This happens when migration gathering gets disrupted. Those who wont fly away marches to the frozen lake.

---

Size: 4800px × 3200px
Photo credit: © Arto Hakola / Alamy / Afripics
License: Royalty Free
Model Released: No

Keywords: animal, beak, bill, bird, birds, brown, bunch, canada, cold, colorful, common, crane, crowd, disruption, disturb, disturbance, escape, eurasian, eye, fauna, feathers, field, flock, formation, frozen, gathering, goose, grey, greylag, group, grus, hornborgasjö, ice, interference, lake, landscape, leg, meadow, meeting, migration, nature, omnivorous, participants, pattern, portrait, snow, speed, swan, view, water, white, wilderness, wildlife, wing, wooper