Habitat Use by Sandhill Cranes Wintering in Western Texas

Iverson, George C.; Vohs, Paul A.; Tacha, Thomas C.

doi:10.2307/3801398

Cited by 25 publications

(21 citation statements)

References 3 publications

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“…No past estimates of postharvest grain sorghum were available for comparison. However, Iverson et al (1985) reported average grain sorghum biomass in harvested fields was 292 kg/ha in January, which was 15 times greater than our January estimate (19 kg/ha). Despite increased crop yields since the 1980s (NASS 2008), improvements in harvesting technology may be resulting in less grain deposited by combines, hence available for waterfowl (Krapu et al 2004, Manley et al 2004).…”

Section: Available Seed Postharvest and Postdrydowncontrasting

confidence: 87%

“…Given that Tennessee is located north of most states in the Southeast, our estimates of seed mass in harvested corn, soybean, and grain sorghum fields probably are liberal for this region. Further, our estimates of seed mass are for harvested fields without postharvest treatment (e.g., grazing, tilling), which can reduce seed abundance in harvested fields by 73-100% (Frederick and Klaas 1982, Baldassarre et al 1983, Iverson et al 1985, Warner et al 1985.…”

Section: Available Seed Postharvest and Postdrydownmentioning

confidence: 99%

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Agricultural Seed Biomass for Migrating and Wintering Waterfowl in the Southeastern United States

2010

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Waterfowl frequently acquire high‐energy agricultural seeds in harvested and unharvested croplands during migration and winter. Estimates of agricultural seed biomass in harvested and unharvested corn, soybean, and grain sorghum fields do not exist or are outdated for the southeastern United States. Therefore, we estimated seed biomass in 105 harvested and 59 unharvested corn, soybean, and grain sorghum fields across 4 climate regions in Tennessee, USA, from September through January 2006 and 2007. We also used estimates of seed biomass to calculate duck‐energy days (DEDs) in December and January when migratory waterfowl abundance peaks in the southeastern United States. Mean biomass of corn, soybean, and grain sorghum seed in harvested fields declined 239 kg/ha to 39 kg/ha, 118 kg/ha to 26 kg/ha, and 392 kg/ha to 19 kg/ha, respectively, from postharvest to January. Continuous monthly rates of decline were 64% for corn, 84% for soybean, and 74% for grain sorghum. Agricultural seed biomass in harvested corn and grain sorghum fields dropped below the waterfowl giving‐up density (i.e., 50 kg/ha) in 3 months; soybean dropped below this threshold 1 month postharvest. Mean DEDs/ha in harvested corn, soybean, and grain sorghum fields were low (274, 90, and 27, respectively) in January, and DEDs were zero in >85% of fields. In unharvested corn, soybean, and grain sorghum fields, mean DEDs/ha in January were high (69,000, 18,000, and 26,000, respectively), and continuous rates of decline (3%, 7%, and 18%, respectively) were much lower than for harvested crops. Waterfowl biologists in the Southeast should use our estimates of agricultural seed biomass in DED calculations. We also recommend that biologists provide unharvested grain fields and natural wetlands for migrating and wintering waterfowl because seed resources are low in harvested agricultural fields.

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Section: Available Seed Postharvest and Postdrydowncontrasting

confidence: 87%

Section: Available Seed Postharvest and Postdrydownmentioning

confidence: 99%

Agricultural Seed Biomass for Migrating and Wintering Waterfowl in the Southeastern United States

2010

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“…Thomas et al (2004) proposed a Bayesian multinomial model for analyzing categorical habitat selection data. Other examples include a geometric method (Kincaid and Bryant 1983), a multiple-response permutation method (Alldredge et al 1991), principal components (Edwards and Collopy 1988), discriminant analysis (Dunn and Braun 1986), multiple regression (Porter and Church 1987), and several one-resource-at-a-time tests (e.g., Hobbs and Bowden 1982, Talent et al 1982, and Iverson et al 1985. Jaenike (1980) proposed a method to assess spatial or temporal changes in preference without reference to availability.…”

Section: Survey Of Methodsmentioning

confidence: 99%

Design and Analysis of Resource Selection Studies for Categorical Resource Variables

Alldredge

Griswold

2006

Journal of Wildlife Management

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Design and analysis of resource selection studies, where resources, such as habitats, are categorical have been commonly used for the past four decades. These methods have been evaluated, criticized, modified, and extended in the wildlife and statistical science literature. In this paper, we review some of the history of resource selection studies and place these studies in the context of wildlife science. Several variations of resource studies are presented along with historical data sets to illustrate the type of data obtained from some study designs. Common methods of analysis are introduced and compared in the terms of appropriate application to data from the various study designs, underlying assumptions, and hypotheses being tested. Criticisms of several of the methods of analysis are reviewed along with fundamental concerns about resource selection studies from the recent literature. Implications for analysis and interpretation of results are presented along with suggestions for future development. Resource selection studies can provide useful management information but only if the design is sound, analysis is appropriate, and much care is taken in the interpretation of results.

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“…Numerous statistical tests for evaluating overall resource selectivity have been employed, as shown in Table 1.3, and, in addition, several confidence interval procedures, and tests that consider one resource at a time have been used to assess selectivity. These latter tests include procedures described by Hobbs and Bowden (1982), Talent et al (1982), and Iverson et al (1985), as well as intervals for many of the selectivity indices listed in Table 1.1. A comparison of several simultaneous confidence interval procedures (Cherry, 1996) concluded the Neu et al (1974) method was inferior to intervals given by Goodman (1965) and Bailey (1980) with respect to the rate of type I and II errors.…”

Section: Hypothesis Tests and Confidence Intervalsmentioning

confidence: 99%

Resource Selection by Animals

2004

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Habitat Use by Sandhill Cranes Wintering in Western Texas

Cited by 25 publications

References 3 publications

Agricultural Seed Biomass for Migrating and Wintering Waterfowl in the Southeastern United States

Agricultural Seed Biomass for Migrating and Wintering Waterfowl in the Southeastern United States

Design and Analysis of Resource Selection Studies for Categorical Resource Variables

Resource Selection by Animals

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