Wintering Whooping Crane Update, February 6, 2020

Wade Harrell, U.S. Whooping Crane Recovery Coordinator

whooping crane abundance survey
Birds on the ground, viewed from the survey plane (original photo: Tom Stehn)

We completed our annual whooping crane abundance survey last week, and were able to fly three primary surveys and two secondary surveys. Areas surveyed stretch along the Texas coast from Matagorda to Port Aransas.  Phil Thorpe, pilot with the USFWS Migratory Birds program, flew the survey crew in a wheeled Kodiak again this year. In addition to an overall estimate of the winter population size, the survey provides us an estimate of how many juveniles were “recruited” into the population last summer. Better juvenile recruitment this past year in Canada (37) compared to 2018 (24) should result in a larger population this year.  For more information on our wintering abundance survey, click here.

Our secondary survey (on the edges of the core wintering range) is crucial in determining future expansion areas for a growing population. We are getting reports of whooping cranes in quite a variety of places outside our primary survey area this year, including a pair near Matagorda, Texas, three adults in Port Aransas, and marked birds in Colorado County.  A juvenile whooping crane marked last summer in Wood Buffalo National Park stopped migrating in Kansas, and is currently with a flock of sandhill cranes at Quivira National Wildlife Refuge (NWR).

Efforts to trap and mark whooping cranes here at Aransas NWR for our telemetry study is ongoing, and thus far this winter we have marked 6 whooping cranes with cellular telemetry devices. With these devices providing locations every 15 minutes, we are able to understand daily movements (night and day) and habitat use at a level that was not available even a few short years ago. You can find more about our use of this revolutionary technology to conserve whooping cranes here.

There are several opportunities for visitors to Aransas National Wildlife Refuge to view whooping cranes in publically accessible areas this winter. Whooping cranes have been consistently sighted this winter from the Heron Flats viewing deck at a much closer distance than the pair at the observation tower, providing visitors a more intimate viewing experience.  You can find a map of the refuge trails here.

Habitat Management on Aransas NWR:

Due to wet weather, we are just getting started on prescribed burning.  Our goal is to burn approximately 13,000 acres this year, the majority of which is whooping crane habitat.  So far we have completed prescribed burns totaling 1,600 acres on the Blackjack Peninsula and plan to burn at least 900 acres more this week.

Fire crews responded to a wildfire on Matagorda Island in early December.  Although this fire was unplanned, it will provide immediate and long-term benefits to whooping cranes and other wildlife. Part of the area that burned was scheduled to be burned this winter to improve habitat for whooping cranes and other wildlife. Whooping and sandhill cranes will both feed in “blackened” or freshly burned habitat and burning woody/brush species around freshwater ponds removes cover for predators. Fire also maintains coastal prairie habitat that benefits Aplomado Falcons and other prairie-dependent species.

Recent Precipitation/Salinity around Aransas NWR:

January-February-current precipitation: 4.85” @ Aransas HQ
Salinity at GBRA 1: averaging around 19 ppt

Share

Whooping Crane Survey Results: Winter 2018–2019

504 Wild Whooping Cranes Estimated at ANWR this past winter

 

Whooping Crane Population
Whooping Crane at Aransas National Wildlife Refuge. Photo by Kevin Sims®

U.S. Fish and Wildlife Service biologists have completed analysis of last winter’s aerial surveys of the Aransas-Wood Buffalo whooping crane population. “Preliminary data analysis indicated 504 whooping cranes, including 13 juveniles, in the primary survey area (approximately 153,950 acres) centered on Aransas National Wildlife Refuge near Austwell, Texas.

This is comparable with the prior winter’s estimate of 505 whooping cranes, indicating the population remained stable but did not experience the growth this year that it has the past several years. An additional 12 birds were noted outside the primary survey area during the survey. This marks the 2nd year in a row that the population has topped the 500 mark. The lack of population growth last winter likely resulted from a low chick production season on the breeding grounds of northern Canada during the spring-summer of 2018.”

 

Delay in Whooping Crane survey

During winter 2018–2019, the U.S. Fish and Wildlife Service continued to use a Quest Kodiak aircraft and surveys were conducted in mid-February. The primary survey area (approximately 153,950 acres; Figure 1) was surveyed multiple times during February 9–14, 2019. San Jose Island, West Marsh, Lamar-Tatton, Matagorda Island Central, and Welder Flats-Dewberry were surveyed 4 times and Blackjack was surveyed 5 times. Due to logistical constrains and poor weather conditions, the secondary survey areas (approximately 169,300 acres; Figure 1) were not surveyed this winter. Due to unforeseen circumstances, the U.S. Fish and Wildlife Service conducted the survey later than planned which likely resulted in underestimates of recruitment due to late season changes in plumage coloration.

