Science Support for Recovery of Southwestern Willow Flycatcher (Empidonax traillii extimus) on Conserved Lands in San Diego County 

 A study that planted 474 trees and measured their growth characteristics for more than a year. Logistic regression was used to evaluate whether tree height, elevation above the river channel, distance to existing cottonwood or coyote willow, soil conductivity, soil texture, planting depth, planting method (mechanical auger vs. hand-digging), and provision of natural and commercial supplements affected survival probability. The authors found that survival probability was greater in auger-dug than hand-dug holes and increased with elevation above the river channel bottom.