Map of Whooping Crane stopover site use intensity within the Great Plains from satellite telemetered birds, 2010-2014

Whooping cranes (Grus americana) of the Aransas-Wood Buffalo population migrate twice each year through the Great Plains in North America. Recovery activities for this endangered species include providing adequate places to stop and rest during migration, which are generally referred to as stopover sites. To assist in recovery efforts, initial estimates of stopover site use intensity are presented, which provide opportunity to identify areas across the migration range used more intensively by whooping cranes. We used location data acquired from 58 unique individuals fitted with platform transmitting terminals that collected global position system locations. Radio-tagged birds provided 2,158 stopover sites over 10 migrations and 5 years (2010-14). Using a grid-based approach, we identified 1,095 20-square-kilometer grid cells that contained stopover sites. We categorized occupied grid cells based on density of stopover sites and the amount of time cranes spent in the area. This assessment resulted in four categories of stopover site use: unoccupied (white), low intensity (beige), core intensity (green), and extended-use core intensity (red).

阿肯萨斯-伍德布法罗种群的美洲鹤（Whooping crane, Grus americana）每年会两次穿越北美大平原进行迁徙。针对这一濒危物种的恢复工作，包括为迁徙途中的鹤类提供充足的停歇休憩场所，这类场所通常被称为停歇地（stopover site）。为助力该物种的恢复工作，本研究提出了停歇地利用强度的初步估算方法，借此可识别迁徙范围内被美洲鹤高频利用的区域。我们使用了58只佩戴平台发射终端（platform transmitting terminal）的个体的定位数据，该终端可采集全球定位系统（global position system）定位信息。带有无线电标记的个体在10次迁徙周期与5年（2010-2014年）的监测期间，共计记录到2158个停歇地。我们采用基于网格的分析方法，共识别出1095个包含停歇地的20平方千米网格单元。我们依据停歇地密度以及鹤类在该区域的停留时长，对已占用的网格单元进行分类。经此评估，最终将停歇地利用强度划分为四类：未占用（白色）、低强度利用（米色）、核心强度利用（绿色）以及长期利用核心强度（红色）。