@misc{indiciaee3d8c7d29eaa,
  title = {A survey for mallard pairs in the Atlantic flyway},
  author = {H.W. Heusmann and John R. Sauer},
  year = {1997},
  doi = {10.2307/3802116},
  url = {https://pubs.usgs.gov/publication/5223388},
  note = {Source identifier: 5223388}
}