@misc{indiciae27b8eae7ddbf,
  title = {Densities of breeding American black ducks in southcentral Maine: 1958-60 and 1978-80},
  author = {J. R. Longcore and J.K. Ringelman},
  year = {1997},
  url = {https://pubs.usgs.gov/publication/5210974},
  note = {Source identifier: 5210974}
}