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At least 361 records · Page 20Linked to original sources
USGS1996

Relationship between subcellular cadmium distribution in prey and cadmium trophic transfer to a predator

We tested the hypothesis that exposure-related alterations in the subcellular Cd distribution in prey relate to changes in Cd absorption by a predator. Oligochaete worms, Limnodrilus hoffmeisteri were exposed for 1 wk or 6 wk to 0.5 μg Cd 1 −1 , 47 μg Cd 1 −1 , or 140 μg Cd 1 −1 (including 109 Cd as a tracer) and relationships between oligochaete subcellular Cd distribution and Cd absorption by a predator, the grass shrimp ( Palaemonetes pugio ), were determined. Concentration and duration of Cd exposure had direct effects on oligochaete subcellular Cd distribution. Changes in oligochaete subcellular Cd distribution were characterized by increases in both the amount and proportion of Cd bound to the cytosolic fraction. The induction of Cd-binding proteins (e.g., metallothioneins) were suspected to be responsible for these changes. We found 1∶1 relationships between the amount and percentage of Cd in oligochaete cytosol and the amount and percentage of Cd adsorbed by shrimp. These results demonstrate that only metal bound to the soluble fraction of prey is available to higher trophic levels, and that factors influencing subcellular metal distribution in prey will directly alter metal trophic transfer to predators.

Estuaries↗
USGS1980

High duck nesting success in a predator-reduced environment

Duck nesting and production were studied during 1969-74 on a 51-ha field of undisturbed grass-legume cover and a surrounding 8.13-km 2 area in north-central South Dakota. The principal mammalian predators of ducks were reduced within a 259-km 2 zone from May 1969 through August 1971. Dabbling duck nest densities, hatching success, and breeding populations attained high levels. Seven duck species produced 1,062 nests on the 51-ha field during 6 years, 864 (81%) hatched, 146 (14%) were destroyed, and 52 (5%) had other fates. During 1970-72, when predator reduction was most effective, the hatching success for 756 nests was 94%. The number of mallard ( Anas platyrhynchos ) nests increased from 37 (0.7/ha) in 1969 to 181 (3.5/ha) in 1972. Mallard pairs increased from 2.8/km 2 to 16.8/km 2 on the 8.13-km 2 area during the same period. A minimum of 7,250 ducklings hatched on the 51-ha field during the 6 years, including 2,342 ducklings in 1972. Exceptionally high duck nesting densities and hatching rates occurred when predators were controlled.

South Dakota↗
USGS2018

Energy-rich mesopelagic fishes revealed as a critical prey resource for a deep-diving predator using quantitative fatty acid signature analysis

Understanding the diet of deep-diving predators can provide essential insight to the trophic structure of the mesopelagic ecosystem. Comprehensive population-level diet estimates are exceptionally difficult to obtain for elusive marine predators due to the logistical challenges involved in observing their feeding behavior and collecting samples for traditional stomach content or fecal analyses. We used quantitative fatty acid signature analysis (QFASA) to estimate the diet composition of a wide-ranging mesopelagic predator, the northern elephant seal ( Mirounga angustirostris ), across five years. To implement QFASA, we first compiled a library of prey fatty acid (FA) profiles from the mesopelagic eastern North Pacific. Given the scarcity of a priori diet data for northern elephant seals, our prey library was necessarily large to encompass the range of potential prey in their foraging habitat. However, statistical constraints limit the number of prey species that can be included in the prey library to the number of dietary FAs in the analysis. Exceeding that limit could produce non-unique diet estimates (i.e., multiple diet estimates fit the data equally well). Consequently, we developed a novel ad-hoc method to identify which prey were unlikely to contribute to diet and could, therefore, be excluded from the final QFASA model. The model results suggest that seals predominantly consumed small mesopelagic fishes, including myctophids (lanternfishes) and bathylagids (deep sea smelts), while non-migrating mesopelagic squids comprised a third of their diet, substantially less than suggested by previous studies. Our results revealed that mesopelagic fishes, particularly energy-rich myctophids, were a critical prey resource, refuting the long-held view that elephant seals are squid specialists.

