Whooping Crane Conservation Association

Tom Stehn, Aransas National Wildlife Refuge completed the first 2009 fall whooping crane census recently. Tom reports, “The first aerial census of the 2009-10 whooping crane season was conducted 12 November, 2009 in a Cessna 210 piloted by Gary Ritchey of Air Transit Solutions of Castroville, Texas with USFWS observer Tom Stehn.

Weather conditions were ideal during the 4-hour flight with sunshine and light east winds. Sighted were 87 adults and 4 juveniles = 91 total. Based on August fledging surveys done on the nesting grounds by CWS, I am expecting up to 22 juveniles. With that number of juvenile produced, the flock may experience a break-even year with a flock total around 247 expected.”

November 12th – Recap of cranes (91) found at Aransas on the aerial:
[TABLE=4]

Migration Update: The first whooping crane arrival at Aransas was reported the morning of October 17th by refuge staff going over to Matagorda Island that saw a pair. This sighting was just one day after the average first whooping crane arrival date of October 16th. A cold front that reached Aransas early on 10/16 brought great migration conditions through 10/17 that aided the arrival of the first migrants. The next strong cold front at Aransas on the afternoon of 10/26 brought multiple reports of sandhill cranes moving through Texas and I had my first sighting of 125 sandhills in the farm fields north of the refuge on November 27th. A cold front October 30th brought favorable migration conditions lasting through November 5th. The next front on November 9th brought favorable migration conditions through November 12th.

Minimum # of Cranes
[TABLE=5]

From this and weather records, it appears that a low number of whooping cranes reached Aransas in the second half of October and the first week in November, but quite a few cranes arrived between November 7-12. These later than average arrivals were simply due to birds not moving down the flyway. The migration appears to be about a week later this year than average. Last year, we flew on November 14th and tallied 239 cranes, quite
a difference from the 91 counted on today’s flight. Numerous whooping cranes have been reported November 2-11 in Kansas and Oklahoma, including 39 at Quivira NWR in central Kansas on November 10. Quivira at one point had 36 cranes together, a record flock size for whooping cranes in migration. A flock of 32 was seen the following day by Salt Plains NWR in Oklahoma. The next strong pacific cold front is forecast to reach Aransas on November 16th, which I think will allow a large number of additional whooping cranes to reach Aransas.

Habitat Use: Tides were an estimated 1 foot above what I consider to be high water levels for the crane area. The high water levels were a result of Hurricane Ida that crossed the Gulf and reached Alabama as a tropical storm on November 10th. Ida raised tides 2.5 feet along the central Texas beaches. The cranes responded to the high water by being mostly in vegetated marsh, with 19 cranes on uplands next to the marsh. The distribution seen on today’s flight looked like the cranes were mostly responding to wolfberries that seems to have had a good crop this year.

Not a single commercial blue crab trap was seen in the crane area, including in the shallow bays edges next to the crane marshes. This is unusual and indicative of the poor harvest that has been ongoing all summer caused by the drought and insufficient inflows reaching the crane area.

Marsh salinities are approximately 24 ppt and continue above the threshold when whooping cranes must seek out fresh water to drink. Two cranes were observed on today’s flight at a fresh water dugout. Two cranes were observed at a private game feeder. The largest group size observed was 5 birds seen on a high salt prairie at Welder Flats.

– Tom Stehn, Aransas National Wildlife Refuge

Tom Stehn, Whooping Crane Coordinator,U.S. Fish and Wildlife Service has prepared a lengthy, detailed report concerning the 2008 – 2009 whooping crane population. The following summary of the report provides much new information. To read the entire report, you may download it by clicking here. The download is a PDF file.

The Aransas-Wood Buffalo population (AWBP) of whooping cranes reached a record population of 270 at Aransas in December, 2008. The number would have been substantially higher but for the loss of 34 birds that left Aransas in the spring, 2008 and failed to return in the fall. Faced with food shortages from an “exceptional” drought that hammered Texas, record high mortality during the 2008-09 winter of 23 cranes (8.5% of the flock) left the AWBP at 247 in the spring, 2009. Total flock mortality for the 12 months following April, 2008 equaled 57 birds (21.4% of the flock). The refuge provided supplemental feed during the 2008-09 winter to provide some cranes with additional calories. Two whooping cranes failed to migrate north, but survived the hot and dry 2009 Aransas summer.

A below-average 2009 production year in Canada with 22 fledged chicks from 62 nests was half the production of the previous summer and is expected to result in a break-even year for the AWBP. Threats to the flock including land and water development in Texas, the spread of black mangrove on the wintering grounds, and wind farm construction in the migration corridor all remained unabated in 2009.

