
By Tom Stehn, USFWS Whooping Crane coordinator
January 21, 2010
The fifth aerial census of the 2009-10 whooping crane season was conducted January 21, 2010 in a Cessna 210 piloted by Gary Ritchey of Air Transit Solutions of Castroville, Texas with USFWS observer Tom Stehn. Sighted on the flight were 235 adults and 18 juveniles = 253 total whooping cranes. This was 10 birds less than the last flight conducted 1-05-10. However, flight time was limited by fog that did not burn off until 10:30 AM, so some cranes were presumably overlooked, as search time had to be condensed. More telling than the total number of cranes tallied was the distribution observed that seemed to confirm the estimated flock size. However, it definitely appears that one juvenile has died since arriving at Aransas. This juvenile had been found in the refuge’s South Sundown Island territory. On today’s flight, a pair believed to be the S. Sundown Island pair was seen very close to their territorial neighbors to the south. It seemed clear that I was looking at adjacent territorial pairs, and that the S. Sundown Island pair was missing its chick. It is also possible that the Dewberry Island pair at Welder’s Flats has lost their chick, but it is also possible they had moved over to the refuge’s Power Lake on Matagorda Island where there was an unexpected family.
The territories of adult cranes remain difficult to figure out as many of the crane pairs have left their marsh and are searching for food on the uplands. On today’s flight, an unusually high 52 cranes were on unburned uplands, 4 were on the C14 refuge burn, 13 were in open bays, two were at a game feeder south of the Big Tree on Lamar, and 182 (72%) were in salt marsh. Blue crabs are at extremely low levels and the cranes are having to look for other sources of food. This is a very stressful time of winter for the whooping cranes. One additional juvenile that apparently separated from its parents during migration was sighted near Medford, Oklahoma December 14-25 has not been re-sighted but is presumably doing okay in an unknown location.
The flock size is currently estimated at 244 adults + 19 juveniles = 263.
January 21st - Recap of whooping cranes (253) found at Aransas:
Adults + Young
San Jose 58 + 4 = 62
Refuge 53 + 5 = 58
Lamar 16 + 1 = 17
Matagorda 84 + 6 = 90
Welder Flats 22 + 2 = 24
Hynes Bay 2 + 0 = 2
Total 235 + 18 = 253*
* The presence of one chick last seen in Oklahoma makes the current estimated flock size 263, including 19 chicks. One chick has died since arriving at Aransas.
One whooping crane was sighted on 1/17/10 by a TPWD biologist on the Smith Marsh in Matagorda County. The Smith Marsh is private property just to the west of the Nature Conservancy's Mad Island Marsh Preserve a considerable ways up the coast from Aransas.
Flight Conditions: Visibility was excellent throughout the flight, though the sun angle on late afternoon transects made for difficult viewing conditions when heading into the sun. Winds were light and flight conditions were smooth, enabling us to travel at approximately 130 knots for most of the flight. Due to reported crane movements, the search area was expanded much further out into upland areas. However, only three additional cranes were found in the uplands at Welder Flats, whereas 12 had been located there the previous week. This difference seemed to account for the 10 fewer cranes found on today’s flight compared to the previous flight. In addition, no cranes were found at the refuge’s Burgentine Lake, whereas seven had been present on the previous flight. The largest group size observed was seven birds seen on the uplands on San Jose and in the marsh on Matagorda Island.
Tom Stehn, Aransas National Wildlife Refuge
January 5, 2010
The fourth aerial census of the 2009-10 whooping crane season was conducted January 5, 2010 in a Cessna 210 piloted by Gary Ritchey of Air Transit Solutions of Castroville, Texas with USFWS observer Tom Stehn. Sighted on the flight were 244 adults and 19 juveniles = 263 total. This was an increase of 19 cranes since the previous flight conducted December 10th when some birds had still been in migration and 244 cranes were accounted for. One additional juvenile separated from its parents was sighted near Medford, Oklahoma December 14-25 which brings the current estimated flock size to 264. In addition, the South Sundown Island chick known to be at Aransas was not found on today’s flight, so one chick can be added to the peak flock size for the 2009-10 winter (244+21=265). It is not known if the entire South Sundown Island family group was overlooked on today’s flight, or possibly the chick has died and its parents were sighted off of their territory but not identified as such during the flight.
January 5th - Recap of whooping cranes (264) found at Aransas and Oklahoma:
Adults + Young
San Jose 57 + 4 = 61
Refuge 59 + 6 = 65
Lamar 12 + 1 = 13
Matagorda 87 + 5 = 92
Welder Flats 27 + 3 = 30
Hynes Bay 2 + 0 = 2
Oklahoma 0 + 1 = 1*
Total 244 + 20 = 264*
* The presence of one chick last seen in Oklahoma makes the current estimated flock size 264, including 20 chicks.
The discovery of 19 additional cranes is really good news. If cranes moved around during the flight, I am concerned that perhaps this tally is artificially high by a few birds due to double counting them. Future census flights will attempt to pin this down. The current estimated flock size of 264 is surprisingly high but indicates that survival between spring and fall, 2009 was excellent. The 21 wintering chicks that successfully migrated out of the 22 fledged in Canada added to the estimated flock size of 247 in spring, 2009 meant that a maximum of 268 cranes could have arrived at Aransas this fall. One crane seen injured in Saskatchewan in the fall migration is believed to have perished. The fact that we are accounting for 265 out of the potential 267 is excellent news.
Migration Update: The solitary whooping crane near Medford, Oklahoma was last seen Christmas Day. It apparently has moved further south. Four cranes in the second week in December west of Mad Island Preserve in Matagorda County Texas about 40 miles northeast of Aransas have moved on and presumably were seen on today’s census flight. Two cranes that have been staying east of Tivoli about 15 miles north of Aransas were re-located on today’s flight in the Hynes Bay Unit of the Guadalupe Delta Wildlife Management Area operated by Texas Parks and Wildlife.
