Cranes are among the oldest living birds on the
planet. Fossil records place cranes in Nebraska more than nine million years
ago, long before there was a Platte River, which by comparison, is a
youthful 10,000 years of age. Sandhill cranes have
adapted well to the change in landscapes over time and their populations are healthy and continue to rise.
Here are some quick facts about sandhill cranes.
Height: 3 to 4 feet
Weight: 6 to 12 pounds
Wingspan: 6 to 7 feet
Lifespan: 20 to 40 years
Diet: Cranes are omnivorous and their diet varies depending
on the season and where they are at. The cranes that visit the
Platte River valley feed primarily on waste grain left in corn fields,
making up 90% of their diet while here. The other 10% comes from
plant and animal foods found in wet meadows adjacent to the river.
Seeds, fleshy tubers of plants, grubs, earth worms, snails, amphibians,
small reptiles and small rodents are all fair game.
Color: Adult is gray with a red crown (bald patch of skin);
juvenile is browner overall and has a feathered crown
Subspecies: There are at least five subspecies of sandhill
cranes, possibly six depending on who you ask. Migratory subspecies
include the lesser, greater, and according to some, the Canadian sandhill
crane. Non-migratory subspecies are the Florida, Mississippi and
Cuban sandhill crane.
Flight speed & distance: 25 - 35 mph; cranes typically
travel 200 - 300 miles in a day, but can reach 500 miles with a good tail
wind
Nesting: For migratory populations, nesting begins early
April to late May. Non-migratory populations begin in December to
early March. Nests are usually low mounds of vegetation located in
wetlands, but are occasionally located in uplands. The female
typically lays two eggs, with incubation lasting 29 - 32 days.
Status: Stable to increasing, except for the isolated
populations in Mississippi and Cuba. The total for all subspecies
numbers between 600,000 - 800,000, with lesser sandhill cranes being the
most abundant.
Sandhill Cranes and the Platte River
Sandhill cranes have been found as far north as
Alaska and Eastern Siberia. In order to reach these destinations, cranes
must build up enough energy to complete their long journey and to begin
breeding. For the cranes, the
Platte River Valley is the most important stopover on this migration. The
river provides the perfect spot to rest, and the nearby farmlands
and wet meadows offer an abundance of food. Without the energy gained along
the Platte, cranes might arrive at their breeding grounds in a weakened
condition -- where food may be limited until the spring growing season
begins.
The Platte River region has a variety of
habitats that support cranes. The most important is the Platte River
itself. The river is very shallow and sandbars dot the channels. It is
here the cranes rest at night, gaining protection from
predators like coyotes.
In the morning, cranes shuffle up and down the river waiting for the
sun to pop up over the horizon. As the sun rises,
cranes head out to feed and loaf in the surrounding fields. During
the day, cranes "dance" to relieve the stress of migration and strengthen
pair bonds. Cranes are very "social" birds and in the evening,
congregate in wet meadows before heading back to
the river for the night.
Additional crane info
Cranes are opportunistic
fliers, relying on thermals and tail winds to carry them along.
Thermals are rising columns of warm air and when southerly winds start to
blow in late March and early April along the Platte, you will see cranes
testing them for flight conditions. Cranes ride thermals so efficiently that they
have been seen flying over Mt. Everest (~28,000 feet).
Their bills and
feet are important tools. A crane's bill is very sharp and
sturdy, useful when probing frozen soil. The edges are
serrated to grasp slippery food like worms and snakes. Not only is it used
for preening, it is also used as a weapon.
The feet and legs work in conjunction with the beak. The foot has three
long toes with claws on the end. These claws are very sharp and can be
used for scratching in dirt to find food and for protection. When a crane
is threatened, it will use its wings to maintain its balance and then
jump up and strike at the attacker with its feet.
How do they do that?
Do you ever wonder how cranes
stay warm while standing for hours in near-freezing water? They can reduce the amount of blood that has to be warmed by constricting
blood vessels in their feet. Also, the arteries and vessels in their
legs
are
right next to each other so the colder blood is warmed before it reaches
the body.
