Argos Satellite Transmitters Help Track Large Scale Movements of Whooping Cranes Reintroduced into Southwestern Louisiana
 

Story and photos by: Eva Szyszkoski and Sara Zimorski, Louisiana Department of Wildlife and Fisheries

​

Whooping Cranes, previously found throughout North America, came perilously close to extinction when only 21 birds remained during the winter of 1942. In the United States, the Whooping Crane was listed as endangered in 1970. This listing was grandfathered into the Endangered Species Act of 1973. In 1995, separate Whooping Crane Recovery Teams (in the United States and Canada) were joined together to form an international team which developed the conservation actions that would be required to protect the species from extinction  with the eventual goal of delisting.  Although the migratory, naturally occurring wild flock is slowly growing, the majority of the population occupies the same geographic locations during the summering and wintering months, and travel along the same narrow corridor through the central U.S. during migration. This leaves them potentially susceptible to the same threats, for example, a chemical spill or a natural disaster. Additionally, any contagious disease could be easily spread throughout the population. Therefore, the recovery plan calls for the establishment of additional, separate, self-sustaining populations to safeguard against a catastrophic loss of the remnant flock.
 

The Louisiana non-migratory population of Whooping Cranes was established by the Louisiana Department of Wildlife and Fisheries (LDWF), along with partners, in 2011. Although it is the fourth attempt to establish a new population of Whooping Cranes, it is the first time a reintroduction is taking place in an area where Whooping Cranes were historically present. The last documented breeding in the United States, prior to breeding in reintroduced populations, occurred in 1939 on land that is now the White Lake Wetlands Conservation Area. Juvenile cranes have been released here each winter since 2011.
 

Each bird in the first four cohorts (n = 50) received an Argos GPS satellite transmitter to allow close monitoring of movement and survival. Additional types of transmitters have since been used, but the majority of the birds continue to carry Argos GPS satellite transmitters. As the cranes have reached breeding age, transmitter data has also assisted biologists with monitoring nesting activity.
 

Transmitters are programmed to collect three points per day and transmit the data every two days. Using these data, we are able to track the cranes as they move around the landscape. While most cranes remain in southwestern Louisiana and eastern Texas, a few have made significant movements that may not have been detected if not for the Argos transmitters.
 

Movement into Canada

​

In May 2017, two individuals (both one-year-old males) moved west into Texas before turning north and traveling approximately 1,700 miles to reach the Canadian province of Saskatchewan. Although transmitter data was available from only one of the birds, both cranes were observed and photographed in southeast Saskatchewan later that month. In early June, one of the cranes flew farther west, eventually settling in southern Alberta. He was observed alone at this location and the status of the second crane remains unknown. In mid-September, after almost three months in southern Alberta, transmitter data indicated he was on the move again; back in the United States, and on a trajectory towards southwestern Louisiana. Based on his movements, we believe that he encountered migrating Sandhill Cranes somewhere in Nebraska or Kansas, as his trajectory changed slightly. He is now wintering with a large flock of Sandhill Cranes in northwest Texas.

​

Movement to Arkansas

​

Through data from their Argos transmitters, we have documented birds from the Louisiana non-migratory population traveling into Arkansas on three separate occasions.

 

Two of these instances involved young birds on extended exploratory flights, where they spent only a few nights in Arkansas before returning to Louisiana. However, in mid-June 2017 we documented a pair of three-year-old birds moving north through Louisiana into southeastern Arkansas. They settled on private property in Chicot County where they remained for almost three months before returning to Louisiana. Local landowners and state officials were easily able to assist with monitoring the pair due to the location data provided by an Argos satellite transmitter on one of the cranes.

​

Movement into the eastern flyway

​

In late November 2017, a newly released juvenile female left the White Lake Wetlands Conservation Area and flew east, spending several weeks in the coastal marshes of southeast Louisiana. Data indicated she initially began moving back west in early December, however she then turned and continued farther east and then north, eventually settling in southeastern Alabama. This region of the United States is part of the eastern migratory corridor for Sandhill Cranes as well as a reintroduced population of Whooping Cranes. While she has not been observed near any other cranes, it is possible that she may come across some and this could greatly influence whether or not she returns to Louisiana in the future. With her Argos enabled transmitter, we will be able to track her future movements.

​

The data from the Argos satellite transmitters has proved invaluable when the Louisiana non-migratory birds make long distance movements. The data enables LDWF biologists to provide regular updates to state and federal officials when Whooping Cranes travel outside of Louisiana. Due to the nature of the Endangered Species Act, tracking these movements is especially important. While in Louisiana, the Whooping Cranes, while still protected under the ESA, are considered “non-essential, experimental” which allows for greater management flexibility of the population and allows landowners to continue normal activities, farming for example, on their property even if a Whooping Crane is present. This designation is geographic however, and Whooping Cranes that move into Texas or other states in the western United States are considered fully endangered and stricter regulations can be enforced.  Without the use of Argos enabled devices, these long distance movements may not have been known or documented, as the focus of aerial and ground tracking is limited to a smaller geographic area where the majority of the cranes reside.