A BRIEF HISTORY OF CRANE MIGRATION
Migrations for many animal species on land, in water, and in the air are quite remarkable. For Sandhill Cranes, they have the anatomical abilities with six foot wing spans, hollow bones, long legs, and light, streamlined bodies to fly long distances and to have the built- in migration 'software' inside their brains. These evolutionary tools have been refined and changed over many generations to insure the survival of the species. It is an ongoing process, for if a species can stay put in one place and survive, it is advantageous to do so. How did the process actually begin? The driving forces for migration are the same as are the needs for humans, food, water, shelter, clothing and an environment in which to raise a family.
'Clothing' for Sandhill Cranes is in the form of several layers of feathers. For their diet, because they migrate, and to increase their chances of survival, Sandhill Cranes have evolved to be omnivorous, meaning they can eat a variety of grains, plants, insects, amphibians and small rodents. This versatile diet serves them well throughout the year.
The Rocky Mountain Sandhill Cranes have evolved over millions of years and up until the last 200 years or so have only had their population numbers fluctuate because of weather events such as drought, which affects their food supplies. But sadly, in the 1940s, because of over hunting, when the Cranes were down to only 150-200 breeding pairs, wildlife management people stepped in to insure their survival. Even though their numbers had dwindled, the migration patterns remained the same. They spend winters along the Rio Grande in southern New Mexico, in the Chihuahua state of Mexico, eastern Arizona and western Texas, with most spending the winter at the Bosque Del Apache in New Mexico, a few hundred miles downstream from Alamosa. They migrate north beginning in late February through March on their way to breeding grounds in western Montana, Wyoming and Idaho. Their migration pattern is a learned behavior for each generation passes it on to the next. Cranes follow the Rio Grande from New Mexico North into Colorado. When the river ends at its headwaters in the western parts of the San Luis Valley, they turn to the Northwest for a few hundred more air miles to their summer homes where they raise their families. Their babies, called fledglings, can fly and begin to forage for food in a few weeks out of an egg. Within a few months the baby cranes will be ready to fly a thousand miles with their parents back to their wintering grounds. Talk about a crash course in life!
MONTE VISTA CRANE FESTIVAL Mid-March 2016
For the 33rd annual Crane Festival held March 11-13, 2016, the cranes proved, once again, to be quite reliable and on time. They always show up for the 'party' being thrown for them! With longer days, and warmer temperatures down south, they begin to get restless in February because of hormonal controls and decide it is time to head upstream and Monte Vista is the one stop where virtually the whole population of Rocky Mountain Sandhill Cranes, from all their different winter homes, stays for several weeks together, before dispersing to their various birth site nesting grounds up north.
On Friday afternoon March 11, I boarded one of the four busloads of 'Crane Festers' in Monte Vista to head out to the Monte Vista National Wildlife Refuge 6 miles south of town. My continuing education about cranes began. Two employees from the U.S. Fish & Wildlife Service were on the bus to tell us about the life cycles of the cranes and open up discussion for anyone with questions.
What I found to be the most interesting was when the discussion followed a path on how the food supplies for the crane was now supplemented due to habitat loss because of human activities. In this valley, 500 acres have been set aside to grow grain for the hungry migrating cranes. Due to the nature of growing grain, the acreage must be split and the crops rotated so as not to deplete the nitrogen and other nutrients in the soil. Half of those 500 acres is planted in alfalfa, which the farmers can use for their animals, or sell to offset the cost of what it takes to plant food for the cranes. This works well for all parties concerned.
Fortunately, cooperative efforts of our governmental agencies at the local, state, and federal levels, combined with international assistance, keep cranes and other migrating species at safe numbers. Imagine being one of the field biologists who has the job of monitoring and counting numbers of birds during the year. Some operations require being in low flying planes to get an approximate head count. Biologists on the ground confirm the rough count. Other scientists are monitoring pollution levels that may affect populations because of toxins in the water or food supplies. Remember DDT and Bald Eagles? Some study the effect of habitat loss due to human activities. Others may be involved in law enforcement to stop poaching and on a world wide scale in an attempt to prevent illegal wildlife trade. When population numbers of any species are checked regularly, it helps provide a picture of the overall health of the environment, including ours!
Observing Animal Behavior at the Monte Vista Crane Festival
As a wildlife ecologist, I have seen Sandhill Cranes in winter at the Bosque Del Apache in New Mexico. I have seen them at the Blue Mesa Reservoir west of Gunnison later in March catching thermals off a sun drenched mountainside only a few hours after they have left the San Luis Valley, spiraling upwards and gaining perhaps 6,000 vertical feet before exiting their self-made 'vortex of cranes' and continuing on their journey. But, I had yet to see them at the Crane Festival where the Sand Cranes and Canada Geese hang out together, along with a few snow geese and a few other random migratory species.
Unlike the Hatfield’s and McCoy’s, Sandhill Cranes and Canada Geese get along quite well. The Canada Geese don't seem to mind that the Cranes get top billing for the Festival. While standing in the Refuge Parking Lot with several hundred observers, all of whom had cameras of course. This is a photo-op event! Many observers had binoculars and telescopes, these being necessary to get close-ups of bird behavior, as we are a hundred yards or more away from the nearest birds. The real star of the Festival show is the collective behavior of all the birds. Geese number in the thousands with other geese and the cranes are with their own in the thousands. But, some of each species have no problem mingling amongst the other group. They wander around and seem to be socializing and having a good time like humans at a giant backyard wedding reception. It is also a noisy gathering as the cranes cackle and the geese honk. Random take-offs of individuals, or small groups (we were told this is usually a family group) or occasionally hundreds at a time will take flight. From a human observers point, there seems to be no organization to their behavior but why must there be? Another star of the show was a breeding pair of great horned owls in the trees beside the parking lot. The momma owl had two ears that could be seen above the nest and the male in a nearby tree sat observing us. Unlike the geese and cranes, the Owls remain motionless. They are nocturnal. Flying at night is their time for being active.
We boarded the buses and stopped at two more observation points. One was near water. I noticed incoming geese landed directly on the water while the cranes would land nearby on land and looked like paratroopers hitting the ground, doing several hoppity hops before coming to a stop. Both species are quite graceful in their landings. As the sun fell behind the San Juan Mountains and the temperature dropped it was time to leave the geese and the cranes to their night. We would see them again at dawn... Next blog up - The people at the festival