The Cooperative Whooping Crane Tracking Project documented 79 confirmed sightings of whooping cranes in the U.S. Central Flyway during fall, 2008 and 38 sightings in spring, 2009.

The captive flocks had a very good production season in 2009. Twenty-nine chicks were reintroduced into the eastern migratory population, bringing that flock to 106 total birds. Three chicks of high genetic value were held back for the captive flocks.

Production in the wild from reintroduced flocks in 2009 was disappointing. In Florida because of the continuing drought, only 4 of 11 pairs nested and fledged 1 chick. In Wisconsin, all 12 nesting pairs abandoned their nests. Five or 6 pairs re-nested hatching 2 chicks, but neither chick survived. The major hurdle of nest abandonment in Wisconsin must be overcome for that reintroduction to have a chance of success. Although efforts to clear this hurdle should continue, the Recovery Team recommended starting reintroductions in different areas, both looking for other release sites in Wisconsin for the migratory whooping cranes, and starting a nonmigratory flock in Louisiana.

In 2009, total production could not quite keep up with mortality, with the total population of wild and captive birds dropping from 538 to 534 during a12-month period. The drop was primarily due to the high mortality experienced by the AWBP.

The first migrating whooping crane was sighted in North Dakota last week (Sept 24). It departed the Wood Buffalo nesting grounds in Canada recently. The crane is now on its 2,400 mile journey to Aransas National Wildlife Refuge in Texas. We hope that all the whoopers have a safe migration because of the unusually high mortality in the flock this past year. And hopefully the recent rains in Texas have had a beneficial impact on whooping crane winter habitat.

Lea Craig-Moore, Canadian Wildlife Service reports that, ” The June chick surveys were conducted June 16-20 in Wood Buffalo National park by Jim Bredy and Tom Stehn from the US Fish and Wildlife Service and Lea Craig-Moore from the Canadian Wildlife Service. A total of 52 chicks were seen from 62 nests (61 nests had been found in May, and one additional family was found in June). Two chicks were seen at ten nests, one chick at 32 nests and 18 nests had no young. Two nests were still being incubated on the last day of surveys. This year’s June production is 0.84 chicks per nest which is on target with the long term average of 0.8 chicks/nest.”

Lea also advised that, “Water conditions were excellent in May but have dropped over the month due to negligible precipitation. August surveys are scheduled to begin about the 18th.”

I flew for 2.3 hours on June 30th and did NOT find any whooping cranes at Aransas.

Surveys done June 16-20 in Wood Buffalo National Park documented 52 chicks, including 10 sets of twins, hatching from the 62 nests.

During the last census report from Aransas National Refuge in Texas, several
whooping cranes were still there. Tom Stehn, Whooping Crane Coordinator,U.S. Fish
and Wildlife Service recently reported that, “I flew for 2.3 hours on June 30th
and did NOT find any whooping cranes at
Aransas.”

Tom Stehn, Whooping Crane Coordinator reports that, “ Four whooping cranes were seen by experienced staff this afternoon (May 28, 09) at Aransas NWR along the Intracoastal Canal that runs through the Aransas National Wildlife Refuge. The cranes were grouped as a duo, and then about 5 miles away were two singles separated by 100+ yards. I presume all 4 are subadults.”

Tom adds that, “I have not done a census flight since April 21st , and probably will not do so until July to see if these 4 decide to spend the summer and whether any others are still around. These 4 cranes could still migrate, but they also could spend the summer at Aransas.”

Brian Johns, Wildlife Biologist, Canadian Wildlife Service sends a brief report on the most recent events concerning the Aransas-Wood Buffalo whooping crane flock, the Wisconsin-Florida migratory experimental flock and the Florida non-migratory experimental flock.

Aransas/Wood Buffalo flock:
Brian reports that, “Some whoopers that departed their Aransas, Texas wintering habitat have migrated to Canada while others continue on their way. The cranes are in the process of completing their migration to Wood Buffalo. There have been fewer sightings in Canada this spring compared to other years, which may mean that the birds have had good migration conditions and have moved on through or that there are still a few birds to come. Habitat conditions on the breeding grounds appear to be near normal and Lea Craig-Moore will begin nesting surveys in about 10 days.”

Wisconsin/Florida:
Brian advised that, “Twelve nests were initiated this spring in Wisconsin and as of May 3 all nests had failed.”

Florida:
Biologist Johns wrote that, “Three nests were initiated by whoopers in Florida’s non-migratory flock. One nest failed, one is being incubated and one has a 46 day old chick.”

