scholarly journals Tidal drift removes the need for area-restricted search in foraging Atlantic puffins

2019 ◽  
Vol 15 (7) ◽  
pp. 20190208 ◽  
Author(s):  
Ashley Bennison ◽  
John L. Quinn ◽  
Alison Debney ◽  
Mark Jessopp
Keyword(s):  
Trophic Level ◽  
Optimal Strategy ◽  
Encounter Rate ◽  
Brownian Movement ◽  
Marine Predators ◽  
Fratercula Arctica ◽  
Movement Strategies ◽  
The Cost ◽  
Atlantic Puffin ◽  
Feeding Grounds

Understanding how animals forage is a central objective in ecology. Theory suggests that where food is uniformly distributed, Brownian movement ensures the maximum prey encounter rate, but when prey is patchy, the optimal strategy resembles a Lévy walk where area-restricted search (ARS) is interspersed with commuting between prey patches. Such movement appears ubiquitous in high trophic-level marine predators. Here, we report foraging and diving behaviour in a seabird with a high cost of flight, the Atlantic puffin ( Fratercula arctica ), and report a clear lack of Brownian or Levy flight and associated ARS. Instead, puffins foraged using tides to transport them through their feeding grounds. Energetic models suggest the cost of foraging trips using the drift strategy is 28–46% less than flying between patches. We suggest such alternative movement strategies are habitat-specific, but likely to be far more widespread than currently thought.

scholarly journals Size variation in mid-Holocene North Atlantic Puffins indicates a dynamic response to climate change

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0246888
Author(s):  
Samuel James Walker ◽  
Hanneke Johanna Maria Meijer
Keyword(s):  
North Atlantic ◽  
Size Variation ◽  
Risk Groups ◽  
Archaeological Remains ◽  
Biometric Data ◽  
Climatic Oscillations ◽  
Fratercula Arctica ◽  
Modern Breeding ◽  
Atlantic Puffin ◽  
Osteological Characters

Seabirds are one of the most at-risk groups, with many species in decline. In Scandinavia, seabirds are at a heightened risk of extinction due to accelerated global warming. Norway is home to significant portion of the European Atlantic Puffin (Fratercula arctica) populations, but Norwegian populations have declined significantly during the last decades. In this paper we use biometric data from modern and archaeological F. arctica specimens to investigate patterns in body size variation over time of this iconic species. We aimed to set out a baseline for our archaeological comparison by firstly investigating whether modern subspecies of F. arctica are reflected in the osteological characters and are enough to distinguish subspecies from the bones alone. We then investigated if archaeological remains of F. arctica differ in size from the modern subspecies. Our results show that the subspecies Fratercula arctica naumanni was distinctly larger than the other subspecies. However, Fratercula arctica arctica and Fratercula arctica grabae were difficult to separate based on size. This generally supports ornithological observations. Post-Medieval F. arctica bones from Måsøy were similar to modern F. a. arctica populations. The mid-Holocene remains from Dollsteinhola overlaps with the modern size ranges of F. a. arctica and F. a. grabae but are generally shorter and more robust. Dollsteinhola is located close to the borders of the modern breeding ranges of both F. a. arctica and F. a. grabae. We consider it therefore likely that given the mid-Holocene climatic oscillations, breeding ranges of the two subspecies shifted north or south accordingly. However, this does not explain the different proportions of the Dollsteinhola specimens. Our data provide the first evidence for shifting distributions in ancient Atlantic Puffins and represent the first osteological analysis of Fratercula arctica subspecies.