Frontiers in Marine Science↗
USGS2006

Predation on walleye eggs by fish on reefs in western Lake Erie

We examined diets of fishes from gillnet and egg pump collections conducted on reefs in western Lake Erie during walleye ( Sander vitreus ) egg incubation periods from 1994–1999 and 2004 to assess incidence of walleye eggs in fish diets. We collected no potential egg predators in samples taken in 1994 but from 1995–1999 and in 2004 we caught 22 different species of fish on reefs in addition to spawning walleye. In most years, white perch ( Morone americana ) stomachs contained more walleye eggs than any other species on the reefs averaging 253 eggs per stomach. We also found lower numbers of walleye eggs in the stomachs of channel catfish ( Ictalurus punctatus ; 53 eggs/stomach), johnny darter ( Etheostoma nigrum ; 2 eggs/stomach), logperch ( Percina caprodes ; 10 eggs/stomach), quillback ( Carpiodes cyprinus ; 184 eggs/stomach), rock bass ( Ambloplites rupestris ; 3 eggs/stomach), round goby ( Neogobius melanostomus ; 4 eggs/stomach), sculpin ( Cottidae ; 21 eggs/stomach), silver chub ( Macrhybopsis storeriana ; 3 eggs/stomach), spottail shiner ( Notropis hudsonius ; 14 eggs/stomach), trout-perch ( Percopsis omiscomaycus ; 30 eggs/stomach), white sucker ( Catastomus commersonii ; 20 eggs/stomach), and yellow perch ( Perca flavescens ; 181 eggs/stomach). Similar to other studies of predation on walleye eggs, our results indicate that prolonged incubation periods increase the potential for egg loss due to predation.

Journal of Great Lakes Research↗
USGS1982

Electric fences to reduce mammalian predation on waterfowl nests

We evaluated electric fences as predator barriers to reduce high losses of waterfowl nests to mammalian predation at Waterfowl Production Areas (WPAs). The work was done in 1978-81 on 3 paired sites in central North Dakota and western Minnesota. Resident mammalian predators were trapped from inside the exclosures. All 3 fences operated during the study period with few major maintenance problems. Nest success in the exclosures was 65% in North Dakota and 55% in Minnesota vs. 45 and 12% in the respective controls. Cover inside the electric fence produced 7.8 more young/ha than cover in control plots in North Dakota during the 3 years. Cover inside the 2 electric fences in Minnesota yielded 9.5 and 4.3 more young/ha than cover in control plots during the 3 years. Using construction costs only we estimated that each additional duckling produced in cover protected by electric fencing cost $0.65 in North Dakota and $0.87 in Minnesota.

Wildlife Society Bulletin↗
USGS1993

Using Pop-II models to predict effects of wolf predation and hunter harvests on elk, mule deer, and moose on the northern range

The effects of establishing a gray wolf ( Canis lupus ) population in Yellowstone National Park were predicted for three ungulate species—elk ( Cervus elaphus ), mule deer ( Odocoileus hemionus ), and moose ( Alces alces )—using previously developed POP-II population models. We developed models for 78 and 100 wolves. For each wolf population, we ran scenarios using wolf predation rates of 9, 12, and 15 ungulates/wolf/year. With 78 wolves and the antlerless elk harvest reduced 27%, our modeled elk population estimated were 5-18% smaller than the model estimate without wolves. With 100 wolves and the antlerless elk harvest reduced 27%, our elk population estimated were 11-30% smaller than the population estimates without wolves. Wolf predation effects were greater on the modeled mule deer population than on elk. With 78 wolves and no antlerless deer harvest, we predicted the mule deer population could be 13-44% larger than without wolves. With 100 wolves and no antlerless deer harvest, the mule deer population was 0-36% larger than without wolves. After wolf recovery, our POP-II models suggested moose harvests would have to be reduced at least 50% to maintain moose numbers at the levels predicted when wolves were not present. Mule deer and moose population data are limited, and these wolf predation effects may be overestimated if population sizes or male-female ratios were underestimated in our population models. We recommend additional mule deer and moose population data be obtained.

