Predation by House Cats, Felis catus (L.), in Canberra, Australia. I. Prey Composition and Preference

1997 ◽  
Vol 24 (3) ◽  
pp. 263 ◽  
Author(s):  
D. G. Barratt
Keyword(s):  
Small Mammals ◽  
Prey Availability ◽  
Felis Catus ◽  
Night Time ◽  
Substantial Impact ◽  
Predatory Behaviour ◽  
Residential Developments ◽  
Prey Composition ◽  
Spatial Habitat

Studies of predation by house cats in Australia have not attempted to compare the composition of prey taken by cats with the relative availability of prey. Information on the composition of vertebrate prey caught by house cats in Canberra was collected by recording prey deposited at cat owners’ residences over 12 months. A total of 1961 prey representing 67 species were collected or reported. In all, 64% of prey were introduced mammals, especially mice and rats, with birds comprising 27% (14% native, 10% introduced, 3% unidentified), reptiles 7%, amphibians 1% and native mammals 1%. Predatory behaviour by house cats appeared largely opportunistic with respect to spatial (habitat) and temporal (daily and seasonal) prey availability and accessibility, although there is mounting evidence from this and other studies that small mammals are the preferred prey. While this means that introduced mice and rats are common prey of house cats in urban and suburban environments, it also suggests that in relatively undisturbed environments adjoining new residential developments, predation by house cats may have a substantial impact on locally abundant, patchily distributed populations of native fauna, particularly mammals. Imposing night-time curfews on cats is likely to lessen predation of mammals but will probably not greatly reduce predation of birds or reptiles.

An attempt to determine the size of the Common Barn-owl’s (Tyto alba) hunting area based on its prey composition

2021 ◽  
pp. 175815592110660
Author(s):  
Jenő J Purger ◽  
Dávid Szép
Keyword(s):  
Functional Groups ◽  
Small Mammals ◽  
Small Mammal ◽  
Barn Owl ◽  
Tyto Alba ◽  
Mammal Species ◽  
Open Forest ◽  
Prey Composition ◽  
Small Mammal Species ◽  
Owl Pellets

The relative abundance of small mammal species detected from Common Barn-owl pellets reflects the landscape structure and habitat pattern of the owl’s hunting area, but it is also affected by the size of the collected pellet sample and the size of the supposed hunting area. The questions arise: how many pellets should be collected and analyzed as well as how large hunting area should be taken into consideration in order to reach the best correspondence between the owl’s prey composition and the distribution of habitats preferred by small mammals preyed in supposed hunting areas? For this study, we collected 1045 Common Barn-owl pellets in a village in southern Hungary. All detected small mammal species were classified into functional groups (guilds) preferring urban, open, forest and wetland habitats. The proportion of functional groups was compared to the proportion of these habitats around the pellet collection site within circles of one, two, and three km radius. Saturation curves showed that at least 300 pellets or ca. 600 mammalian remains are required for the detection of the 19 small mammal species. The share of small mammals detected in the prey and their functional groups according to their habitat preference showed an increasing consistency with the distribution of real habitats in the potential hunting area of a radius of 3 km around the owl’s breeding or resting place.

Irruptive White Ibis breeding is associated with use of freshwater crayfish in the coastal Everglades

The Condor ◽  
2021 ◽  
Vol 123 (1) ◽  
Author(s):  
Tasso C Cocoves ◽  
Mark I Cook ◽  
Jeffrey L Kline ◽  
Lori Oberhofer ◽  
Nathan J Dorn
Keyword(s):  
Prey Availability ◽  
Freshwater Crayfish ◽  
Seasonal Wetlands ◽  
Important Prey ◽  
Procambarus Alleni ◽  
Eudocimus Albus ◽  
Hydrologic Restoration ◽  
Prey Composition ◽  
White Ibis ◽  
Nesting Activity

