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Reclamation Biologist Participates in Western Yellow-Billed
Cuckoo Migration Study Featured in Western Bird Magazine

by Susan Kendrick
Reclamation Albuquerque Area Office

photo: Biologist holding Western yellow-billed cuckoo
Western yellow-billed cuckoo

A study on the migration of the Western yellow-billed cuckoo bird was the subject of a recent article published in Western Birds magazine.

Vicky Ryan, Biologist at the Bureau of Reclamation’s Albuquerque Area Office said she was thrilled to be part of the project. “It was a pro-active study, and I felt privileged to represent the Bureau of Reclamation and learn more about a species about to be listed under the Endangered Species Act.”

Thirteen breeding yellow-billed cuckoo birds were captured near Elephant Butte Reservoir on the Middle Rio Grande in 2009, so that researchers could study their migration strategies and understand the ecology and conservation of migratory birds across their entire cycle.  Miniaturized light-level geolocators were used instead of the old, outdated tracking methods. These Western yellow-billed cuckoos are a sparse and suffering bird with declining populations. In 2010, one yellow-billed cuckoo was recaptured and data was downloaded and analyzed from the year of travel that was recorded on the geolocator.

The Western Bird article went into detail on the accuracy of the geolocators, the migration routes and wintering areas, the movement patterns. So what did they discover after a year of study and tracking?

 “After the equinox (early October) it moved through the Mexican states of Queretaro, Hidalgo, and Guerreo. It then traveled through Central America and arrived in northern Colombia on or about 18 October 2009. By mid-November, the bird had traveled south along the east side of the Andes through central Colombia, northeastern Peru, western Brazil, and western Bolivia. The overall estimated maximum distance traveled during fall migration was 7250 km. The minimum estimated migration rate (maximum distance traversed divided by estimated numbers of travel days was 94 km/day.”

photo: Biologist holding Western yellow-billed cuckoo
Reclamation biologist Vicky Ryan holds a
Western yellow-billed cuckoo

The cuckoo then spent five months in a winter range that included Bolivia, Brazil, Paraguay, and Argentina. The estimated maximum distance it traveled during this period was 1050 km.

The bird island hopped through the eastern Caribbean before heading back to Mexico. It entered Texas in June 2010 and then followed the Pecos River up before finding its way back to the Middle Rio Grande by mid-June.

“In the end, it’s pretty amazing that a little 12 inch bird weighing in at only 75 grams can travel so incredibly far in such a short timeframe and then wind up within a mile of its original location the previous year,” Ryan said of the bird’s 7,750 km journey.

If you’re interested in learning more please visit the Western Birds website at http://www.westernfieldornithologists.org/journal.php. The article appeared in Volume 43-1.

Western yellow-billed cuckoo migration map

Western yellow-billed cuckoo migration map


Last updated: September 5, 2012