Distribution and Demography of Coastal Cactus Wrens (Campylorhynchus brunneicapillus) in Southern San Diego County, California—2020 Data Summary

Data Series 1138
By:  and 


Executive Summary

Surveys for coastal Cactus Wren (Campylorhynchus brunneicapillus) were done in 378 established plots in southern San Diego County in 2020, encompassing three genetic clusters (Otay, Lake Jennings, and Sweetwater/Encanto genetic clusters). Two surveys were completed at each plot between March 1 and July 31. Cactus Wrens were detected in 131 plots (35 percent of plots). This is a slight increase over the proportion of occupied plots in 2019. One hundred and nine Cactus Wren territories were detected across all survey plots in 2020, an increase from 83 in 2019. At least 85 percent of Cactus Wren territories were occupied by pairs, and 62 fledglings were observed in 2020.

There were 89 color-banded Cactus Wrens observed in 2020, 84 of which we could identify to individual. Adults of known age ranged from 1 to at least 6 years old. Adult Cactus Wrens moved on average 0.2 kilometers (km; maximum 3.8 km) from their 2019 territories to their 2020 territories. Cactus Wrens that fledged in 2019 moved on average 1.2 km (maximum 9.9 km) to their 2020 territories. No known-identity Cactus Wrens moved between genetic clusters from 2019 to 2020.

Vegetation at Cactus Wren plots typically was dominated by coastal sage scrub shrubs such as California sagebrush (Artemisia californica), lemonadeberry (Rhus integrifolia), California buckwheat (Eriogonum fasciculatum), and broom baccharis (Baccharis sarothroides). Very little dead or unhealthy cactus was observed within Cactus Wren survey plots. Thirty-eight percent of plots had at least 25 percent of the cactus crowded or overtopped by vines and shrubs. Non-native annual cover was greater than 25 percent at 35 percent of plots.

Suggested Citation

Lynn, S., and Kus, B.E., 2021, Distribution and demography of coastal cactus wrens (Campylorhynchus brunneicapillus) in southern San Diego County, California—2020 data summary: U.S. Geological Survey Data Series 1138, 12 p., https://doi.org/10.3133/ds1138.

ISSN: 2327-638X (online)

Study Area

Table of Contents

  • Acknowledgments  
  • Executive Summary 
  • Introduction  
  • Study Area and Methods 
  • Results  
  • Summary 
  • References Cited 
Publication type Report
Publication Subtype USGS Numbered Series
Title Distribution and demography of coastal cactus wrens (Campylorhynchus brunneicapillus) in southern San Diego County, California—2020 data summary
Series title Data Series
Series number 1138
DOI 10.3133/ds1138
Year Published 2021
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Western Ecological Research Center
Description Report: vi, 12 p.; Data Release
Country United States
State California
Other Geospatial Southern San Diego County
Online Only (Y/N) Y
Google Analytic Metrics Metrics page
Additional publication details