Detecting ecological traps in human-altered landscapes: A case study of the thick-billed longspur nesting in croplands

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 spring cereal and pulse crop fields during the breeding season in northeastern Montana, USA 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 these crop fields may function as ecological traps; specifically, we expected that crop fields may provide cues for territory selection, but frequent h..., ,