Acoustic signalling mediates key animal behaviours, but the factors driving inter- and intra-specific variation remain elusive, especially in non-learning suboscine birds. Acoustic traits may evolve to signal an individual’s quality through a process termed honest signalling. Most studies on bird song evolution via honest signalling focus on oscine bird species (song learners) while fewer evaluate honest signalling in suboscines.
Applying Satellite-based Habitat Models to Inform Riparian Habitat Restoration and Management Actions for Two Listed Riparian Species, the Southwestern Willow Flycatcher and the Yellow-billed Cuckoo
James Hatten1, Jennifer Holmes2, and Matthew Johnson3*
This chapter from The Codex of the Endangered Species Act, Volume II: The Next Fifty Years describes how genetic information is used to inform decision-making for the Endangered Species Act. In one section of this chapter (page 4 of the PDF, page 162 of the book), the use of genomics to differentiate between subspecies of willow flycatcher (Empidonax traillii) is described.
This article describes how researchers discovered that southwestern willow flycatchers in southern California have evolved in response to climate change. Southwestern willow flycatcher (SWFL) populations are threatened by climate change and habitat loss. By sequencing DNA from historical SWFL samples and comparing these to modern samples, researchers determined that modern SWFL were more likely to have beneficial genes that help them cope with changing climate.
An Integrated Pest Management Plan for the Bill Williams River National Wildlife Refuge. This plan outlines the biological degradation of native riparian forest habitat along the Lower Colorado River and the invasive species management actions needed to protect and restore riparian forests and marshlands of the Bill Williams River.
DeRango, B., 2023. Integrated Pest Management Plan Bill Williams River National Wildlife Refuge.
A look at the evolutionary response to climate change in the endangered southwestern willow flycatcher (Empidonax traillii extimus) using whole-genome comparisons between historic and modern specimens from California. While introgression led genomes of neighboring E. traillii extimus populations (California and Arizona) to become more similar, the specific loci linked to climate shifted in a way consistent with climate adaptation rather than becoming more similar to those of neighboring populations.
A look into the use of invasive Tamarix (saltcedar, tamarisk) as habitat for birds in the southwestern United States and its implications for Tamarix control. While Tamarix habitat supports fewer birds than native habitat, data from Arizona Breeding Bird Atlas and Birds of North America demonstrate that 49 bird species use Tamarix as breeding habitat. The use and quality of Tamarix as bird habitat varies depending on geographic location and species and few studies have quantified the effects of Tamarix habitat on bird survivorship and productivity.
Poster by Megan M. Friggens and Deborah M. Finch documenting a maximum entropy (maxent) model to predict future habitat along the Rio Grande for SWFL, yellow-billed cuckoo, and Lucy’s warbler.
Detailed report of the development of a satellite model utilizing flycatcher breeding territory data from six states as well as five years of tamarisk beetle defoliation data from the Lower Virgin River. Change detection showed a large shift in predicted habitat due to drought. A spatially explicit analysis showed a 94% decrease in predicted flycatcher habitat due to beetle defoliation on the Lower Virgin River. However, the model predicts that after beetle defoliation 64% and 45% of habitat will remain in the Lower Colorado and Gila River systems respectively.
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.