Record-Sized Flock of Whooping Cranes (Grus americana) Observed Staging in the Central Platte River Valley During Autumn 2021

Abstract

Increases in population size and reductions in suitable migration stopover habitat associated with drought, water development, and agricultural practices, along with conspecific attraction, are hypothesized mechanisms for increasing flock sizes of migrating Whooping Cranes. During autumn 2021, we observed such a phenomenon during a period of drought in the central Great Plains when 46 Whooping Cranes gathered as a single flock in the central Platte River valley. We provide a detailed account of how this larger aggregation formed from 5 smaller groups, behavioral observations, and environmental conditions experienced during this event including river flow, ambient temperature, and wind and drought conditions. Here, we report considerations for environmental and hydrologic conditions preceding and during this event as well as use patterns and behaviors we observed while the largest single flock of Whooping Cranes ever documented in the United States portion of the migration corridor was in the central Platte River valley.

Editorial: Looking Back While Looking Forward

“…Muñoz (2022) describes an unusual predation of a ray by the Great Blue Heron (Ardea herodias), suggesting that this species has a much wider feeding niche than was previously known. Baasch et al (2022) recorded flocking habits of the reintroduced Whooping Cranes (Grus americana) and report on the largest flock observed so far, suggesting that this reintroduced population is beginning to behave like other natural crane populations that form large seasonal flocks. Jia et al (2022) conduct the first GPS tracking on the very poorly studied White-eared Night Heron (Gorsachius magnificus) and report on the findings of deploying one transmitter.…”