THE CHISANA CARIBOU RECOVERY PROGRAM

1
THE CHISANA CARIBOU RECOVERY PROGRAM Calving in
captivity Protocol and efficacy of a field
application to raise recruitment of a threatened
woodland caribou population Michelle Oakley (YTG,
Canada), Richard Farnell (YTG, Canada), Don E.
Russell (CWS, Canada), Craig L. Gardner (ADFG,
U. S.), Mason Reid (NPS, U.S.) Robert G. White
(IAB, U.S.).
ABSTRACT
The Chisana herd of western Yukon Territory and
Wrangle-St. Elias area of Alaska is the latest
threatened woodland caribou (Rangifer tarandus
caribou) population (Farnell Gardner 2003).
This genetically distinct population (Zittlau et
al. 2000) currently numbers less than 350 animals
and annually recruits only 0-14 calves per 100
adult cows. Thus, the population is ageing, has
a highly skewed sex-ratio (17-23 m 100 f),
suffers high neonatal predation, and is subject
to extirpation. Managers and stakeholders agree
the population should be protected. Management
approaches include encourage predator control by
local people through trapping and hunting, a
complete hunting closure on this herd in the
Yukon and Alaska, and use of a predator exclosure
for captive calving to increase neonatal calf
survival. In March 2003 we enclosed 8 ha of
white spruce woodland and open upland tussock
tundra using a 1.5 m fence of geocloth as a
visible barrier. The enclosure was adjacent to
preferred post-calving habitats, close to a lake
for transport and water, and situated on a side
hill for ease of visibility. From 25-27 March
2003, 20 cows were net-gunned and individually
transported inside a helicopter to the enclosure.
They were weighed, ultra-sounded for pregnancy
and to measure rump-fat, and examined for overall
body condition. Blood was collected to confirm
pregnancy status, and a radio-collar with visual
band was fitted. Natural forage in the enclosure
was supplemented with moistened lichens (Cladina
sp.) and a commercial pelleted reindeer ration
(15 CP Unifeed, Okotoks, Alberta). Seventeen
cows were pregnant and gave birth between 13 May
and 7 June. Cows and calves were released 13
June, when the median age was 3 wk. Cows and
calves moved 20 km to their typical range in
Alaska, and were joined by other caribou. As of
18 August, between 10-14 calves were alive. This
compares with 23 radio-collared cows in the wild,
16 were pregnant and calved during late May and 2
calves were alive as of 18 August.
ALASKA
YUKON
NWT
THE PROBLEM

• Most calves die in first 3 weeks of life
• Cows healthy predation likely cause

POST-RELEASE RESULTS .... SO FAR
OUR PROPOSED SOLUTION
Although our final criteria for success is calf
survival to autumn initial surveys indicate
that a minimum of 10-14 calves are still alive
(59-82). This compares with 2 of 16 (12)
survival in calves of collared cows born in the
wild.

• Provide protection to calves for 3 weeks
  after birth by holding them in a predator proof
  enclosure. Our measure of success is survivorship
  of calves to autumn.

THE PILOT PROJECT

• Built predator proof enclosure within their
  traditional range
• Captured adult females in early April
• (20 cows captured, 17 diagnosed as pregnant)
• All cows healthy with good subcutaneous fat
  deposits
• 17 calves born between May 11 June 11
• All calves survived until release, June 14

NOW WHAT?
Depending on the results this autumn, the team
plans to double the size of the pen and
capture 40 cows for release next year.