Vol. 14, No. 1, July 2002

The Ninth North American Crane Workshop will be held January 21-25, 2003 in Sacramento, California.  We are looking forward to many interesting presentations covering topics of crane biology, ecology, migration and conservation.  A field trip to the Sacramento River Delta to view wintering flocks of sandhill cranes also promises to be exciting.  Please see the insert in this newsletter for a workshop agenda, a registration form and other pertinent information.  We hope to see you all at the Workshop!

Fledge!

This spring 7 pairs of nonmigratory whooping cranes in Florida laid clutches of eggs.  Despite the ongoing drought, one pair hatched 2 chicks and raised 1 of them to fledging (a bald eagle took the 2nd chick off the nest when it was just a few hours old).  This was the first chick of the project to fledge, and the first whooper to fledge in the United States since 1939 (a non-migratory whooping crane in the Louisiana flock).

The successful pair of whoopers raised their chick in Lake County near the home of Gene and Tina Tindell.  These people have spent untold hours watching the family of whoopers and sharing the information with us.  Because this pair of whoopers chose to nest and raise their chick within view of the Tindell's home, Gene and Tina have now observed more in the life of a whooper family than anyone else on earth, literally.  Gene and Tina have selflessly welcomed countless people into their back yard to witness this event. 

Despite the fact that the pair of whoopers were at the young-end of the scale for breeding (they hatched 2 chicks before they turned 4 years of age), and were first-time parents, they have shown "model" parent behavior: 

--They successfully tended their eggs for the month-long incubation period, protecting the eggs through several episodes of freezing temperatures and also protecting the eggs from overheating when it was in the 90's.

--They protected Lucky (the Tindell's name for the chick that survived) from numerous attacks by a pair of bald eagles.  About the last time the pair of eagles was seen at the marsh, the whooper parents attacked and "hospitalized" one of the eagles for several weeks before rehabilitators could release the eagle.

--They protected Lucky a number of times from dogs.  At the approach of dogs, one parent would run with the chick while the other parent would "distract" the dogs by running toward them and diverting their attention.

--As is normal for cranes, the parents kept the chick warm at night by sitting with it on the nest platform.  When the water dried up around the nest, the parents built new platforms wherever the water was left in the marsh (this provided a protective "moat" of water around them).  The fact that the parents built these platforms after hatching was something previously unknown to us.

--For weeks after the chick hatched, the parents spent a majority of their waking hours catching small prey items to feed Lucky.  They fed the chick a high-protein diet, concentrating on earthworms, insects, and other organisms small enough for the chick to swallow.  On one occasion when Lucky was 26 days old, the parents were observed to feed it 37 times in 5 minutes.

Lucky took his first flight at 76 days of age and had become a skilled and strong flier within 2 weeks. 

Marty Folk, Kissimmee, FL, and Steve Nesbitt, Gainesville, FL

“Lucky” in flight with one of his parents.  Photo by Steve Nesbitt

CANADA

The southern prairies of Canada experienced a colder than normal spring with monthly mean temperatures about 4 degrees cooler than normal. Along with the cool temperatures, there were several late snow storms to add to the lateness of the spring. Whooping Cranes migrated into Canada around their normal time, during the last 10 days of April and into May. The cranes moved through the southern prairies and were held up by the cold and snow at the southern edge of the boreal forest in Saskatchewan during the first week of May. When they arrived on the breeding grounds they were greeted with snow and nesting ponds that were still frozen to the bottom.  Nest initiation was delayed and a few pairs did not nest. The good news is that water conditions throughout the breeding grounds are very high, with all ponds full. The Canadian Wildlife Service conducted breeding pair surveys from May 18 - 23 and discovered 48 nesting pairs.  Several other pairs were also on their territories but had yet to nest.

Brian Johns, Saskatoon, Saskatchewan 

GREAT LAKES

For the first time on record, several thousand sandhill cranes overwintered at Jasper-Pulaski Fish and Wildlife Area (J-P) in northwestern Indiana.  Mild temperatures and no snow cover persisted for most of winter 2001-02, and the lowest winter estimate was 10,000 cranes. J-P is the major fall migration stopover for the eastern greater sandhill crane flock. An estimated 10,000-12,000 individuals were present through mid-January when some southbound migration apparently occurred. Some of these cranes apparently went only as far south as Hiwassee Wildlife Refuge in southeastern Tennessee before returning to J-P 2-3 weeks later.  Approximately 10,000 birds were present on Hiwassee until late January.

