To cite auk in publications use:

Strimas-Mackey M, Miller E, Hochachka W (2018). auk: eBird Data Extraction and Processing with AWK. R package version 0.3.0, https://cornelllabofornithology.github.io/auk/.

Corresponding BibTeX entry:

  @Manual{,
    title = {auk: eBird Data Extraction and Processing with AWK},
    author = {Matthew Strimas-Mackey and Eliot Miller and Wesley
      Hochachka},
    year = {2018},
    note = {R package version 0.3.0},
    url = {https://cornelllabofornithology.github.io/auk/},
  }