Habitat Use and Food Resources: Tides have lowered somewhat with about 30% of the mud flats dry on San Jose Island. However, few observations have been made this winter of cranes feeding in open bay habitat, and only 6 cranes were in open bay habitat on today’s flight. Salinities in San Antonio Bay are currently 14 parts per thousand, low enough that the cranes are drinking directly from the salt marsh. On today’s flight, 65 cranes were located in unburned uplands, 10 were on refuge prescribed burns, 12 were at feeders on private lands, and 2 were on shell roads. The presence of so many cranes in the uplands and cranes traveling longer distances than usual into uplands is indicative of food scarcity. A crab count conducted December 18th found only 1 crab. No commercial crab traps were sighted on today’s flight, another indication that crab populations are at low levels. The cranes since Christmas have not been observed catching blue crabs, whereas before that, some crabs were still being taken. A few wolfberries were still available to the cranes the week before Christmas but have tapered off since then. With blue crabs in very short supply and the wolfberry crop finished for the year, the cranes are entering the period of the winter when food shortages sometimes occur and the cranes end up using up fat reserves to survive.
Flight Conditions: Visibility was excellent for most of the flight. Due to reported crane movements, the search area was expanded much further out into upland areas. This turned out to be very important in finding additional cranes. Eight cranes were found in an area rooted up by hogs in the former farm field enclosure across the refuge’s East Shore Road about 0.7 miles from the salt marsh. Twelve cranes were sighted at feeders at Welder Flats, 8 of them at a location that is rarely searched. Seven cranes were found northwest of the refuge’s Burgentine Lake where cranes had been reported back on December 10th. The largest group size observed was 8 birds seen both on the uplands on San Jose and at a game feeder at Welder Flats. Large groups seen in salt marsh included 7 birds on the south end of Matagorda Island and 6 on Lamar’s Cow Chip Bayou.
Tom Stehn, Aransas National Wildlife Refuge
December 10, 2009
The third aerial census of the 2009-10 whooping crane season was conducted December 10, 2009 in a Cessna 210 piloted by Gary Ritchey of Air Transit Solutions of Castroville, Texas with USFWS observer Tom Stehn. Sighted on the flight were 211 adults and 19 juveniles = 230 total. This was an increase of 20 cranes since the previous flight conducted December 2nd. With 230 at Aransas and 8 known to still be in migration, currently 238 whooping cranes can be accounted for. I am expecting up to 22 juveniles based on August fledging surveys done on the nesting grounds by CWS. With that number of juvenile produced, the flock may experience a break-even year with a flock total around 247 expected.
December 10th - Recap of whooping cranes (230) found at Aransas on the aerial:
|
|
Adults + Young
|
Increase from Dec. 2nd
|
|
San Jose |
49 + 4 = 53 |
12 |
|
Refuge |
58 + 6 = 64 |
1 |
|
Lamar |
10 + 1 = 11 |
0 |
|
Matagorda |
72 + 5* =77 |
3 |
|
Welder Flats |
20 + 3 = 23 |
4 |
|
Hynes Bay |
2 + 0 = 2 |
0 |
|
Total
|
211+ 19 = 230
|
20
|
* Since 6 family groups were present on Matagorda Island on the December 2nd flight, it is possible that one family group was overlooked on today’s flight. However, it is also possible a Matagorda Island family group from N. Power Lake had moved over to N. Shoalwater Bay where there was an additional family on today’s flight.
Migration Update: Cold fronts that reached Aransas on December 4th and 9th helped 20 additional cranes complete their 2,400-mile long migration. Additional cranes are known to still be in migration. Four were present at Quivira NWR on December 7th even though the marshes were about 90% frozen. Four were recently sighted west of Mad Island Preserve in Matagorda County Texas about 40 miles northeast of Aransas. Two cranes that have been staying east of Tivoli about 15 miles north of Aransas were located on today’s flight in the Hynes Bay Unit of the Guadalupe Delta Wildlife Management Area operated by Texas Parks and Wildlife.
Crane Identities: We are not sure if the Lobstick pair has returned this fall. However, 2 cranes that may have been the Lobsticks were sighted on the Lobstick territory on December 9 and 10. If present, the Lobstick male is 31 years old.
Habitat Use: Tides measured at the refuge boat ramp were high (2.7 feet). Salinities currently at 8 parts per thousand in San Antonio Bay have dropped noticeably in November and December so that the cranes are drinking directly from the marsh and have stopped making flights to fresh water dugouts. An extremely heavy rain event on November 20th with some coastal areas getting up to 16 inches has filled refuge dugouts and swales and flooded portions of the uplands on San Jose Island and Welder Flats. Conditions are very wet. Since that rain event, some blue crabs seem to have moved into the marshes, and some cranes have recently been observed catching blue crabs 2-3 inches in size. However, 65 cranes on today’s flight were sighted on uplands. These cranes were mostly foraging on patches of bare ground, some flooded and some dry. This behavior is indicative of a less than optimal food situation for the cranes. Although some wolfberry flowers are still present in the marshes, few berries are present and have stopped making up a significant part of the crane diet. An additional 5 cranes on today’s flight were on a shell road in the uplands. No cranes were at game feeders or in open bay habitat, and there are currently no prescribed burns in the crane area. The largest group size observed was 8 birds seen on the uplands on San Jose accompanied by sandhill cranes. More black mangrove was noted on Ayes and Roddy islands.
Flight Conditions: Visibility was good for most of the flight, but darker overcast at times made for somewhat challenging viewing conditions. Due to limited flight hours, the aircraft was usually kept at 140 knots making it a lively task to find all the cranes. Total flight time was 4.6 hours and we felt a very good count was achieved despite some crane movements that had to be sorted out as cranes moved to and from the uplands.
Tom Stehn, Aransas National Wildlife Refuge
The third aerial census of the 2008-09 crane season was conducted December 5, 2008 in a Cessna 210 piloted by Gary Ritchey of Air Transit Solutions of Castroville, Texas with USFWS observers Tom Stehn and Carey Strobel.
Visibility was difficult for finding cranes due to heavy overcast skies during the 8.0-hour flight. Located were 198 adults + 31 juveniles = 229 total.
This was 37 fewer cranes than the previous flight conducted November 25th.
Recap of cranes (229) found at Aransas on the aerial.
|------------+---------------|
| |Adults + young |
|------------+---------------|
| Refuge | 54 + 11 |
|------------+---------------|
| Lamar | 6 + 3 |
|------------+---------------|
| San Jose | 43 + 4 |
|------------+---------------|
| Matagorda | 79 + 11 |
|------------+---------------|
| Welder | 16 + 2 |
| Flats | |
|------------+---------------|
| farm fields| - |
|------------+---------------|
| Total |198 + 31 = 229|
|------------+---------------|
Explanation of numbers
Experience indicates that only 85-90% of the flock can usually be located when skies are a thick overcast. This was definitely the case on today’s census.
