scholarly journals Nonrandom territory occupancy by nesting Gyrfalcons (Falco rusticolus)

2019 ◽  
Vol 5 (3) ◽  
pp. 148-160
Author(s):  
David L. Anderson ◽  
Peter J. Bente ◽  
Travis L. Booms ◽  
Leah Dunn ◽  
Christopher J.W. McClure
Keyword(s):  
Site Selection ◽  
Spatial Scales ◽  
Site Occupancy ◽  
Brood Rearing ◽  
Falco Rusticolus ◽  
Occupancy Patterns ◽  
Information Gap ◽  
Competing Models ◽  
Nonrandom Pattern ◽  
Habitat Variables

We know little regarding how specific aspects of habitat influence spatial variation in site occupancy by Arctic wildlife, yet this information is fundamental to effective conservation. To address this information gap, we assessed occupancy of 84 Gyrfalcon (Falco rusticolus Linnaeus, 1758) breeding territories observed annually between 2004 and 2013 in western Alaska. In line with the theory of population regulation by site dependence, we asked whether Gyrfalcons exhibited a nonrandom pattern of site selection and if heterogeneous landscape attributes correlated with observed occupancy patterns. We characterized high- and low-occupancy breeding territories as those occupied more or less often than expected by chance, and we evaluated land cover at 1 and 15 km circles centered around nesting territories to identify habitat variables associated with observed occupancy patterns. We tested 15 competing models to rank hypotheses reflecting prey and habitat variables important to nesting Gyrfalcons. We confirmed a nonrandom pattern of site selection but found only weak evidence that the distribution of prey habitat was responsible for this pattern. We reason that preferential habitat use by nesting Gyrfalcons may be determined by spatial scales other than those we measured or may be driven by landscape-level attributes at time periods other than during the brood rearing period.

scholarly journals Territory and Nest-Site Selection of Cerulean Warblers in Eastern Ontario

The Auk ◽  
2001 ◽  
Vol 118 (3) ◽  
pp. 727-735 ◽  
Author(s):  
Jason Jones ◽  
Raleigh J. Robertson
Keyword(s):  
Site Selection ◽  
Nest Site ◽  
Deciduous Forest ◽  
Spatial Scales ◽  
Nest Site Selection ◽  
Population Characteristics ◽  
Dendroica Cerulea ◽  
Large Trees ◽  
Eastern Ontario ◽  
Cerulean Warblers

Abstract We examined habitat selection by breeding Cerulean Warblers (Dendroica cerulea) at three spatial scales in eastern Ontario over three years (1997–1999). Territories were characterized by well-spaced large trees, with high canopies and dense foliage cover at heights between 12–18 m. Nesting habitat additionally was characterized by dense foliage cover above 18 m. The results of our nest-patch (0.04 ha circle around nest) and nest-site (0.01 ha circle) analyses indicate that male Cerulean Warblers may take active roles in nest-site selection when selecting territories. We conclude from our nest-patch and nest-site selection analyses that territories likely contain multiple nest patches and sites and that male Cerulean Warblers may defend areas with multiple nest patches or sites, which may attract females to settle with them. Whether or not Cerulean Warbler females use nest-site availability as a mate- or territory-choice cue remains unknown. We also tested the validity of a commonly made assumption that a random sampling of habitat by researchers is representative of the habitat actually available to birds and found that, in our study area, the assumption was invalid. Taken together, our results point toward the need to maintain sizeable stands of mature, deciduous forest to ensure the persistence of Cerulean Warblers in eastern Ontario. Population characteristics such as lower minimum area requirements and a resilience to habitat disturbance may make that an easier job in eastern Ontario than elsewhere in this species' breeding range.

scholarly journals Greater Sage-Grouse nest bowls buffer microclimate in a post-megafire landscape although effects on nest survival are marginal

The Condor ◽  
2021 ◽  
Vol 123 (1) ◽  
Author(s):  
Christopher R Anthony ◽  
Christian A Hagen ◽  
Katie M Dugger ◽  
R Dwayne Elmore
Keyword(s):  
Site Selection ◽  
Nest Site ◽  
Spatial Scales ◽  
Nest Success ◽  
Nest Survival ◽  
Nest Site Selection ◽  
Bare Ground ◽  
Sage Grouse ◽  
Burned Areas ◽  
Visual Obstruction

