Avian Use of Harvested Crop Fields in North Dakota During Spring Migration

Broad-spectrum herbicide applications and improved harvesting efficiency of crops have reduced the availability of weed seeds and waste grains for game and nongame wildlife. Over the last decade, corn and soybean plantings have steadily increased in the Prairie Pothole Region (PPR) of North Dakota, while sunflower plantings have declined. The PPR is an important corridor for migratory birds, and changes in food availabilities at stopover habitats may affect how food resources are used. In early spring 2003 and 2004, we compared bird use of harvested fields of sunflower, soybeans, small grains, and corn in the PPR of North Dakota. Across both years and all crop types, we observed 20,400 birds comprising 29 species. Flocks of Lapland Longspurs (Calcarius lapponicus) and Horned Larks (Eremophila alpestris) and flocks of Red-winged Blackbirds (Agelaius phoeniceus) made up 60% and 15%, respectively, of the bird counts. We found that species richness and bird densities were higher in harvested sunflower fields and cornfields than in harvested small-grain and soybean fields, with soybean fields harboring the fewest species and lowest bird density. Blackbird densities tended to be lower in fields tilled after fall harvest than in fields not tilled. These results suggest that some granivorous bird populations in the Northern Great Plains could be positively affected by planting of row crops with postharvest vertical structure (e.g., sunflower, corn) and use of no-till land management practices.

Impacts of Plant Size, Density, Herbivory, and Desease on Native Platte Thistle (Cirsium Canescens)

Abstract. Based on prior field observations, we hypothesized that individual and interacting effects of plant size, density, insect herbivory, and especially fungal disease, influenced seedling and juvenile plant growth in native Platte thistle populations (Cirsium canescens Nutt.). We worked at Arapaho Prairie in the Nebraska Sandhills (May - August 2007), monitoring plant growth, insect damage, and fungal infection within different density thistle patches. In the main experiment, we sprayed half of test plants in different density patches with fungicide (Fungonil© Bonide, containing chlorothalonil) and half with a water control. Fungal infection rates were very low, so we found no difference in fungal attack between these treatments. However, plants that received the fungicide treatment had significantly faster growth over the season than did the control plants. At the same time, plants in the fungicide treatment had significantly reduced insect herbivory. These results strongly suggest that the fungicide had insecticidal effects and that insect herbivory significantly decreases juvenile Platte thistle growth. Further, damage by insect herbivores tended to be higher for larger plants, and herbivory was variable among different patches. However, plant density did not appear to have a large effect on the amount of insect herbivory that individual juvenile Platte thistle plants received. In the second experiment, we examined germination and survival success in relationship to seed density, and found that germination success was higher in areas of lower seed density. In the third experiment, we tested germination for filled seeds categorized primarily by color variation and size, and found no difference in germination related to either color or seed weight. We conclude that seed density, but not seed quality as estimated by color or size, affects germination success. Further, although herbivory was not significantly affected by plant density at any of the scales examined, insect herbivory significantly reduces the growth and success of juveniles of this characteristic native sand prairie plant.

The Probe, Issue 189 – June 1998

When Deer Are Too Dear and Elk Are Too Elegant -- Gary W. Witmer, NADCA Regional Director, Southern Rockies Region, Region 2 Understanding Home Range -- Jeff Jackson, Extension Wildlife Specialist, School of Forest Resources, University of Georgia Notes from Nigeria: Wildlife Crop Interactions in Threatened Sahelian Wetland -- Augustine U. Ezealor, Dept. of Biological Sciences, Ahmadu Bello University, Zaria, Nigeria, and Robert H. Giles, Jr., Dept. of Fisheries and Wildlife Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0321. Two Women Animal Rights Activists Protest Prairie Dog Control Rats on the Rise-Urban Wildlife Control Proves to Be Bonanza for Florida Man Wildlife Up Close and Personal for Suburbanites An ADC Story from the Internet Stray Cats Pose Expensive Problem

SCWDS BRIEFS: Volume 18, Number 3 (October 2002)

• Chronic Wasting Disease Update: Wisconsin, Minnesota, South Dakota, Colorado; National CWD Management – USDA & USDI National Plan for Assisting States, Federal Agencies, and Tribes in Managing Chronic Wasting Disease in Free-ranging and Captive Cervids • West Nile virus (WNV) reaches the Pacific coast • West Nile Virus in Blue Jays • Idaho Brucellosis Linked to Wildlife: All of the epidemiological and laboratory information clearly indicates that brucellosis-infected elk transmitted the disease to the cattle herd. • Tularemia caused a die-off of captured wild prairie dogs this summer at a Texas commercial exotic animal facility that distributes the animals for sale as pets. • Raptors can acquire avian vacuolar myelinopathy (AVM) via ingestion of other affected birds. • House Finch Mycoplasmosis: bacterial eye disease of house finches • Raccoon Rabies report • Toxoplasmosis – The newest finding regarding sea otters in California is the importance of toxoplasmosis as a mortality factor. Toxoplasma gondii is a protozoan parasite that can invade visceral organs and the central nervous system to cause acute, disseminated tissue necrosis and fatal meningoencephalitis in susceptible animals. In recent years, 36% of dead sea otters examined have been infected. Another tissue-invading protozoan, Sarcocystis neurona, also was found in 4% of the otters. • Recovery of remnant populations of the endangered black-footed ferret have been hampered by sylvatic plague, which is caused by the bacterium Yersinia pestis. • Dr. Samantha Gibbs received the Wildlife Disease Association’s Student Research Recognition Award. Dr. Cynthia Tate was selected by the American Association of Veterinary Parasitologists to receive the Best Student Presentation Award. Dr. Andrea Varela won second place in the Student Presentation Award for her presentation at the meeting of the American Association Veterinary Parasitologists. Mr. Michael Yabsley received the Wildlife Disease Association Student Scholarship and the S.A. Ewing Vectorborne Parasitology Award from the University of Georgia’s College of Veterinary Medicine.