Q. What are the best weather conditions for crane migration?
A. Cranes usually migrate with a tailwind or no wind. In spring,
the cranes usually depart when high pressure systems bring sunshine to
Texas
(Western natural flock) or Florida (Eastern reintroduced flock) and winds
coming from the south or east. Thermals and
strong southeast winds provide ideal
northward migration
conditions.
By taking
advantage
of these
thermals
and tailwinds,
the birds soar more and flap less. This saves their energy.
Thermal currents aid the birds' flight by allowing them to spiral up to
about a
mile in
altitude
and then glide at speeds up to 60 mph. In fact, all along their migration
path the whoopers wait for high
pressure and favorable
winds (tailwind or no wind) to continue
their journey.
Q. What are the least favorable weather conditions for
migrating cranes?
A. The least favorable conditions for crane migration in spring
(northbound) are low pressure systems with north winds (winds coming from
the north). Low pressure systems are associated with storms.
When the migrating whoopers encounter these storms with their north winds,
the birds will quickly find a place to land. They'll wait for for as many
days as it takes until the north winds rotate back around to come out
of the south.
Q. What do migrating whoopers do during bad weather?
A. Fortunately, cranes can tolerate cold weather very well. They
will simply wait until a winter storm is over to resume their journey
north.
During these storms, the whoopers will make short daily flights out to
grain fields to feed, and return to wetlands to roost (spend
the night). It
is during these short low altitude flights where they might collide with
power lines and be killed, especially during rain or snow storms when
the
power lines are not very visible. If northbound cranes encounter winds
from the north, the birds choose not to migrate that day. Instead
they will spend
the day feeding in wetlands or agricultural fields.
Q. How do whooping cranes find their way when storms
blow them far off course?
A. Birds have an amazing ability to recognize star patterns at night
and to pay attention to the sun's angle in the sky during day. Using their
internal biological clock they can tell if the sun is where it's supposed
to be as the day progresses. When blown off course by bad weather, they
can move in the right direction to get the sun where they need it to be
to indicate the right direction for flying.
Q. What are some of the hazards that whooping cranes
face on their long flight between Aransas National Wildlife Refuge and Wood
Buffalo National Park?
A. Power lines, towers, hail storms, tornadoes, Peregrine Falcons,
Bald and Golden Eagles, foxes, raccoons, wolves, coyotes, and steel leg
traps are all potential hazards to these huge but fragile creatures. The
development of wind farms is occurring at a rapid pace in the migration
pathways. Wind turbines in the migration corridor
are a risk to migrating birds. Read
more about Migration
Dangers and a main hazard: cell
phone towers. Biologists in migration corridors are trying to consult
with other experts to express concerns about these issues as power lines
increase in number everywhere.
Q. Do all the cranes survive the migration?
A. Each year a certain number of Whooping Cranes do not survive
the entire migration. For example, some years as many as a dozen adult
cranes that leave
Aransas in the spring fail to survive to return in the fall. Migration
is hard work and some of the cranes simply will not be able to withstand
the
harsh conditions of spring blizzards or other bad weather. They also die
from the human-caused hazards such as cell phone towers or illegal
shooting by hunters. Because of migration dangers,
the number of young hatched each year are not added to population totals
until they reach Aransas in the fall. Some of the young cranes of the
new Eastern flock have died on migration as well, victims
of power lines, disease, or predators. In unusual events in 2007, most
of the Class of 2006 in the new Eastern flock died in a Florida storm,
and a
juvenile whooping crane died
when struck by a jet plane at the airport in Madison, WI. (Keep up with
the new Eastern
flock's history by checking each year's Meet
the Flock charts.)
Q. How do humans affect the migration of the Whooping
Crane?
A. Humans have a long history of filling in and draining wetlands,
which reduces the safe places where cranes may rest and feed. Now the
demand
for fresh water needs
for the fast-growing human population has become a real problem for Whooping
Cranes' winter home in Texas. Long ago people shot at migrating cranes,
and even now cranes are not safe from hunters. That's because their fall
migration may coincide with goose hunting season, and hunters sometimes
forget that not all white birds with black wingtips are Snow Geese. Some
are Whooping Cranes! Humans also build tall communication towers and power
lines that cranes can't see. Power
line collisions are the biggest cause of crane deaths during migrations.
Poachers and hunters have illegally shot
some Whooping cranes too.