The eleventh aerial census of the 2008-09 crane season at Aransas was conducted April 21, 2009 with USFWS observer Tom Stehn in a Cessna 210 piloted by Gary Ritchey of Air Transit Solutions of Castroville, Texas. Viewing conditions were ideal with clear skies and moderate winds. Nearly all parts of the crane range were flown.

Migration
Today’s flight tallied 20 adults plus 1 juvenile = 21 total. BLACKJACK! Thirteen of the cranes were located on the BLACKJACK Peninsula (Aransas NWR), 6 were on Matagorda Island, and 2 at Welder Flats. Thus, 91.5% of the flock has started the migration (226 birds out of 247), including all known adult pairs. Eighty-eight cranes have started the migration since the last flight on April 7th when 109 cranes were estimated present. Whooping cranes in migration have recently been reported as far north as Saskatchewan. Some cranes not tallied above presumably headed north today since conditions were very good for migration with sunny skies and mostly southwest and south winds after several days of unfavorable migration weather.

Eight of the 21 cranes located on today’s flight were singles. The one juvenile present was closely associated in a group with 3 white-plumaged cranes, the largest group observed on today’s flight. The juvenile’s parents have presumably started the migration and left “junior” behind. This juvenile crane will be fine and has the knowledge to make the return migration to Wood Buffalo National Park on its own or with other subadult cranes.

Whooping Crane Numbers
With estimated losses that have occurred at Aransas this winter, the current flock size is estimated at 225 adults + 22 juveniles = 247. The estimated peak winter flock size was 232 adults + 38 juveniles = 270 total.

Habitat use
For the first time all winter, all the whooping cranes on today’s flight were found in salt marsh. The cranes are believed to be feeding on fiddler crabs since blue crabs in the marsh ponds are still scarce due to the continuing drought. A blue crab count done on April 1st found zero crabs in the marsh. The refuge has discontinued its program of supplemental feeding with corn since most of the cranes have migrated.

A lightning-caused wildfire that started April 18th on Matagorda Island burned approximately 10,000+ acres of upland prairie lands. The fire, located between Pringle Lake and Power Lake, was contained on April 20th and allowed to burn out. The burn will benefit the prairie habitat by recycling nutrients and controlling brush.
– By Tom Stehn – Aransas National Wildlife Refuge

The tenth aerial census of the 2008-09 crane season at Aransas was conducted April 7, 2009 with USFWS observer Tom Stehn in a Cessna 210 piloted by Gary Ritchey of Air Transit Solutions of Castroville, Texas. Viewing conditions were ideal with clear skies and light winds, although turbulence made the ride uncomfortable most of the time. Nearly all parts of the crane range were flown.

Migraton
Today’s flight tallied 103 adults + 6 juveniles = 109 total. Thus, 56% of the flock has started the migration. Whooping cranes have been confirmed on April 2nd as far north as Nebraska. I expect a considerable number of cranes will start the migration in the next week. Conditions should be ideal for departure with very strong southeast winds forecast for Aransas April 8-9.

Whooping Crane Numbers
With estimated losses that have occurred at Aransas this winter, the current flock size is estimated at 225 adults + 22 juveniles = 247. The estimated peak winter flock size was 232 adults + 38 juveniles = 270 total.

Mortality
Today’s flight provided evidence of 2 additional mortalities, with total winter mortality now estimated for the winter at 7 adults and 16 chicks totaling 23 whooping cranes, a loss of 8.5% of the flock that was a record 270 in the fall. In the last 20 years, the current winter ranks as the worst in terms of mortality, ahead of 1990 when 7.5% of the whooping cranes (11 out of 146) died at Aransas. The 3rd worst winter in 1993 showed a 4.9% loss at Aransas (7 out of 143). Mortality in the 2008-09 winter (23 birds) can be added to the 34 whooping cranes that left Aransas in the spring of 2008 and failed to return in the fall. Thus, 57 whooping cranes have died in the last 12 months, or 21.4% of the flock of 266 present at Aransas in the spring, 2008.

The 2 additional mortalities confirmed on today’s flight that had been reported earlier by volunteers and staff are as follows:

Tour Boat Naturalist Ray Kirkwood had seen March 19-29 the Rattlesnake Island juvenile with a very bad limp, using its wings when it moved to try to reduce the weight put on its injured leg. The bird retained flight ability but was lethargic and may have stopped eating. The chick was not observed on April 1st when I looked for it from a boat and had presumably died. The pair believed to be its parents was observed on their territory on today’s flight with no sign of the juvenile.

The second mortality involved a grouping of 1 adult with 1 chick observed twice about 4 hours apart on April 1st in the marsh west of the airstrip on the south end of Matagorda Island. This same grouping of 1+1 was observed on their East Bray territory on today’s flight, providing confirmation that one adult has died.

