@misc{indiciaeca9c545a6ed2,
  title = {Tree Swallows: A Nationwide Sentinel Species for Assessing and Monitoring Aquatic Contamination},
  author = {Christine Custer and Thomas Custer},
  year = {2004},
  doi = {10.3133/fs20043042},
  url = {https://pubs.usgs.gov/publication/fs20043042},
  note = {Source identifier: fs20043042}
}