Abstract As avian reproductive success is generally prey limited, identifying important prey types or sizes and understanding mechanisms governing prey availability are important objectives for avian conservation ecology. Irruptive White Ibis (Eudocimus albus) nesting at coastal colonies in the southern Everglades numbered over 100,000 nests in the 1930s. A century of drainage and altered hydrologic patterns reduced aquatic prey availability and eliminated large nesting events; nesting activity in recent decades has been typically less than 5% of historical peaks. Hydrologic restoration is expected to increase ibis nesting activity, but which prey types will support high nesting effort is less clear. In 2017 and 2018, we collected food boluses from White Ibis chicks at coastal colonies in Everglades National Park. We also monitored regional nesting activity from 1999 to 2018. In 2017, the region had 1,075 nests, typical of the past several decades; but in 2018, there were 30,420 nests, representing the highest recorded nesting activity in 87 yr. Prey composition varied between years; estuarine crabs dominated nestling boluses in 2017, while crayfish and fish were dominant prey in 2018. Crayfish, especially Procambarus alleni, were heavily exploited by ibis early in the 2018 breeding season, while fish were used more at the end. Crayfish abundances in wetlands near the colonies were higher prior to 2018, and more crayfish-producing short-hydroperiod wetlands remained available for ibis foraging in 2018. Our results support previous studies indicating that crayfish are important prey for breeding ibises and suggest that unprecedented, extensive flooding of seasonal wetlands promoted crayfish production and initiated the irruptive breeding in 2018. Our observations indicate that rehydration of the southern Everglades could restore ibis nesting activity at coastal colonies, but further investigations of hydrologic variation, crayfish production, and ibis foraging and nesting activity will be helpful to understand these dynamics and the importance of short-hydroperiod wetlands.

Nocturnally constrained foraging of a lotic minnow (Rhinichthys cataractae)

1989 ◽  
Vol 67 (8) ◽  
pp. 2008-2012 ◽  
Author(s):  
Joseph M. Culp
Keyword(s):  
Seasonal Changes ◽  
Prey Availability ◽  
Diel Periodicity ◽  
Foraging Activity ◽  
Light Levels ◽  
Prey Composition ◽  
Rhinichthys Cataractae ◽  
Nocturnal Foraging ◽  
Gut Fullness ◽  
Foraging Pattern

Diel periodicity in foraging activity of the longnose dace (Rhinichthys cataractae) was determined by measuring dace activity over the stream bed, gut fullness, and the digestive state of prey items. Although most species of minnows are either diurnally or crepuscularly active, dace began foraging within 1 h after sunset with light levels near 10 lx and ceased before sunrise throughout the ice-free period. During the day few prey were taken as the dace remained under the shelter of stones. This nocturnal foraging pattern did not appear to be affected by spawning or seasonal changes in prey composition. Nocturnal foraging in dace is not likely a response to prey availability, but may be a response to avoid diel periods when salmonid competitors or visual predators are active.

The diet of a forest-dependent frog species, Odorrana morafkai (Anura: Ranidae), in relation to habitat disturbance

2020 ◽  
Vol 41 (1) ◽  
pp. 29-41
Author(s):  
Duong Thi Thuy Le ◽  
Jodi J.L. Rowley ◽  
Dao Thi Anh Tran ◽  
Huy Duc Hoang
Keyword(s):  
Rainy Season ◽  
Prey Availability ◽  
Feeding Strategy ◽  
Habitat Disturbance ◽  
Habitat Modification ◽  
Prey Composition ◽  
Frog Species ◽  
Disturbed Habitats ◽  
The Impact ◽  
Prey Items

Abstract While deforestation is one of the greatest drivers of biodiversity loss, our understanding of the effects of habitat modification on species is limited. We investigated the diet of a forest-dwelling frog species, Morafka’s frog (Odorrana morafkai), in a highland forest in Vietnam in relation to habitat disturbance, sex and season. We surveyed the species at 45 sites in forest of varying disturbance and examined its diet using stomach flushing, estimating prey availability via trapping. We detected significantly fewer O. morafkai in highly disturbed habitats compared to moderately disturbed or non-disturbed habitats. We revealed that O. morafkai is a dietary generalist, identifying 28 prey types, primarily invertebrates. Prey composition, the number of prey items per stomach and prey volume per stomach did not vary between disturbance levels. Diet did not vary significantly between sexes, except that females had a higher prey volume. Prey composition in the species varied between seasons, with Coleoptera and Orthoptera dominating the diet in the rainy season and Lepidoptera in the dry season. The number of prey items per stomach and prey volume were significantly higher in the rainy season. There was a significant correlation between prey availability and diet composition. The low number of O. morafkai detected in highly disturbed habitats suggests that this habitat may not be optimal for the species, despite having a generalist feeding strategy and presumed high mobility. This study provides a window into the impact of an increasing threat, habitat disturbance, on forest-dependent amphibian species.

