@misc{indiciae674698f61a37,
  title = {An aerial sightability model for estimating ferruginous hawk population size},
  author = {L.W. Ayers and S.H. Anderson},
  year = {1999},
  doi = {10.2307/3802489},
  url = {https://pubs.usgs.gov/publication/70022046},
  note = {Source identifier: 70022046}
}