December 22, 2015

Wintering Whooping Crane Update, December 22, 2015
Wade Harrell, U.S. Whooping Crane Recovery Coordinator

We successfully completed our annual whooping crane abundance survey last week.  We flew 6 surveys, beginning on Monday, December 7 and ending this past Thursday, December 17, 2015. We did have several weather-related delays such as lingering fog, so we feel extremely fortunate that we were able to complete the 6 survey flights that our whooping crane abundance survey protocol requires. Once again, Terry Liddick, pilot/biologist from our migratory birds program, served as pilot, flying a U.S. Fish & Wildlife Service Cessna 206. Observers were Wade Harrell and Beau Hardegree (Coastal Program Biologist, Corpus Christi FWS office). Doug Head (Refuge Inventory & Management biologist) served as ground survey coordinator and Diane Iriarte (Refuge biologist) served as data manager.

Data management and analysis once the actual survey is complete is a significant effort conducted by multiple staff members, so we won’t have the final results to present for a few months. However, here are some general post-survey observations:

We consistently observed whooping cranes using 4 units of Aransas National Wildlife Refuge (Blackjack, Matagorda, Tatton and Lamar) and 3 Texas coastal counties (Aransas, Calhoun and Matagorda).

  • Overall, habitat appeared to be in excellent condition compared to the past few years. We observed a significant amount of freshwater and green, lush vegetation in upland areas. Coastal marshes had higher than normal water levels due to high tides.
  • Linear distance from the southernmost whooping crane group observation to the northernmost crane group observation was 63 miles (101 km).  Note that Stehn and Prieto (2010) reported that the linear distance between crane groups in 2007 was 43 miles (69 km).
  • Similar to last year, we observed larger than average group sizes (>8) of whooping cranes in several of our primary survey blocks, with these groups consistently observed in the Blackjack and Welder Flats primary survey blocks.
  • We did not observe any family groups that included 2 juveniles (i.e. commonly referred to as “twins”).
  • Whooping cranes were detected in 4 of our secondary survey areas (Holiday Beach, Powderhorn Lake, Matagorda Island North and Mad Island).
  • While coastal salt marsh was the most common habitat type that we observed whooping cranes using during the survey, we observed whooping cranes using a wide variety of other habitat types as well including freshwater wetlands, upland prairies and shrublands and open-water bay edges.


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 from the Heron Flats viewing deck, the observation tower and the tour loop near Mustang Slough (recent prescribed burn).

I want to note that the annual whooping crane abundance survey is a collective effort, with the pilot and observers in the plane only serving one small role within the overall survey. I would like to personally thank Joe Saenz, Aransas NWR project leader, for serving as overall manager of the effort; Doug Head, Refuge Inventory & Monitoring biologist for serving as survey coordinator; Diana Iriarte, Aransas NWR biologist, for serving as our go-to data collection technology and data management specialist; Susie Perez and Josie Farias, administrative staff at Aransas NWR, for assisting with logistics; and Grant Harris and Matthew Butler from our Refuge Regional Office Inventory & Monitoring Team for survey protocol development and data analysis.

We will be flying some additional training surveys in early January in order to get 2-3 new observers up to speed and ready to start collecting data for next year’s survey.

Habitat Management on Aransas NWR:

Refuge staff completed one 654 acre burn on the Blackjack Unit of the Refuge in early December. We have plans in place to implement additional prescribed burns on the Blackjack Unit, Tatton Unit and Matagorda Island Unit of Aransas NWR this winter.

Recent Precipitation/Salinity around Aransas NWR:

November precipitation: 1.23” @ Aransas HQ

December precipitation (as of 12/20): 0.64” @ Aransas HQ

Salinity at GBRA 1: averaging around 13 ppt

Literature Cited: Stehn and Prieto. 2010. Changes in winter whooping Crane territories and range 1950-2006. Proc.  North Am Crane Workshop 11, 40-56.