Flock Estimate
For the second week in a row, only 2 family groups were located on Welder Flats. This makes me postulate that the 4 family groups seen at Welder Flats on the November 14th flight may have cranes that had recently arrived that later moved on to other parts of the crane range. Thus, I cannot add two family groups on to the estimated flock size as I had done after the November 25th flight. Therefore, the current estimated flock size is 230 adults + 40 juveniles = 270. Those numbers are NOT firm and are lower than my previous estimate of 275. Future flights will focus on determining the number of juveniles present and total flock size.
Migration Update
Migration sightings of a pair of cranes were as follows:
11/24 - pair last seen at Cheyenne Bottoms, central Kansas
11/28-11/29 - pair seen at Salt Plains in northern OK
12/03 - pair seen 4 miles north of Aransas in the farm fields Given the group size and timing, I am guessing these could very well be the same pair tracked across 3 states.
The solitary juvenile crane that had been near Alma in southcentral Nebraska near the Kansas border resumed migration on December 5th despite strong southwest winds. It had been at that same location since at least October 15, so it was not the juvenile from the family group reported in migration near Alma. The crane’s roost pond froze up on the December 4th and presumably was a factor in the chick’s decision to continue the migration. It has not been reported since it left Alma.
Sightings near Aransas
Whooping cranes are showing up in unusual places this fall presumably related to food shortages and the need to seek fresh water to drink. On December 5th around mid-morning, a single whooper was seen flying near Colomo Creek about 1/3 mile west of FM 1289. Coloma Creek empties into Powderhorn Lake and is located southwest of Indianaloa, Texas north of Aransas.
In the farm fields between Austwell and the refuge, whooping cranes have been sighted among the 600+ sandhill cranes utilizing different fields as
follows:
group dates
remarks
0+1 November 19 – December 8 juvenile whooping crane by
itself
4+0 November 10-14
1+0 November 18-20
2+1 November 23 presumed new
arrival from the migration
2+0 December 2-8
2+1 December 9 new arrival or
returnee from Aransas marshes?
Fourteen different whooping cranes have been seen at wild game feeders this fall. Locations of the feeders on private property include just north of the refuge headquarters, and three locations on the Lamar Peninsula.
Habitat use
Cranes on the flight included 24 observed at fresh water sources, 16 on burned uplands, 4 on unburned uplands, and 3 in open bay habitat. On a boat trip over to Matagorda Island on December 11th, I noted two pairs of cranes feeding in open bay habitat in Sundown Bay.
Items of interest
On December 1st, I picked up a very emaciated whooping crane from near a water hole by the refuge boat ramp. The crane could not stand and after capture was having difficulty holding up its head. The crane died while I was driving it to a veterinarian in Port Lavaca. The bird was shipped to the National Wildlife Health Center in Madison, Wisconsin and was necropsied the next day. The crane was a 2-yr-old subadult male, extremely emaciated, with a bad left “knee”. Organisms are being cultured from the knee to see if it was badly infected that could have been making the bird very sick and limiting its food intake. There was no other indication of disease, although additional tests are being conducted. A whooping crane was observed in Saskatchewan in the fall migration with a severe limp of the left leg and could well have been the bird that died at Aransas.
Food sources for whooping cranes seem very low this winter, primarily due to the summer drought. I expect to confirm a record number of whooping cranes at Aransas this winter, but the flock will probably experience additional mortality. A blue crab count conducted by refuge volunteer Katherine Cullen on December 1st found only 1 crab in an hour of walking through the marsh. However, observations by the tour boat captains the first week in December noted some blue crabs were still available for the cranes. Only a few wolfberry fruits and flowers were seen during the crab count. Follow-up searches for wolfberries conducted on Matagorda Island confirmed that this year’s wolfberry crop was lower than normal. Tides have been lowered by recent low pressure systems, and bay salinities remain high at 30 parts per thousand. Cut-off marsh ponds had salinities levels of 43 ppt.
By Tom Stehn - Aransas National Wildlife
Refuge
WHOOPING CRANE RECOVERY ACTIVITIES
November, 2007 – September, 2008
by Tom Stehn
U. S. Fish and Wildlife Service
Whooping Crane Coordinator
HIGHLIGHTS
The
Aransas-Wood Buffalo
whooping crane flock reached a record population of 266 at Aransas in December,
2007. No mortality was documented during
the 2007-08 winter. During the spring
2008 migration, the Cooperative Whooping Crane Tracking Project documented 39
confirmed sightings of whooping cranes in the U.S. Central Flyway. An excellent production year in Canada in 2008 totaling 41 fledged chicks from a
record 66 nests should equate into a substantial population increase in the
Aransas-Wood Buffalo
flock in the 2008-09 winter. However,
threats to the flock including water and land development in Texas,
wind farm construction in the migration corridor, and tar sands waste ponds in Canada all
increased in 2008.
The captive flocks had a good production season. Twenty-two chicks are expected to be reintroduced into the eastern migratory population in the fall of 2008 bringing that flock to 91 total birds. Two chicks of high genetic value have been added to the captive flock. Production in 2008 lifted the total population of wild (n=387) and captive (n=152) whooping cranes to 539.
Production in the wild from reintroduced flocks in 2008 was a disappointing “zero”. In Florida, 5 chicks hatched from a total of 3 first nests and 2 re-nests, but none of the chicks survived past 25 days of age. In Wisconsin, all 11 nesting pairs abandoned their nests just prior to expected hatching.
The Whooping Crane Recovery Team met in September, 2008 in Wisconsin. The team decided that the probability of success was too low for the Florida non-migratory flock to justify any further releases of captive-reared juveniles. The Team recommended continuing steps to proceed with reintroduction of non-migratory whooping cranes into their historic range in Louisiana if studies can demonstrate that this would not increase the risk of infectious bursal disease to the Aransas-Wood Buffalo flock. The Recovery Team also recommended doing field tests with GPS satellite transmitters on migratory cranes in preparation for radioing birds in the Aransas-Wood Buffalo population. This project has been proposed by the Platte River Recovery Implementation Program to focus on whooping crane use of habitat and causes of mortality in the migration corridor.
