Small Mammal Predators Research Articles

Population Dynamics of Gypsy Moth in North America

SUMMARY AND CONCLUSION Recent studies (52) support the earlier conclusions of Bess et al (16) and Campbell & Sloan (30,31) that gypsy moth populations are maintained at low densities primarily by the action of small mammal predators. Spatially densi­ty-dependent parasitism by tachinids such as C. concinnata may also be important in suppressing incipient outbreaks (63). The reasons such factors fail in certain years and allow gypsy moth populations to escape into outbreak phase have not been elucidated. Factors that affect small mammal population density such as overwintering food supply are important possible causes of population release. Other factors that affect predation rates by small mammals such as berry crops which compete with gypsy moth as a food item (147) may also be important. However, changes in factors that affect fecundity or survival of early instars may in certain years result in densities of late instar larvae or pupae that approach the satiation points of predators. The syn­chronous behavior of gypsy moth populations over fairly large regions sug­gests that weather conditions drive the system in some manner, but the mechanisms remain obscure. It is entirely possible that different weather events and the failure of different mortality agents are responsible for the onset of outbreak phase in different years. The factors controlling outbreak populations are better understood. In recent years major advances have occurred in our understanding of

Gradients in population fluctuations of Tengmalm's owl Aegolius funereus in Europe.

I studied the importance of geographical location, snow cover and food to the fluctuations in 30 breeding populations of Tengmalm's owl (Aegolius funereu) in Europe. Cyclicity indices were positively related both to latitude and longitude, but within Fennoscandia they were better correlated with snow cover. Population fluctuations increased northward, while food niche breadth and degree of site tenacity decreased northwards.Microtine fluctuations become more pronounced northwards and are more synchronized, while number of alternative prey increases southwards. These factors promote instability in North European and stability in central European owl populations. Furthermore, snow conditions were more important within Fennoscandia, since this small owl cannot hunt voles protected by deep snow. Environmental predictability and diversity of available food for Tengmalm's owl increase southwards in Europe. Thus, the owl is a resident generalist predator of small mammals and birds in central Europe and adopts a partial migration strategy (males being resident and females nomadic) in South and West Finland, changing its habits to nomadic microtine specialist in areas with pronounced vole cycles (in northern Fennoscandia). These changes fit well with the recent suggestion that gradients in density variations of small rodents are related to sustainable numbers of generalist predators.

Cocoon Predation by Small Mammals, and Pine Sawfly Population Dynamics

Neodiprion sertifer (Hymenoptera: Diprionidae) cocoons were planted singly (50 cocoons per site), in groups of 10 (20 groups per site) and in groups of 50 (10 groups per site) at 21 mostly one-hectare sites representing a wide range of forest types. Small mammals destroyed 70% (range 28-99.6%) of the cocoons in one month at the 21 sites. In stands of barren pine forest on poor soil the numbers of predators were positively correlated with predation rate, but at more fertile sites, where predators were twice as numerous, there was no such correlation, perhaps because of more abundant alternative food. The masked shrew Sorex caecutiens and the bank vole Clethrionomys glareolus were the two most important predators. The shrew destroyed especially scattered cocoons while the vole destroyed especially clumped cocoons. The shrew and the vole memorized the locations of the cocoon groups within their home ranges, distinguished between small and large groups, and their movements were affected for (at least) one to five weeks by the previous presence of cocoon groups. We tested whether bird predation of cocoons in tree canopies would be less severe than small-mammal predation on the ground, where larvae spin cocoons. It would not: 85% in trees vs 70% on the ground. Small-mammal predation may contribute to two observations about pine sawfly outbreaks in northern Europe: the vulnerability of stands on poor soils (few predators) and the high outbreak frequency of N. sertifer, the only northern European pine sawfly with a short cocoon period in summer (short predation period).

A preliminary report of small mammal predation upon the larch sawfly

A preliminary report of small mammal predation upon the larch sawfly

Foods of feral house cats (Felis catusL.) in forest of the Orongorongo Valley, Wellington

Abstract The foods of feral house cats in forest in the Orongorongo Valley, Wellington, were studied over 3 years and related to the availability of prey. Some cats were trapped, tagged, and released, and could be identified individually by coat colour and pattern. The number of cats, estimated from live-trapping and sightings, was stable during the study. Examination of 677 scats revealed that mammals (rat, rabbit, opossum, mouse, and stoat, in descending order of importance) formed the bulk of the diet by weight. Remains of birds occurred in 12% of scats, but birds were estimated to form only 4.5% by weight of the diet. Insect fragments were present in many scats; wetas (Orthoptera), cicadas (Hemiptera), and beetles (Colcoptera) were important seasonally. Although eaten in large numbers, they contributed very little by weight to the diet. Populations of rats, rabbits, and opossums were fairly stable during the study; mice were abundant for most of the first 18 months, but were scarce in the last year. The literature on the food habits of feral house cats is reviewed; it emphasises that cats are primarily predators of small mammals (rodents and lagomorphs). Predation by feral cats can be important in holding rat and rabbit populations at low densities and in reducing seasonal fluctuations in their numbers. Cats can also exert heavy predation pressure on low-density mouse populations. Although the cats now eat few birds, they may have been responsible for reducing the numbers of some forest birds in the past.

