The BTX in Mexico: Impressive shorebird migration and an old Cabot's Tern

May 18 2017 by Leander Khil | Category: Telescopes

The BTX in Mexico: Impressive shorebird migration and an old Cabot's Tern
  • The BTX in Mexico: Impressive shorebird migration and an old Cabot's Tern The banded Cabot's Tern (Thalasseus acuflavidus), waiting for attention.
  • The BTX in Mexico: Impressive shorebird migration and an old Cabot's Tern Waiting for the last numbers on the band's code to become visible.
  • The BTX in Mexico: Impressive shorebird migration and an old Cabot's Tern The patrolling Magnificent frigatebirds (Fregata magnificens) helped a lot.
  • The BTX in Mexico: Impressive shorebird migration and an old Cabot's Tern For a little extra challenge, the band was mounted upside down.
  • The BTX in Mexico: Impressive shorebird migration and an old Cabot's Tern The salt flats at Las Coloradas.
  • The BTX in Mexico: Impressive shorebird migration and an old Cabot's Tern Feeding sandipers, getting ready to migrate back to the north.
  • The BTX in Mexico: Impressive shorebird migration and an old Cabot's Tern Colorful dots on the salt flats: American Flamingos.

Spending more time with the new BTX in a warmer surrounding was high on my list after getting to know it in Winter. The Yucatan peninsula in Mexico served as a great birder's playground, to have many longer birdwatching sessions and to get familiar with the innovations of the BTX. The marvelous Caribbean beaches and the salt flats in the north of the peninsula were my target areas.


Decoding a tern's band with the BTX

Reading and reporting the code on the band of a bird's leg is not only very important for research, it can also enhance your personal birding experience. From the life history of the bird, you can learn about the individual's age, origin and previous sightings.
On a run-down, wooden dock in a remote place of Ascension Bay, I checked the legs of wintering Royal terns (Thalasseus maximus) and Cabot's terns (T. acuflavidus).
Among the resting flock, one Cabot's tern sported a shiny metal ring, with a code engraved on it. Unfortunately, the code stretched all around the band, making just a fraction of it visible from my perspective. In order to read the whole number, I had to wait for the bird to turn 360°, something relaxing terns don't do frequently…

I was glad to have the BTX with me, as I saw a long, meditative session of “staring at terns” coming up. I focused on the band, put on some sunscreen, leaned my head against the forehead rest and waited, keeping the sleeping terns under surveillance. Whenever one of the patrolling frigatebirds would fly over, the terns startled up, opening their wings - getting ready to flee in case of an attack. Thanks to the repeated, short activity, the band slightly shifted position and with time, more and more digits became visible.
Finally, I had the full combination secured, and reported my observation to the institution in charge. I was delighted to read the life history of the bird: it had been banded as a chick in June 2002, in a tern colony in North Carolina, USA. Two thousand two hundred kilometers to the north-east, as the tern flies. Since then, it had not been seen anywhere else. So the observation was the first recovery of this 15 years old Cabot's tern! Patience paid off here and good equipment was essential for the success. By the way: The absolute age record for this species is even a startling 24 years.


American shorebirds ready for takeoff

Getting to see massive gatherings of American shorebirds in the salt flats around Las Coloradas was a definite highlight and another great opportunity to let the BTX do what it was designed for: making long hours of observing birds as comfortable as possible.
Watching feeding flocks of thousands of sandpipers getting ready to migrate back to the high arctic was amazing. But it was a big challenge too: Still in their drab winter plumage, it's not easy to tell apart some of the nearctic species.
First and foremost, the distinction between Western sandpipers (Calidris mauri) and Semipalmated sandpipers (Calidris pusilla) was a trying task. These species reach Europe as rare vagrants only, and you want to be prepared for the day you come across one of them! Immersing myself into the observation, studying the movements, features and tiny details was a great experience. And the BTX did not disappoint. The hours of scanning the flats, discerning features and simply enjoying watching the “peeps” were relaxing and pleasing as never before.

 

About the author

Leander Khil is an ornithologist, birdwatcher and wildlife photographer from Graz, Austria. Driven by his love for birds, adventure and the outdoors he travels the world since he was a child.
web: www.leanderkhil.com facebook: facebook.com/leander.khil instagram: www.instagram.com/khil.birder.photographer

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