This drought that griped the state of Texas in 2007 effecting mostly central Texas and the mid gulf coastal area, has finally been relieved in November 2009. In Port Aransas, Texas and the surrounding area received over 7.8 inches of rain in 26 hours with surround areas getting
higher totals. The rain was wide spread enough to benefit the entire the entire coastal bend. The
Aransas National Wildlife Refuge had significant rain and most of the streams and rivers that feed the surrounding bays and estuaries are flowing with fresh water. This should help the Whooping Crane who were devastated last year because of the harsh conditions brought on by the drought. Lack of fresh water, therefore less food , especially blue crabs.
After the Spring of 2008 the drought that had a strangle hold on most of the state of Texas
ultimately caused last years unusually high mortality rate of our endangered Whooping Cranes. Very high salinity levels and very poor conditions through out their wintering area was caused by lack of fresh water flowing into the bays and estuaries. Wolfberries, a favorite food, was non-existent and the developmental of our blue crabs was severely limited. Blue crabs are the major high quality food source in the Winter. In wet years blue crabs are plentiful for food and the Whooping Cranes are able to find plenty to eat in the bays and estuaries.
The Whooping Crane population which hit an all time record of 270 when they arrived in
the Fall of 2008, however they lost 8.5% of the population over the winter - a total of 23 died.
Most died from malnutrition and those that made their return to Buffalo National Park in Canada
arrived in such poor condition and had very little breeding success. Out of 63 nests only 22 chicks fledged. Hopefully the recent rains will improve their habitat at the Aransas Reserve along the Texas gulf of Mexico and the ones that return to Canada nest Spring will be in good shape for a better breeding season.
(Note:) The definition of an estuary is where salty sea water meets the land and mixes with the fresh water from creeks and rivers. They are the nursery grounds for our marine organisms
such as fish, shrimp, crabs, mussels, clams and such. They are not only important to out wildlife
but ultimately to our own existence.
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| Photos courtesy of Bruce Rosenstiel. The dickcissel, above, and the scissor-tailed flycatcher, below, are grassland Neotropical migrants. |
Drought reduces bird populations in a 15-state region in the central United States, according to “Effects of Drought on Avian Community Structure,” published Dec. 21 in Global Change Biology, coauthored by Dr. Brian Wardlow, GI Science program area leader at the National Drought Mitigation Center. Wardlow was part of a team led by researchers at the University of Wisconsin-Madison.
“Our big motivation for this project is to find out to what extent extreme weather is affecting bird communities across the United States,” said Dr. Thomas P. Albright, a post-doc in the SILVIS Lab at UW-Madison. “There are pretty strong measured effects if you select precipitation at the right time frame. “
The researchers found that both the number of individual birds and the number of bird species in a given area declined during and after droughts of 32 weeks or longer, Albright said. Overall, bird populations declined by more than 10 percent in dry areas.
The effects of drought varied according to climate regimes – mountainous, arid plains, or more humid temperate areas. They also varied according to birds’ migratory patterns.
The most vulnerable were those that migrated long distances. Birds that migrated short distances suffered smaller declines in population, and birds that stayed put had the smallest declines. In fact, non-migrating birds in western mountainous areas saw populations increase by an average of 10 percent during drought. Birds that receive food, water or habitat from humans also fared comparatively well. The effects of drought were more pronounced in the arid central plains than in the more humid eastern states.
The most vulnerable were those that migrated long distances. Birds that migrated short distances suffered smaller declines in population, and birds that stayed put had the smallest declines. In fact, non-migrating birds in western mountainous areas saw populations increase by an average of 10 percent during drought. Birds that receive food, water or habitat from humans also fared comparatively well. The effects of drought were more pronounced in the arid central plains than in the more humid eastern states.
After examining various possibilities, the researchers determined that the Standardized Precipitation Index, with its flexible time scale, was the most useful way to characterize drought. The researchers compared periods of drought with bird counts from the North American Breeding Bird Survey, a monitoring program established in 1966 by the U.S. Geological Survey and the Canadian Wildlife Service. Subsequent research is likely to focus on finding the precise mechanisms responsible for the population declines, Albright said. Possibilities he cited included birds dying from lack of water, food or habitat; birds dispersing to alternate locations; and/or birds not reproducing when they are under drought stress.
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.
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.