Richard P. Urbanek, Necedah, Wisconsin

 ARANSAS

The peak population of whooping cranes in the Aransas/Wood Buffalo flock during the 2001-02 winter equaled 161 white-plumaged birds and 15 juveniles totaling 176 cranes.  This was a decline from the 180 cranes in the 2000-2001 winter and the record peak of 188 in the 1999-2000 winter.  With the addition of 15 young that arrived at Aransas in the fall, the flock could have grown from the 174 cranes present in the spring, 2001 and reached a maximum of 189 whoopers.  Thus, the peak population of 176 represents a loss of 13 cranes (7.5 % of the spring, 2001 population).  An estimated one adult and one juvenile died during the winter, and one adult female died hitting a power line in Comanche County, Texas during the spring migration, leaving 173 cranes in spring, 2002.  The population decline the past two years was anticipated from the unexplained 10-year cycle in the population that has always declined right after the turn of a decade.  If the pattern from the past 60 years continues, the population should increase through the rest of the current decade.

The flock consisted of 136 adults (68 pairs or potential pairs), 25 subadults, and 15 juveniles.  Adult cranes and/or potential pairs occupied 68 territories and/or use areas, 9 more than last winter.  Twenty-eight cranes were color marked, representing 15.9% of the population.

Food resources were much improved in 2001-02 compared with the previous winter.  Blue crabs were abundant in the fall and available to a lesser degree the rest of the winter.  Wolfberries were available for the cranes in November and December.  Use of clams and/or invertebrates such as mudshrimp or bloodworms in open bay habitat was observed January to March.  Some acorns were available on prescribed burns from an average mast crop.  Refuge burns received moderate use initially, but crane visits quickly tapered off as the cranes preferred to eat crabs.  Salinities were moderate throughout the winter, with only a small number of crane visits to freshwater sources observed on aerial census flights in the spring as bay and marsh salinities reached 22+ parts per thousand.  With food resources adequate and salinities not too high, the cranes remained predictably in salt marsh areas throughout the winter, making it easier to do an accurate census.

In the spring, 2002, departures from Aransas were about average.  Approximately 82 percent of the cranes departed between April 4 and 18, and all cranes had migrated by May 2.  Mr. Wally Jobman, USFWS in Grand Island, Nebraska, reported the following;

The first dates for confirmed observations of migrating whooping cranes were March 19 in the U.S. and April 17 in Canada.  The last sighting date was May 12.  With the exception of an early migrant confirmed in Nebraska on March 19th (a single bird on the Platte River), all of the sightings in the U.S. were reported between April 4 and May 7.  The migration progressed quickly, probably the reason that only 16 sightings were confirmed in the U.S.  Spring sightings were reported from Texas (1); Nebraska (3); South Dakota (2); North Dakota (10); Alberta, Canada (1); and Saskatchewan, Canada (20).

Tom Stehn, Aransas, Texas and Wally Jobman, Grand Island, Nebraska

Wintering and Spring Migration of the First Cohort of Migratory Whooping Cranes Reintroduced into Eastern North America

Seven juvenile whooping cranes were released into a remote, open-topped  pen on Chassahowitzka National Wildlife Refuge (NWR) on the central Gulf  Coast of Florida in Fall 2001. Six of these birds were led by Operation Migration ultralight aircraft from Necedah NWR in central Wisconsin and reached Chassahowitzka NWR on 5 December. Another bird, transported in a box by truck during migration, had been released at Chassahowitzka NWR the previous day. This latter bird was killed by a bobcat on 17 December.  After another bird was killed on the night of 9 January, more rigorous overnight protection measures (i.e., making sure the birds roosted either within the predator-proofed pen or in water more than 20 feet from shore) were implemented, and no further mortalities occurred.

The five remaining cranes began migration as a single flock on 9 April and flew to Wilcox County in southcentral Georgia. After being grounded for  2 days with rain, they made a short flight to Henry County, Georgia, just south of Atlanta on 12 April. After another day of rain, they resumed migration on 14 April, when a female (no. 7) separated in flight from the other four birds over northern Georgia. She landed in McMinn County, southeastern Tennessee, while the main group of four proceeded to Fentress County, northeastern Tennessee. The group of four flew on 4 of 5 more days with stops in Johnson County, southcentral Indiana, Cook County (Chicago Metro Area), Illinois, and Dodge County, southeastern Wisconsin, before landing at Necedah NWR on 19 April. The entire migration had taken the group 11 days, of which 7 were flight days. The route was roughly direct; distance covered per flight day varied from 93 to 238 miles; mean = 170 miles. Meanwhile, through 18 April crane no. 7 stopped in northcentral Kentucky (exact location unknown) and Jasper County, northwestern Indiana, before landing in Rock County, southcentral Wisconsin. She remained at the latter location until 30 April when she flew to Crawford County in southwestern Wisconsin and then flew into Necedah NWR on 3 May.

