@article{Jerzak:2012,
  author  = "L. Jerzak and O. Ciebiera and J. Boehner",
  title   = "Seasonal changes in group size and foraging activity in an urban population of Magpies (Pica pica)",
  journal = "International Studies on Sparrows",
  volume  = "Vol. 36",
  pages   = "80--87",
  year    = "2012",
}