ARANSAS – WOOD BUFFALO FLOCK
Summary of the Spring 2008 Migration in the Central Flyway
written by Martha Tacha, U. S. Fish and Wildlife Service (USFWS),
Grand Island, Nebraska
With the help of numerous cooperators up and down the Central Flyway, the Cooperative Whooping Crane Tracking Project documented 39 confirmed sightings of whooping cranes in the U.S. Central Flyway during the spring 2008 migration (Table 1). No mortality was documented during the 2008-09 winter, and an estimated record 266 whooping cranes moved north to the breeding grounds at Wood Buffalo National Park in Canada.
The first push of the migration occurred during the last week of March and first week of April. Whooping cranes were first observed leaving Aransas National Wildlife Refuge (NWR) on March 25 by Tom Stehn and all but 34 had left Aransas by April 10. One of the record 266 whooping cranes in the population remained at Aransas NWR until at least May 15, but was not re-sighted and presumably migrated sometime thereafter.
The first migrants confirmed north of Aransas were observed in central Kansas the morning of March 28; three groups totaling 12 cranes were observed at and southwest of Quivira NWR. Between March 30 and April 2, six groups totaling 24 cranes were confirmed in south central and central Nebraska. On April 14, another strong front pushed these and other migrating whooping cranes north. The initial or final observation of nearly half of the sightings in the flyway (19, or 49 percent) occurred during the 5 days from April 13 to April 17, inclusive. The last sighting in the U.S. Central Flyway north of Aransas occurred on May 8, when a single crane left Medicine Lake NWR in northeastern Montana.
Generally, observed groups of whooping cranes hustled through the migration: 27 groups (69 percent) were observed during a single day only. However, 7 groups were observed for 6 consecutive days or more. One group stopped for 16 days and 2 groups rested for 15 days each (these 3 groups in the rainwater basins in Nebraska), and stopovers of 12 days (Montana), 8 days (south central Nebraska), 7 days (southern Nebraska), and 6 days (South Dakota) were also observed.
The size of migrating groups varied, as expected. Group sizes (followed by observation frequency) were as follows: 13 cranes (1), 11 cranes (1), 8 cranes (1), 6 cranes (3), 5 cranes (2), 4 cranes (7), 3 cranes (11), 2 cranes (8), and a single crane (5). Juveniles were identified in 10 instances, including one set of twins, but juveniles are easy to overlook in the spring, particularly when seen at a distance.
Three whooping cranes from the reintroduced eastern migratory population of whooping cranes (Wisconsin-Florida flock) wandered into North Dakota and were observed near Woodworth in Stutsman County on June 5 and 6. These three were next re-sighted in late summer in east central Minnesota. Another group of four young birds from the reintroduced flock has been observed for some time in western Minnesota, about 15 miles from the South Dakota border. All of these young cranes are expected to wander back east and migrate to Florida in the fall.
The success of the Cooperative Whooping Crane Tracking Project is due to the efforts of the many volunteers and observers in the field who report sightings, and the State and Federal key contacts who gather and transmit the information to the Project Coordinator. The cooperation and diligence of those associated with the project is truly appreciated.
Table 1. Number and dates of confirmed sightings of whooping cranes in the U.S. Central Flyway during spring migration (i.e., north of Aransas NWR), 2008.
|
State |
Number of Observations |
Earliest Date Observed |
Latest Date Obs |
|
Texas |
1 |
4/1 |
4/1 |
|
Oklahoma |
2 |
4/6 |
4/9 |
|
Kansas |
8 |
3/28 |
4/11 |
|
Nebraska |
12 |
3/30 |
5/4 |
|
South Dakota |
8 |
4/7 |
4/16 |
|
North Dakota |
6 |
4/15 |
4/18 |
|
Montana |
2 |
4/17 |
5/8 |
|
Total or Cumulative |
39 |
4/1 |
5/8 |
Wood Buffalo National Park, Canada
Aerial surveys, 2008
Three summer surveys of the nesting area were carried out in 2008. In May, Brian Johns and Kathy St. Laurent of the Canadian Wildlife Service (CWS) located a record 66 nests. In June, the USFWS Partanavia with Pilot Jim Bredy and Biologists Brian Johns and Tom Stehn (USFWS) documented the hatching of 64 chicks, including 12 sets of twins. This compared with 65 nests and 84 chicks including 28 sets of twins in 2007. Fifty-two of the 66 nests (79%) produced one or more chicks compared with 86% success in 2007. Thus, the chick production in 2008 resulted from both high productivity and a large number of nests. Fourteen nests were unsuccessful. In addition, 6 known adult pairs failed to nest but were sighted present on their territories. Thus, there were a minimum of 72 breeding pairs in the population. This number matched the 72 adult pairs identified present at Aransas during the 2007-08 winter.
Habitat conditions in Wood Buffalo in June were better than expected with water levels considered to be good. The weather during the June production surveys was exceptionally warm with no cold, wet weather. The moderate weather conditions favored the survival of the young chicks early on. One of the highlights of the June surveys was finding one whooping crane pair with twin chicks and then spotting two wolves 1.5 km distant from the cranes. The crane family was re-checked 5 days later and both chicks were still alive with no sign of the wolves.
Surveys carried out in August by CWS located 41 chicks. This total included 2 sets of twins, down from the 12 sets that had been present in June. This high level of production is expected to raise the size of the Aransas-Wood Buffalo population to a record 280+ in the 2008-09 winter from its record 266 the previous winter. An increase of the population is anticipated since it is in the growth portion of the 10-year population cycle that has occurred during the middle of every decade.
Threats
The following based on information supplied by Ernie Kuyt is from the May 2008 issue of “Grus americana”, a newsletter of the Whooping Crane Conservation Association:
Threats to whooping cranes are also present “north of the border”. The Alberta government recently decided that Environmental Assessments (EAs) would no longer be necessary for large power lines. Getting more electricity to the citizens has become so urgent that EAs were determined to cost too much, take too long, and were largely “unnecessary”. Another threat in Canada was brought to light recently when 500 ducks entered toxic tailing ponds in the oil sands area north of Fort McMurray, Alberta. Only 5 ducks had any hope for recovery from exposure to the oily chemicals. There are 50 square kilometers of these toxic ponds, and they lie within the migration path of the whooping crane. Propane cannons are routinely used to haze birds from this area. A whooping crane family group that apparently became oiled in fall, 2006 could have gotten into these tar sands waste ponds.
