January 10, 2013

Whooping Crane Update

 Wade Harrell, U.S. Whooping Crane Recovery Coordinator

Whooping Crane News:
The tracking partnership continues to provide us new insight into whooping crane use of traditional coastal marsh areas. For example, we continue to note more extensive movement of family groups from the Blackjack peninsula to Matagorda/San Jose Islands during the winter season than previously documented.

Items of note from Texas Whooper Watch and other observers of whooping cranes observed outside the winter survey area include the following (from LeeAnn Linam, TPWD): 

•Sightings since mid-December have indicated that only one family group and one pair remain at Granger Lake. The family group using the area includes one satellite radio marked bird, so we are able to monitor movements. However, LeeAnn reported that she has an unconfirmed sighting of another family group using farm fields nearby, so there still may be a total of 8 birds in the area. The Granger Lake manager recently observed some courtship behavior, including object tossing, and other observers have noted some dancing.

•Local biologists, game wardens, and landowners continue to sight 5 whooping cranes (a family group and a pair) northwest of El Campo. One of these birds is a radio marked chick, and we have noted quite a bit of movement over the past several weeks. These cranes are using rice fields and flooded impoundments, along with numerous waterfowl and sandhill cranes.

•Guadalupe Delta – Brent Ortego (TPWD) reports that the Guadalupe Delta Christmas Bird Count on December 20 detected at least two pairs of whoopers, one near River Road and one near the Barge Canal. We had previously noted a pair in the southern part of the Guadalupe Delta while flying our secondary survey areas. At this time, the Guadalupe Delta is not in our primary survey area, but we will continue to evaluate if the area is supporting enough overwintering cranes to warrant adding it to the primary survey area in future years.

 We are working to confirm several other reports of whooping cranes outside the normal coastal winter range, stay tuned!

Surveys & Monitoring:
As reported in the last update, we have completed aerial surveys for our peak winter abundance estimate. Our regional office Biological Inventory and Monitoring team is diligently working to analyze the data and we hope to be able to release a peak whooping crane estimate by the next update. The final draft protocol for our abundance estimates is close to completion, and it will be sent out for external peer review sometime in February.

Satellite Tracking Study:
The US Geological Survey, International Crane Foundation, Gulf Coast Bird Observatory and other partners have marked a total of twelve whooping cranes as of January 7th. The trapping team worked over this past weekend and early this week to mark 3 additional birds and hope to mark one more bird before finishing the winter field season the end of this week. Currently, over 40 marked birds in the flock are being tracked.

Relatively dry conditions persist around the Refuge, since the last update we have received about 2 inches of rain. We expect the low pressure system currently in place will increase our rainfall totals significantly and hopefully enhance coastal marsh conditions for the whooping cranes. The salinity level in San Antonio Bay was reported at 24 parts per thousand on January 9, and we expect that salinity will decline following the recent rains. NOAA reported this morning that the lower Guadalupe River will reach minor flood stage at Bloomington this weekend, which should give us a needed freshwater influx into San Antonio Bay.

Food Abundance:
Given the colder water temperatures (54F reported Jan. 9) and associated low tides we recently experienced, it appears that blue crabs and wolfberries are becoming less abundant in the marshes and whooping cranes are likely beginning to transition to increased use of other late-winter food sources. Refuge staff plan to prescribe burn a total of 8,000 -10,000 acres this winter to assist in providing food sources for the cranes. To date, 6,500 acres have been burned since October 2012.