An experimental analysis of prey availability for sanderlings (Aves: Scolopacidae) feeding on sandy beach crustaceans

1980 ◽  
Vol 58 (9) ◽  
pp. 1564-1574 ◽  
Author(s):  
J. P. Myers ◽  
S. L. Williams ◽  
F. A. Pitelka
Keyword(s):  
Prey Density ◽  
Prey Capture ◽  
Prey Size ◽  
Prey Availability ◽  
Capture Rate ◽  
Search Time ◽  
Beach Sand ◽  
Sand Surface ◽  
Prey Capture Rate ◽  
Bodega Bay

We investigated the role of prey size, prey depth, prey microdistribution, and substrate penetrability in affecting prey availability to sanderlings (Calidris alba Pallas). Five experiments were performed in the laboratory manipulating these availability factors and prey density in beach sand. The effects on prey risk and sanderling prey capture rate were measured.Prey risk increased linearly with prey size. Prey within 10 mm of the surface were vulnerable to predation but their risk decreased sharply below that depth. Substrate penetrability affected prey risk by controlling how deeply a sanderling could probe beneath the sand surface while searching for prey.Prey capture rates varied between 0.01 and 0.84 captures per second of search time over a range of prey density between 60 and 1200 prey per square metre. Prey size and substrate penetrability affected capture rate through their effect on prey risk, and substrate penetrability also influenced capture rate directly. Prey density had the strongest effect on prey capture rate. Measurements in the field around Bodega Bay, California, indicate that prey density, prey size, prey depth, and substrate penetrability can have significant impact on sanderling foraging under field conditions.

Behavioral Energetics of Overwintering in the Rifleman, Acanthisitta-Chloris

1991 ◽  
Vol 39 (6) ◽  
pp. 643 ◽  
Author(s):  
A Lill
Keyword(s):  
Population Density ◽  
Prey Capture ◽  
Activity Rhythm ◽  
Capture Rate ◽  
Microhabitat Use ◽  
Lowland Forest ◽  
Time Activity ◽  
Ambient Temperatures ◽  
Prey Capture Rate ◽  
Autumn And Winter

The role of behavioural adjustments in meeting increased daily energy requirements in winter was investigated in rifleman, Acanthisitta chloris, inhabiting lowland forest in South I., New Zealand, by comparing their population density, time-activity budget and foraging behaviour in autumn and winter. Rifleman foraged for 83% of daytime in both seasons. The combined effects on the birds' winter energy budget of increased thermoregulation costs and the shorter daylength for foraging were at least partly offset by an estimated 23-29% decrease in the amount of energy expended daily on activity and a 78% increment in prey caught per day. The reduced energy expenditure on activity resulted from rifleman spending less time on expensive flying and more time roosting. The increase in prey capture rate may have stemmed from a 35% seasonal reduction in the birds' population density and reduced prey mobility at lower ambient temperatures. Marked sexual size dimorphism was not reflected in gender differences in activity budgeting or prey capture rate, but the sexes differed in their relative use of foraging substrates. Rifleman showed few seasonal changes in daily activity rhythm or microhabitat use. The behavioural energetic overwintering tactics of rifleman are compared with those of other Australasian and north temperate zone land-birds.

A test of optimal foraging and the effects of predator experience in the lizards Sceloporus jarrovii and Sceloporus virgatus

Behaviour ◽  
2010 ◽  
Vol 147 (8) ◽  
pp. 933-951 ◽  
Author(s):  
Keyword(s):  
Success Rate ◽  
Prey Capture ◽  
Prey Availability ◽  
Search Time ◽  
Handling Time ◽  
Foraging Efficiency ◽  
Prey Choice ◽  
Foraging Experience ◽  
Time Optimality ◽  
Sceloporus Virgatus

AbstractForaging efficiency of predators can be evaluated by using optimality or profitability models which incorporate prey choice, handling time and pursuit or search time. Optimality of a diet could vary based on the age, sex, size, predation risk, or foraging experience of the predator. This study tested the effects of a predator's age and foraging experience by observing prey capture attempts and success rate, and by calculating diet profitability for adult and neonate Sceloporus jarrovii and adult Sceloporus virgatus. Prey availability was assessed in order to determine prey preference and profitability. Neonates showed an increased number of prey capture attempts, but success rate was similar for neonates and adults of both species. Total diet profitability of neonates was lower than adults of either species, which could be a result of poor prey choice or gape limitation (although body size showed no direct effect). Overall, the diets of all three groups were less profitable than would be expected based on the types of prey in the environment, although this is likely due to low availability (from the lizard's perspective) of highly profitable items. Lizards seem to be eating prey items in the same proportion as they are found in the environment.