Passage of Infectious Nuclear Polyhedrosis Virus Through the Alimentary Tracts of Two Small Mammal Predators of the Gypsy Moth, Lymantria dispar1

The white-footed mouse, Peromyscus leucopus Rafinesque, and the short-tailed shrew, Blarina brevicauda Say, 2 small mammal predators of the gypsy moth, have demonstrated the ability to pass significant amounts of infectious nuclear polyhedrosis virus (NPV) through their alimentary tracts. Ninety-five percent of the gypsy moth larvae fed fecal preparations from NPV-challenged mammals died during infectivity tests, whereas only 6% of larvae fed control fecal preparations died. The ability of these mammals to pass large amounts of infectious NPV may be important in the distribution of NPV in the wild.

The Gray Jay as a predator of small mammals

The Gray Jay as a predator of small mammals

White-Tailed Kite Predation on a Fluctuating Vole Population

White-tailed Kites (Elanus leucurus) are obligate predators of diurnal small mammals (Waian and Stendell, Calif. Fish & Game 56:188, 1970). Brown and Amadon (Eagles, Hawks and Falcons of the World, vol. 1, Hamlyn House, Feltham, 414 p. 1968) indicate that movement and nesting of kites are governed to a considerable extent by concentrations of mice, usually voles. Throughout much of the kite's range in California, the vole (Microtus californicus) is the major prey species. Hawbecker (Condor 42:106, 1940) noted a correlation between the nesting of White-Tailed Kites and vole density and suggested that a high population of voles is necessary for successful nesting of kites. This note compares annual changes in food habits of WhiteTailed Kites with measured changes in the density of California voles in fields over which the kites were hunting. At Hastings Natural History Reservation in Monterey County, California, populations of small mammals have been censused during the summers of 1969, 1970, and 1971, by means of mark and recapture techniques. The Reservation is a mosaic of grassland, oak woodland, and chaparral. Microtus predominately utilize the grassland areas. Estimated vole densities are shown in table 1. Although only one field was censused accurately, search for runways and occasional trapping in all other suitable fields within a 2-mile radius of the kite roosting site indicated vole densities similar to those of the censused field. TABLE 2. Species composition (%) of prey in kite pellets, 1969-71.

Mortality of Cocoons of the Larch Sawfly, Pristiphora erichsonii (Htg.), in Relation to Distance from Small-Mammal Tunnels

The relationship between the fate of cocoons of the larch sawfly, Pristiphora erichsonii (Htg.), and distance from small-mammal tunnels was studied during 1958 in the Whiteshell Forest Reserve of eastern Manitoba. The objects were to determine the distance that small mammals can detect cocoons and to observe possible effects of the interactions of small-mammal predation and other natural mortality factors of the insect. Additional analyses of the data provided information on the behaviour of the predators and the ecology of the prey insect.

The Assessment of Larch Sawfly Cocoon Predation by Small Mammals

Current investigations at the Forest Biology Laboratory, Winnipeg, are being directed towards the formulation of life tables for the larch sawfly, Pristiphora erichsonii (Htg.) (Lejeune, 1955). Because small mammal predation is a major factor in reducing cocoon populations of the sawfly (Buckner, 1953), an adequate method of assessing this source of mortality is desirable

The Components of Predation as Revealed by a Study of Small-Mammal Predation of the European Pine Sawfly

The fluctuation of an animal's numbers between restricted limits is determined by a balance between that animal's capacity to increase and the environmenta1 cheks to this increase. Many authors have indulged in the calculating the propressive increase of a population when no checks nrerc operating. Thus Huxley calculated that the progeny of a single Aphis in the course of 10 generations, supposing all survived,would “contain more ponderable substance than five hundred millions of stout men; that is, more than the whole population of China”, (in Thompson, 1929). Checks, however, do occur and it has been the subject of much controversy to determine how these checks operate. Certain general principles—the density-dependence concept of Smith ( 1955) , the competition theory of Nicholson (1933)—have been proposed both verbally and mathematically, but because they have been based in part upon untested and restrictive assumptions they have been severelv criticized (e.g. Andrewartha and Birch 1954). These problems could be considerably clarified if we knew the mode of operation of each process that affects numbers, if we knew its basic and subsidiary components. predation, one such process, forms the subject of the present paper.

The Larval Elateridae of Eastern Spruce Forests and Their Role in the Natural Control of Gilpinia hercyniae (Htg.) (Hymenoptera: Diprionidae)

One of the objects of the investigations on the European spruce sawfly, Gilpinia hercyniae (Htg.), in Eastern Canada was to discover and evaluate the factors of natural control affecting this introduced species in its new environment. Small mammal predators were found to be the most important factor affecting the sawfly cocoons, which were spun in the moss or litter of the forest floor (4, 5). These predators chewed large openings in the cocoons and pulled out the contents. Cocoons were also found with smaller openings made by the entry of insect predators, and occasionally such a cocoon was found with a larva of the family Elateridae partly inside (Fig. 1).