Idaho, Montana, Wyoming↗
USGS2002

Effects of acute thermal stress on the survival, predator avoidance, and physiology of juvenile fall Chinook salmon

We subjected juvenile fall chinook salmon from the Hanford Reach of the Columbia River to acute thermal stressors in the laboratory that were derived from field data. We assessed the effects of thermal stress on: (1) the extent of direct mortality; (2) the vulnerability of fish to predation by smallmouth bass; and (3) some general physiological stress responses and synthesis of heat shock protein 70 (hsp70). Thermally-stressed fish showed little direct mortality and no increases in vulnerability to predation. However, these fish showed transient increases in plasma concentrations of cortisol, glucose, and lactate, and a dramatic (25-fold higher than controls) and persistent (lasting 2 wk) increase in levels of liver hsp70. Our results indicate that exposure of Hanford Reach juvenile fall chinook salmon to such stressors did not lead to significant increases in direct mortality or vulnerability to predation, but did alter physiological homeostasis, which should be of concern to those managing this resource. Because our fish received only a single exposure to one of the stressors we examined, we are also concerned about the consequences of exposing fish to multiple, cumulative stressors - a likely scenario for fish in the wild.

Northwest Science↗
USGS1996

Sea otter predation on Dungeness crabs in Glacier Bay, Alaska

Sea otter ( Enhydra lutris ) populations are increasing and expanding into areas of Southeast Alaska where Dungeness crabs ( Cancer magister ) are commercially harvested. Although sea otters are known to feed on Dungeness crabs, their effects upon crab demography have not been quantified. We censused Dungeness crabs in adjacent areas within Glacier Bay National Park and Preserve with and without sea otters in April 1993, 1994, and 1995 to investigate the effects of sea otter predation. Two different crab survey techniques were used. Commercial crab pots with sealed escape rings and baited similarly were soaked for 24 hours to measure CPUE in 0-25 m depths. A minimum of 50 pots was used for each site; 25 additional pots were used in 1994 and 1995 to sample crabs to 95 m depths. Divers censused crabs along belt transects (2 m x 100 m) laid perpendicular to shore from 0 m depth to 18 m; 15 transects were surveyed at each site on each date. Sea otter numbers were estimated from aerial surveys and boat observers. Prey types and feeding rates of sea otters were made from telescopic observations. In Outer Dundas Bay, where 46, 39, and 40 sea otters were present in 1993, 1994, and 1995 respectively, CPUE of Dungeness crabs in pots was 0.04, 0.04, and 0.2 crabs per day, respectively, at depths to 25 m, but was higher (4.0 crabs per day) at deeper depths (95 m). Only two Dungeness crabs were observed in 45 diver transects surveyed during three years in Outer Dundas Bay, however Dungeness crabs were a common prey item (15%) of sea otters. Approximately 16 km N in Inner Dundas Bay, where no sea otters were observed any year, CPUE of Dungeness in pots was 2.7, 1.8, and 2.5 crabs per day for 1993, 1994, and 1995, respectively. Adult crab density estimated from diver transects was 236, 78, and 50 crabs/ha in 1993, 1994, and 1995, respectively. Significantly lower crab densities and CPUE occurred in the site occupied by sea otters. Our data imply that sea otter predation decreases Dungeness crab abundance and may induce movement of crabs to greater depths. A depth refuge for crabs from sea otter predation may vary with local bathymetry.

Alaska↗
USGS1995

Winter wolf predation in a multiple ungulate prey system, Gates of the Arctic National Park, Alaska

We investigated patterns of winter wolf predation, including prey selection, prey switching, kill rates, carcass utilization, and consumption rates for four wolf packs during three different study periods (March 1989, March 1990, and November 1990) in Gates of the Arctic National Park and Preserve, Alaska. Wolves killed predominantly caribou (165 caribou, seven moose, and five Dall sheep) even when moose and sheep were more abundant. Prey selection varied between study periods. More moose were killed in march 1989, a particularly deep snow year, and more sheep were killed in November 1990 than during other periods. Overall kill rates ranged from 0-8 days/ungulate killed ( x̅ = 2.0, SD = 1.6) and did not vary between study periods. Pack size and species killed explained significant variation in the length of time intervals between kills. Although caribou density varied nearly 40-fold between pack territories, it had little influence on predation characteristics except at low densities, when kill rates may have declined. Caribou distribution had marked effects on wolf predation rate.

