@misc{indiciae090f3193ffb9,
  title = {Population trends of the purple martin in North America, 1966 - 1986},
  author = {J.R. Sauer and M. K. Klimkiewicz and Sam Droege},
  year = {1987},
  url = {https://pubs.usgs.gov/publication/5220747},
  note = {Source identifier: 5220747}
}