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Answers from the Whooping Crane Expert


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Answers from the Whooping Crane Expert
Special thanks to ornithologist Laura Erickson for providing her time and expertise in responding to your questions below.

From: Saskatchewan

Q: If people are looking after Whoopers, then how do the young learn to fly and know where to migrate?


A: The Whoopers raised by people are imprinted on costumed humans. These cranes never see normal people just people who are entirely covered in a white costume with a mechanical puppet that looks pretty much exactly like a real live Whooping Crane parent. When the babies are brought to Necedah NWR in Wisconsin, they follow their parent even when the parent is near and inside an Ultralight plane. When the babies try flying, the human parent takes off in the Ultralight, and the babies follow! Then when the babies are ready for their first migration, they follow the Ultralight all the way to the Chassahowitzka NWR in Florida. This is exactly what wild baby Whoopers do. And, exactly like wild Whoopers, the babies return north in the spring on their own, having a strong homing instinct for the place where they grew up. After this, they can migrate both ways entirely on their own.


Q: What are some of the dangers Whoopers encounter during migration?

A: Probably the biggest dangers facing them are bobcats, raccoons and power lines. Raccoons and bobcats attack Whoopers when they’re sleeping on the ground or in shallow water. They sometimes hit power lines. Birds making return trips can sometimes get lost or find themselves in dangerous areas. They have been raised so carefully away from humans and cars, that so far they’ve stayed safe during their migration.


Q: How long do Whoopers live?

A: The oldest known Whooping Crane to live out its life in the wild lived to be at least 18 years and 10 months old, according to the Patuxent Bird Banding Laboratory.


From: Omaha, Nebraska

Q: Currently how many Whooping Cranes are there in all of the known populations? What are the best estimates of how many Cranes there were before they began to be adversely impacted by anthropogenic activities? What is the number (the restoration goal) of Whooping Cranes in the population that is needed before the USFWS can down list them to just “threatened”?

A: Tom Stehn’s report regarding this years Aransas population:

The 2005-06 winter for the Aransas-Wood Buffalo flock was one of disappointment. Despite the arrival of 30 juveniles including one set of twins in the fall, the total population only reached 220, an increase of 3 birds from the previous winter. Starting in December, food resources were limited and salinities were high, forcing the cranes to make daily flights to fresh water to drink. One 28-year-old male and 5 juveniles died during the winter, leaving the population at 214 in the spring, 2006. This was one bird less than the previous spring.

In the wild, there were also 59 birds in the introduced non-migratory Florida population that was established beginning in 1993, and 64 birds in the introduced flock that migrates between Wisconsin and Florida; that makes a total of 337 birds in the wild. There are also 135 birds in captivity, not counting birds that have hatched already this year. That makes a total of 472 birds.

As far as the Wisconsin-Florida population, the goal is to have 125 birds in Wisconsin by 2020, including 25 nesting pairs. But the species is still hanging on by a thread. The decision to de-list it will be based on the entire species well-being.

Right now the wild migratory Whooping Cranes are following two separate flyways, even if they aren’t any farther west than Texas. (See map at right.)

There was an attempt in the 1970’s to reestablish Whooping Cranes in the West. This early attempt involved putting Whooping Crane eggs in Sandhill Crane nests, and allowing the Sandhill Cranes to raise the baby Whoopers. That plan worked great as far as successfully raising babies that learned a natural migration route.

Unfortunately, the baby Whoopers all imprinted on their Sandhill Crane parents, and when it came time to breed, they only seemed willing to accept Sandhill Cranes for mates. Meanwhile, of course, all the Sandhill Cranes had also been raised by Sandhill parents, so NO cranes would accept a Whooper for a mate except for one Sandhill. That pair did raise a hybrid baby, but the entire family was lost in a storm. The rest of those Whoopers have all died out now.

Q: Historically I understand that cranes used to also inhabit Idaho and used the Western flyway. It would seem to make sense to further disperse the population so a catastrophic event or disease couldn't wipe out most of the population. Why isn't the USFWS establishing another population that would use the western flyway and winter in Mexico?

A: You are absolutely right that it’s important to disperse the population. The problem is that we’re still ironing out the best techniques for reestablishing cranes. It isn’t easy to start a population because the birds must learn their migration route from their parents (or foster parents in an Ultralight). And reintroducing cranes has proven to be extremely expensive and labor-intensive. I’m sure there simply won’t be any funding for starting another population until this project proves successful. That will be known after the birds are nesting and raising their young successfully. Right now prospects are excellent! But even if this group grows well, finding funding to establish a western population will be difficult when so many other endangered and threatened species also need help. And with changing weather patterns and increasing human populations contributing to ever increasing pressures on water resources in the West, prospects for cranes there are lower than where the climate is wetter.

Q: Are there any critical habitat limitations that are adversely impacting population recovery? If yes, what are the limitations, where are they occurring and how many birds could the known habitat sustain if something is not done to improve it?