Alaska↗
USGS1995

Wolf predation on caribou calves in Denali National Park, Alaska

During 1987-1991, 29 to 45 radio-collared caribou cows were monitored daily during calving each year and their calves were radio-collared (n = 147 calves) to investigate calf production and survival. We determined characteristics of wolf predation on caribou calves and, utilizing information from a companion wolf study, evaluated the role of spacing by caribou cows in minimizing wolf predation on neonates (calves < 15 days old) during a period when wolf abundance doubled. On average, 49% of the neonates died, ranging from 30% in 1987 to 71% in 1991. Overall, wolves killed 22% of the neonates produced and were the most important mortality agent. Wolves preyed on calves primarily during six days following the peak of calving and usually killed calves five to 15 days old. The mortality rate for neonates was strongly inversely correlated with average birthweight. Neonatal losses to wolves were also correlated with birthweight but not spring wolf density or mean calving elevation. Caribou concentrated on a calving ground when spring snow conditions allowed and adjusted their distribution on the calving ground depending on snow conditions and wolf distribution and abundance. Even though the wolf population doubled, the exposure of caribou calves to wolf predation did not increase, when spacing by caribou at the wolf pack territory scale was accounted for.

Occasional Publication of the Canadian Circumpolar↗
USGS1995

Bullfrogs: Introduced predators in southwestern wetlands

In the American Southwest, much of the native fish fauna is facing extinction (Minckley and Deacon 1991); frogs in California (Fellers and Drost 1993) and frogs and garter snakes in Arizona (Schwalbe and Rosen 1988) are also in critical decline. Habitat destruction and introduced predators appear to be primary causes of native frog declines (Jennings and Hayes 1994), and habitat modification often yields ponds and lakes especially suitable for introduced species. Introduced bullfrogs ( Rana catesbeiana ) have been blamed for amphibian declines in much of western North America (e.g., Hayes and Jennings 1986; Leonard et al. 1993; Vial and Saylor 1993). Extensive cannibalism by bullfrogs renders them especially potent predators at the population level. The tadpoles require only perennial water and grazeable plant material; hence, transforming young can sustain a dense adult bullfrog population even if alternate prey are depleted. This may increase the probability that native species may be extirpated by bullfrog predation. Introduced predatory fishes are apparently an important cause of frog declines (Hayes and Jennings 1986). They have been strongly implicated in one important case of decline of native ranid frog (family Ranidae, the "true" frogs; Bradford 1989). Some introduced crayfish may also be devastating in some areas (Jennings and Hayes 1994). In our study region, however, neither introduced fishes nor crayfish are dominant. We present results that sustain a "bullfrog hypothesis" for some native ranid declines, and we present our study as an example of how evidence accumulates to support such a hypothesis. In 1985 we began documenting historical localities for wetland herpetofaunas (reptiles and amphibians), based on museum records and personal interviews, then revisited these and additional areas to determine current species' status. Results of this process, plus circumstantial evidence, suggested that the bullfrog was a primary cause for declines of leopard frogs and garter snakes in southern Arizona (Schwalbe and Rosen 1988). In 1986-89 and 1992-93 we conducted removal censuses of bullfrogs at San Bernardino National Wildlife Refuge (SBNWR), Cochise County, Arizona. We simultaneously monitored native Chiricahua leopard frogs ( R. chiricahuensis ) and Mexican garter snakes ( Thamnophis eques ) at the sites of bullfrog removal. A control site, with no bullfrog removal, was established in comparable habitat at Buenos Aires National Wildlife Refuge (BANWR), Pima County, Arizona.

Book chapter↗
USGS1999

Terrestrial predator alarm vocalizations are a valid monitor of stress in captive brown capuchins (Cebus apella)

The vocal behavior of captive animals is increasingly exploited as an index of well-being. Here we show that the terrestrial predator alarm (TPA) vocalization, a robust and acoustically distinctive anti-predation vocal response present in many mammal and bird species, offers useful information on the relative well-being and stress levels of captive animals. In a 16-week experiment evaluating the effects of varying levels of physical environmental enrichment (control < toys < foraging box < foraging box and toys) in the cages of eight singly housed adult male brown capuchins, we quantified the 1) emission rate of TPAs, 2) proportions of normal and abnormal behavior sample intervals, and 3) fecal and plasma cortisol levels. Variation in TPA emission across the experimental conditions was significant. We found significant reductions in the mean TPA production rate by the group in the enriched (toys, foraging box, and foraging box and toys) compared to the control condition; pre- and post-experimental conditions, however, did not differ from the control condition. Mean TPA production by the group was also significantly positively correlated to mean group levels of fecal cortisol and proportion of abnormal behavior sample intervals, and significantly negatively correlated to the average proportion of normal behavior sample intervals in the group. Based on group means, plasma cortisol levels were positively, but not significantly, related to increasing TPA rate. At the level of the responses of an individual subject, however, the covariation between the vocal and non-vocal behavioral measures and the cortisol assays seldom attained significance. Nevertheless, the direction of the relationships among these parameters within individual subjects typically mirrored those correlations based on group means. At both the group mean and individual levels, our results are consistent with the interpretation that in conditions of low environmental enrichment the study subjects were more stressed, and therefore more reactive to the presence of a threatening terrestrial stimulus (human observer), than when in more enriched conditions. We suggest that protocols to evaluate the effectiveness of enrichment for captive species other than brown capuchins could also profitably exploit TPAs as a first-line monitor or as corroboratory evidence of current well-being.

