Xingu rivers basins, Midwest Brazil. The teleost fishes were observed closely following the stingrays during the behavior of stirring the substrate to uncover invertebrates, which cause discrete sediment clouds. Apparently this sediment perturbation attracts the fishes that approached the foraging stingrays to feed on small preys and other food types exposed this way. This is a typical example of a commensal relationship in which one participant is benefited while the other is unaffected, and represents the second published record of nuclear-follower feeding association between potamotrygonid rays and teleost fishes, demonstrating the potential of naturalistic studies in discovering new interactions involving species of freshwater fish.


2021 ◽  
Vol 288 (1949) ◽  
Author(s):  
Lilian Lieber ◽  
Roland Langrock ◽  
W. Alex M. Nimmo-Smith

Understanding physical mechanisms underlying seabird foraging is fundamental to predict responses to coastal change. For instance, turbulence in the water arising from natural or anthropogenic structures can affect foraging opportunities in tidal seas. Yet, identifying ecologically important localized turbulence features (e.g. upwellings approximately 10–100 m) is limited by observational scale, and this knowledge gap is magnified in volatile predators. Here, using a drone-based approach, we present the tracking of surface-foraging terns (143 trajectories belonging to three tern species) and dynamic turbulent surface flow features in synchrony. We thereby provide the earliest evidence that localized turbulence features can present physical foraging cues. Incorporating evolving vorticity and upwelling features within a hidden Markov model, we show that terns were more likely to actively forage as the strength of the underlying vorticity feature increased, while conspicuous upwellings ahead of the flight path presented a strong physical cue to stay in transit behaviour. This clearly encapsulates the importance of prevalent turbulence features as localized foraging cues. Our quantitative approach therefore offers the opportunity to unlock knowledge gaps in seabird sensory and foraging ecology on hitherto unobtainable scales. Finally, it lays the foundation to predict responses to coastal change to inform sustainable ocean development.


2009 ◽  
Vol 6 (3) ◽  
pp. 304-307 ◽  
Author(s):  
Meera Anna Oommen ◽  
Kartik Shanker

Mixed-species foraging associations may form to enhance feeding success or to avoid predators. We report the costs and consequences of an unusual foraging association between an endemic foliage gleaning tupaid (Nicobar treeshrew Tupaia nicobarica ) and two species of birds; one an insectivorous commensal (greater racket-tailed drongo Dicrurus paradiseus ) and the other a diurnal raptor and potential predator ( Accipiter sp.). In an alliance driven, and perhaps engineered, by drongos, these species formed cohesive groups with predictable relationships. Treeshrew breeding pairs were found more frequently than solitary individuals with sparrowhawks and were more likely to tolerate sparrowhawks in the presence of drongos. Treeshrews maintained greater distances from sparrowhawks than drongos, and permitted the raptors to come closer when drongos were present. Treeshrew foraging rates declined in the presence of drongos; however, the latter may provide them predator avoidance benefits. The choice of the raptor to join the association is intriguing; particular environmental resource states may drive the evolution of such behavioural strategies. Although foraging benefits seem to be the primary driver of this association, predator avoidance also influences interactions, suggesting that strategies driving the formation of flocks may be complex and context dependent with varying benefits for different actors.


Author(s):  
Joel Berger ◽  
Carol Cunningham

This year was the first of our five year project. We established three primary study areas to examine possible biological effects of large predators on moose. Sites where fieldwork was conducted included apparent heavy predation by grizzly bears [the eastern slopes of the Talkeetna Mountains (Alaska)], little or no predation (Grand Teton National Park), and human predation (Bridger-Teton National Forest), the latter two in the southern portion of the Greater Yellowstone Ecosystem. Data were gathered in Alaska from April until August and, in Wyoming, for all months from February until August (except during April). At the southern Greater Yellowstone sites, information was collected on pregnancy rates, calf production, twinning, and juvenile and adult survivorship. Ecological and behavioral data gathered from all three sites included home range locations, foraging associations and rates, habitat use, group size, social interactions, migration, and responses to humans and potential predators. Twenty animals were radio-collared at the Wyoming site; as of December 1995 only 15 survived. One apparently starved to death, one was poached, one was legally shot, and two died of unknown causes. We improved our sample by using 13 females previously radio-collared on national forest lands by University of Wyoming and Wyoming Department of Game and Fish personnel. Of these, two died during the 1994-1995 winter and three had slipped their collars.


2013 ◽  
Vol 17 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Sreejani Sen Majumder ◽  
Anandarup Bhadra ◽  
Arjun Ghosh ◽  
Soumitra Mitra ◽  
Debottam Bhattacharjee ◽  
...  

2020 ◽  
Vol 101 (4) ◽  
Author(s):  
Pierre Labourgade ◽  
Laurent Ballesta ◽  
Charlie Huveneers ◽  
Yannis Papastamatiou ◽  
Johann Mourier

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