scholarly journals Interactive Effects of Vegetation and Predators on the Success of Natural and Simulated Nests of Grassland Songbirds

The Condor ◽  
2000 ◽  
Vol 102 (3) ◽  
pp. 629-634 ◽  
Author(s):  
Nancy Dion ◽  
Keith A. Hobson ◽  
Serge Larivière
Keyword(s):  
Small Mammals ◽  
Ground Squirrels ◽  
Interactive Effects ◽  
Grass Cover ◽  
Predator Removal ◽  
Nest Sites ◽  
Mammalian Predators ◽  
Vertical Density ◽  
Vegetation Characteristics ◽  
Grassland Songbirds

Abstract We examined the influence of vegetation and predator community on nesting success of songbirds in the grasslands of eastern North Dakota, USA. Each year, eight sites were chosen: four were subject to predator removal, and four were non-removal sites. On each site, nests of grassland songbirds were monitored, and simulated nests were used to examine how vegetation characteristics at nests affect nest success. Vegetative characteristics at simulated nests did not differ from those at natural nests, but successful natural nests had greater forb and lesser grass cover than unsuccessful nests, whereas no differences in vegetation were detected between successful and depredated simulated nests. On non-removal sites, small mammals and ground squirrels (Spermophilus sp.) depredated nests in taller and denser cover when compared to nests destroyed by medium-sized mammals and birds. On removal sites, we found no difference in vegetation characteristics of nests depredated by different predator types. However, each group of mammalian predators depredated simulated nests with different vegetation characteristics on removal versus non-removal sites. On sites where predators were removed, small mammals and ground squirrels preyed on simulated nests in shorter vegetation containing fewer forbs, ground squirrels preyed on nests with higher grass cover and lower vertical density, and medium-sized carnivores preyed on nests in taller vegetation. These results support the hypothesis that high predator diversity may reduce the chance of “safe” nest sites, and suggest that the behavior of low-level predators may change when top-level predators are removed.

Effects of removing duck-nest predators on nesting success of grassland songbirds

1999 ◽  
Vol 77 (11) ◽  
pp. 1801-1806 ◽  
Author(s):  
Nancy Dion ◽  
Keith A Hobson ◽  
Serge Larivière
Keyword(s):  
Small Mammals ◽  
Ground Squirrels ◽  
Short Term ◽  
Red Foxes ◽  
Predator Removal ◽  
Grassland Songbirds ◽  
Striped Skunks ◽  
Long Term Studies ◽  
Nest Predators

During 1995 and 1996 we monitored natural and simulated nests of grassland songbirds following removal of duck-nest predators, primarily raccoons (Procyon lotor), striped skunks (Mephitis mephitis), and red foxes (Vulpes vulpes), in North Dakota, U.S.A. We were unable to detect an effect of predator removal on survival of natural (n = 153 nests) or simulated (n = 2264 nests) nests of grassland songbirds in either year. However, the assemblage of predators destroying simulated nests differed between removal and non-removal sites in 1995, when medium-sized carnivores and small mammals were the most important predators on non-removal sites, whereas ground squirrels were most important on removal sites. Our study indicates that grassland songbirds were not negatively affected, at least in the short term, by removal of duck nest predators. However, changes in the relative importance of predators on removal sites in 1995 suggest that smaller predators that were not targeted by removal efforts (i.e., ground squirrels) may have caused compensatory predation. Long-term studies are necessary to determine if the removal of duck-nest predators affects the numerical or functional response of predators at a lower trophic level, such as ground squirrels and other small mammals.

Small Mammals as Predators of Sawflies

1955 ◽  
Vol 87 (3) ◽  
pp. 121-123 ◽  
Author(s):  
C. H. Buckner
Keyword(s):  
Small Mammals ◽  
Biological Control Agent ◽  
Control Agent ◽  
Moderate Risk ◽  
Neodiprion Abietis ◽  
Ample Opportunity ◽  
Pristiphora Erichsonii ◽  
Mammalian Predators ◽  
One Year

The greatest predatory effect of small mammals is exerted upon insects that spend a portion of their life cycle on the ground or in the soil. Sawflies afford ample opportunity for mammalian predation, since they drop to the ground as mature larvae and spin cocoons in the soil. Such sawflies as Neodiprion abietis Harr., which remain within the cocoon for about three weeks, undergo only moderate risk of being preyed upon by small mammal. However, Pristiphora erichsonii (Htg.) remains within the cocoon from about mid-August until the following June, or even over more than one year, thus greatly extending the vulnerable period. Earlier investigations suggest that small mammals may comprise the largest single biological control agent acting against this insect (Graham 1928, Lejeune 1951), but the exact role of mammalian predators of forest insects has yet to be established.