scholarly journals Nutrient balance affects foraging behaviour of a trap-building predator

2009 ◽  
Vol 5 (6) ◽  
pp. 735-738 ◽  
Author(s):  
David Mayntz ◽  
Søren Toft ◽  
Fritz Vollrath
Keyword(s):  
Foraging Behaviour ◽  
Prey Capture ◽  
Prey Availability ◽  
Capture Rate ◽  
Nutrient Balance ◽  
Nutrient Composition ◽  
Web Architecture ◽  
First Instar ◽  
Predator Foraging ◽  
Web Building

Predator foraging may be affected by previous prey capture, but it is unknown how nutrient balance affects foraging behaviour. Here, we use a trap-building predator to test whether nutrients from previous prey captures affect foraging behaviour. We fed orb-weaving spiders ( Zygiella x-notata ) prey flies of different nutrient composition and in different amounts during their first instar and measured the subsequent frequency of web building and aspects of web architecture. We found that both the likelihood of web building and the number of radii in the web were affected by prey nutrient composition while prey availability affected capture area and mesh height. Our results show that both the balance of nutrients in captured prey and the previous capture rate may affect future foraging behaviour of predators.

scholarly journals Captive culture of two sea snake species Hydrophis curtus and Hydrophis cyanocinctus

2021 ◽  
Vol 20 (4A) ◽  
pp. 105-114
Author(s):  
Nguyen Trung Kien ◽  
Hua Thai An ◽  
Huynh Minh Sang ◽  
Do Huu Hoang ◽  
Cao Van Nguyen ◽  
...  
Keyword(s):  
Body Weight ◽  
Survival Rate ◽  
Prey Capture ◽  
Prey Selection ◽  
Capture Rate ◽  
The Body ◽  
Sea Snake ◽  
Snake Species ◽  
Prey Capture Rate

Acclimation culture and trial culture of two sea snake species Hydrophis curtus and H. cyanocinctus in composite tanks were conducted to determine growth, survival rate, predation behavior and prey selection. The results showed that adults of H. curtus and H. cyanocinctus did not capture any prey such as anchovy, eel and shrimp in a period of 30 days of acclimation culture. The body weight of two these species reduced gradually from 783.3 ± 76.4 g and 360.0 ± 60.0 g to 660.0 ± 135.2 g and 315.0 ± 77.8 g, respectively. Survival rate was 100% in H. curtus and 80% in H. cyanocinctus. Meanwhile, the results of acclimation culture of sea snake juvenile revealed that frozen anchovy was preferred prey in both of two species. The body weight of H. curtus increased from 49.8 ± 0.5 g to 70.0 ± 8.2 g and that of H. cyanocinctus was 44.3 ± 3.1 g to 47.1 ± 5.2 g. The prey capture rate of H. curtus and H. cyanocinctus was 100% and 60%, respectively. Survival rate of the juvenile of two species was 100% after 30 days of acclimation culture. In 60 days of trial culture, similar results as acclimation culture were observed in adults of two sea snake species, they still did not capture any prey and the body weight reduced gradually. The result of 60-day culture of sea snake juvenile showed that the prey capture rate was 100% in both of two species. The body weight of H. curtus and H. cyanocinctus increased from 70.0 ± 8.2 g and 57.5 ± 5.8 g to 78.3 ± 15.3 g and 65.0 ± 14.1, respectively. SGR of H. curtus was 0.16 ± 0.32 %/day and that of H. cyanocinctus was 0.52 ± 0.36%/day. The survival rate of H. curtus and H. cyanocinctus was 60% and 40% in period of 60 day trial.

scholarly journals Prey Size Decline as a Unifying Ecological Selecting Agent in Pleistocene Human Evolution

