Poplar Island Tern followed to Aruba


A new tagging system aims to track young Chesapeake waterfowl that overwinter in the south. And thanks to a bird watcher from Aruba, we can see that it works.

From terns to ospreys, the summer-born chicks in the bay face the daunting challenge of migrating thousands of miles and more to Central and South America just a month after learning to fly and fly. catch fish.

It is always a risky trip for these young, inexperienced seabirds, and mortality is high, but clear sightings are rare. The digital age offers advanced radio telemetry (tagging) systems in tiny packages that even a bird as small as a common tern can carry without hindering its activities, including fishing, breeding, rearing young and migrating. The challenge is how to tag a still growing chick without hampering its ability to continue to develop.

Biologists from the Eastern Ecological Science Center (USGS EESC) of the US Geological Survey at the Patuxent Research Refuge combined digital magic with engineering to develop two types of flexible harnesses that would allow a tern chick to wear the transmitter ( with two leg tags standardized according to the US Fish & Wildlife Service system). Working with surrogate chicks of similar size, feathers and weight (Japanese quail), they found that leg loop harnesses constructed from elastic cords and teflon-type tape backpack harnesses are suitable. to be attached to growing juveniles. Working with biologists from the Maryland Department of Natural Resources and the USFWS, they banded 18 adult common terns and 24 chicks at the Poplar Island restoration site in June.

An adult originally given leg bands on Poplar Island in 2017 and fitted with a flexible harness transmitter this year has traveled more than 1,850 miles to Aruba, where a local naturalist saw him and photography. The EESC report suggests that “this tern will stay until next spring or rest before continuing its migration to wintering grounds as far south as Peru”.

The Aruban Community Scientist’s report is particularly useful because the radio beacons used in this project rely on receivers to collect detections, and none of those receivers are located in the area where the bird was seen.

“The information gained from tracking the movements of these common terns and others will improve understanding of how individuals breeding on Poplar Island use habitat locally and globally.” Ultimately, the data collected through this project will help inform habitat conservation and management efforts for common terns, which are listed as endangered in Maryland. ”

Now, when we see terns flying over the bay next summer, we’ll know a little more about the epic migrations of these little birds, thanks to the tagging project.

-John Page Williams

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