March 2021, ScientificAmerican.com 53

GREG JODER

T

he year was 1902. Paul Bartsch, a mollusk researcher at the smithsonian

Institution, wondered whether the aquatic snails he was studying could be spread

from one body of water to another by aquatic birds. To find out, he needed to

track the movements of birds. Bartsch hatched a plan. He fastened lightweight

aluminum rings inscribed with the year, a serial number and a Smithsonian

return address around the legs of 23 nestling black-crowned night herons that

he captured along the Anacostia River outside Washington, D.C. And then Bartsch

waited for news of the banded birds—where they were sighted, what had become of them.

Only one of the 23 herons was reported to him. The bird was

shot shortly after being banded, but its resighting revealed where

the creature had been headed in the interim: the heron turned

up in Abington, Md., 55 miles northeast of where Bartsch had

banded it. Although that initial insight was modest, Bartsch’s

approach to obtaining it was revolutionary: he had just become

the first person in North America to systematically band birds for

scientific research.

Bartsch outfitted more herons with serially numbered bands

the following year, and other researchers began banding other

kinds of birds elsewhere in North America. In 1920 the federal bird

banding office was established in the U.S. Known today as the U.S.

Geological Survey Bird Banding Laboratory, it works with its Cana-

dian counterpart to run the North American Bird Banding Pro-

gram, which manages more than 77  million archived banding

records and more than five million records of encounters with

banded birds from the past 100 years. Every year the program sends

about a million bands to banders in the U.S. and Canada and adds

some 100,000 new encounter reports to its database. Birds may

also be equipped with auxiliary markers such as color bands or sat-

ellite transmitters. Researchers around the world use the data to

monitor resident and migratory birds.

Banding studies have illuminated the hidden lives of most of

the more than 900 avian species that spend time in North Ameri-

ca, from raptors to waterfowl, from seabirds to songbirds. A pere-

grine falcon monitoring project in coastal Washington State has

found that in addition to hunting on the wing, this formidable

predator—the fastest species on earth—actually scavenges food

fairly often. On Midway Atoll, a female Laysan albatross named

Wisdom, first banded in 1956 and sighted as recently as November

2020 incubating a new egg, has helped show that seabirds live and

reproduce far longer than previously thought.

In many cases, banding data have identified imperiled species

and populations—and informed the development of management

strategies aimed at protecting the birds. The whooping crane, a

spectacular five-foot-tall bird with snow-white plumage native to

North America, is one of the shining success stories to come out of

banding work, according to Antonio Celis-Murillo, head of the Bird

100

A rich archive of data illuminates the secret lives of birds

By Kate Wong (text), Jan Willem Tulp (graphics) and Liz Wahid (bird illustrations)

CONSERVATION

YEARS OF BIRD BANDING