Q. How did the study of whooping cranes begin?
A. For years, no one knew where whoopers went to nest and raise
their young. Then, in 1954, a pilot flying over the remote Wood Buffalo
National
Park in the Northwest Territories, Canada, spotted a pair of whooping cranes
and a possible chick. This discovery helped scientists in the US an Canada
to better study the birds and plan ways to save them from extinction. They
began tracking the spring and fall migrations, and telling the whooping
cranes'
story to the public. Read 4th-grader Hunter's description of How
the Western Flock's Nesting Grounds Were Discovered.
Q. What is the whooping cranes' status as an endangered
species?
A. The
population of the natural migratory flock hit an all time low in 1941
when only 15 cranes were at Aransas NWR. That same year, there were
still 6 cranes in the nonmigratory flock in Louisiana. So 15
at Aransas + 6 in Louisiana = 21, the all-time
low for Whooping Cranes in North America. Thanks to joint
efforts by Canada and the United States, their numbers have been
struggling back from the brink of extinction. The long-term fate of
the Whooping
Crane is still uncertain.
-
|
|
|
Photo
Jane Duden |
In 2001
crane specialists began the first effort to reintroduce a second
wild, migratory flock of whooping cranes to a part of their former
range.
A tiny flock of whoopers was hatched in captivity,
costume-reared,
and led
by
ultralight
aircraft
on migration
between
Florida and Wisconsin in Five
survived the winter and returned to Wisconsin unaided in spring. Each
year more whoopers will be added to the new reintroduced flock, with
ultralight
aircraft leading additional chicks south each fall for several years. After
five years, the oldest of the birds will likely be reproducing. To
help build the flock's numbers, additional new
captive-bred
chicks
will be released to learn migration from the experienced birds.
- Since
1993, a non-migratory
flock lives year round in central Florida. These Whooping Cranes
come from
captive-bred whoopers. They are part of a separate and ongoing
reintroduction effort.
- Additional
Whooping Cranes are in captive centers in North America.
Q.
What is scientists' biggest worry about Whooping Cranes?
A. The world's only wild flock
of Whooping Cranes, with one summer
home and one winter home,
might be lost to disease,
bad weather, or other
natural or human-caused disaster. That's why in 2001 the Whooping
Crane Eastern Partnership began reintroducing a new
flock into eastern North America. You can read all about
that first
ultralight-led
migration
in 2001 as well as the progress of the new Eastern flock by clicking here.
Q. How fast is the Whooping Crane population growing?
A. Some recent record years for the last remaining natural
flock were 1995 with an increase of 25 cranes, and 1997 with
an increase of 22 cranes.
The year
1999 was
a
struggle
for
the Whooping Cranes and disappointing for crane biologists.
The flock
managed to increase their numbers by only ONE crane. But
in fall of 2004,
the
number of whooping cranes in this flock (the Aransas/Wood
Buffalo flock, or Western flock) finally went over the 200 mark! In 2007
the Western flock passed the 250 mark. Since 2001, a
tiny new Eastern flock has been slowly growing, too, except
for a disastrous winter that only a few of the hatch year 2006 chicks
survived. In 2007, the combined number of captive and wild whooping cranes
in the
world
passed
the
500 mark! Click
here for recent numbers .
Q. What has been done to increase the numbers of this
endangered species?
A. In 1975 scientists and wildlife officials decided
to use a new technique to start a second wild whooper flock.
They
began collecting
whooper
eggs from nests in Canada and taking them to Gray's Lake
National Wildlife Refuge in Idaho. The whooper eggs were placed in the
nests of sandhill
cranes.
(Removing one egg did not affect growth of the wild flock
since whoopers normally lay two eggs but usually raise
only
one chick
successfully.)
The
sandhill crane foster parents hatched and raised 4 whooper
chicks in 1975.
They taught the young whoopers to find food and to avoid
predators such
as coyotes and eagles. In the fall, the sandhills led the chicks
on an 850-mile migration to the Bosque del Apache National
Wildlife Refuge
in New Mexico.
The young whoopers returned to Gray's Lake in the spring.
By 2002, the number of Whooping Cranes in the Rocky Mountains
was down to zero.