Platte River, Nebraska
The Platte River Recovery Implementation Program agreed upon by federal agencies and 4 states was signed by President Bush in May, 2008. More than 10 years in negotiation, the measure benefits endangered species yet allows continued water use and development along the Platte.
The year 2008 marks the 30th anniversary of the Platte River Habitat Whooping Crane Trust, Inc. This non-profit conservation outfit originated as a result of court litigation over a proposed water reservoir on the Platte River located in Wyoming. It mission is to protect habitat for cranes and other migratory birds along the Big Bend Region of the Platte River Valley. The Trust has made a big difference not only in protecting habitat for the whooping crane, but also improving the environment in south central Nebraska. It currently manages nearly 10,000 acres along the Platte. The Trust also does research to make sure management activities are science-based.
Aransas National Wildlife Refuge, Texas
2007-08 Winter
Whooping Crane Coordinator Tom Stehn stationed at the Aransas NWR wrote up his findings from the 2007-08 winter.
Abstract: The number and distribution of whooping cranes were studied on the wintering grounds at Aransas during the 2007-08 winter. The peak population equaled 227 white-plumaged birds and 39 juveniles totaling 266 cranes. This was 29 birds higher than the 237 cranes present the previous winter. Mortality between spring and fall, 2007 was estimated at 9 cranes. No mortality was documented at Aransas during the 2007-08 winter.
The peak population of 266 consisted of 144 adults, 83 subadults, and 39 juveniles. At most, 21 cranes were color-marked, representing 7.9% of the population. The estimate of 72 pairs occupying territories was 5 more than the previous winter. Territories and/or use areas were located on the Aransas NWR (20), Lamar Peninsula (3), San Jose Island (16), Matagorda Island (25), and Welder Flats (8). Cranes generally were found on the refuge (74), Lamar (8), San Jose Island (71), Matagorda Island (85), and Welder Flats (27). One juvenile whooping crane that was separated from its parents was sighted in November in West Texas. Record highs were set in the 2007-08 winter for most cranes on Lamar (13), San Jose (77), Matagorda (87), and tied the record on Welder Flats (31). Matagorda Island that held 34.2% of the flock has in recent years surpassed the refuge for supporting the most cranes.
Quality food resources were considered to be very good throughout the fall and winter. The cranes fed heavily on wolfberry, blue crabs and fiddler crabs while at Aransas. Wolfberries were available for the cranes in November and December. Blue crabs declined in mid-winter, but a few were always present. Cranes used open bay habitats to some extent during winter low tide periods foraging on clams and/or invertebrates such as mud shrimp or bloodworms. Some upland use was observed on prescribed burns. Bay and marsh salinities were low the first half of the crane season but increased to around 20 parts per thousand by spring. Moderate use of fresh water sources was observed
Aransas NWR project leader Charlie Holbrook retired in June, 2008 after 8 years at the refuge. Many accomplishments occurred during his time at Aransas. The new manager starting in October is Dan Alonso.
Land Development
Whooping cranes use wetlands and adjacent upland habitats off of Aransas and Matagorda Island NWRs. Some of these areas are included in designated Critical Habitat; others are not. Real estate development pressures are rapidly increasing along these formerly isolated shores. It will bring many new residents to a formerly sparsely populated portion of the Texas coast. Six waterfront developments are planned between Seadrift and Port O’Connor which are considerably larger than either of those towns. The population of Seadrift is expected to double in the next decade. Additional developments are occurring on the Lamar Peninsula directly west of Aransas NWR. These developments will limit the area the whooping crane flock needs for expansion if the flock continues to grow. Permanent protection of this habitat is essential in the near term in order for the species to reach long-term recovery goals.
To try to conserve key lands currently used by whooping cranes as well as set aside lands expected to be used in the future, conservationists undertook some actions to try to counter the rapid development. The Texas Nature Conservancy (TNC) in partnership with other agencies is working hard to protect key areas with conservation easements placed on key buffer areas as a means for people and wildlife to coexist. Two areas slated for protection using Section 6 grants are located in the crane area at Welder Flats. Matching funds will come partially from one development currently under construction in the crane area near Port O’Connor. The TNC applied for a 1.5 million dollar grant from the Coastal Impacts Assistance Program to protect 5,000 acres of crane habitat in the next 3 years primarily through purchase of conservation easements. This grant application was not funded in 2008. However, it made the cut of worthwhile projects for which there just weren’t sufficient funds available, and was re-applied for in 2009. In the meantime, 5 developments are either under construction or in the planning stages in areas where crane use has been documented. I strongly recommend that a Habitat Conservation Plan be prepared for future developments occurring in the current and anticipated future crane range.
In September 2008, Tom Stehn and Felipe Prieto presented a paper at the 11th North American Crane Workshop on the change in territories and range of wintering whooping cranes at Aransas between 1950 and 2006. Based on estimates of minimum territory sizes, they calculated that the current range and nearby adjacent areas of unoccupied habitat will support approximately 511 cranes. If the cranes expand outwards into new areas as far as 69 miles from Aransas NWR, they estimated there is enough salt marsh habitat on the central Texas coast to support 1,004 whooping cranes. Although this meets the criteria set for down-listing the species to “threatened” status, there is insufficient habitat to fully recover the species. Therefore, with marsh habitat a key limiting factor for whooping crane recovery, it is imperative that as much of the marsh as possible be protected from development.
Freshwater Inflows
Two major processes have continued throughout the past year. The state-appointed Environmental Flows Advisory Group met and held hearings to provide future recommendations to ensure rivers have sufficient flows and the bays have sufficient inflows to remain productive. The second planning process that got underway is the Edwards Aquifer Recovery Implementation Program (EARIP) mandated by the Texas Legislature to determine the sustainable levels of pumping from the aquifer and drought management strategies. The Edwards Aquifer now serves 1.7 million people in South Central Texas, providing San Antonio with 95% of the city’s water. The population is expected to double by mid-century, increasing the demand for water. The EARIP will develop a plan to balance the needs of aquifer stakeholders in San Antonio and surrounding areas with the requirements of the Endangered Species Act (ESA). Although the Edwards Aquifer is a long way from the coast and the EARIP is focused on endangered invertebrate species in several key springs fed by the aquifer, spring flow can be a major component of inflows (up to 80%) into whooping crane critical habitat, especially in times of drought. Sufficient inflows are essential to support abundant blue crab populations, the primary food of whooping cranes during winter.
