Liu et al. • MIGRATION ROUTES OF BLACK-NECKED CRANES 
709 
1994). None of our five tagged cranes traveled to 
Yushu, and it is not clear whether cranes breeding 
in Yushu pass through Daocheng during migra¬ 
tion; it is more likely the cranes breeding in Yushu 
use another migration route via Changdu, Chaya, 
Gongjue, and Mangkang counties in Tibet. This 
route is shorter and follows the low altitude Jinsha 
River Valley. Thus, cranes have no need to cross 
over high mountains (e.g., Queer Mountain 
between Yushu and Baiyu counties: peak 
6,168 m asl) and there is a multitude of suitable 
wetlands along this route (e.g., Mangeuo Lake at 
Mangkang). Daocheng County has also been 
listed as a wintering area for Black-necked Cranes 
(Dolan 1939, Zheng 1987). This suggests migra¬ 
tory behaviors are more complex and/or migration 
patterns may have changed recently. Collecting 
additional multi-year satellite telemetry data from 
multiple cranes would be beneficial in providing 
definitive data. 
Different populations of Black-necked Cranes 
have shown different migration behaviors, For 
example, the shortest migration route is from 
Phobjikha in Bhutan to Phari/Bam-tsho in Tibet, 
only -120 km, and the longest is from Caohai 
Marsh in Guizhou to Ruoergai Marsh in Sichuan, 
-1,351 km. The duration of the migration can 
also vary' from I to 21 days (Zhang 2007; 
Wangmo Rinchcn, pers. comm.). Our study 
documented this variation can occur within a 
subpopulation as well, as migration routes varied 
from 175 to >400 km and lasted from 1 to 
19 days. Movements in Tibet are sufficiently short 
in many cases and Ludlow and Kinnear (1944) 
described the species as “only locally migrato¬ 
ry". This variation in migratory patterns likely 
developed because the topography of the Qinghai- 
fibet Plateau is dynamic with high mountains and 
low valleys within small landscapes, resulting in 
climatic conditions that can differ significantly 
over a 100-km area. 
Migration routes of Black-necked Cranes can 
be short hut require negotiating areas of high 
altitude. Black-necked Cranes used air currents 
such as thermals and other updrafts to complete a 
180-km trip and climb over 1,200 m in altitude 
from Napahai Marsh to Docheng County. Cranes 
usually departed about noon to target the peak 
ihermal period, gaining —500 m in the process 
before (lying north (Liu 2010). 
Soaring birds, such as Black-necked Cranes, 
depend on geographic and topographic character¬ 
istics during migration for navigation. Thus, 
knowing routes these birds use each year during 
migration is important. However, these routes 
often differ between spring and autumn as a result 
of varying wind and weather condition (Newton 
2008), Fall migration routes lor cranes in 
Daocheng County, compared to the tortuous 
spring migration, is direct with no detours 
(Fig. 3). Cranes moved south to lower altitude 
wintering areas where the high snow-capped 
mountains no lunger presented immediate barri¬ 
ers. Crane ID 79631 took a longer route than the 
others and continued in the spring to the Cuoma 
Pond, 200 km north of Daocheng County. The 
terrain between Daocheng County and Cuoma 
Pond is relatively flat with several dispersed small 
lakes and wetlands that can provide roosting and 
feeding sites. Crane ID 79631 chose to take 
advantage of these suitable habitats rather than 
take the most direct route. Crane TD 79631, during 
its next spring migration, moved back to a 
stopover site after reaching its summering area 
at Cuoma Pond. This retrogression could have 
been due to abrupt local heavy snowfall. 
Black-necked Crane families separate before 
spring migration and juveniles do not follow their 
parents to breeding areas (Liu et al. 2008). 
Instead, juveniles flock together and remain 
longer at wintering sites. Juvenile ID 79629 in 
our study started the spring migration up to 
2 months later than adults. Similar observations 
have been made for Red-crowned Cranes (Grits 
japonensis ) (Kamata 1994) and White-naped 
Cranes ( G. vipio) (Lleta et al. 2001). This 
separation may decrease conflicts between off¬ 
spring and their parents in breeding areas (e.g., for 
food) and demonstrates juveniles have the ability 
to migrate to breeding areas without following 
their parents. 
Eighteen Black-necked Cranes, including this 
study, have been tracked using satellite telemetry 
in China and Bhutan. These cranes have provided 
extensive and detailed information about the 
migration ecology of Black-necked Cranes. This 
sample, however, is small. More satellite telem¬ 
etry and traditional color banding are needed. 
Our study identified a new breeding area and 
important stopover sites of Black-necked 
Cranes. These areas are essential for the long 
term survival and conservation of the central 
subpopulation. More research is needed in the 
future; e.g., estimating population si/e, identi- 
lying food resources, and documenting repro¬ 
ductive ecology. 
