Trends in the occurrence of large Whooping Crane groups during migration in the great plains, USA.

摘要: Abstract Recent detections of large gatherings Whooping Cranes suggest that flock sizes may be increasing at some stopover locations during both the spring and fall migrations. We used public sightings database managed by US Fish Wildlife Service from 1942 to 2018 analyze data for long-term trends in group size. then examined spatial distribution groups explore potential explanations these occurrences. The proportion Crane comprised 2, 3, 4–6 individuals showed no trend over time. However, observations a declining 7–9 ≥10 an trend. frequency observed exceeding 5 10 were better predicted survey year than population size suggesting is not sole driver Our results indicate occur disproportionately within 50% migration corridor, staging areas first or last 20–30% path, near conservation-managed wetlands, particularly southern Great Plains. addition growth, conspecific attraction, location habitat loss contributing Further research needed determine degree which factors influence formation. gathering numbers single presents tradeoffs species. While improve threat detection avoidance, it comes cost increased disease mass mortality risk.