Tucker River Fellows Program: Creepy food storage tips from the loggerhead shrike

Louisiana water thrush

After our stormy, sleepless night, we woke early and enjoyed some oatmeal. John and Lizzie had already set the bird nets and collected a bird; it was a migrant called a Louisiana water thrush. It migrates to Central America and breeds in the southern United States. This thrush was banded and we returned close to the collection location to release it - this bird likes to live near the banks of intermittent streams.

getting ready to release the thrush

post-release

The bird nets are fine nets with about 4 pockets positioned perpendicular to the river. Most of the nets were set low and so trap low-flying birds. A canopy net was also set, but we didn’t get any birds collected from this net. The nets need to be checked every 30-45 minutes so after releasing the thrush we walked the nets a second time, where we collected a Carolina Wren- the wren was put beak first into a cloth bag for the return trip to the bird banding station. While on our walk we encountered a Black Locust tree and Lizzie pointed out the extremely spiky bark.

Loggerhead shrike- impales food on spikes

We were surprised to learn that a bird called the loggerhead shrike impales frogs and small rodents on the spikes to create a food cache for itself.

Once back at the station, we observed the unhappy wren having wings and beak length measured, weight taken, and a metal band placed around its ankle. This particular bird is a local resident and a juvenile. While in the lab we learned more about some birds that are repeatedly captured and what happens if an already banded bird is caught. John told us of a bird he captured in the Arctic with a Tasmanian tag he looked up. In the databse, he found that the bird was nine years old and had made the journey from the Arctic to Tasmania 9 times!

We also learned about migration in general. Many birds know when to migrate based on length of days (photoperiod). They are able to find their way using stars, magnetic field, land masses and scent. Often, only 1/2 of the birds that migrate survive. Their travel is threatened by bad weather, hunting/trapping, predators, collisions with windows and light pollution.