The whooping cranes, like previously released experimental sandhill cranes led on fall migration by ultralight aircraft, have continued to move to other locations in Wisconsin, generally south and east of Necedah NWR, during spring 2002.

Richard P. Urbanek, U.S. Fish and Wildlife Service and International Crane Foundation, and Marianne Wellington, Sara Zimorski, Anne Lacy, and Matt Hayes, International Crane Foundation, on behalf of Whooping Crane Eastern Partnership.

West Coast Sandhill Crane Study

Gary L. Ivey, Thomas J. Hoffmann, and Caroline P. Herziger.

In November 2001, the West Coast Crane Working Group initiated a pilot project using satellite telemetry to track movements of sandhill cranes (Grus canadensis) from Ridgefield National Wildlife Refuge (NWR) in southwest Washington and Sauvie Island Wildlife Area (WA), just across the Columbia River in Oregon, to other staging and wintering areas, as well as nesting grounds.  Sandhill cranes use Ridgefield NWR, Sauvie Island WA, and surrounding farm lands. This region serves both as a staging and wintering area, but the nesting locations and migratory routes to nesting areas and other migrating and wintering sites are unknown. It has been assumed that all three subspecies of cranes use this area, however, there is a degree of uncertainty about the subspecies composition of these flocks. Therefore, in order to determine subspecies, breeding areas, migratory paths, and other wintering areas, we initiated this study using satellite transmitters.

Six of the 8 cranes captured were marked with transmiters; 2 others only received colored bands for visual identification. Four each were captured at Ridgefield NWR and Sauvie Island WA. We tracked the movements of the birds via satellite technology, and documented their spring migration routes and destinations. Based on the data we obtained, it appears that the birds move down the Columbia River, follow the Washington coast northward, cross Cape Flattery, across Vancouver Island, and up the coast of British Columbia (BC). One of the birds stopped in southern Alaska, while the other 5 ended their journeys along the coast of northern and central BC.

Initially, the study focus was to be on the lesser subspecies, however, all the birds trapped and those carefully observed in the area did not appear to be lessers, therefore, past theories about lesser sandhill cranes are now in question. Perhaps lessers do use the area during early fall migration, but none were identified during late fall or spring. No greater sandhill cranes were observed using the region either. We believe that the cranes in this study were those that have been morphologically described as Canadian sandhill cranes (G. c. rowani). Measurements of cranes captured were mostly within the range of the Canadian subspecies (Johnson and Stewart 1973, Schmidt and Hale 1997), and the head shape was that of Canadians. The fact that these cranes migrated to the British Columbia and southern Alaska coasts also supports the conclusion that they are Canadians. According to Campbell et al. (1990), about 1,500 Canadian sandhill cranes nest along the B.C. coast.

This study was sponsored by the West Coast Crane Working Group, in partnership with Ridgefield National Wildlife Refuge (U.S. Fish and Wildlife Service) and Sauvie Island Wildlife Area (Oregon Department of Fish and Wildlife), with funding contributed by the Paul L. King Charitable Foundation, the Foley/Frischkorn Wildlife and Conservation Fund, and the Chevron Research and Technology Company.

For additional details, see: http://www.geocities.com/wccwg/Research/PTT051602/PTTstudy.htm

Sources cited:

Campbell, R. W., N. K. Dawe, E. McTaggart-Cowan, J. M. Cooper, G. W. Kaiser, and M. C. E. McNall. 1990. The birds of British Columbia. Royal British Columbia Museum, Victoria, B.C.

Johnson, D. H., and R. E. Stewart. 1973. Racial composition of migrant populations of Sandhill Cranes in the northern plain states. Wilson Bulletin 85:148-162.

Schmidt, G. C., and B. Hale. 1997. Sandhill Crane hunts in the Rio Grande Valley and southwest New Mexico. Proceedings North American Crane Workshop 7:219-231.

The West Coast Crane Working Group’s website is at  www.geocities.com/wccwg

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Editor’s Note:  The Unison Call is a forum to share updates and opinions.  The articles in the “Notes from the Field” section are scientific updates and are not peer reviewed.  Reviews and opinions included in any section of the newsletter are those of the author and do not represent the views of the NACWG.

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