Modeling Least Bell’s Vireo Habitat Suitability in Current and Historic Ranges in California

Open-File Report 2020-1151
Wildlife Program
By: , and 

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Abstract

We developed a habitat suitability model for the federally endangered Least Bell’s Vireo (Vireo bellii pusillus) across its current and historic range in California. The vireo disappeared from most of its range by the 1980s, remaining only in southern California and northern Baja California, Mexico. This decline was due to habitat loss and introduction of brood parasitic brown-headed cowbirds (Molothrus ater) into California in the late 1800s. Habitat protection and management since the mid-1980s increased southern California vireo populations with small numbers of birds recently expanding back into the historic range. The vireo habitat model will help meet the U.S. Fish and Wildlife Service recovery objectives by distinguishing specific areas to survey for new occurrences; characterizing important vireo-habitat relationships; and identifying areas for habitat management. We constructed models based on the vireo’s current range to predict suitable habitat in the historic range, which differs substantially in environmental conditions. We used the partitioned Mahalanobis D2 modeling technique designed to predict habitat suitability in areas not included in a sample of species locations and under novel conditions. We constructed alternative models with different combinations of environmental variables hypothesized to be important components of vireo habitat. We selected a set of best performing models to predict suitable habitat for a riparian vegetation grid buffered 500 meters across California. Most models for southern California did not predict suitable habitat in the historic range. The top performing model has an area under the curve value of 0.93. It is a simple model and discriminated among riparian habitats, with only 6 percent predicted as suitable. On average, suitable vireo habitat had more than 60-percent riparian vegetation and flat land at the 150-meter scale, little-to-no slope, and was within 130 meters of water.

Suggested Citation

Preston, K.L., Kus, B.E., and Perkins, E., 2021, Modeling Least Bell’s Vireo habitat suitability in current and historic ranges in California: U.S. Geological Survey Open-File Report 2020–1151, 44 p., https://doi.org/10.3133/ofr20201151.

ISSN: 2331-1258 (online)

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Table of Contents

  • Acknowledgments
  • Abstract
  • Introduction
  • Methods
  • Results
  • Discussion
  • References Cited
  • Appendixes 1–3
Publication type Report
Publication Subtype USGS Numbered Series
Title Modeling Least Bell’s Vireo habitat suitability in current and historic ranges in California
Series title Open-File Report
Series number 2020-1151
DOI 10.3133/ofr20201151
Year Published 2021
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Western Ecological Research Center
Description Report: vii, 44 p.; Data Release
Country United States
State California
Online Only (Y/N) Y
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