Effects of Habitat Characteristics on Gadwall Nest Predation and Nest-Site Selection

Crabtree, Robert L.; Broome, Linda; Wolfe, Michael L.

doi:10.2307/3801319

Cited by 104 publications

(84 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…On average, active sites, inactive sites, and control sites were 2,227 m, 1,779 m and 1,315 m away from the road respectively. This indicated that shrikes prefer to locate their nests further from the roads to avoid jeopardizing the roadside habitats in predation, which is in accordance with the explanations by [29,31]. We also found that the elevation for active sites and for control sites is significantly different (P < 0.1).…”

Section: Measured Topographical Characteristics Of Different Habitat supporting

confidence: 79%

Exploration of Loggerhead Shrike Habitats in Grassland National Park of Canada Based on in Situ Measurements and Satellite-Derived Adjusted Transformed Soil-Adjusted Vegetation Index (ATSAVI)

Shen

Guo

2013

Remote Sensing

View full text Add to dashboard Cite

Abstract:The population of loggerhead shrike (Lanius ludovicianus excubutirudes) in Grassland National Park of Canada (GNPC) has undergone a severe decline due to habitat loss and limitation. Shrike habitat availability is highly impacted by the biophysical characteristics of grassland landscapes. This study was conducted in the west block of GNPC. The overall purpose was to extract important biophysical and topographical variables from both SPOT satellite imagery and in situ measurements. Statistical analysis including Analysis of Variance (ANOVA), measuring Coefficient Variation (CV), and regression analysis were applied to these variables obtained from both imagery and in situ measurement. Vegetation spatial variation and heterogeneity among active, inactive and control nesting sites at 20 m × 20 m, 60 m × 60 m and 100 m × 100 m scales were investigated. Results indicated that shrikes prefer to nest in open areas with scattered shrubs, particularly thick or thorny species of smaller size, to discourage mammalian predators. The most important topographical characteristic is that active sites are located far away from roads at higher elevation. Vegetation index was identified as a good indicator of vegetation characteristics for shrike habitats due to its significant relation to most relevant biophysical factors. Spatial variation analysis showed that at all spatial scales, active sites have the lowest vegetation abundance and the highest heterogeneity among the three types of nesting sites. For all shrike habitat types, vegetation abundance OPEN ACCESSRemote Sens. 2013, 5 433 decreases with increasing spatial scales while habitat heterogeneity increases with increasing spatial scales. This research also indicated that suitable shrike habitat for GNPC can be mapped using a logistical model with ATSAVI and dead material in shrub canopy as the independent variables.

show abstract

Section: Measured Topographical Characteristics Of Different Habitat supporting

confidence: 79%

Exploration of Loggerhead Shrike Habitats in Grassland National Park of Canada Based on in Situ Measurements and Satellite-Derived Adjusted Transformed Soil-Adjusted Vegetation Index (ATSAVI)

Shen

Guo

2013

Remote Sensing

View full text Add to dashboard Cite

show abstract

“…During fieldwork we have observed Jays and Hooded Crows single or in small flocks which moved throughout linear habitats. Also mammal predators during foraging use linear habitats and in some cases such habitats might be preferred (Crabtree et al 1989).…”

Section: Discussionmentioning

confidence: 99%

Breeding Biology of the Great Grey ShrikeLanius excubitorin W Poland

Antczak¹,

Hromada²,

Grzybek³

et al. 2004

Acta Ornithologica

View full text Add to dashboard Cite

“…The process by which these clusters form is also largely unknown. The inherent spatial clustering of vegetation types may aVect the propensity for waterfowl to nest in clusters, and the vegetation selected may in turn aVect predation risk (Crabtree et al 1989;Clark and Shutler 1999). However, we suspect that waterfowl conspeciWc attraction may play a larger role than previously appreciated.…”

Section: Dispersion Of Nests Within a Weldmentioning

confidence: 96%

Density-dependent nest predation in waterfowl: the relative importance of nest density versus nest dispersion

2011

View full text Add to dashboard Cite

When nest predation levels are very high or very low, the absolute range of observable nest success is constrained (a floor/ceiling effect), and it may be more difficult to detect density-dependent nest predation. Density-dependent nest predation may be more detectable in years with moderate predation rates, simply because there can be a greater absolute difference in nest success between sites. To test this, we replicated a predation experiment 10 years after the original study, using both natural and artificial nests, comparing a year when overall rates of nest predation were high (2000) to a year with moderate nest predation (2010). We found no evidence for density-dependent predation on artificial nests in either year, indicating that nest predation is not density-dependent at the spatial scale of our experimental replicates (1-ha patches). Using nearest-neighbor distances as a measure of nest dispersion, we also found little evidence for "dispersion-dependent" predation on artificial nests. However, when we tested for dispersion-dependent predation using natural nests, we found that nest survival increased with shorter nearest-neighbor distances, and that neighboring nests were more likely to share the same nest fate than non-adjacent nests. Thus, at small spatial scales, density-dependence appears to operate in the opposite direction as predicted: closer nearest neighbors are more likely to be successful. We suggest that local nest dispersion, rather than larger-scale measures of nest density per se, may play a more important role in density-dependent nest predation.

show abstract

Effects of Habitat Characteristics on Gadwall Nest Predation and Nest-Site Selection

Cited by 104 publications

References 17 publications

Exploration of Loggerhead Shrike Habitats in Grassland National Park of Canada Based on in Situ Measurements and Satellite-Derived Adjusted Transformed Soil-Adjusted Vegetation Index (ATSAVI)

Exploration of Loggerhead Shrike Habitats in Grassland National Park of Canada Based on in Situ Measurements and Satellite-Derived Adjusted Transformed Soil-Adjusted Vegetation Index (ATSAVI)

Breeding Biology of the Great Grey ShrikeLanius excubitorin W Poland

Density-dependent nest predation in waterfowl: the relative importance of nest density versus nest dispersion

Contact Info

Product

Resources

About