Wind Energy Development and Power Lines
The development of wind farms is occurring at a rapid pace in the Central Flyway. Multiple wind farms have already been built, and it is important to analyze the potential impact of literally tens of thousands of wind turbines being placed in the whooping crane migration corridor in the coming years. For example, one notably large project on the border of the Dakotas called Titan is proposing to place 4,000 wind turbines over 200 square miles within the whooping crane migration corridor.
With an investment of over $9 billion, the wind industry installed 5,244 megawatts of power in 2007, expanding the nation’s total wind power generating capacity by 45% in a single calendar year. These new installations are expected to power the equivalent of 1.5 million American households. This was the 3rd consecutive year of record-setting growth, establishing wind energy as one of the largest sources of new electricity for the country. The U.S. wind power fleet now numbers 16,818 megawatts across 34 states, about 1% of national usage, powering over 4.5 million homes. Texas has the most installed wind generating capacity of any state.
Projected growth of the wind industry is hard to visualize. Texas billionaire T. Boone Pickens has gotten heavily involved in wind energy development. His vision for wind farms is part of his wider vision for replacing natural gas with wind and solar for power generation, and using the natural gas instead to power vehicles. A newspaper article written April 18, 2008 provided the following description;
“To picture Pickens' energy strategy, imagine a compass. Stretching from north to south from Saskatchewan to Texas* would be thousands of wind turbines, which could take advantage of some of the best U.S. wind production conditions. On the east-west axis from Texas to California would be large arrays of solar generation, which could send electricity into growing Southern California cities like Los Angeles. The end result would be to free up more clean-burning natural gas - primarily a power-generation fuel now - to power automobiles.”
* Note that Texas to Saskatchewan is the exact route of the
whooping crane migration corridor. Many of the best wind
development sites are located in that corridor.
The majority of the wind farms do not require federal permits and thus there is no nexus for the companies to consult with USFWS. However, the projects must avoid “take” of endangered species under Section 10 of the ESA. Wind farms have the potential to directly kill whooping cranes either from the turbines themselves or associated construction of power lines. If whooping cranes completely avoid wind farm areas, wind energy development could result in the removal of hundreds of square miles of migration stopover habitat from use by the cranes. The National Academy of Science Report in 2004 on Platte River endangered species report stated unequivocally the threat to whooping cranes if migration habitat is lost.
I’m concerned that potential impacts to whooping cranes need to be fully evaluated. USFWS biologists throughout the whooping crane migration corridor initiated conference calls to develop a unified approach to wind energy development issues and met in December, 2007 in Lakewood, Colorado. The meeting included both representatives of Endangered Species and Refuges since wind development companies are requesting placing turbines on federal grassland easements in the Dakotas which in some instances USFWS has allowed. From this meeting and follow-up conference calls, it was decided to recommend that the industry prepare a Habitat Conservation Plan (HCP) for wind energy development for the entire U.S. whooping crane migration corridor. An HCP is a document that assigns a level of “take” of an endangered species from development actions that occur on private lands where there is no federal nexus. It legalizes those actions if measures described in the HCP are carried out. Points that involved lots of discussion included whether or not to include in the HCP all endangered species as well as migratory bird issues. A decision was reached to focus primarily on whooping cranes. A whooping crane / wind energy development summit meeting was held in July, 2008 in Denver to discuss all aspects of writing an HCP. Two USFWS Regional Directors attended along with key wind development and utility companies working in the Central Flyway. Discussions are continuing to try to get this HCP process underway.
I made a presentation in September, 2007 to the Avian Power Line Interaction Committee (APLIC) expressing concerns about increased construction of power lines, especially as wind power is developed. APLIC is very interested in continuing to pursue conservation measures needed for whooping cranes and have formed a whooping crane issue subcommittee. Whooping crane collisions with power lines are believed to be the number one source of mortality for fledged whooping cranes. Continued construction of power lines including those associated with proposed wind farms in the migration corridor threatens the recovery of the whooping crane.
Early on in my meeting with wind companies, I talked of two possible scenarios for offsetting anticipated impacts of wind farms. These were;
1. To mark all new power lines as well as an equivalent distance of existing power lines to offset the threat of whooping cranes colliding with a wind turbine or power lines built to support wind development. Existing lines need to be marked so that there is no net increase in the threat of collision since marking lines is only 50-80% effective in reducing avian collisions. Existing lines targeted would hopefully be in the migration corridor located within 2 miles of a suitable crane wetland or known stopover site.
2. To set aside whooping crane migration stopover habitat in perpetuity to counter potential loss of habitat from wind energy development, and
The Nebraska USFWS Endangered Species office in Grand Island, Nebraska using GIS prepared maps with updated information on the location of the whooping crane migration corridor. This is a very important tool for analyzing the risk to the species for specific wind farms. The data showed that 75% of all documented whooping crane stopovers occur in a migration corridor roughly 80 miles wide. This work complemented work done by Dr. Karine Gil de Weir at the Platte River Habitat Whooping Crane Trust.
One wind farm proposed at Wessington Springs in South Dakota entered formal consultation under the ESA, the first case of its kind involving whooping cranes. The federal nexus existed because of the involvement of the Western Area Power Administration (WAPA). An Environmental Assessment was prepared and USFWS wrote a draft biological opinion. No incidental take was granted in the biological opinion, but take of habitat was covered. A second project entering federal review involves 27 miles of transmission line in eastern Montana.
Administration
The Recovery Strategy for the Whooping Crane in Canada was posted in its final version on the SARA Public Registry on November 20, 2007. It can be downloaded at: http://www.sararegistry.gc.ca/virtual_sara/files/plans/
rs_whooping_crane_final_1007_e.pdf
The Crane Conservation Act was re-introduced in both the House and the Senate in Washington and passed by the House in early June, 2008. This legislation is aimed at helping species of cranes world-wide, and would allow 20% of appropriated funds to go towards crane species in North America.