No growth this year for Whooping Crane Population

The long-term growth rate in the whooping crane population has averaged 4.5% (n = 95; 95% CI = 1.77– 6.98%). The population remained stable from winter 2017–2018 to winter 2018–2019  In summer 2018, the Canadian Wildlife Service reported 24 whooping crane chicks were fledged at Wood-Buffalo Nation Park which is lower than normal. Recruitment was low resulting in no population growth.

You can see the full report at the following link:
https://ecos.fws.gov/ServCat/DownloadFile/166739

***** FOTWW’s mission is to help preserve and protect the Aransas/Wood Buffalo population of wild whooping cranes and their habitat. *****

Friends of the Wild Whoopers is a nonprofit 501(c)3 organization.

Share
Wintering Whooping Crane Update

Wintering Whooping Crane Update, February 6, 2019

Wintering Whooping Crane Update Time
Dr. Wade Harrell, U.S. Whooping Crane Recovery Coordinator

Wintering Whooping Crane Update
Getting ready for the annual whooping crane abundance survey at Aransas National Wildlife Refuge

We plan to begin our annual whooping crane abundance survey this week, and our goal is to fly a minimum of six survey days. Phil Thorpe, with our Migratory Birds Program, will be piloting us in a wheeled Kodiak. Hopefully our dreary and wet weather as of late will clear enough to allow safe flying conditions.

Recruitment of juvenile cranes

In addition to an overall estimate of the winter population size, the survey provides us an estimate of how many juveniles were “recruited” into the population this year. Simply put, the only way to effectively grow a population is for births to exceed deaths—i.e. recruiting juveniles into the adult population. The past few years’ increases have been tied to high numbers of fledged chicks on the breeding grounds, but Canada only estimated 23 fledged chicks during their survey this past August. For comparison, that is 40 fewer chicks than reported in the August 2017 survey. Annual variation in fledged chicks is to be expected and we’ve seen this amount of fluctuation in the historic survey records dating back to the 1950’s. Weather in the breeding grounds is often a major driver of chick fledging rate in Wood Buffalo National Park. This past June, when most eggs were hatching, was unseasonably cold and wet—not ideal conditions for early chick survival.

Technology allows for better tracking

Wintering Whooping Crane Update
Whooping Crane family in the morning sunlight at Aransas NWR. Photo by Kevin Sims – Aransas Bay Birding Charters (Click on photo to view full size)

Efforts to trap and mark whooping cranes here at Aransas National Wildlife Refuge (NWR) for our telemetry study is ongoing, and thus far this winter we have marked 6 adult whooping cranes here on the Refuge with cellular telemetry devices. With these devices providing locations every 15 minutes, we are able to understand daily movements (night and day) and habitat use at a level that wasn’t available even a few short years ago. You can find more about our use of this revolutionary technology to conserve whooping cranes here.

One of the new developments that this technology is revealing is how and when whooping cranes move around here on the wintering range. In the past, we understood wintering whooping cranes, particularly mated pairs, to stay in a “territory” or one general area of a few hundred acres, all winter. With the telemetry data, we are starting to see a much more complex picture of movement, with some whooping crane pairs mostly following our traditional understanding of a single territory and others making multiple movements across the entire wintering range throughout the winter. It is difficult to say whether this is related to food availability or simply individual differences, but it does help us understand the need to focus our conservation efforts at a landscape scale—well beyond Refuge boundaries.

Opportunities for viewing whooping cranes

There are several opportunities for visitors to Aransas NWR to view whooping cranes in publicly accessible areas this winter. Whooping cranes have been consistently sighted from the Heron Flats viewing deck, the observation tower and the tour loop near Mustang Slough. We also consistently observed a family group of whooping crane in the Mustang Lake salt marsh in front of the observation tower, so you have an excellent opportunity to view whooping cranes at a respectful distance. Please come by and say hello to us at this year’s upcoming Whooping Crane Festival starting February 21 in Port Aransas!

Habitat Management on Aransas NWR

No prescribed burns have taken place yet this winter due to the wet conditions.  However, we are planning for prescribed burns on the Blackjack Unit of Aransas NWR this winter pending drying conditions.