Sightings near Aransas
Three whooping crane subadults that used the farm fields south of Austwell for much of the winter were last reported present on March 14th. They have either returned to the salt marsh or have started the migration.

Habitat use
For the first time all winter, nearly all the whooping cranes were found in the salt marsh on today’s flight. The cranes are believed to be feeding on fiddler crabs since blue crabs in the marsh ponds are still scarce due to the continuing drought. A blue crab count done on April 1st found zero crabs in the marsh.

Whooping crane locations on the flight included 2 observed at man-made fresh water sources, 2 at a game feeder, and 9 in open bay habitat. No cranes were on burned or unburned uplands. Tides were low caused by a very strong “norther” that had brought northwest winds on April 6th. Salinities remain high, measured recently at 29 ppt in the refuge boat canal and 39 in the adjacent marsh. One monitoring station in San Antonio Bay has a salinity of 25 ppt. The drought rated as “exceptional” shows no sign of ending in central and south Texas. Many counties have imposed prescribed burn bans due to the fire danger. Corpus Christi, Texas is 4.5 inches below normal rainfall starting January 1st.

Overall, these continue to be some of the worst conditions I have ever observed for the cranes at Aransas, with some birds looking thin and with disheveled plumage. The refuge is continuing its program of supplemental feeding with corn. A moderate response by the whooping cranes has continued. The cranes are getting somewhat of an energy boost by catching fiddler crabs just prior to migration.
– By Tom Stehn – Aransas National Wildlife Refuge

The ninth aerial census of the 2008-09 crane season at Aransas was conducted March 15, 2009 with USFWS observer Tom Stehn in a Cessna 210 piloted by Gary Ritchey of Air Transit Solutions of Castroville, Texas. Viewing conditions were less than ideal with overcast skies and occasional light rain. Parts of the crane range were not flown as rain and lightning ended the flight after 3.7 hours.

Whooping Crane Numbers
With estimated losses that has occurred at Aransas this winter, the current flock size is estimated at 226 adults + 23 juveniles = 249. The estimated peak winter flock size was 232 adults + 38 juveniles = 270 total.

Mortality
Today’s flight provided evidence of 3 additional mortalities, with total winter mortality now estimated for the winter at 6 adults and 15 chicks totaling 21 whooping cranes, a loss of 7.8% of the flock that was a record 270 in the fall. In the last 20 years, the current winter ranks as the worst in terms of mortality, ahead of 1990 when 7.5% of the whooping cranes (11 out of 146) died at Aransas. The 3rd worst winter in 1993 showed a 4.9% loss at Aransas (7 out of 143). Mortality in the 2008-09 winter (21 birds) can be added to the 34 whooping cranes that left Aransas in the spring of 2008 and failed to return in the fall. Thus, 55 whooping cranes have died in the last 12 months, or 20.7% of the flock of 266 present at Aransas in the spring, 2008.

Four dead whooping cranes have been picked up this winter; at least two were emaciated, and the virus IBD (infectious bursal disease) has been isolated from one of the juveniles by Dr. Hon Ip at the National Wildlife Health Center in Madison, Wisconsin. It is not yet known if this strain of IBD is pathogenic to whooping cranes, but it seems probable. The 4th carcass discovered this winter was an old pile of white-plumaged feathers discovered March 2nd during a blue crab count conducted by volunteer Katherine Cullen and two Chinese biologists. The two Chinese that have cranes on their refuges in China expertly identified the feathers. On today’s flight, observations confirmed that one additional adult is missing leaving a one-adult family just south of Panther Point on Matagorda. Also, the refuge’s Pipeline and Matagorda’s Airport juveniles are missing and listed as dead. These last 3 mortalities had presumably all occurred prior to the February 25th flight, with observations on today’s flight confirming the losses.

Migration
One juvenile whooping crane was confirmed on the Platte River in Nebraska on February 20th. This is presumably the juvenile that had over-wintered in Oklahoma and probably moved north with sandhill cranes. It was still present on the Platte through March 9 and presumably is still there.

I have been asked how the current poor conditions of the cranes may affect the migration. I have no idea how that may affect the timing of the migration which seems to vary by only about one week from year to year. Low numbers of whooping cranes start leaving Aransas the last week in March, with the majority of the cranes departing the first 2 weeks in April. The last of the breeding pairs have all gone by April 21st; a few subadults occasionally stay into May. I expect the migration to proceed normally, with birds making it all the way to Wood Buffalo National Park in Canada. However, mortality in the migration could increase. My next census flight is scheduled for the week of April 6th to see how the migration is progressing.