Energy Metabolism in the Locomotor Muscles of the Common Murre (Uria aalge) and the Atlantic Puffin (Fratercula arctica)

The Auk ◽  
1987 ◽  
Vol 104 (4) ◽  
pp. 733-739 ◽  
Author(s):  
M. Benjamin Davis ◽  
Helga Guderley
Keyword(s):  
Krebs Cycle ◽  
Columba Livia ◽  
Oxygen Storage ◽  
Uria Aalge ◽  
Common Murre ◽  
Fratercula Arctica ◽  
Metabolic Systems ◽  
Flight Muscles ◽  
The Common ◽  
Atlantic Puffin

Abstract To compare the metabolic systems that support the combination of flying and diving with those used to support burst flying and sustained flying, myoglobin concentrations and maximum enzyme activities were determined for selected enzymes of glycolysis, the Krebs cycle, and amino acid metabolism in the pectoral, supracoracoideus, and sartorius muscles of the Common Murre (Uria aalge), Atlantic Puffin (Fratercula arctica), Rock Dove (Columba livia; hereafter "pigeon"), and Ring-necked Pheasant (Phasianus colchicus). Glycolytic enzyme levels in the flight muscles were lower in the murre and the puffin than in the pheasant, while both glycolytic and Krebs-cycle enzyme levels resembled those in the pigeon. We believe puffins and murres do not rely extensively on anaerobic glycolysis during diving. In concordance with a role in oxygen storage for diving, the levels of myoglobin in the flight muscles of murres and puffins were higher than those in pigeons or pheasants. They were lower than published values for penguins, however. In contrast to the trends for pigeon and pheasant muscles, the alcid sartorius muscles had a considerably lower aerobic orientation than the flight muscles.

scholarly journals Environmental context explains Lévy and Brownian movement patterns of marine predators

Nature ◽  
2010 ◽  
Vol 465 (7301) ◽  
pp. 1066-1069 ◽  
Author(s):  
Nicolas E. Humphries ◽  
Nuno Queiroz ◽  
Jennifer R. M. Dyer ◽  
Nicolas G. Pade ◽  
Michael K. Musyl ◽  
...  
Keyword(s):  
Movement Patterns ◽  
Environmental Context ◽  
Brownian Movement ◽  
Marine Predators

scholarly journals Effect of prefeeding, sowing rate and sowing pattern on efficacy of aerial 1080 poisoning of small-mammal pests in New Zealand

2011 ◽  
Vol 38 (3) ◽  
pp. 249 ◽  
Author(s):  
Graham Nugent ◽  
Bruce Warburton ◽  
Caroline Thomson ◽  
Peter Sweetapple ◽  
Wendy A. Ruscoe
Keyword(s):  
New Zealand ◽  
Large Scale ◽  
Treatment Effectiveness ◽  
Rattus Rattus ◽  
Fine Tuning ◽  
Encounter Rate ◽  
Forested Areas ◽  
Experimental Treatments ◽  
The Cost ◽  
Scale Control

Context Aerial poisoning using sodium fluoroacetate (1080) is an important but controversial technique used for large-scale control of brushtail possums (Trichosurus vulpecula) and other pests in New Zealand. The technique reliably produces near total kills of possums and rats, provided that many tens of baits (and therefore many tens of individually lethal doses) are sown for each target animal present. Aim The aim of this study was to further refine aerial 1080 poisoning by determining the effect of prefeeding, sowing rate, and sowing pattern on effectiveness. Methods Eighteen experimental treatments comprising all possible combinations of three sowing rates (1, 2, and 5 kg/ha of bait), three frequencies of non-toxic prefeed (0, 1, and 2) and two sowing patterns (parallel and cross-hatched) were applied to each of two forested areas. Treatment effectiveness was assessed from changes in the rate of interference recorded on baited cards for three species: possum, ship rat (Rattus rattus) and mouse (Mus musculus). Key results Outcomes were highly variable, ranging from increases in pest activity to near total reductions. Possum reductions were highest where one or two prefeeds were used, and at the higher sowing rates (2 or 5 kg/ha), but with some interactions between these factors. For rats, two prefeeds resulted in the highest reductions but sowing rate had no effect. For mice, post-poisoning indices were often high, indicating low effectiveness. Conclusions Some treatments were highly effective so poor kills were unlikely to have resulted from pests not encountering bait, or the bait being unpalatable. Rather they appeared to reflect sub-lethal poisoning either as a result of low acceptance (as a result of a lack of familiarity and/or satiation) or bait fragmentation. We infer that for possum and rats prefeeding helps reduce this risk of sub-lethal poisoning not only by increasing familiarity, but also (in conjunction with high sowing rates) by increasing the bait encounter rate, particularly for possums. Implications There is scope to further reduce the amount of toxic bait sown and the cost of poisoning, without compromising efficacy, by fine-tuning the balance between prefeeding and sowing rate based on which species are being targeted and, for possums, reducing bait fragmentation.