Recent Precipitation/Salinity around Aransas NWR

December-current precipitation: 6.38” @ Aransas HQ

Salinity at GBRA 1: averaging around 11 parts per thousand.

 

Share

Estimated Texas Wintering Whooping Crane Population Breaks 500

U.S. FISH AND WILDLIFE SERVICE

FOR IMMEDIATE RELEASE

Date:  August 21, 2018

Contact:  Wade Harrell, 361/676-9953 wade_harrell@fws.gov

Beth Ullenberg, 505/248-6638 beth_ullenberg@fws.gov

Estimated Texas Wintering Whooping Crane Population Breaks 500

Whooping Crane Population
Whooping Crane at Aransas National Wildlife Refuge. Photo by Kevin Sims®

Survey accuracy improved with shift from December to February timeframe

The first winter after Hurricane Harvey ravaged the Texas Gulf Coast, an estimated 505 whooping cranes arrived on their Texas wintering grounds after migrating 2,500 miles from their breeding grounds in Wood Buffalo National Park in Canada.  Each fall the birds make their way back to Aransas National Wildlife Refuge and surrounding habitats, where they spend the winter.  Once they have arrived, wildlife biologists with the U.S. Fish and Wildlife Service survey the birds by air and analyze population trends.

Biologists have completed analysis of aerial surveys of the Aransas-Wood Buffalo whooping crane population done last winter.  A switch in aircraft the previous winter and a shift to surveying later in the winter when a larger proportion of the population had arrived helped improve accuracy of the counts.  Preliminary data analysis indicated 505 whooping cranes, including 49 juveniles, in the primary survey area (approximately 153,950 acres) centered on Aransas National Wildlife Refuge near Austwell, Texas. An additional 21 birds were noted outside the primary survey area during the survey. This marks the 6th year in a row that the population has increased in size and the first time the population has topped the 500 mark.

“Breaking the 500 mark for this wild population is a huge milestone”, stated Amy Lueders, the Service’s Southwest Regional Director. “Seeing this iconic bird continue to expand demonstrates how the Endangered Species Act can help a species recover from the brink of extinction.  I have to credit our biologists and our partners and local communities who continue to invest so much time and effort to improve our ability to make sure future generations have the chance to marvel at the beauty of these amazing wild birds.”

The U.S. Fish and Wildlife Service has implemented several small changes that have greatly improved the agency’s capacity to survey the birds. “After two years of testing a shift of our December survey timeframe to later in the winter, we believe our previous survey estimates were likely low given that not all the whooping cranes had completed migration by mid-December. We had indications of a later than expected fall migration over the last several years via migration reports and telemetry data. This is the first year that we have based our winter abundance estimate from a February survey timeframe rather than a December timeframe. It may seem like population numbers jumped more than usual, but in reality we are just capturing a more complete proportion of the population, with most birds having completed migration by early February” stated U.S. Fish and Wildlife Service Whooping Crane Coordinator Wade Harrell.

Harrell said biologists will continue to conduct flights in late January and early February for future surveys.  He also stated that staff at Aransas National Wildlife Refuge continue to make progress in recovering from the impacts of Hurricane Harvey.  “The good news is that the coastal marsh that supports our wintering whooping cranes was not significantly damaged by the hurricane and recovered quickly from any impacts, demonstrating how resilient intact wetland habitats can be.”

Whooping cranes are one of the rarest birds in North America and are highly endangered. Cranes have been documented to live more than 30 years in the wild.   Adults generally reach reproductive age at four or five years, and then lay two eggs, usually rearing only one chick.

More information about the survey and whooping cranes can be found on the Aransas National Wildlife Refuge website at http://www.fws.gov/refuge/Aransas/ or by calling the Aransas National Wildlife Refuge Visitor Contact Station at: (361) 349-1181.

To read an in depth report of the survey results in PDF format, click here.

The mission of the U.S. Fish and Wildlife Service is working with others to conserve, protect, and enhance fish, wildlife, plants, and their habitats for the continuing benefit of the American people. We are both a leader and trusted partner in fish and wildlife conservation, known for our scientific excellence, stewardship of lands and natural resources, dedicated professionals, and commitment to public service.

 For more information on our work and the people who make it happen, visit www.fws.gov. Connect with our Facebook page at www.facebook.com/usfws, follow our tweets at www.twitter.com/usfwshq, watch our YouTube Channel at http://www.youtube.com/usfws and download photos from our Flickr page at http://www.flickr.com/photos/usfwshq.

Share