FLORIDA NONMIGRATORY POPULATION
Work by Drs. Clint Moore and Sarah Converse of the Patuxent Wildlife Research Center was completed on an adaptive management study of the Florida non-migratory population. The model that was developed considered the future of releases into the flock under various release scenarios, taking into consideration expected performance of the flock, costs, public relations, learning opportunities, and other aspects. Three meetings were held in Florida involving key state and federal wildlife personnel to fine tune the model. The analysis was presented in September, 2008 to the Florida Fish and Wildlife Conservation Commission (FLFWCC) and the Recovery Team. The Recovery Team met in September, 2008 in Wisconsin. Although the Team recognized the difficulties of reintroducing avian species, optimistic assumptions in the Patuxent study provided no more than a 41% chance of achieving a self-sustaining population, and most values were around 20% or less. The Team felt that 24 whooping crane chicks per year were not available for continued releases in Florida. Releasing fewer than 24 birds annually lowered the probability for success even further. The Team felt that the water regimes produced by periodic droughts in Florida make it extremely unlikely that reproduction in wild-hatched Florida whooping cranes will ever achieve production rates adequate for success. In addition, crane habitat in Florida is faced with tremendous pressure from developers and is expected to decline in the coming decades. Therefore, the Team concluded that the probability of successful establishment of a self-sustaining population was too low to justify continuing the reintroduction. The Team recommended that no further releases of captive-reared whooping cranes be made into the Florida non-migratory population. The Team did recommend that the FLFWCC continue to study the remaining non-migratory whooping cranes to maximize learning.
The following information is from the April-June, 2008 quarterly report written by Whooping Crane Project Leader Marty Folk of the Florida Fish and Wildlife Conservation Commission:
The 2008 spring nesting season occurred in the ongoing drought conditions that hindered success. There were 5 nests (2 were re-nests) by 3 pairs, with 3 nests hatching 5 chicks; none of the chicks lived past 25 days. Four of 5 nest locations were in lakes because marsh water levels were too low for nesting.
During the spring quarter 2008, seven birds went missing. In addition, 3 mortalities were documented. The mortality and movements of birds were likely associated with drought and the lack of water in marshes. One of the mortalities was a wild-fledged bird, the fourth mortality from the 9 wild-fledged birds produced in the 16-year life of the project. At the end of June 2008, 26 birds (8 pairs) were being monitored with the total population estimated at 30.
EASTERN MIGRATORY POPULATION
The eastern migratory whooping crane population currently includes 69 adult birds and 22 juveniles. Most of the whooping cranes in the eastern migratory population make the desired migration between Wisconsin and Florida. A few birds continue to summer in Michigan, and a few wander into Minnesota and Iowa. In early June, 2008, 3 birds wandered into North Dakota before returning to Minnesota.
Five whooping crane breeding facilities (Patuxent Wildlife Research Center, International Crane Foundation, Calgary Zoo, San Antonio Zoo, and Species Survival Center {SSC} in New Orleans) either provided eggs or hatched and raised chicks in 2008. Eggs were shipped across international borders and between facilities to meet production targets for the ultralight (UL) and direct autumn release (DAR) reintroduction programs. Twenty-two chicks were raised for the release programs in central Wisconsin (15 UL, 7 DAR). This compares with fall 2007 when 27 birds were re-introduced into the eastern migratory population (17 UL and 10 DAR). Chicks were hatched and trained at Patuxent prior to shipment to Necedah NWR for the UL project. The Windway Capital Corporation flight team transported the chicks to Wisconsin. Additional eggs were hatched and chicks reared for several weeks at ICF before being transported to Necedah NWR for the DAR project.
The nesting season for the wild migratory whooping cranes in Wisconsin was a disappointment. All 11 nests built in central Wisconsin were abandoned just prior to expected hatching. Four of 6 eggs rescued from the nests successfully hatched at Patuxent. Nesting failure is currently the project’s foremost concern. Project Biologist Dr. Richard Urbanek has postulated that the cranes are all abandoning the nests due to a huge hatch of black flies correlated with warm, spring weather late in the incubation period. He noticed hundreds of black flies on the abandoned eggs, photographed one crane with numerous flies on it, and noted one crane pair leaving their nest and running into thick brushy vegetation presumably to find relief from the biting flies. Efforts in 2009 will focus on getting additional evidence for this theory and attempting to control the black fly hatch.
Two substantial changes in the Whooping Crane Eastern Partnership (WCEP) are planned for fall, 2008. Operation Migration has laid out a new migration route west of the Appalachians to try to avoid the rough mountain weather and reduce the number of days they are unable to fly. Also, plans have been formulated to split the flock upon arriving in Florida between St. Marks and Chassahowitzka NWRs. The main reason for this split is to avoid one disasterous event happening to the all the birds at once as happened in February 2007 with the loss of 17 cranes from a lightning strike at Chassahowitzka.
WCEP special advisor John Christian is among 16 national recipients of the U.S. Fish and Wildlife Service's 2007 National Recovery Champion awards. The Recovery Champion award recognizes outstanding contributions of USFWS employees and their partners toward efforts aimed at recovering threatened and endangered species in the United States. USFWS Director Dale Hall was quoted in a press release: “These Recovery Champions are extraordinary conservationists dedicated to protecting and restoring our nation’s wildlife and ensuring that future generations of Americans enjoy the natural treasures we experience today”. Mr. Christian was recognized for eight years of coordination with a variety of public and private landowners to re-establish the endangered whooping crane as a breeding species in eastern North America. In his former role as chair person of WCEP, he organized a group of ultra-light pilots, species experts, conservationists, and federal, state and private biologists who work together to breed, raise and “flight train” whooping cranes. Christian’s dedication has led to the current population of 91 wild migrant whooping cranes in the eastern U.S. He currently serves as the Midwest Region’s assistant regional director for migratory birds and state programs.
WCEP held meetings in February and September, 2008 to plan operations for the reintroduction. With so many partners involved in the eastern reintroduction, including agencies and non-profits, the semiannual meetings are important to handle the many issues that arise. The Recovery Team endorsed continued UL and DAR releases in 2009, but urged WCEP to focus on determining the reason for nest abandonment.