Landscape-scale habitat associations of small mammals on the western coast of Hudson Bay

2021 ◽  
Author(s):  
Kevin Hawkshaw ◽  
Lee Foote ◽  
Alastair Franke
Keyword(s):  
Small Mammals ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Distance Sampling ◽  
Habitat Associations ◽  
Ground Squirrels ◽  
Suitable Habitat ◽  
Western Coast ◽  
Water Index ◽  
Arctic Ground Squirrels

Availability of suitable habitat affects the distribution and abundance of Arctic fauna, influencing how species respond to climate change and disturbance from resource extraction in the region. We surveyed Arctic ground squirrels (Urocitellus parryii Richardson, 1825) using distance sampling transects and concurrently counted microtine rodent burrows. Abundance of Arctic ground squirrels and microtine burrows was positively correlated with terrain ruggedness. Microtine burrows were more abundant inland and in areas with freshwater, while Arctic ground squirrels were more often found at low elevation without freshwater. Arctic ground squirrel abundance was positively related to the normalized difference water index, a proxy for vegetation water content, while microtine burrows were weakly correlated with the normalized difference vegetation index. Our study highlights the habitat associations of ecologically significant small mammals in an underrepresented Arctic study area.

Interactive effects of fire and nonnative plants on small mammals in Grasslands

2011 ◽  
Vol 176 (1) ◽  
pp. 1-31 ◽  
Author(s):  
Andrea R. Litt ◽  
Robert J. Steidl
Keyword(s):  
Small Mammals ◽  
Interactive Effects ◽  
Nonnative Plants

scholarly journals Natal nest location and small mammal tracking with a spool and line technique

1986 ◽  
Vol 64 (4) ◽  
pp. 1034-1036 ◽  
Author(s):  
Rudy Boonstra ◽  
Ian T. M. Craine
Keyword(s):  
Success Rate ◽  
Small Mammals ◽  
Small Mammal ◽  
Inexpensive Method ◽  
Natal Nest ◽  
Meadow Voles ◽  
Nest Location ◽  
Nest Sites

We describe a simple, inexpensive method for tracking small mammals accurately for distances up to 180 m. A small spool of thread is attached to the back of the animal with srgical glue. As the animal moves along, it leaves behind it a trail of thread that can be followed along the route taken and to nest sites. Of 157 lactating meadow voles spooled, we found 62 nests with young. This success rate can probably be doubled by reducing two sources of spooling failure and by spooling a second time within the same trapping session.

Effects of food and predators on the home-range sizes of Arctic ground squirrel (Spermophilus parryii)

1998 ◽  
Vol 76 (3) ◽  
pp. 592-596 ◽  
Author(s):  
Anne H Hubbs ◽  
Rudy Boonstra
Keyword(s):  
Home Range ◽  
Ground Squirrel ◽  
Large Scale ◽  
Yukon Territory ◽  
Ground Squirrels ◽  
Home Ranges ◽  
Spermophilus Parryii ◽  
Mammalian Predators ◽  
Core Areas ◽  
Arctic Ground Squirrels

We used radiotelemetry to study the effects of food addition and predator reduction on the home-range sizes of adult Arctic ground squirrels (Spermophilus parryii) on large-scale experimental grids in the boreal forest of the southwestern Yukon Territory. Home ranges were 2-7 times smaller on food-supplemented grids than on nonsupplemented grids, regardless of whether large mammalian predators were present. Similarly, core areas (where 50% of activities occur) were 8-11 times smaller on food-supplemented grids. Food availability rather than predator presence primarily determined the sizes of home ranges and core areas of Arctic ground squirrels.

Holocene environmental change in the eastern Snake River Plain of Idaho, USA, as inferred from stable isotope analyses of small mammals

2016 ◽  
Vol 85 (3) ◽  
pp. 358-370 ◽  
Author(s):  
Amy S. Commendador ◽  
Bruce P. Finney
Keyword(s):  
Small Mammals ◽  
Ground Squirrels ◽  
Snake River Plain ◽  
Early Holocene ◽  
Snake River ◽  
Potential Contribution ◽  
Pocket Gophers ◽  
Carbon And Nitrogen ◽  
River Plain ◽  
Isotope Analyses

Previous research on the small mammal population recovered from archeological excavations at the Wasden Site in southeastern Idaho suggests that changing frequency distributions through time represent a shift in climate during the early Holocene from a cooler, wetter regime to a warmer, drier one. This conclusion was re-evaluated using stable carbon and nitrogen isotope analyses of bone collagen from the three species of small mammals examined in the earlier studies: pocket gophers (Thomomys talpoides), pygmy rabbits (Brachylagus idahoensis), and ground squirrels (Spermophilus townsendii). Resulting carbon and nitrogen isotopic values are consistent with known differences in feeding ecology, suggesting high fidelity as proxies for past vegetation (and thus climate) regimes. Patterns of 15N enrichment and increased representation of C4-CAM vegetation observed in the pocket gophers, and to a lesser extent ground squirrels, suggests increasing warmth and/or aridity from the early Holocene until ∼7000 cal yr BP, thus supporting previous hypotheses of climate change on the eastern Snake River Plain. The results highlight the potential contribution of such studies for archeological research by providing additional proxies for environmental conditions that bear on paleoecological adaptations to climatic change, including past human use and occupation of the region.

