@misc{indiciaee5402eada788,
  title = {Monitoring of colonial waterbirds in the United States: Needs and priorities},
  author = {R.M. Erwin and P. C. Frederick and John Trapp},
  year = {1993},
  url = {https://pubs.usgs.gov/publication/5210547},
  note = {Source identifier: 5210547}
}