A:
The biggest limiting factor right now seems to be water quality on the natural population's wintering grounds in Texas. In years when the rivers feeding the estuaries in the area around the Aransas National Wildlife Refuge are low, the estuary grows more saline (salty). This lowers the population of Blue Crabs, which are the cranes' most important food resource in winter. Higher salinity also increases the cranes' need for fresh water. So in those years (such as this past winter), the birds must fly inland every day for fresh water and also more food. This increases their chances of being injured in accidents or shot by hunters who mistake them for other species. And when they don’t get enough proper food in winter, they are much less likely to be in good condition when they reach their breeding grounds, significantly reducing their reproduction the following summer.

The rivers that feed into the estuary get lower from droughts, but this problem is much worse, and growing, because the human population along the rivers draws out water for regular use: drinking, bathing, irrigation, swimming pools, etc. And the human population is growing dramatically in that part of the country.


Q: I understand that the more critical factor limiting recovery is crane loss during migration (hitting high power lines and predators). Is this true, and if so, what is being done to reduce these losses or eliminate the conditions that are contributing them? Are the locations of the death of the birds plotted and where repeat occurrences occur being considered for modification (i.e. burying high power lines or improving a marsh)?

A:
It is very expensive for power companies to bury high power lines, and at this point, they’re just not required to do this. At the Audubon Rowe Sanctuary where Sandhill Cranes collide with power lines every year, sometimes in large numbers, the power company has, with financial help from Audubon and individual contributions, put bird flight diverters (BFDs) on the wires. BFDs make the wires more visible to flying birds, but they don’t help during foggy conditions or other bad weather conditions.

The quality and acreage of wetlands are also obviously very important. Whooping Crane pairs require fairly large territories, so improving one large wetland won’t be as important in the long run as improving many large wetlands, if we really are committed to helping this and other wetland species to thrive.


Q: Do Whooping Cranes exhibit any preference for roosting at night in a riverine setting (such as the Platte River) versus a marsh or shallow pond? Are there any other states they pass through on their migration north that they typically seek out a riverine habitat to roost in, other than Nebraska? What percentage of cranes that do stop in Nebraska roost in a wet meadow or marsh versus the Platte River?

A:
Cranes are safest roosting in shallow open water where they can notice predators approaching. The Platte used to be called the river that was a mile wide and an inch deep, and was so perfect for crane roosting that over hundreds of thousands of years it became THE central staging ground for migrating Sandhill Cranes and for many Whooping Cranes. Even Whoopers who might not be familiar with it are more likely to notice it because of the huge number of other cranes already there. It is unique, and a place that cranes return to year after year after year. But except for that, crane migration routes can vary from year to year. Favorable winds and high thermals may carry birds farther some days than others, and wind can push them off course. So for the most part they stop where they notice suitable habitat for finding food. When migrating conditions are good, a day’s flight may end in midafternoon or later. Birds drop down to what appears from above to be a suitable feeding area, where they eat and rest. They’re safest when they can roost in shallow water in lakes, ponds, or riverine areas, and choose ones that are as close as possible to their feeding area.


From: Maryland

Q: Is there any prediction about the future for the Whooping Crane species in terms of returning to a normal, healthy population, or is it too early to tell? I'm worried about them, because of the way their habitat is disappearing and because of the hazards, such as power lines, that they encounter on their migrations. I'm especially concerned because so many cranes were lost this past year, in spite of all the efforts to help them. What else can people (maybe the government?) do to protect the species better?

A:
I share your concern, and so does Tom Stehn, who wrote in this year's Whooping Crane Recovery report: "The National Audubon Society's list of the top ten endangered birds in the continental United States for 2006 has the whooping crane listed third behind the ivory-billed woodpecker and California condor. This shows that whooping cranes still have a long way to travel on the road to recovery."

During migration, power lines are a danger. Ensuring that there are plenty of clean wetlands is just as important. When cranes get exhausted while migrating, they need to see good places to come down. I am most concerned about their wintering grounds. The Aransas National Wildlife Refuge is SO vulnerable when there is little rain. This winter five cranes died when water levels were low and blue crabs were in short supply. As people continue to draw more and more water out of the rivers feeding the Refuge, cranes will have bigger and bigger problems. What can WE do about that? Water conservation by everyone will make the world better for birds AND for humans. And the more the government can do to promote water conservation and to protect wetlands, the better for everyone, too.

Laura Erickson
Staff Ornithologist
Binoculars.com
www.birderblog.com


How to Use FAQ's About Journey North Species
Since 1995, experts have contributed answers to students' questions about each Journey North species. These questions and answers are archived in our FAQ's (Frequently Asked Questions) section. You can use today's Answers from the Expert above, along with those from previous years, in the activities suggested in the lesson, "FAQ's About Journey North Species."

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