Whooping Crane Conservation Association

October 2009 to September 2010

Highlights:

The Aransas-Wood Buffalo population (AWBP) of whooping cranes rebounded from 247 present in the spring of 2009 to 263 in the spring, 2010. With 46 chicks fledging from a record 74 nests in August, 2010 the flock size should reach record levels this fall expected somewhere around 290. Threats to the flock including land and water development in Texas, the spread of black mangrove on the wintering grounds, the long-term decline of blue crab populations in Texas, sea level rise / land subsidence, and wind farm and power line construction in the migration corridor all continued to be important issues.

Two whooping cranes captured at Aransas and nine in Wood Buffalo National Park (WBNP) were fitted with GPS transmitters and tracked by satellite. Crews visited migration stopover sites after the birds were present to gather habitat use data. This project is being carried out by The Crane Trust headed up by Dr. Felipe Chavez-Ramirez. It is funded by the Platte River Recovery Implementation Program, The Crane Trust, and the USGS Northern Prairie Wildlife Research Center. The tracking is the first done on the AWBP in 25 years and is a top research priority of the Whooping Crane Recovery Team! Since the 1950s, 474 AWBP whooping cranes have died, with 37 carcasses recovered, and cause of death determined in only 17 instances. With the loss of 21.4% of the flock in the 12 months following April 2008, it is imperative that we learn more about whooping crane mortality.

Based on opportunistic sightings, the Cooperative Whooping Crane Tracking Project documented 103 confirmed sightings of whooping cranes in the U.S. Central Flyway during fall, 2009 and 52 sightings in spring, 2010.

A study by Dr. Ken Jones at the University of Georgia genomics lab to better describe the genetic composition of the captive flock got underway in September, 2010. The new genomics technology will derive genetic information from 454 single nucleotide polymorphisms, a substantial increase from the 12 loci used in the past on which most of our genetic decisions involving whooping crane pairings are currently based.

Planning efforts continued for the proposed reintroduction of a nonmigratory flock of whooping cranes at White Lake, Louisiana. White Lake is where the last whooping crane nest in Louisiana had been found in 1939.

Production in the wild from reintroduced flocks in 2010 was somewhat disappointing, though better than last year. In Florida with improved water conditions, 8 of the 9 remaining pairs nested and hatched 4 chicks, but only 1 chick survived to fledge. In Wisconsin, 12 pairs nested, with 3 first nests and 3 re-nests incubated full term and hatching 7 chicks. Two chicks fledged. Nest abandonment consistent with the presence of black flies continued to be a major hurdle for the reintroduction at Necedah National Wildlife Refuge (NWR).

The captive flocks had a very good production season in 2010. Twenty-four chicks entered the migratory reintroduction program in Wisconsin, and 11 chicks are being formed into a cohort for a possible nonmigratory release in Louisiana in February, 2011. Three chicks of high genetic value were held back for the captive flocks.

Flock sizes are estimated at 263 for the AWBP, 119 for the WI to FL flock, and 25 nonmigratory birds in Florida. With 167 cranes in captivity, the world total (all located in North America) of whooping cranes is 574, up 38 from one year ago.

The full report can be read here…

Whooping Crane Recovery Update: October 2009 to September 2010

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An aerial census flight was conducted May 19, 2010 in a Cessna 210 piloted by Gary Ritchey of Air Transit Solutions of Castroville, Texas with USFWS observer Tom Stehn. This is the first flight since the airplane was damaged by a bird strike on the March 23rd census. The plane’s windshield, several instruments, and interior were replaced.

A single white-plumaged whooping crane was sighted on the refuge’s Dunham Point Marsh. I could not tell if the crane is the one we refer to as Scarbaby that has failed to migrate several years. Dunham Point is adjacent to the Lobstick territory, the parents of Scarbaby, so that is why I think the crane could be him.

The spring migration proceeded ahead of schedule this year. The highlight of the migration was the presence of 76 whooping cranes in 5 separate groups on the Quivira NWR on April 1st. Another interesting report was the presence of 5 whooping cranes 2 miles from the Titan I wind project in South Dakota April 3-5. The turbines were shut down during critical times, and were actually ordered shut down by a biological monitor as the birds began their migration flight. The two cranes radioed at Aransas were tracked successfully and both completed the migration. One is sitting on a nest, and the radioed juvenile was recently located north of Wood Buffalo National Park and across Great Slave Lake.

