Bird use and nesting in cropland.

Bird Use and Nesting in Conventional, Minimum-tillage, and Organic Cropland

John T. Lokemoen & Julia A. Beiser,¹

Northern Prairie Science Center
National Biological Service
Jamestown, ND 58401-7317, USA

Abstract: We examined seasonal bird use and nesting activity in fallow, sunflower, and wheat fields among conventional farms (using fall and spring tillage and pesticides), minimum-tillage farms (using reduced tillage), and organic farms (using zero synthetic pesticides) in southeast North Dakota. Observers recorded 18 species in crop fields in spring, 70 in summer, 40 in fall, and only 11 in winter. Birds counted in cropland in spring were mainly transient migrants. Spring bird densities were highest in minimum-tillage fallow fields that provided enhanced food and cover. There were no differences in bird densities among crops or field types in fall or winter, but mean densities in summer were highest in fallow fields (14 - 23/10 ha). Fallow fields also had the greatest mean number of nesting species (1.9/field) and the highest mean nest densities (15 nests/10 ha) probably due to increased amounts of plant litter cover. Compared to conventional fields, the mean number of nesting species (1.6 and 1.9/field) and mean nest densities (10 - 12 nest/10 ha) were higher in minimum-tillage and organic fields. Overall, hatching success was low for waterfowl (0%) and shorebirds (18%) and nest success was low for passerines (14%). Hatching success for shorebirds and passerines was not different among field types or crops when all loss factors were considered. Nest losses were caused primarily by predation and farming activities. When predation was not considered, hatching success was higher in minimum-tillage fields for passerines and in wheat fields for shorebirds. Although it would be difficult to reduce predation to increase nest success, mortality of nests and young might be lowered by reducing tillage frequency.

Key words: agriculture, bird populations, birds, farming practices, minimum-tillage, nesting, North Dakota, no-tillage, organic.

This resource is based on the following source (Northern Prairie Publication 1013):

Lokemoen, John T, and Julia A. Beiser.  1997.  Bird use and nesting in 
     conventional, minimum-tillage, and organic cropland.  Journal of 
     Wildlife Management 61(3):644-655.

This resource should be cited as:

Lokemoen, John T, and Julia A. Beiser.  1997.  Bird use and nesting in 
     conventional, minimum-tillage, and organic cropland.  Journal of 
     Wildlife Management 61(3):644-655.  Northern Prairie Wildlife Research Center 
     Home Page. http://www.npwrc.usgs.gov/resource/othrdata/birduse/birduse.htm
     (Version 01DEC97).

Introduction
Study Area
Methods
- Definitions and Field Selection Criteria
- Bird Counting Techniques
- Estimating Bird Densities
- Nest Searching Techniques
- Daily Survival Rates
- Plant Cover and Field Treatment Measurements
- Statistical Analyses
Results
- Bird Use by Season
- Bird Density by Season
- Nesting Species and Nesting Period
- Nest Densities
- Hatching Success and Fledging Success
- Bird and Nest Density Associations with Vegetative Cover
- Tillage Treatments
Discussion
- Seasonal Use of Cropland
- Nesting Aspects
Management Implications
Literature Cited
Tables
- Table 1: Percent frequency of species and the total number of individuals recorded.
- Table 2: Back-transformed mean density of birds/10 ha by crop and field type in spring, fall, and winter.
- Table 3: Back-transformed mean density of birds/10 ha by crop and field type in summer.
- Table 4: Nesting species on all crop and field types.
- Table 5: Comparison of number of nesting species on all crop and field types.
- Table 6: Density of nests on all crop an field types.
- Table 7: Percent hatching success of breeding waterfowl, shorebirds, and passerines on each field type.

¹ Present address: Washington University, School of Medicine, Division of Urologic Surgery, 4960 Childrens Place, St. Louis, MO 63110, USA.

Downloading Instructions -- Instructions on downloading and extracting files from this site.

birduse.zip ( bytes) -- Bird Use and Nesting in Conventional, Minimum-tillage, and Organic Cropland

Installation: Extract all files and open birduse.htm in a web browser.

Bird Use and Nesting in Conventional, Minimum-tillage, and Organic Cropland

Table of Contents