Aug 072015

Two weeks ago, when we received the news that five of the migratory thrushes tagged with radio-transmitters in Colombia had been detected in North America, we considered ourselves pretty lucky. However, these amazing long-distance migrants had even more surprises in store for us. Remarkably, an additional 14 thrushes have been detected since then, passing through a narrow region primarily in the state of Indiana. The majority of individuals were Gray-cheeked Thrushes, each covering over 3000 km between the Sierra Nevada de Santa Marta in north-east Colombia and southern Indiana, and seemingly taking around 15 days to do so.

However, there is one individual that left us all in shock, having flown 3250 km in just 3.3 days. To cover that distance in such a short time, it is likely that this bird flew non-stop  for three days, potentially only resting for one or two hours. Presumably it overflew the Caribbean Sea and the Gulf of Mexico in one go and may have taken a quick breather somewhere inland from the Gulf Coast. Endurance flights of this nature never cease to amaze and judging by the travel times of several of the other individuals detected, this flight may not be unusual.

Gray-cheeked Thrush - SNSM

Another remarkable finding was that several birds were detected at multiple towers. By far the most impressive was the Gray-cheeked Thrush that first flew 3400 km to Indiana and then continued a further 2000 km to Hudson Bay, in the far north of Canada (see map). Finally, we cannot help but marvel at the incredible recovery rate of the Gray-cheeked Thrushes carrying radio-transmitters. Of the 36 birds tagged, 38% or 14 birds were subsequently detected in North America!

North America - GCTH

Two of the incredible journeys realized by Gray-cheeked Thrushes from Colombia

These fascinating insights into the routes, timing and speed of migration of inter-continental migratory thrushes were only made possible through multiple collaborations and SELVA would like to thank all those involved in making this possible: Stu Mackenzie (Bird Studies Canada), Keith Hobson (Environment Canada), Dr. Phil Taylor (Bird Studies Canada Chair of Ornithology at Acadia University), Motus Wildlife Tracking System, Universidad de los Andes, Colciencias, University of Saskatchewan, Coastal Bend Bays and Estuaries Program, Texas Tech University, Southern Illinois University, USFWS, Swarovski Optik, BirdLife International, Natural Sciences and Engineering Research Council of Canada, Western University, University of Guelph, and the Canada Foundation for Innovation.

We also want to thank the owners of Hacienda La Fragua, Cundinamarca, and Hacienda La Victoria in the Sierra Nevada for opening the doors to their farms and for their stewardship that makes their farms such excellent refuges for migratory birds.

For more information and an interactive map click here.