From the Gulf oil spill, models predict 1 percent chance of oily waters reaching the central Texas coast. However, tar balls are expected to be hitting the Texas beaches. The refuge has videotaped the beach and marsh edges. Additional biological monitoring will be done in the near future to assess potential future damage from oil impacts.
– Tom Stehn

The seventh aerial census of the 2009-10 whooping crane season was conducted March 9th, 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 193 adults and 18 juveniles = 211 total whooping cranes. Fog rolling in off the Gulf in the late afternoon prevented completion of the census. No evidence of mortality was noted on the flight other than the one juvenile that had died earlier in the winter. The flight again provided solid evidence of 20 family groups currently at Aransas. With one juvenile last seen in Oklahoma December 25th that apparently separated from its parents during migration and is presumably okay and wintering in an unknown location, and the S. Sundown Island chick that has died at Aransas, this accounts for 22 of the 22 juveniles found in Canada during the mid-August fledging surveys. With the one documented mortality this winter, the current flock size is estimated at 242 + 21=263.

March 9th – Recap of whooping cranes (211) found at Aransas:

[TABLE=9]

* Census incomplete due to presence of fog.

Some cranes continue to leave their marsh territories and are searching for food on the uplands. Upland areas on the barrier islands are flooded, with numerous wet swales on the uplands up to the beach dunes. Overall habitat use documented on the flight included 27 cranes on unburned uplands (13%, or half of the previous flight’s total), 2 in open bays, 3 at a game feeder at Welder Flats, 0 on prescribed burns, and 179 (85%) in salt marsh. Low numbers of 2-3 inch blue crabs have moved into the marshes with recent high tides, and more foraging on crabs has been noted, although blue crab numbers are still low.

Flight Conditions: Winds were light and flight conditions were smooth. Visibility was challenging throughout the flight due to all the moisture in the air. Late afternoon sunshine was often shining in our faces so that it was only possibly to see cranes reliable heading away from the sun. Late afternoon fog rolling onto the barrier islands prevented us from completing the census. The largest group sizes observed were 9 birds seen in the marsh on San Jose and 7 on the uplands on Matagorda Island.

Spring Migration, 2010

The single white-plumaged whooping crane confirmed present at Salt Plains NWR in northern Oklahoma on February 24th and 26th apparently moved on to the Platte River in Nebraska where it was confirmed on March 5th. No other whooping cranes are believed to have left Aransas.
– Tom Stehn, Aransas National Wildlife Refuge

The sixth aerial census of the 2009-10 whooping crane season was conducted February 16, 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 237 adults and 19 juveniles = 256 total whooping cranes. No evidence of mortality was noted on the flight other than the one juvenile that had died earlier in the winter. The radioed family on Lamar Peninsula was overlooked on the flight, but GPS data indicates it was on Lamar before and after the census flight. Since it has not been documented leaving Lamar since being tagged in December, it is considered very unlikely that they had moved over to San Jose to account for the extra family found there during the census. The flight provided a firm tally of the 20 family groups currently at Aransas. With one juvenile last seen in Oklahoma December 25th that apparently separated from its parents during migration and is presumably okay and wintering in an unknown location, and the S. Sundown Island chick that has died at Aransas, this accounts for 22 of the 22 juveniles found in Canada during the mid-August fledging surveys. This is one more juvenile accounted for than on previous survey flights this winter. With the one documented mortality this winter, the current flock size is estimated at 242 + 21=263.

February 16th – Recap of whooping cranes (256) found at Aransas:

[TABLE=8]

* One family group was overlooked.
** Ties record high for Matagorda Island set during the 2008-09 winter.

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. Upland areas on the barrier islands are flooded, with numerous wet swales on the uplands up to the beach dunes. Three cranes on Matagorda Island were in one of these flooded swales next to the dunes. Overall habitat use documented included an unusually high 67 cranes (26%) on unburned uplands, 16 in open bays, two at a game feeder south of the Big Tree on Lamar, 0 on prescribed burns, and 171 (67%) in salt marsh. Blue crabs are at low levels and the cranes are having to look for other sources of food, although some cranes continue to catch a few crabs. This is a stressful time of winter for the whooping cranes as evidenced by all the cranes on uplands.