Then, in
2000, ultralight
aircraft successfully led a flock of sandhills
between Wisconsin and Florida . This paved the way
to do the same migration experiment with endangered Whooping
Cranes
in 2001 — and
each year after
that for several more years. This tiny flock is becoming
the ancestral flock for a second migratory flock in
eastern North America, where Whooping
Cranes
disappeared over a century ago. In addition, Whooping Cranes
in a few captive breeding centers are laying eggs and
hatching chicks that will
become part
of the growing new eastern flock in the future. In addition,
a small reintroduced flock (started in 1993) lives year-round
in central Florida.
This flock
does NOT migrate because none of the cranes have ever
been taught a migration route by wild parents or by human
assistance.
Q. What is the most fascinating thing wildlife biologist
Dr. Tom Stehn has learned about the Whooping Crane since
conducting research on
cranes?
A. Tom
says: "For
me, the most
fascinating
thing is that
the babies imprint. The very first
moving creature that a baby crane sees when it hatches becomes
its image
of adult cranes and when the baby grows up, that will be what
it seeks in a mate. So when cranes were raised in captivity
and fed by humans,
they
fell in love with humans. The most famous example of this is Tex,
a crane that was originally raised at the Patuxent Wildlife
Research Center
in Maryland and then sent to the International Crane Foundation
in Wisconsin. Tex bonded with crane scientist George Archibald,
who had
to jump up
and
down flapping his arms doing a crane dance with Tex every
spring in order for her to lay eggs."
Q. How long do Whooping Cranes live?
A. A whooper in the wild they usually
lives 25-30 years. On June 2, 2007, a crane named "Rattler" at
ICF broke the record for longevity of a Whooping Crane in captivity!
Rattler hatched
at the Patuxent Wildlife Research Center in Maryland on June 2, 1968
and lived there until 1989. He was given special food treats all during
his birthday week to celebrate, and the aviculturalists ate
cupcakes for Rattler's birthday party. The previous record was 38 years,
7 months for "Canus," an
injured wild-caught chick who died at Patuxent WRC in 2003. Banding
studies help us learn this information, but voice
prints are the newest way way
of keeping track of cranes individual
cranes over the years.
Q. How are whooping cranes important to the ecosystem?
A. Whooping cranes eat a wide variety of foods, both
plant and animal, and they in turn are prey for predators
such as foxes,
wolves,
coyotes,
lynxes, bobcats, raccoons, and even Golden eagles.
Q. Why are Whooping Cranes being reintroduced to
eastern North America?
A. Whooping Cranes are a highly endangered species. The only naturally
occurring flock of wild migratory whooping cranes left
in the world has been the one that migrates between Aransas
National
Wildlife Refuge
in Texas
and Wood Buffalo National Park in Canada. It is a huge
risk to have all of the wild whooping cranes using one
wintering
and
one breeding
location.
With all of the cranes concentrated in one small area,
the population could be wiped out by disease, bad weather,
or human
impacts
such as oil spills
or freshwater demands. Whooping Crane survival depends
on additional, separate populations being established. Survival also
depends on good crane habitat remaining available at their
winter and summer homes and along their migration routes.
Q. Who decides how many additional populations
are needed?
A. After a species is listed as threatened or endangered,
the Endangered Species Act requires that a recovery plan be designed.
A
recovery plan
is
a blueprint to improve
population health of threatened and endangered species. The
recovery plan
for whooping cranes was developed by the Whooping Crane Recovery
Team, made up of five specialists from Canada and five from the
United States.
The
Recovery Team has also decided that any new flock should be
established in areas where there is very a low chance of contacting
the
existing wild
flock. This separation will minimize the possibility of spreading
diseases between newly established flocks and other existing
whooping cranes.
Q. Was Wisconsin the first site considered for reintroduction?
A. No. A non-migratory flock has been reintroduced in the Kissimmee
Prairie region of central Florida. As of August 2002, 89 birds
were in that flock.
Most of those birds are young, but two
whooping crane chicks hatched in Florida for the first
time in 60 years. Both chicks were taken by predators, but
in the
summer of
2002 one chick
lived to flege. Named Lucky, it was the first wild chick fledged
in the U.S. dating back to the last nesting of whooping cranes
in Louisiana
in
1939. Lucky is the first whooping crane fledged in Florida
since the reintroduction of the nonmigratory flock started
in 1993.
