Lawrence Igl, PhD (Former Employee)

Keys to Chestnut-collared Longspur (Calcarius ornatus) management are providing and maintaining native pastures with fairly short overall vegetation and sparse litter accumulation but with areas of taller and denser vegetation and accumulated litter for nesting, and tailoring grazing intensity to local conditions. Chestnut-collared Longspurs have been reported to use habitats with 10–77...

Keys to Lark Bunting (Calamospiza melanocorys) management include providing short vegetation with protective nest cover and tailoring grazing systems to the type of grassland. Lark Buntings have been reported to use habitats with 6–72 centimeter (cm) average vegetation height, 2–11 cm visual obstruction reading, 13–71 percent grass cover, less than or equal to (≤) 48 percent forb cover,...

The key to Merlin (Falco columbarius) management is maintaining an interspersion of groves of deciduous or coniferous trees for nesting and open grasslands for hunting. Merlins do not build their own nests but rather use former nests of other bird species, including those of corvids (crows, ravens, and magpies) and accipitrids (hawks). In recent decades, Merlins have established breeding...

Keys to Sprague’s Pipit (Anthus spragueii) management include providing suitable grassland habitat, especially native prairie, with intermediate vegetation height and low visual obstruction, and controlling succession therein. Sprague’s Pipits have been reported to use habitats with no more than 49 centimeters (cm) average vegetation height, 4–14 cm visual obstruction reading, 15–53...

Estimating the number of breeding pairs in a mixed-species waterbird colony is difficult because colonial waterbirds are vulnerable to human intrusion and their colonies are often in remote areas with limited access. We investigated methods to estimate the number of nests of waterbirds at a large, mixed-species colony at Chase Lake National Wildlife Refuge in south-central North Dakota...

Mercury is a persistent, biomagnifying contaminant that can cause negative behavioral, immunological, and reproductive effects in wildlife and human populations. We examined the role of wetland water-management on mercury bioaccumulation in songbirds and ducks at Kellys Slough National Wildlife Refuge Complex, near Grand Forks, North Dakota USA. We assessed mercury concentrations in...

Recent work has suggested that a tradeoff exists between habitat area and habitat heterogeneity, with a moderate amount of heterogeneity supporting greatest species richness. Support for this unimodal relationship has been mixed and has differed among habitats and taxa. We examined the relationship between habitat heterogeneity and species richness after accounting for habitat area in...

The key to Thick-billed Longspur (Rhynchophanes mccownii) management is providing short, sparsely vegetated native grasslands of adequate size. Mixed-grass prairies can be made suitable for breeding Thick-billed Longspurs by implementing moderate-to-heavy or season-long grazing. Thick-billed Longspurs have been reported to use habitats with 5–42 centimeters (cm) average vegetation height...

The key to Northern Harrier (Circus hudsonius) management is providing tall, dense vegetation in extensive mesic or xeric grasslands or in wetlands. Northern Harriers have been reported to use habitats with 15–106 centimeter (cm) average vegetation height, 28–75 cm visual obstruction reading, 24–53 percent grass cover, 18–25 percent forb cover, less than or equal to 2 percent shrub cover...

The key to Eastern Meadowlark (Sturnella magna) management is providing large areas of contiguous grassland of moderate height with significant grass cover and moderate forb density. Eastern Meadowlarks have been reported to use habitats with 10–187 centimeters (cm) average vegetation height, 6–88 cm visual obstruction reading, 53–86 percent grass cover, 4–50 percent forb cover, less...

Keys to Ferruginous Hawk (Buteo regalis) management are providing suitable nest sites, protecting active nest areas from human disturbance, and providing suitable habitat for prey.

The key to Swainson's Hawk (Buteo swainsoni) management is providing open grasslands that contain patches of trees for nesting and perching, sometimes near cultivated areas.