Abstract Temperature at fine spatial scales is an important driver of nest site selection for many avian species during the breeding season and can influence nest success. Sagebrush (Artemisia spp.) communities have areas with high levels of vegetation heterogeneity and high thermal variation; however, fire removes vegetation that provides protection from predators and extreme environmental conditions. To examine the influence of microclimates on Greater Sage-Grouse (Centrocercus urophasianus) nest site selection and nest success in a fire-affected landscape, we measured black bulb temperature (Tbb) and vegetation attributes (e.g., visual obstruction) at 3 spatial scales (i.e. nest bowl, microsite, and landscape) in unburned and burned areas. Nest bowls exhibited greater buffering of Tbb than both nearby microsites and the broader landscape. Notably, nest bowls were warmer in cold temperatures, and cooler in hot temperatures, than nearby microsites and the broader landscape, regardless of burn stage. Nest survival (NS) was higher for nests in unburned areas compared to nests in burned areas (unburned NS = 0.43, 95% confidence interval [CI]: 0.33–0.54; burned NS = 0.24, 95% CI: 0.10–0.46). The amount of bare ground was negatively associated with NS, but effects diminished as the amount of bare ground reached low levels. Shrub height and visual obstruction were positively associated with NS during the entire study period, whereas minimum Tbb had a weaker effect. Our findings demonstrate that thermoregulatory selection by Greater Sage-Grouse at nest sites had marginal effects on their NS. However, given that increases in vegetation structure (e.g., shrub height) provide thermal refuge and increase NS, vegetation remnants or regeneration in a post-fire landscape could be critical to Greater Sage-Grouse nesting ecology.

scholarly journals Marbled Murrelet nest site selection at three fine spatial scales

2021 ◽  
Vol 16 (2) ◽  
Author(s):  
Thomas E. Hamer ◽  
Kim Nelson ◽  
Jay Jones ◽  
Jake Verschuyl
Keyword(s):  
Site Selection ◽  
Nest Site ◽  
Spatial Scales ◽  
Nest Site Selection ◽  
Marbled Murrelet

scholarly journals Deciding Where to Sleep: Spatial Levels of Nesting Selection in Chimpanzees (Pan troglodytes) Living in Savanna at Issa, Tanzania

2020 ◽  
Vol 41 (6) ◽  
pp. 870-900 ◽  
Author(s):  
R. Adriana Hernandez-Aguilar ◽  
Trond Reitan
Keyword(s):  
Pan Troglodytes ◽  
Site Selection ◽  
Spatial Scales ◽  
Tree Height ◽  
Important Variable ◽  
Physical Characteristics ◽  
Individual Tree ◽  
Trunk Diameter ◽  
Nesting Site ◽  
Nesting Sites

AbstractTo understand how animals select resources we need to analyze selection at different spatial levels or scales in the habitat. We investigated which physical characteristics of trees (dimensions and structure, e.g., height, trunk diameter, number of branches) determined nesting selection by chimpanzees (Pan troglodytes) on two different spatial scales: individual nesting trees and nesting sites. We also examined whether individual tree selection explained the landscape pattern of nesting site selection. We compared the physical characteristics of actual (N = 132) and potential (N = 242) nesting trees in nesting sites (in 15 plots of 25 m × 25 m) and of all trees in actual and potential nesting sites (N = 763 in 30 plots of 25 m × 25 m). We collected data in May and June 2003 in Issa, a dry and open savanna habitat in Tanzania. Chimpanzees selected both the site they used for nesting in the landscape and the trees they used to build nests within a nesting site, demonstrating two levels of spatial selection in nesting. Site selection was stronger than individual tree selection. Tree height was the most important variable for both nesting site and tree selection in our study, suggesting that chimpanzees selected both safe sites and secure trees for sleeping.

scholarly journals Foraging Site Selection by Nonbreeding White-Faced IBIS

The Condor ◽  
2000 ◽  
Vol 102 (1) ◽  
pp. 211-215 ◽  
Author(s):  
Rebecca J. Safran ◽  
Mark A. Colwell ◽  
Craig R. Isola ◽  
Oriane E. Taft
Keyword(s):  
Benthic Macroinvertebrates ◽  
Site Selection ◽  
Freshwater Wetlands ◽  
Emergent Vegetation ◽  
Prey Abundance ◽  
Foraging Site ◽  
Managed Wetlands ◽  
Density And Biomass ◽  
Habitat Variables ◽  
Bird Foraging

