Tagging Black-crowned Night-Herons

July 18, 2014 by Devin Murphy


Every spring and summer the National Zoo's Bird House hosts some very special migratory guests—about 100 Black-crowned Night-Herons.

For the past century, the birds arrive at the Bird House—their only rookery in Washington D.C.—every April. Yet, where the birds go after they leave in August or September remains a mystery. For the past century, the birds arrive in April each year and depart between August and September, but scientists did not know where their southern destinations were or what challenges they faced to reach them.

Last summer, Smithsonian Migratory Bird Center scientists attached tracking devices to four birds, gaining the first glimpse into the birds' migration south. A couple birds had made it to Florida before the transmitter batteries died.

This July, scientists outfitted six birds with more advanced tracking devices, thanks to support from the Smithsonian Women's Committee. The light-weight, solar-powered trackers use cell phone technology to transmit location data every two hours. This more precise system will allow scientists to track the birds in near real-time and gather clues about what challenges they face on their marathon journeys.

The backpack-like transmitters do not harm the birds and are custom fit to each individual. Zoo visitors can see the six herons with the trackers flying around the Bird House.