Zoo Biology↗
USGS2023

Addressing a potential weakness in indices of predation, herbivory, and parasitism

Quantification of predation, herbivory, and parasitism is critical to understanding the dynamics and trophic interactions of populations in an ecosystem. Such quantification can be challenging if the availability or consumption of the taxa are difficult to assess. Sometimes the consumption of a single prey, forage, or host is used as an overall index of the predation, herbivory, or parasitism for a population of interest. Occasionally, human-manipulated baits are used to derive similar indices. However, all such indices are susceptible to influence by variation in the abundance of the preferred taxon relative to other taxa as the result of preference switching. In this article, I describe a test for preference switching (and an adjustment, if detected) that does not require availability and consumption of the prey (forage, or host) to be measured on the same scale. The ability to detect and adjust for preference switching in such situations may advance the understanding of biological preference in taxa not previously studied in this respect.

Population Ecology↗
USGS2024

Comparison of seven DNA metabarcoding sampling methods to assess diet in a large avian predator

DNA metabarcoding is a rapidly advancing tool for diet assessment in wildlife ecology. Studies have used a variety of field collection methods to evaluate diet; however, there is a pressing need to understand the differences among sampling methods and the downstream inferential consequences they may have on our ability to document diet accurately and efficiently. We evaluated seven DNA metabarcoding sampling methods to assess the diet of a large avian predator: Buteo lagopus (rough-legged hawk). We collected beak swabs, talon swabs, cheek (buccal) swabs, cloacal swabs, and cloacal loops from captured birds, and collected fecal samples from both captured and uncaptured birds. We described and compared variation in prey recovery within and among the seven sampling methods and identified appropriate analytical methods to compare diet among individuals sampled via different methods. Beak and talon swabs produced the highest prey detection rates, yielded the greatest prey richness per sample, and contributed the most to an individual's total prey richness per sampling occasion compared to other sampling methods. Within individuals sampled using five methods during a single capture occasion, cloacal swabs and cheek swabs positively predicted prey richness and average prey mass, respectively, from fecal samples. While all methods identified similar dominant prey taxa that were consistent with prior diet studies, beak and talon swabs detected greater prey richness at both the individual and population levels. We propose a food residue duration hypothesis whereby methods which sample areas containing food DNA consumed from longer and more continuous pre-sampling time intervals explain variation among sampling methods in observed prey richness. Choice of sampling method can influence predator diet characterization and is particularly important if researchers wish to quantify uncommon diet items or compare diet metrics using samples collected via different methods.

Environmental DNA↗
USGS2021

Exploring the contemporary relationship between predator and prey in a significant, reintroduced Lahontan Cutthroat Trout population

Lahontan Cutthroat Trout (LCT) Oncorhynchus clarkii henshawi have experienced some of the most marked reductions in abundance and distribution among Cutthroat Trout subspecies. The population of LCT in Pyramid Lake, Nevada has returned from the brink of extirpation, and although it is highly managed via stocking, the population is thriving and has recently started to reproduce naturally. Our objectives were to determine (1) whether predator and prey remain tightly coupled, (2) whether LCT are food limited, and (3) the status of the LCT population with regard to the potential prey-based contemporary carrying capacity. We used a multifaceted approach, including intensive field sampling of fish, bioenergetics modeling, cohort reconstruction, and comparisons of prey availability to consumption. We estimated that the average population of LCT in Pyramid Lake is 1.2 million, average annual stocking is 650,000, and the number of fish angled ranges from 5,000 to 14,000 per year, with a 90% release rate. Driven by seasonal and size variation in consumption, individual annual consumption by LCT varied from 667 to 992 g/year for small LCT (200–400 mm TL) and from 2,388 to 3,057 g/year for large LCT (>400 mm TL). Lahontan Cutthroat Trout are consuming, on average, 14–63% of the standing crop of Tui Chub Siphateles bicolor annually, indicating that LCT are currently not exceeding their prey-based carrying capacity. The LCT in Pyramid Lake remain tightly coupled to their primary native prey, Tui Chub, despite considerable changes to the ecosystem; therefore, managing for a robust population of LCT translates largely to managing for forage fish. This supply-versus-demand issue is of particular concern for Pyramid Lake given that the density of Tui Chub may be declining concordant with declining lake elevation. Given the conservation importance of this LCT population, careful monitoring is critical; however, “predation inertia” indicates that effective short-term management in response to fluctuations in forage fishes is likely possible.