In 1975,
another attempt to reintroduce
whooping cranes began in Idaho when whooping crane eggs were
placed in sandhill crane nests. The sandhill cranes then became
foster parents.
The attempt
did not succeed because the whooping cranes only recognized
sandhills and would not breed with other whooping cranes when
they reached
adulthood.
Q. Why was Wisconsin considered as a reintroduction
site?
A. The most important reason was that the Wisconsin flock will be
separated from other wild flocks. Also, Wisconsin has a lot of
suitable crane
habitat
on federal, state, and private lands. Wisconsin's long tradition
of environmental commitment and suppport from the public adds up
to better
chances for the
project to succeed. For a simulation game about choosing a
new home for the whoopers, see Whoopers
for Wisconsin?.
Q. How was the specific site for reintroduction in Wisconsin
chosen?
A. Three Wisconsin release sites were investigated in 1999. Site
selection was based on habitat analysis, local community support,
and protection
potential.
In September 1999, the Whooping Crane Recovery Team selected Necedah
National Wildlife Refuge for a test release using sandhill
cranes in 2000. The migration experiment with sandhills was
a success, paving
the
way for the same experiment to be repeated with whooping cranes
beginning in 2001.
Q.
Where do the birds for reintroductions come from?
A. The U.S. and Canada are working together to help whooping cranes. A few captive
flocks have been established and they produce cranes (crane
eggs) for reintroduction to the wild. Click
here to see some locations
with captive whooping cranes.
Q.
How are the birds reintroduced?
A. In the wild, chicks follow their parents south on the fall
migration, then return north the next spring on their own. When bringing
back a new population of whooping cranes to a former range, no adult
cranes are available to teach the young and show the way. Humans
and tiny ultralight airplanes become "stand-in
parents" to teach the little chicks where to go on their first
migration. See "Bringing
Back the Cranes: Photo Overview." Eventually, the
planes won't be needed anymore. The whoopers will begin hatching and
teaching their own chicks the way. This takes years, so chicks will
also be added another way; a few captive-bred chicks will be released
around the adult whooping cranes in Wisconsin in hopes they'll follow
the adults on migration. (This is called Direct
Autumn Release, or DAR, and it began in 2005.) One migration is
all it takes, and the birds willl know the route for the rest of their
lives.
Q. How do ultralight-led birds know the way back
home by themselves?
A. Research has shown that birds can be raised at a captive
breeding center and then transported to the site chosen for their
introduction,
as long as the move takes place BEFORE they learn to fly. Birds seem
to focus on the first location they can explore from the air. They
will
return to that place year after year. (Males are more dependable in
returning, and while some females seem to wander more.)
Q. Why is the new Wisconsin/Florida migratory flock
called nonessential experimental?
A. This population is designated as "experimental"
because it will be isolated from other populations whoopers. It is
called "nonessential" because these birds will not be esssential
to the survival of the entire species. Under this designation, the
reintroducd
whooping cranes will not receive full Endangered Species Act protection.
This allows greater management flexibility. It also solves
some
possible conflicts between people (such as farmers or landowners on
the migration route) and whooping crane conservation. However, if the
new Eastern whooping cranes stray outside a certain protected
area
of states
and provinces
in the new Eastern migration route, they will be protected under the
Endangered Species Act. For more, click
here.
Q. What is the reintroduction goal in Wisconsin?
A. The Wisconsin/Florida reintroduction project will be a 10- to 15-year
effort.The goal is a flock of 125 birds in Wisconsin by 2020, including
25 nesting pairs, with
introduction of 18-20 chicks each year. Ultralight-led migrations
will take place for at least five years after the first flight in 2001.
Q. What will it take to get Whooping Cranes off
the endangered species list?
A. In May
2007 the third revision of the Recovery Plan was adopted. For the
first time it includes needed recovery actions for both Canada and
the U.S. The long-term recovery goal for whooping
cranes is to establish a self-sustaining population of a minimum of
1,000 whooping crane s
in North America by the year 2035. The goal in the Aransas-Wood Buffalo
flock (the Western flock) is to maintain a minimum of 40 nesting pairs.
The goal for the new Eastern flock is to establish 25 breeding pairs
from 125 birds released in the Eastern Migratory Flyway by 2020, with
introduction of 18-20 chicks each year.
| |
 |
Copyright
1997-2009 Journey North. All Rights Reserved. Questions or comments?
Contact us. |
 |
|