Abstract We examined foraging site selection by White-faced Ibis (Plegadis chihi) wintering in the Grasslands Ecological Area, which contains the second largest population of nonbreeding ibis in California. We compared habitat variables at White-faced Ibis foraging sites with paired, random locations in managed wetlands of the Grasslands. We contrasted the density and biomass of benthic macroinvertebrates between a subsample of bird foraging locations and random sites. Compared to random locations, the foraging locations of White-faced Ibis were closer to emergent vegetation > 10 cm in height. Moreover, ibis selected foraging locations with significantly higher chironomid and lower oligochaete biomasses relative to random sites. These findings suggest that ibis foraged close to vegetation where prey abundance may be greater and illustrate the importance of maintaining the presence of emergent vegetation in freshwater wetlands.

Scale-dependent habitat selection in three didelphid marsupials using the spool-and-line technique in the Atlantic forest of Brazil

2005 ◽  
Vol 21 (3) ◽  
pp. 337-342 ◽  
Author(s):  
Maíra C. Moura ◽  
Alice C. Caparelli ◽  
Simone R. Freitas ◽  
Marcus V. Vieira
Keyword(s):  
Habitat Selection ◽  
Multiple Scales ◽  
Structural Characteristics ◽  
Spatial Scales ◽  
Direction Change ◽  
Selection For ◽  
Habitat Scale ◽  
Didelphis Aurita ◽  
Metachirus Nudicaudatus ◽  
Habitat Variables

Habitat selection can be detected at different scales. For small mammals, habitat studies normally evaluate micro- or meso-habitat selection, but rarely are multiple scales analysed simultaneously. These studies use quantitative data of structural characteristics around the trap stations to evaluate selection. We test an alternative method to evaluate habitat selection in three didelphid marsupials (Didelphis aurita, Philander frenatus and Metachirus nudicaudatus), using a spool-and-line device, and measure habitat selection at two spatial scales. Habitat was characterized by seven habitat variables measured at ten points of direction change along the path traversed by each individual, and at 25 trap stations distributed in a 1-ha area. Micro-habitat selection was estimated at each point by comparing habitat measures between the direction selected against other directions. Meso-habitat selection was estimated by comparing habitat measurements on the whole path of an individual against habitat measures on the 25 trap stations. Patterns of selection for each species could only be detected at the meso-habitat scale, although a few individuals in each species were selective at the micro-habitat scale. Studies of habitat selection need to address the scale of study quantitatively, if possible comparing two or more scales to determine the scale of selection.

scholarly journals Velocity of Spread of Wheat Stripe Rust Epidemics

2005 ◽  
Vol 95 (9) ◽  
pp. 972-982 ◽  
Author(s):  
Christina Cowger ◽  
LaRae D. Wallace ◽  
Christopher C. Mundt
Keyword(s):  
Disease Severity ◽  
Stripe Rust ◽  
Field Experiments ◽  
Average Rate ◽  
Spatial Scales ◽  
Management Strategies ◽  
Plant Diseases ◽  
Pure Stand ◽  
Wheat Stripe Rust ◽  
Competing Models

Controversy has long existed over whether plant disease epidemics spread with constant or with increasing velocity. We conducted largescale field experiments with wheat stripe rust at Madras and Hermiston, Oregon, where natural stripe rust epidemics were rare, to test these competing models. Data from three location-years were available for analysis. A susceptible winter wheat cultivar was planted in pure stand and also in a 1:4 or 1:1 mixture with a cultivar immune to the stripe rust race utilized in the experiments. Plots were 6.1 m wide and varied from 73 to 171 m in length. A 1.5 by 1.5-m focus was inoculated in either the center (2001) or upwind of the center (2002 and 2003) of each plot. Disease severity was evaluated weekly throughout the epidemics in each plot at the same points along a transect running upwind and downwind from the focus. Velocity of spread was calculated from the severity data and regressed separately on time and on distance from the focus. In all location-years and treatments, and at all levels of disease severity, velocity consistently increased linearly with distance, at an average rate of 0.59 m/week per m, and exponentially with time. Further, across epidemics there was a significant positive relationship between the apparent infection rate, r, and the rate of velocity increase in both space and time. These findings have important implications for plant diseases with a focal or partially focal character, and in particular for the effectiveness of ratereducing disease management strategies at different spatial scales.