Nevada↗
USGS2012

New parasites and predators follow the introduction of two fish species to a subarctic lake: implications for food-web structure and functioning

Introduced species can alter the topology of food webs. For instance, an introduction can aid the arrival of free-living consumers using the new species as a resource, while new parasites may also arrive with the introduced species. Food-web responses to species additions can thus be far more complex than anticipated. In a subarctic pelagic food web with free-living and parasitic species, two fish species (arctic charr Salvelinus alpinus and three-spined stickleback Gasterosteus aculeatus ) have known histories as deliberate introductions. The effects of these introductions on the food web were explored by comparing the current pelagic web with a heuristic reconstruction of the pre-introduction web. Extinctions caused by these introductions could not be evaluated by this approach. The introduced fish species have become important hubs in the trophic network, interacting with numerous parasites, predators and prey. In particular, five parasite species and four predatory bird species depend on the two introduced species as obligate trophic resources in the pelagic web and could therefore not have been present in the pre-introduction network. The presence of the two introduced fish species and the arrival of their associated parasites and predators increased biodiversity, mean trophic level, linkage density, and nestedness; altering both the network structure and functioning of the pelagic web. Parasites, in particular trophically transmitted species, had a prominent role in the network alterations that followed the introductions.

Takvatn Lake↗
USGS2026

Light-dependent activity of deepwater sculpin (Myoxocephalus thompsonii) across substrates with and without predation risk

Light availability strongly influences predator–prey interactions in deepwater ecosystems, where visual constraints shape both foraging success and prey behavior. The behavioral response of deepwater sculpin ( Myoxocephalus thompsonii ) to siscowet lake trout ( Salvelinus namaycush siscowet ) was studied under ecologically relevant light intensities spanning several orders of magnitude typical of daytime downwelling light in the 20–100 m depth range of Lake Superior. Trials were conducted over varying substrates (gravel, sand, and black fabric). Deepwater sculpin showed a significant preference for gravel over sand and black fabric. In the absence of siscowet, sculpin movement frequency increased as light intensity decreased. Sculpin reaction distance to siscowet was influenced by both light and substrate. Reaction distance was shortest at low light intensities, peaked at intermediate light intensities (3.05 × 10⁹ to < 6.0 × 10⁹ photons m⁻2 s⁻1), and declined again at the highest light intensities tested. In the presence of siscowet, sculpin activity was suppressed at the upper end of the light range (≥ 6.0 × 10⁹ photons m⁻2 s⁻1). The greatest increase in movement occurred between 6.0 × 10⁹ and 3.05 × 10⁹ photons m⁻2 s⁻1, which corresponded to the range where siscowet prey capture declined, suggesting sculpin exploit this low-light window to move with reduced risk. Reduced activity in the presence of predators is common among cryptic species, and our findings suggest that sculpin restrict movement at higher light levels to avoid detection by siscowet.

Wisconsin↗
USGS1989

Predator-prey interactions, resource depression and patch revisitation

Generalist predators may be confronted by different types of prey in different patches: sedentary and conspicuous, cryptic (with or without refugia), conspicuous and nonsocial, or conspicuous and social. I argue that, where encounter rates with prey are of most importance, patch revisitation should be a profitable tactic where prey have short 'recovery' times (conspicuous, nonsocial prey), or where anti-predator response (e.g. shoaling) may increase conspicuousness. Predictions are made for how temporal changes in prey encounter rates should affect revisit schedules and feeding rates for the 4 different prey types.

Behavioural Processes↗