Feeding ecology of breeding Long-eared Owls in southwestern Idaho

1984 ◽  
Vol 62 (8) ◽  
pp. 1528-1533 ◽  
Author(s):  
Jeffrey S. Marks
Keyword(s):  
Small Mammals ◽  
Feeding Ecology ◽  
Food Selection ◽  
Prey Type ◽  
Birds Of Prey ◽  
Snake River ◽  
Feeding Niche ◽  
Prey Composition ◽  
Breeding Seasons ◽  
Mammal Faunas

Feeding ecology of Long-eared Owls (Asio otus) was investigated in the Snake River Birds of Prey Area, southwestern Idaho, during the breeding seasons of 1980 and 1981. The owls preyed mainly on five genera of small mammals: Peromyscus, Perognathus, Dipodomys, Microtus, and Reithrodontomys. There was considerable variation in prey composition among sites but not between years. In both years the proportion of Perognathus in the diet increased after the young owls fledged. Compared with other North American studies, Long-eared Owls in the Snake River Birds of Prey Area had a wider feeding niche and preyed more extensively on nonmicrotines. The range of prey sizes in Long-eared Owl diets was similar to that in other areas, with most prey weighing less than 100 g. Interlocality differences in the Long-eared Owl feeding niche probably reflect differences in the composition of small mammal faunas. Long-eared Owls in the Snake River Birds of Prey Area appeared to feed opportunistically on a diversity of available small mammals; prey size, rather than prey type, was the most important factor in food selection.

scholarly journals Reversed sexual dimorphism and altered prey base: the effect on sooty owl (Tyto tenebricosa tenebricosa) diet

2011 ◽  
Vol 59 (5) ◽  
pp. 302 ◽  
Author(s):  
Rohan J. Bilney ◽  
John G. White ◽  
Raylene Cooke
Keyword(s):  
Sexual Dimorphism ◽  
Small Mammals ◽  
Prey Availability ◽  
Mammalian Species ◽  
Control Programs ◽  
European Settlement ◽  
Mammal Conservation ◽  
Reversed Sexual Dimorphism ◽  
Conservation Concern ◽  
And Function

The ecology and function of many Australian predators has likely been disrupted following major changes in prey base due to declines in distribution and abundance of small mammals following European settlement. This study investigated various aspects of the dietary ecology of sooty owls (Tyto tenebricosa tenebricosa), including sexual variation as they potentially exhibit the greatest degree of reversed sexual dimorphism of any owl species worldwide. Sooty owls are highly opportunistic predators of non-volant small mammals, consuming most species known to exist in the region, so their diet fluctuates seasonally and spatially due to varying prey availability, and is particularly influenced by the breeding cycles of prey. Significant intersexual dietary differences existed with female sooty owls predominantly consuming much larger prey items than males, with dietary overlap at 0.62. The current reliance on relatively few native mammalian species is of conservation concern, especially when mammal declines are unlikely to have ceased as many threatening processes still persist in the landscape. Sooty owl conservation appears inextricably linked with small mammal conservation. Conservation efforts should be focussed towards improving prey densities and prey habitat, primarily by implementing control programs for feral predators and preventing the loss of hollow-bearing trees throughout the landscape.

Day- and night-time prey availability for waterbirds in a tropical lagoon

1995 ◽  
Vol 73 (5) ◽  
pp. 869-878 ◽  
Author(s):  
Raymond McNeil ◽  
Oscar Díaz Díaz ◽  
Ildefonso Liñero A. ◽  
José R. Rodríguez S.
Keyword(s):  
Prey Availability ◽  
The Other ◽  
Shallow Waters ◽  
Sampling Techniques ◽  
Benthic Organisms ◽  
Dabbling Ducks ◽  
Night Time ◽  
Marsh Birds ◽  
Tropical Lagoon ◽  
Time Availability

