Date Published: November 24, 2009
Publisher: Public Library of Science
Author(s): John P. McCarty, Joel G. Jorgensen, L. LaReesa Wolfenbarger, Cilla Kullberg. http://doi.org/10.1371/journal.pone.0008000
Abstract: Understanding the behavior of birds in agricultural habitats can be the first step in evaluating the conservation implications of birds’ use of landscapes shaped by modern agriculture. The existence and magnitude of risk from agricultural practices and the quality of resources agricultural lands provide will be determined largely by how birds use these habitats. Buff-breasted Sandpipers (Tryngites subruficollis) are a species of conservation concern. During spring migration large numbers of Buff-breasted Sandpipers stopover in row crop fields in the Rainwater Basin region of Nebraska. We used behavioral observations as a first step in evaluating how Buff-breasted Sandpipers use crop fields during migratory stopover.
Partial Text: Row-crop agriculture is one of the most intensive human uses of land. Many bird species use these heavily modified landscapes  and both positive ,  and negative ,  effects on birds have been documented. The implications for bird populations using agricultural lands as habitat are not always clear. In some cases agricultural land may provide a suitable substitute for native habitats, while in other cases birds may be forced to use agricultural lands that are not suitable because other, better habitats are unavailable. The first step in identifying possible resource needs is to document what behaviors birds are engaged in while using the habitat type. Likewise, the first step in evaluating risks is to document possible modes of exposure to risk, such as ingesting contaminants while foraging or while preening, or by dermal exposure during bathing.
We conducted 170 flock scan samples. Observations occurred at 75 different locations on 24 different days. Mean number of birds included in the flock scan was 11.5±0.9 birds (all means given as ±1 SE, range = 1 to 95). Approximately half of all birds observed during scans were engaged in foraging behavior (Table 1). Birds resting, engaged in maintenance behavior, social interactions, and walking accounted for between 8 and 16% of observations, while less than 3% of individuals were classified as alert (Table 1).
Foraging was a primary activity for Buff-breasted Sandpipers during stopover in agricultural fields in the Rainwater Basin. Comparatively little foraging was observed when birds were at wetlands. Instead wetlands were visited for short periods of time and used for bathing and drinking. While foraging was the most common activity, it was not as prevalent as observed in some other shorebirds during migratory stopover , . For example, in the southern Great Plains shorebirds such as Least Sandpipers (Calidris minutilla), Western Sandpiper (Calidris mauri), and Long-billed Dowitchers (Limnodromus scolopaceus) spent over 70% of their time foraging . Within the Rainwater Basin region, shorebirds associated with wetlands varied in what proportion of their time was spent foraging, though overall foraging intensity was similar to what we observed by Buff-breasted Sandpipers in upland agricultural sites .
Buff-breasted Sandpipers were observed during migration through the eastern Rainwater Basin region of Nebraska in May of 2007 and 2008. This distinct geologic region is dominated by corn and soybean agriculture and contains numerous playa wetlands (for detailed descriptions of the study area see , ).