Nest-site selection by the Swainson's Hawk on the Regina plain, Saskatchewan

1995 ◽  
Vol 73 (10) ◽  
pp. 1887-1890
Author(s):  
Laura C. Groskorth
Keyword(s):  
Site Selection ◽  
Nest Site ◽  
Nest Site Selection ◽  
Nesting Habitat ◽  
Nest Sites ◽  
Buteo Swainsoni ◽  
Trees And Shrubs ◽  
Habitat Variables

Swainson's Hawk (Buteo swainsoni) nest sites on the Regina plain were compared with randomly selected sites. Various immediate and surrounding habitat variables were examined to determine whether this hawk shows a preference for nesting habitat. Results showed that hawks selected nest sites with significantly less surrounding wheatland and more surrounding grassland, trees, and shrubs than random sites. Nest sites were also farther from buildings and water and closer to larger communities than random sites. These results suggest that this hawk selects nest sites least affected by agriculture.

scholarly journals Habitat selection of Marbled Teal and White-headed Duck during the breeding and wintering seasons in south-eastern Spain

2012 ◽  
Vol 23 (3) ◽  
pp. 344-359 ◽  
Author(s):  
ESTHER SEBASTIÁN-GONZÁLEZ ◽  
CRISTINA FUENTES ◽  
MARCOS FERRÁNDEZ ◽  
JOSÉ L. ECHEVARRÍAS ◽  
ANDY J. GREEN
Keyword(s):  
Habitat Selection ◽  
Spatial Scales ◽  
Management Strategies ◽  
Open Water ◽  
Spatial Diversity ◽  
Suitable Habitat ◽  
Brood Rearing ◽  
South Eastern ◽  
Natural Park ◽  
Selection Of

SummaryUnderstanding habitat requirements is vital for developing successful management strategies for threatened species. In this study we analyse the habitat selection of two globally threatened waterbirds (Marbled Teal Marmaronetta angustirostris and White-headed Duck Oxyura leucocephala) coexisting in an internationally important wetland (El Hondo Natural Park, south-eastern Spain) at three spatial scales. We surveyed adults and broods of these species fortnightly during two consecutive years and we related density and presence of birds to several habitat variables. At a pond-selection scale, the density of both species was related to the surface area of the ponds, with Marbled Teal showing avoidance of medium-sized ponds, and White-headed Ducks strong selection for the largest ponds. Within ponds, Marbled Teal avoided open waters, and was mainly associated with Phragmites reedbeds, but also selected areas with saltmarsh and Scirpus vegetation, especially for brood-rearing. White-headed Duck made more use of deeper areas with open water, especially in winter, and Phragmites was the only emergent vegetation with which it associated. When breeding success was very high in 2000, strong creching of broods was observed in White-headed Duck, but not in Marbled Teal. In order to provide suitable habitat for both species, there is a need to maintain spatial diversity with a combination of large wetlands suitable for both species and small, vegetated ones suitable for the Marbled Teal.

Spatial and temporal distributions of smallmouth bass (Micropterus dolomieu) nests in Lake Opeongo, Ontario

1997 ◽  
Vol 54 (9) ◽  
pp. 2007-2013 ◽  
Author(s):  
C Rejwan ◽  
B J Shuter ◽  
M S Ridgway ◽  
N C Collins
Keyword(s):  
Reproductive Success ◽  
Littoral Zone ◽  
Nest Site ◽  
Spatial Scales ◽  
Smallmouth Bass ◽  
Competitive Interactions ◽  
Micropterus Dolomieu ◽  
Spatial And Temporal Distributions ◽  
Nest Site Choice ◽  
Habitat Variables

Smallmouth bass (Micropterus dolomieu) nests were patchily distributed within the littoral zone of Lake Opeongo at two spatial scales (1 km and 100 m shoreline segments). Nest locations were recorded by snorkelling along 155 and 6.3 km of littoral zone over 4 and 11 years, respectively. The degree of patchiness was greater and occurred more consistently at the 1-km than at the 100-m spatial scale. However, the degree of patchiness was not significantly affected by 200% differences in spawning population size, implying that competitive interactions did not strongly influence nest locations over the study period. High-density nesting areas remained stationary between years at the 1-km and 100-m scales. This suggests that habitat variables having stationary spatial characteristics, influence nest site choice. Since the locations of nest patches are less stationary and less consistent among 100-m than among 1-km scale sites, influential habitat variables at the 100-m scale are either less important to the locations of nests or less stationary from year-to-year in their effects on nest distributions. If stationary nest patches are typical of spawning smallmouth bass in lakes, permanent protection of known patch locations could enhance their reproductive success.

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