loading page

Detecting Ecological Traps in Human-Altered Landscapes: A Case Study of the Thick-billed Longspur Nesting in Croplands
  • +2
  • Amber Swicegood,
  • Kevin Ellison,
  • Marisa Sather,
  • Scott Somershoe,
  • Lance McNew
Amber Swicegood
Montana State University
Author Profile
Kevin Ellison
American Bird Observancy
Author Profile
Marisa Sather
US Fish and Wildlife Service
Author Profile
Scott Somershoe
US Fish and Wildlife Service Mountain-Prairie Region
Author Profile
Lance McNew
Montana State University

Corresponding Author:[email protected]

Author Profile


Conversion of the North American prairies to cropland remains a prominent threat to grassland bird populations. Yet, a few species nest in these vastly modified systems. The thick-billed longspur (Rhynchophanes mccownii) is an obligate grassland bird whose populations have declined 4% annually during the past 50 years. Thick-billed longspurs historically nested in recently disturbed or sparsely vegetated patches within native mixed-grass prairie, but observations of longspurs in crop fields during the breeding season suggest such fields also provide cues for habitat selection. Maladaptive selection for poor quality habitat may contribute to ongoing declines in longspur populations, but information on thick-billed longspur breeding ecology in crop fields is lacking. We hypothesized that crop fields may function as ecological traps; specifically, we expected that crop fields may provide cues for territory selection but frequent human disturbance and increased exposure to weather and predators would have negative consequences for reproduction. To address this hypothesis, we compared measures of habitat selection (settlement patterns and trends in abundance) and productivity (nest density, nest survival, and number of young fledged) between crop fields and native sites in northeastern Montana, USA. Settlement patterns were similar across site types and occupancy ranged from 0.52 ± 0.17SE to 0.99 ± 0.01 on April 7 and 30, respectively. Early season abundance differed by year and changes in abundance during the breeding season were associated with precipitation-driven vegetation conditions, rather than habitat type. Standardized nest density (0.19 ± 0.27SD nests/plot/hour), the number of young fledged per successful nest (2.9 ± 0.18SE), and nest survival (0.24 ± 0.03 SE; n=222 nests) were similar for crop and native sites. Collectively, the data did not support our hypothesis that crop fields are ecological traps: longspurs did not exhibit a clear preference for cropland and reproductive output was not significantly reduced. Our results indicate that crop fields provide alternative breeding habitat within a human-dominated landscape.
19 Nov 2022Submitted to Ecology and Evolution
21 Nov 2022Submission Checks Completed
21 Nov 2022Assigned to Editor
08 Dec 2022Reviewer(s) Assigned
03 Feb 2023Review(s) Completed, Editorial Evaluation Pending
10 Feb 2023Editorial Decision: Revise Minor
11 Mar 20231st Revision Received
13 Mar 2023Submission Checks Completed
13 Mar 2023Assigned to Editor
13 Mar 2023Review(s) Completed, Editorial Evaluation Pending
13 Mar 2023Reviewer(s) Assigned
24 Mar 2023Editorial Decision: Accept