Quaternary ◽  
2021 ◽  
Vol 4 (1) ◽  
pp. 7
Author(s):  
Miki Ben-Dor ◽  
Ran Barkai
Keyword(s):  
Prey Size ◽  
Prey Availability ◽  
Stone Tool ◽  
Foraging Efficiency ◽  
Energetic Cost ◽  
Large Prey ◽  
Biomass Density ◽  
Cultural Changes ◽  
Progressive Decline ◽  
Brain Expansion

We hypothesize that megafauna extinctions throughout the Pleistocene, that led to a progressive decline in large prey availability, were a primary selecting agent in key evolutionary and cultural changes in human prehistory. The Pleistocene human past is characterized by a series of transformations that include the evolution of new physiological traits and the adoption, assimilation, and replacement of cultural and behavioral patterns. Some changes, such as brain expansion, use of fire, developments in stone-tool technologies, or the scale of resource intensification, were uncharacteristically progressive. We previously hypothesized that humans specialized in acquiring large prey because of their higher foraging efficiency, high biomass density, higher fat content, and the use of less complex tools for their acquisition. Here, we argue that the need to mitigate the additional energetic cost of acquiring progressively smaller prey may have been an ecological selecting agent in fundamental adaptive modes demonstrated in the Paleolithic archaeological record. We describe several potential associations between prey size decline and specific evolutionary and cultural changes that might have been driven by the need to adapt to increased energetic demands while hunting and processing smaller and smaller game.

scholarly journals Diet composition and feeding habits of the eyespot skate, Atlantoraja cyclophora (Elasmobranchii: Arhynchobatidae), off Uruguay and northern Argentina

2016 ◽  
Vol 14 (3) ◽  
Author(s):  
Santiago A. Barbini ◽  
Luis O. Lucifora
Keyword(s):  
Body Size ◽  
Diet Composition ◽  
Prey Size ◽  
Prey Availability ◽  
Feeding Habits ◽  
Warm Season ◽  
Cold Season ◽  
The North ◽  
Multiple Hypothesis ◽  
Modelling Approach

ABSTRACT The eyespot skate, Atlantoraja cyclophora, is an endemic species from the southwestern Atlantic, occurring from Rio de Janeiro, Brazil, to northern Patagonia, Argentina. The feeding habits of this species, from off Uruguay and north Argentina, were evaluated using a multiple hypothesis modelling approach. In general, the diet was composed mainly of decapod crustaceans, followed by teleost fishes. Molluscs, mysidaceans, amphipods, isopods, lancelets and elasmobranchs were consumed in lower proportion. The consumption of shrimps drecreased with increasing body size of A. cyclophora. On the other hand, the consumption of teleosts increased with body size. Mature individuals preyed more heavily on crabs than immature individuals. Teleosts were consumed more in the south region (34º - 38ºS) and crabs in the north region (38º - 41ºS). Shrimps were eaten more in the warm season than in the cold season. Prey size increased with increasing body size of A. cyclophora , but large individuals also consumed small teleosts and crabs. Atlantoraja cyclophora has demersal-benthic feeding habits, shifts its diet with increasing body size and in response to seasonal and regional changes in prey availability and distribution.

An Experimental Analysis of Macrophyte Growth Forms as Fish Foraging Habitat

1991 ◽  
Vol 48 (1) ◽  
pp. 123-131 ◽  
Author(s):  
Michele Dionne ◽  
Carol L. Folt
Keyword(s):  
Plant Growth ◽  
Growth Form ◽  
Plant Density ◽  
Prey Capture ◽  
Capture Rate ◽  
Habitat Associations ◽  
Growth Forms ◽  
Plant Growth Form ◽  
Macrophyte Growth ◽  
Capture Rates

In this laboratory study we measured the independent effects of macrophyte growth form, plant density, and prey abundance on the foraging rate of the pumpkinseed sunfish (Lepomis gibbosus). We demonstrate that macrophyte growth forms are not all similar in their effects on fish foraging. Prey capture rates of pumpkinseeds foraging among Scirpus validus (cylindrical stems) were 53 and 365% times greater than for Potamogeton amplifolius (leafy stems) for cladoceran (Sida crystallina) and larval damselfly (Coenagrionidae) prey, respectively. Plant growth form influenced prey capture rates more than charges in natural plant density. Plant density effects ranged from none on damselfly capture rates to a 29% decline in cladoceran capture rate over a twofold increase in plant density. Our results indicate that in plant-structured habitats, variation in plant growth form can be an important determinant of fish foraging and habitat associations.

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