Sightings near Aransas
Three whooping crane subadults continue to use farm fields south of Austwell. They were seen in a pond next to an agricultural field on March 12th, but were not searched for on today’s flight due to lack of time.

Habitat use
Management practices are aiding the cranes this winter. Crane locations on the flight included 7 observed at man-made fresh water sources, 17 on burned uplands, 33 on unburned uplands mostly foraging for tubers where feral hogs have rooted up the earth, 4 at game feeders, 1 on a well pad, and 23 in open bay habitat. Two cranes were on a recent burn on Matagorda Island conducted March 10th. Tides have risen somewhat since the previous flight on February 25th. Salinities remain high, measured recently at 30 ppt in the refuge boat canal. The drought rated as “exceptional” shows no sign of ending in central and south Texas. Many counties have imposed prescribed burn bans due to the fire danger. However, rain received in south Texas on March 14-15 has helped a little.

Blue crabs are still scarce due to the drought. These are the worst conditions I have ever observed for the cranes at Aransas, with some birds looking thin and with disheveled plumage. I wish I had better news to report. The refuge is continuing its program of supplemental feeding with corn. A moderate response by the whooping cranes has been observed with 76 photographs taken by remote motion-activated cameras in the past week of whooping cranes at refuge feeders. Other animals eating the corn include feral hogs, deer, raccoons, grackles and just a few remaining wintering sandhill cranes.

The USFWS used 2 airboats the week of February 23rd to pick up 411 abandoned crab traps in the crane area. This was done in conjunction with a program organized by Texas Parks and Wildlife Department to pick up abandoned traps all along the Texas coast. Waters within the boundary of Matagorda Island National Wildlife Refuge have recently been closed permanently to commercial crabbing with signs posted at most entrances into the marsh.
– By Tom Stehn – Aransas National Wildlife Refuge

By Anton Caputo – Express-News

The severe drought gripping Texas is turning a promising year for the endangered whooping crane into the second-deadliest on record.

Eighteen of the majestic birds have died in their winter home on the coast this season, likely because of food and water shortages caused by the record drought, Aransas National Wildlife Refuge Manager Dan Alonso said.

The 18 birds represent almost 7 percent of the flock’s population this season. The highest mortality rate on record was 1990 when 7.5 percent of the flock died while wintering in Texas.

The desperate situation has prompted wildlife biologists to break a “wildlife management taboo” and put out corn and water to help the birds make it through the winter.

The U.S. Fish and Wildlife Service also is making efforts to more stringently enforce its no-crabbing rules within the 115,000-acre confines of the refuge. That’s an attempt to save the dwindling population of blue crabs for the whooping cranes.

“That is what we are presently doing to help the whooping crane get back on their feet or at least keep any more from dying,” Alonso said.

The cranes will migrate within the next month on their 2,400-mile journey to their summer home in Wood Buffalo National Park in Canada.

Standing 5 feet tall, the whooping crane is one of the most iconic and endangered birds in the world.

Habitat loss and hunting nearly wiped out the species in the past century. The number of cranes dipped to as low as 15 in 1945and the crane was declared endangered in 1970.

But a concerted effort to bring back the birds has been successful. Last year, there were 500 whooping cranes in North America for the first time in a century. And the Texas flock, which is the last wild migratory flock in the world, hit a record 270 this season before the die-off.

Most agree that the record-setting drought afflicting Texas is behind this year’s high mortality. But one dead bird also tested positive for a virus that has been detected in a captive whooping crane flock in Florida. It’s the first time the virus has appeared in the wild Texas flock.

“They are running a number of tests to determine what else might be present,” Alonso said. “There could be other issues out there that we are not aware of.”

Many have pointed directly to the drought’s impact on the state’s blue crab population as a likely cause of the strain on the whooping crane flock. Alonso said many of the areas surveyed in the refuge that typically contain blue crab were devoid of the critters this year. Blue crabs, which can make up as much as 85 percent of the bird’s diet, require a freshwater inflow in the coastal estuaries for a healthy habitat.

Norman Boyd of the Texas Parks and Wildlife Department said blue crab numbers have been running low in the Guadalupe estuary since the mid 1990s, and he cautioned against blaming the current lack of fresh water solely on the downfall of the whooping crane’s favorite food. The state is investigating a number of possible causes, he said, and over-fishing may be one of them.

“Make no mistake, freshwater inflows are very important to crabs, but it’s hard to pin down a one-to-one relationship in our crab catch rate and freshwater inflows,” Boyd said. “Our catch rate has dropped off during the past decade and we’ve had wet years since then and we don’t see the crab population spiking during those wet years.”
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