One of the main hypotheses formulated to explain why marsh birds, wildfowl, and shorebirds forage at night postulates that the birds prefer to feed at night because the feeding opportunities are most profitable then. To investigate this hypothesis, we compare day- and night-time availability and describe the diel abundance rhythm of swimming and benthic organisms inhabiting the shallow waters of a tropical lagoon complex in northeastern Venezuela. Three sampling techniques were used by day and by night: net sampling for swimming organisms, core sampling for those in the sediments (10 cm deep), and sight counts for organisms on the surface of substrata. Overall, in the case of swimming organisms, fishes, isopods, amphipods, shrimps (Penaeus spp.), and corixids were 3–30 times more abundant at night than during daytime. In general, infaunal organisms were about equally abundant during the day and the night, or slightly more abundant during the day. At the surface, isopods, amphipods, and polychaetes were greater than 10 times more abundant at night than during the day. However, gastropods were slightly more numerous during daytime on the substrata, while pelecypods were about equally numerous during day- and night-time. Fiddler crabs (Uca sp.) were generally more available during daytime. Considering all organisms together, the prey for marsh birds, wildfowl, and shorebirds were significantly more abundant at night. In conclusion, tactile-foraging species (e.g., spoonbills, skimmers, ibises, dabbling ducks, and several species of shorebirds) should profit by foraging only at night and resting during the day, and foraging during daylight only to top up a nighttime deficit. On the other hand, despite limited nighttime visual capacity, some sight-feeding species (e.g., herons, plovers) may take advantage of increased prey availability at night, at least on moonlit nights.

Consequences of forest fragmentation on territory quality of male Ovenbirds breeding in western boreal forests

2002 ◽  
Vol 80 (11) ◽  
pp. 1841-1848 ◽  
Author(s):  
Daniel F Mazerolle ◽  
Keith A Hobson
Keyword(s):  
Forest Fragmentation ◽  
Vegetation Structure ◽  
Boreal Forests ◽  
Prey Availability ◽  
Forest Fragments ◽  
Territory Quality ◽  
Seiurus Aurocapillus ◽  
Prey Biomass ◽  
Prey Composition ◽  
Territory Selection

We evaluated the effects of forest fragmentation caused by agriculture on arthropod prey biomass and vegetation structure found in territories of male Ovenbirds (Seiurus aurocapillus) breeding in the southern boreal mixed woods of Saskatchewan, Canada. The objective of this study was to determine if previously documented differences in pairing success of male Ovenbirds in contiguous forests and forest fragments in our study area were associated with differences in arthropod prey biomass and vegetation structure between contiguous and fragmented forests. A secondary objective was to examine the correspondence between vegetation and arthropods to evaluate whether vegetation cues could be useful for birds attempting to predict future arthropod biomass during territory selection. Our results indicate that both vegetation structure and arthropod prey composition in Ovenbird territories differed between fragmented and contiguous forests, whereas total arthropod biomass did not. Furthermore, the correspondence of vegetation with arthropod prey composition and total prey biomass was weak, a result that questions the use of vegetation structure by male Ovenbirds for predicting future prey availability during territory selection. Overall, the current extent of forest fragmentation in our study area is not likely reducing pairing success of territorial male Ovenbirds by lowering the biomass of arthropod prey. However, landscape differences in vegetation structure could influence pairing success of male Ovenbirds in forest fragments by reducing suitable microhabitats for nesting or by increasing habitat suitability for nest predators and Brown-headed Cowbird (Molothrus ater) parasites.

Influence of snow depth on prey availability and habitat use by red fox

1988 ◽  
Vol 66 (3) ◽  
pp. 587-592 ◽  
Author(s):  
Margaret A. Halpin ◽  
John A. Bissonette
Keyword(s):  
Habitat Use ◽  
Small Mammals ◽  
Snow Depth ◽  
Red Fox ◽  
Prey Availability ◽  
Habitat Preferences ◽  
Hardwood Forests ◽  
Red Foxes ◽  
Mixed Stands ◽  
Snow Conditions

Habitat use by red fox (Vulpes vulpes) was studied during the winters of 1982 and 1983. A total of 125 km of fox trails in eastern Maine were followed during periods of snow cover to examine the influence of snow conditions on fox habitat selection and prey availability. Red foxes used all available habitats but showed preferences for softwood stands and open areas. Hardwood forests were avoided. During both winters, snow depth was greatest in hardwood and mixed stands where soft, powdery conditions prevailed. Windblown, supportive crusts were found in open barrens. Foxes showed habitat preferences for traveling and hunting. Fox sinking depths were least in all habitats when crust conditions prevailed, and during these periods travel distances were more evenly distributed among habitats. Snow influenced relative prey availability. Hunting activities shifted among habitats for small mammals during most of the second winter, when snow was shallow. Proportions of small mammals in the fox diet decreased as snow accumulated and as crusts formed. When snow was deep, foxes hunted in habitats with softwood regeneration and other dense understories that supported snowshoe hare concentrations.

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