Fig 1.
Predicted effect of relevant habitat features on chestnut-collared longspur nest density.
Predicted effects of plot-scale herbaceous biomass, forb cover, slope, and exotic grass cover on the number of chestnut-collared longspur nests in Phillips County, Montana during May–June 2017–2018. Shaded areas represent 95% confidence intervals adjusted for overdispersion.
Table 1.
Model selection table for nest detection probability and nest density of chestnut-collared longspurs from 272 rope drag surveys of 100 9-ha plots in Phillips County, MT during May–June of 2017 and 2018.
Fig 2.
Estimated and observed chestnut-collared longspur nests per study plot.
Estimated and observed (raw counts) number of chestnut-collared longspur nests at100, 9-ha plots in Phillips County, MT during May–July of 2017 and 2018. The Pearson’s correlation coefficient indicated a weak positive correlation (r = 0.2, P = 0.044).
Fig 3.
Estimated effect sizes of nest site features on survival of chestnut-collared longspur nests.
Estimated effect sizes and 95% confidence intervals from standardized covariates measured at the nest site on daily survival of 263 chestnut-collared longspur nests in 100 9-ha plots in Phillips County, MT, during May–July of 2017 and 2018.
Table 2.
Model selection table for daily survival rate of 263 chestnut-collared longspur nests in 100 9-ha plots in Phillips County, MT, during May–July of 2017 and 2018.
Fig 4.
Estimated effect sizes of habitat features on survival of chestnut-collared longspur nests.
Estimated effect sizes and 95% confidence intervals from standardized covariates measured at the plot scale on daily survival of 263 chestnut-collared longspur nests in 100 9-ha plots in Phillips County, MT, during May–July of 2017 and 2018. Covariates ending in SD represent the effect of the standard deviation of the covariate at the plot scale.
Fig 5.
Estimated productivity of chestnut-collared longspurs by plot-scale biomass.
Estimated mean productivity (successful nests per 9 ha plot) in relation to average plot-scale herbaceous biomass in Phillips County, MT during May–July of 2017 and 2018.