Bird Use and Nesting in Conventional, Minimum-tillage, and Organic Cropland
John T. Lokemoen and Julia A. Beiser
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.
Table of Contents
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.
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. Jamestown, ND: Northern Prairie Wildlife Research Center
Online. http://www.npwrc.usgs.gov/resource/birds/birduse/index.htm
(Version 01DEC1997).
John T. Lokemoen and Julia A. Beiser*, Northern Prairie Science Center, National Biological Service, Jamestown, ND 58401-7317, USA.
*Present address: Washington University, School of Medicine, Division of Urologic Surgery, 4960 Childrens Place, St. Louis, MO 63110, USA.
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