scholarly journals Risk Response Selection in Construction Projects

2018 ◽  
Vol 3 (12) ◽  
pp. 1208 ◽  
Author(s):  
Hafeth I. Naji ◽  
Rouwaida Hussein Ali
Keyword(s):  
Risk Management ◽  
Optimal Strategy ◽  
Construction Projects ◽  
Response Selection ◽  
Search Algorithm ◽  
Gravitational Search Algorithm ◽  
Response Strategy ◽  
Risk Response ◽  
Gravitational Search ◽  
The Cost

Risk and its management  is  important  for the success of the project, the  risk management, which encompassed of planning, identification, analysis, and response has an important phase, which is risk response  and it should not be undermined, as its  success going to  the projects  the capability  to overcome the  uncertainty and  thus an effective  tool in project risk management, risk response used the collective information in the analysis stage and in order  to take decision how to improve the possibility to complete the project within time, cost and performance. This stage work on preparing the response to the main risks and appoint the people who are responsible for each response.  When it's needed risk response may be started in quantitative analysis stage and the repetition may be possible between the analysis and risk response stage. The aim of this research is to provide a methodology to make the plane for unexpected events and control uncertain situations and identify the reason for risk response failure and to respond to risk successfully by using the optimization method to select the best strategy. The methodology of this research divided into four parts, the first part main object is to find the projects whose risk response is failed, the second part includes the reasons for risk response Failure, the third part includes   finding   the most important risks generated from risk response that leads to increasing the cost of construction projects, the fourth part of the management system is selecting the optimal risk response strategy. An optimization model was used to select the optimal strategy to treat the risk by using Serval constraints such as the cost of the project, time of the project, Gravitational Search Algorithm and particle swarm used. The result of the risk response selection shows that The investment (contractor, bank) strategy shows a very good strategy as it saves the cost about 30%, while the Mitigate (pay for advances with interest 0. 1) Strategy show saving the cost 40%   and giving land to contractors show saving the cost 40% finally the BIM strategy show saving the cost 25%. The risk response is an important part and should give a great attention and it must be used sophisticated method to select the optimal strategy, the two techniques both show high efficiency in selecting the strategy but Gravitational Search Algorithm show better performance.

scholarly journals Same-sex sexual behavior and selection for indiscriminate mating

2020 ◽  
Author(s):  
Brian A Lerch ◽  
Maria R Servedio
Keyword(s):  
Sexual Behavior ◽  
Sexual Reproduction ◽  
Optimal Strategy ◽  
Strong Support ◽  
Same Sex ◽  
Evolutionary Origins ◽  
Wide Range ◽  
Selection For ◽  
The Cost ◽  
Time And Energy

The widespread presence of same-sex sexual behavior (SSB) has long been thought to pose an evolutionary conundrum1-3, as participants in SSB suffer the cost of failing to reproduce after expending the time and energy to find a mate. The potential for SSB to occur as part of an optimal strategy has received almost no attention, although indiscriminate sexual behavior may be the ancestral mode of sexual reproduction4. Here, we build a simple model of sexual reproduction and create a theoretical framework for the evolution of indiscriminate sexual behavior. We provide strong support for the hypothesis that SSB is likely maintained by selection for indiscriminate sexual behavior, by showing that indiscriminate mating is the optimal strategy under a wide range of conditions. Further, our model suggests that the conditions that most strongly favor indiscriminate mating were likely present at the origin of sexual behavior. These findings have implications not only for the evolutionary origins of SSB, but also for the evolution of discriminate sexual behavior across the animal kingdom.

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