@misc{indiciaeb6c2556cad95,
  title = {Annual survival rates of adult and immature eastern population tundra swans},
  author = {James D. Nichols and J. Bart and Roland J. Limpert and William J.L. Sladen and James E. Hines},
  year = {1992},
  doi = {10.2307/3808863},
  url = {https://pubs.usgs.gov/publication/5222878},
  note = {Source identifier: 5222878}
}