No whooping cranes have been reported up the coast at Smith Marsh in Matagorda County located west of the Nature Conservancy’s Mad Island Marsh Preserve since 1/17/10. Two whooping cranes are continuing to winter northwest of Austwell on the Guadalupe Delta Wildlife Management Area managed by the Texas Parks and Wildlife Department.

I noted one thing on the flight that I had never observed previously. Twenty sandhill cranes on the southern end of the crane range on San Jose Island flushed from the census aircraft and flew a very short distance to stand in open bay habitat. I had never seen sandhill cranes before in open bay habitat.

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 at Welder Flats. Winds were light and flight conditions were smooth until mid-afternoon, enabling us to travel at approximately 130 knots for most of the flight. Due to reported crane movements, the search area was expanded further out into upland areas. This paid off, as cranes were found near the beach dunes on Matagorda Island, inland in a pasture at Welder Flats and on Aransas National Wildlife Refuge uplands. The largest group size observed was 9 birds seen on the uplands on San Jose and in the marsh on Matagorda Island.

Post-Flight Update
Food availability improved for the cranes during the last week in February with more cranes observed feeding on 2-3-inch blue crabs. Upland swales remain very wet and bay salinities remain moderate < 10 ppt.

Spring Migration, 2010
A single white-plumaged whooping crane was confirmed present at Salt Plains NWR in northern Oklahoma on February 24th and 26th. Since we did not know of any other white-plumaged whooping cranes in the Flyway this winter, this must be a case of a whooper on the Texas coast getting influenced by sandhill cranes and starting the journey ahead of the normal time for whooping cranes. Except for birds that had a history of separating from their parents as juveniles, I think it would be the earliest migration start on record.

– Tom Stehn, Aransas National Wildlife Refuge

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:

[TABLE=7]
* 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

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:

[TABLE=6]

*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

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:
[TABLE=2]
*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 second aerial census of the 2009-10 whooping crane season was conducted 02 December 2009 in a Cessna 210 piloted by Gary Ritchey of Air Transit Solutions of Castroville, Texas with USFWS observer Tom Stehn. Visibility was very good for most of the flight, but mid-day winds gusting to 25 from the northwest made for a bumpy ride and made the made the task of finding cranes more difficult. Sighted were 191 adults and 17 juveniles = 208 total. This was an increase of 117 cranes since the last flight conducted November 12th. 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.

November 12th – Recap of cranes (208) found at Aransas on the aerial:

[TABLE=3]

Migration Update: Cold fronts that reached Aransas on November 16, 20, 24, and 30 helped the cranes complete their 2,400-mile long migration that had begun 2 months ago for some birds.
Additional cranes are known still in migration in KS, OK, and TX, although numbers are much lower than the big wave of cranes that moved through OK and KS in mid-November. Three other whooping cranes are presently near the coast. On December 1st, one whooping crane was confirmed in a flock of sandhills near Collegeport, about 50 miles northeast of Aransas. Two cranes have been staying north of Tivoli about 15 miles north of Aransas. The addition of these 3 cranes brings the estimated total on the coast to 211.

Crane Identities: The Mustang Lake pair of cranes visible from the refuge observation tower arrived approximately November 24th.

Habitat Use: Tides measured at the refuge boat ramp were high (2.5 feet). The marshes on San Jose Island were notably flooded with large expanses of open water. Salinities dropped noticeably in November so that the cranes are drinking directly from the marsh and have stopped making flights to fresh water dugouts. Salinities on 12/02 were measured at 15 parts per thousand (ppt) at the refuge boast ramp and at 5 ppt in the adjacent marsh. The refuge received 7.8 inches of rain in November as El Nino ended the drought. The largest rain received was 4.35 inches on November 20th. Other areas including Rockport and Lamar got between 12 and 16 inches of rain during that same storm event.

The cranes have responded to the flooded conditions with 33 cranes seen on uplands during today’s flight. I’ve seen this before when cranes utilized freshly flooded uplands with Aransas having received additional rain December 1st. Two cranes were near an upland crane feeder on the Lamar Peninsula. No cranes were in open bay habitat, and there are currently no prescribed burns in the crane area. The largest group size observed was 7 birds seen on in salt marsh on the south end of Matagorda Island. Numerous photographs were taken to document the spread of black mangrove into the crane area.
– Tom Stehn, Aransas National Wildlife Refuge

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

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