LOUISIANA
At their meeting held in September 2008, the Recovery Team recommended that multiple partners carry out actions working towards a potential future release of non-migratory whooping cranes in Louisiana. Recommended actions include;
· Continue ongoing habitat studies led by Dr. Sammy King in an effort to evaluate potential release sites.
· In consultation with the Whooping Crane Health Advisory Team, initiate studies to evaluate the presence/absence of infectious bursal disease (IBD) in the migration corridor of the AWBP. Study results must demonstrate that the AWBP would not be threatened by IBD by the reintroduction of whooping cranes into Louisiana before the Team will support a reintroduction.
· Evaluate the regulatory actions needed to reintroduce nonmigratory whooping cranes into Louisiana.
· Fully coordinate and partner with the Louisiana Department of Wildlife and Fisheries on all actions as appropriate.
Due to uncertainties with the lack of production in the Wisconsin whooping crane population, it is not possible to say when a reintroduction might take place in Louisiana. The Recovery Team hopes that in the next 1-2 years, these questions in Wisconsin can be resolved and that the population of whooping cranes in the eastern U.S. will be close to the target of 125 birds and be reproducing. At that time, assuming the IBD study provides the reassurances needed and that regulatory actions have been completed, it is suggested that a small initial experimental reintroduction could be carried out in Louisiana. This reintroduction could possibly use cranes that are genetically surplus to the eastern migratory population and would test the habitat before a larger reintroduction would be recommended.
CAPTIVE FLOCKS
The whooping crane breeding facilities had a good production season in 2008 but overall fell slightly below our high expectations. Twenty-two chicks were raised for the release programs in central Wisconsin (15 ultralight, 7 direct autumn release), and 2 chicks of high genetic value were held back to become captive breeders.
Patuxent and ICF successfully carried out programs for the reintroduction of birds into the eastern migratory population. Both facilities also provide personnel for various field operations with that population throughout the year, and are great partners in helping out in all aspects of the reintroduction. Patuxent hatched a total of 27 chicks, including eggs that came from Calgary (8), ICF (3), SSC (1) and Necedah NWR (4). ICF is renovating whooping crane pens and building a new exhibit for their African crane species.
The Calgary Zoo had another very good production season and transported 9 fertile eggs to Patuxent. Their artificial insemination program for the third year in a row greatly increased flock fertility. They had one adult captive crane escape through flight netting from the zoo for 6 weeks during the summer. It wandered as far as 6 miles away. After extensive baiting, it was re-captured in a net trap and the feisty bird was returned to captivity in time before it would get into trouble from winter weather.
The Audubon Freeport-McMoran Species Survival Center (SSC) in New Orleans finished work on the first phase of their new whooping crane facilities. A dedication was held in April, 2008 that was well-attended. Earlier in the winter, 5 whooping cranes had been shipped to the new facility from ICF (2), Calgary (2) and the San Antonio Zoo (1). In July 2008, one crane dropout from the 2007 reintroduction program was shipped from Necedah NWR in central Wisconsin to SSC. SSC also celebrated their second sandhill crane egg fertilized using frozen semen that is thawed and then used to inseminate. Last year was their first successful sandhill chick hatched using frozen semen. They hope to use this technique on a whooping crane in 1-2 years. SSC also had one breeding pair produce eggs for the eastern reintroduction.
A workshop with whooping crane flock geneticist Dr. Ken Jones and the captive flock managers was held September 21, 2008 in Baraboo, Wisconsin. A genetic analysis was done for both the captive flock and eastern migratory population. The studbook was updated, pairing recommendations were made, and crane transfers between facilities were planned. The captive flock continues to make excellent progress towards retaining genetic diversity.
WHOOPING CRANE NUMBERS IN NORTH AMERICA
September 30, 2008
Wild Populations
|
|
Adult |
Young |
Total |
Adult Pairs |
|
Aransas/Wood Buffalo |
227 |
39 |
266A |
72 |
|
Rocky Mountains |
0 |
0 |
0 |
0 |
|
Florida non-migratory |
30B |
0 |
30B |
12 |
|
Wisconsin/Florida migratory |
69 |
22C |
91 |
11 |
|
Subtotal in the Wild |
326 |
61 |
387 |
95 |
A The 266 cranes above is the estimated flock size in spring, 2008. Forty-one chicks fledged from a record 66 nests in 2008. Chicks hatched in 2008 are not added to the count until they reach Aransas in late fall.
B This number reflects the 26 birds regularly monitored in Florida plus 4 additional cranes believed to be alive in unknown locations. No chicks fledged in the wild in 2008.
C The 5 whooping crane breeding facilities (Patuxent Wildlife Research Center, International Crane Foundation, Calgary Zoo, San Antonio Zoo, and Species Survival Center in New Orleans) either provided eggs or hatched and raised chicks in 2008. Four eggs came from abandoned wild nests in Wisconsin and successfully hatched at Patuxent. Twenty-two chicks are currently being raised for the release programs in central Wisconsin (15 ultralight, 7 direct autumn release).
Captive Populations
|
|
Adult |
YoungE |
Total |
Breeding Pairs |
|
Patuxent WRC, Maryland |
62 |
4 |
66 |
13 |
|
International Crane Foundation, WI |
32 |
0 |
32 |
11 |
|
Devonian Wildl. Cons.Cent./Calgary |
24 |
0 |
24 |
6 |
|
Species Survival Center, Louisiana |
12 |
0 |
12 |
1 |
|
Calgary Zoo, Alberta |
2 |
0 |
2 |
0 |
|
New Orleans Zoo, Louisiana |
2 |
0 |
2 |
0 |
|
San Antonio Zoo, Texas |
7 |
0 |
7 |
1 |
|
Homosassa Springs Wildl State Park |
2 |
0 |
2 |
0 |
|
Lowry Park Zoo, Tampa, Florida |
1 |
0 |
1 |
0 |
|
Jacksonville Zoo, Florida |
2 |
0 |
2 |
0 |
|
Milwaukee County Zoo, Wisconsin |
1 |
1 |
2 |
0 |
|
Subtotal in Captivity |
147 |
5 |
152 |
32 |
E Two of these young are genetic holdbacks and will remain in captivity as future breeding stock. The table does not reflect captive young that have entered reintroduction programs in 2008.
TOTALS (Wild + Captive) 387 + 152= 539