Differentiation by Small Mammal Predators Between Sound and Empty Cocoons of the European Spruce Sawfly

In a preliminary paper on the role of small mammals in the natural control of the European spruce sawfly, Gilpinia hercyniae (Htg.), the writer (7) recorded that shrews have a remarkable ability to select sound cocoons in preference to those which are dead or emptied by parasites. This ability was said to be much less apparent, however, in the rodents. However, various experimental aspects of the project on natural control were not completed. This was due mainly to the severe decimation of the sawfly resulting from the combined attacks of small mammals, disease, and parasites. Since the above statements have elicited some interest, it secms worthwhile to present the data on which they were based. Other aspects of the project, particularly those concerned with the populations of small mammals and their relation to forest site, and with the role of larval Elateridae, will be reported later.

Habits of the Short-Tailed Shrew, Blarina brevicauda (Say)

Previous articleNext article FreeHabits of the Short-Tailed Shrew, Blarina brevicauda (Say)A. Franklin ShullA. Franklin Shull Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The American Naturalist Volume 41, Number 488Aug., 1907 Published for The American Society of Naturalists Article DOIhttps://doi.org/10.1086/278820 Views: 192Total views on this site Citations: 12Citations are reported from Crossref PDF download Crossref reports the following articles citing this article:Jacob W. Farriester, Brian C. Peterson, Keith Geluso, W. Wyatt Hoback Threatened American Burying Beetle (Nicrophorus americanus) Consumed by Northern Short-Tailed Shrew (Blarina brevicauda) and Trap Avoidance by Silphidae, Western North American Naturalist 81, no.33 (Oct 2021).https://doi.org/10.3398/064.081.0313Michael A. Barger Tests of Ecological Equivalence of Two Species of Terrestrial Gastropods as Second Intermediate Hosts of Panopistus pricei (Trematoda: Brachylaimidae), Journal of Parasitology 97, no.11 (Feb 2011): 8–13.https://doi.org/10.1645/GE-2528.1Michael A. Barger, John A. Hnida Survey of Trematodes from Terrestrial Gastropods and Small Mammals in Southeastern Nebraska, U.S.A., Comparative Parasitology 75, no.22 (Jul 2008): 308–314.https://doi.org/10.1654/4357.1BURT P. KOTLER, JOEL S. BROWN, MICHAEL HICKEY Food Storability and the Foraging Behavior of Fox Squirrels (Sciurus niger), The American Midland Naturalist 142, no.11 (Jul 1999): 77–86.https://doi.org/10.1674/0003-0031(1999)142[0077:FSATFB]2.0.CO;2C. W. AITCHISON Review of winter trophic relations of soricine shrews, Mammal Review 17, no.11 (Mar 1987): 1–24.https://doi.org/10.1111/j.1365-2907.1987.tb00045.xStephen B. Vander Wall, Kimberly G. Smith Cache-Protecting Behavior of Food-Hoarding Animals, (Jan 1987): 611–644.https://doi.org/10.1007/978-1-4613-1839-2_22 Mark V. Lomolino Immigrant Selection, Predation, and the Distributions of Microtus pennsylvanicus and Blarina brevicauda on Islands, The American Naturalist 123, no.44 (Oct 2015): 468–483.https://doi.org/10.1086/284217 Daniel R. Deavers , and Jack W. Hudson Water Metabolism and Estimated Field Water Budgets in Two Rodents (Clethrionomys gapperi and Peromyscus leucopus) and an Insectivore (Blarina brevicauda) Inhabiting the Same Mesic Environment, Physiological Zoology 52, no.22 (Sep 2015): 137–152.https://doi.org/10.1086/physzool.52.2.30152559C. S. Holling SENSORY STIMULI INVOLVED IN THE LOCATION AND SELECTION OF SAWFLY COCOONS BY SMALL MAMMALS, Canadian Journal of Zoology 36, no.55 (Oct 1958): 633–653.https://doi.org/10.1139/z58-058R. F. Morris Differentiation by Small Mammal Predators Between Sound and Empty Cocoons of the European Spruce Sawfly, The Canadian Entomologist 81, no.55 (May 2012): 114–120.https://doi.org/10.4039/Ent81114-5T. H. Stovell A New Type of Microscope-Slide Cabinet, The Canadian Entomologist 81, no.0505 (May 2012): 120–122.https://doi.org/10.4039/Ent81120-5Royal Norton Chapman A study of the correlation of the pelvic structure and the habits of certain burrowing mammals, American Journal of Anatomy 25, no.22 (Mar 1919): 184–219.https://doi.org/10.1002/aja.1000250204