Vegetation characteristics of Snow Goose nest sites

1979 ◽  
Vol 57 (14) ◽  
pp. 1502-1504 ◽  
Author(s):  
M. I. Heagy ◽  
F. Cooke
Keyword(s):  
Discriminant Analysis ◽  
Plant Species ◽  
Stepwise Discriminant Analysis ◽  
Breeding Colony ◽  
Snow Goose ◽  
Nest Sites ◽  
Ecological Requirements ◽  
Nesting Site ◽  
Lesser Snow Goose ◽  
Vegetation Characteristics

The vegetation at a Lesser Snow Goose breeding colony was examined to determine if particular plant species or species associations were characteristic of the nest sites of the geese. A stepwise discriminant analysis revealed that nest sites could be satisfactorily distinguished from the ambient vegetation using 2 of the 29 plant species growing in the quadrats. These two species, lyme grass (Elymus arenarius ssp. mollis) and arctic daisy (Chrysanthemum arcticum ssp. polare) were strongly associated with Snow Goose nest sites.Possible explanations for the association are examined. It is suggested that rather than a cause and effect relationship between plants and nest sites, E. arenarius and C. arcticum have similar ecological requirements to those of the geese for a nesting site.

scholarly journals Linking nest microhabitat selection to nest survival within declining pheasant populations in the Central Valley of California

2020 ◽  
Vol 47 (5) ◽  
pp. 391
Author(s):  
Ian A. Dwight ◽  
Jessica H. Vogt ◽  
Peter S. Coates ◽  
Joseph P. Fleskes ◽  
Daniel P. Connelly ◽  
...  
Keyword(s):  
Large Scale ◽  
Nest Survival ◽  
Perennial Grass ◽  
Bird Species ◽  
Central Valley ◽  
Perennial Grasses ◽  
Microhabitat Selection ◽  
Grass Cover ◽  
Nest Sites ◽  
Management Actions

Abstract ContextThe ring-necked pheasant (Phasianus colchicus) has experienced considerable population declines in recent decades, especially in agricultural environments of the Central Valley of California. Although large-scale changes in land cover have been reported as an important driver of population dynamics, the effects of microhabitat conditions on specific demographic rates (e.g. nesting) are largely unknown. AimsOur goal was to identify the key microhabitat factors that contribute to wild pheasant fitness by linking individual-level selection of each microhabitat characteristic to the survival of their nests within the California Central Valley. MethodsWe radio- or GPS-marked 190 female ring-necked pheasants within five study areas and measured nest-site characteristics and nest fates during 2013–2017. Specifically, we modeled microhabitat selection using vegetation covariates measured at nest sites and random sites and then modeled nest survival as a function of selecting each microhabitat characteristic. Key resultsFemale pheasants tended to select nest sites with greater proportions of herbaceous cover and avoided areas with greater proportions of bare-ground. Specifically, perennial grass cover was the most explanatory factor with regard to nest survival, but selection for increasing visual obstruction alone was not shown to have a significant effect on survival. Further, we found strong evidence that pheasants selecting sites with greater perennial grass height were more likely to have successful nests. ConclusionsAlthough pheasants will select many types of vegetation available as cover, our models provided evidence that perennial grasses are more beneficial than other cover types to pheasants selecting nesting sites. ImplicationsFocusing management actions on promoting perennial grass cover and increased heights at the microsite level, in lieu of other vegetative modifications, may provide improved quality of habitat for nesting pheasants and, perhaps, result in increased productivity. This is especially important if cover is limited during specific times of the nesting period. Understanding how microhabitat selection influences fitness can help land managers develop strategies to increase the sustainability of hunted populations of this popular game-bird species.

scholarly journals Metapopulations and Feeding Selectivity of Montane and Long-Tailed Voles (Microtus montanus and M. Longicaudus), and Hantavirus and Plague in the Jackson Hole Small Mammal Communtiy

1995 ◽  
Vol 19 ◽  
pp. 33-36
Author(s):  
Frederick Jannett, Jr.
Keyword(s):  
Small Mammals ◽  
Small Mammal ◽  
Ground Squirrels ◽  
Feeding Selectivity ◽  
Microtus Montanus ◽  
Human Contact ◽  
Jackson Hole ◽  
Demographic Processes ◽  
Study Sites

The purpose of the long-term research which began in 1971 on metapopulations of voles is to enumerate patterns in surviorship, reproduction, and morphology across sections of the metapopulations. The study sites for Microtus montanus were chosen to represent primary and secondary habitat and proximate and isolated habitat patches. The purpose of the work which commenced in 1989 is to ascertain how selectively Microtus montanus and M. longicaudus feed, and to assess vegetation as a factor in demographic processes of the two species . The purpose of the more recently initiated study on hantavirus started in 1994 is to ascertain the extent of hantavirus among as many species of small mammals as possible, to identify the strain(s), to understand the presence of hantavirus across species and among the metapopulations of voles, and to assess the potential for human contact. The purpose of the work on plague since 1995 is to test the long-standing hypothesis that voles are a reservoir in the intervals between plague outbreaks among ground squirrels.

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