Data from: Finer-scale habitat predicts nest survival in grassland birds more than management and landscape: a multi-scale perspective

1. Birds may respond to habitat at multiple scales, ranging from
microhabitat structure to landscape composition. North American grassland
bird distributions predominantly reside on private lands, and populations
have been consistently declining. Many of these lands are enrolled in U.S.
federal conservation programmes, and properly guided management policies
could alleviate declines. However, more evaluative research is needed on
the effects of management policies juxtaposed with other multi-scale
habitat features. Furthermore, research focused on nest survival is
arguably more valuable because habitat associations with avian densities
can sometimes be deceptive. 2. We investigated nest survival of a
grassland facultative (red-winged blackbird, Agelaius phoeniceus) an
obligate species (dickcissel, Spiza americana), and two nesting
communities (ground and above-ground nesters) relative to management and
multi-scale habitat (nest-site characteristics, in-field microhabitat,
patch metrics, and landscape context). Our study was conducted on private
lands in Illinois (2011-2014) and directly linked to policy-based
management (disking, herbicidal spraying, spray/interseeding) and
landowner decisions. 3. Multi-scale models explained more variation in
nest survival compared to single scales or management in three of four
analyses (blackbirds, dickcissels, and above-ground nesters). Finer-scale
habitat variables, such as nest-site characteristics, were more often in
top and among the competitive models relative to landscape factors. 4.
Compared with other management types, disking (i.e. tractor-pulled disc
harrows removed approximately 50% of vegetation) displayed distinct
effects and positively influenced nest survival in above-ground nesters.
Also, greater proportions of a field managed cumulatively and yearly,
regardless of type, generally improved nest survival for dickcissels and
above-ground nesters. All groups except above-ground nesters had generally
higher nest survival in native grass fields. 5. Synthesis and
applications. Habitat practitioners can improve nest survival for certain
grassland birds by directly affecting infield-microhabitat vegetation and
structure. However, characteristics associated with specific nest
locations often drive nest survival. We suggest habitat managers and
agency staff promote native grass practices and management, such as
disking, to enhance nest survival of grassland bird populations.
Management will likely be most effective in favourable unfragmented
grassland landscapes with less surrounding forested areas, which also
promote other important responses (e.g. colonization and persistence) of
target species.