SPRING MIGRATION
March 16 through May 15
Total number of bandings shown:
8,591,942On the Move
Long-term banding records can show changes in bird populations, behaviors and environments over time.
That information, in turn, can inform decisions about how to protect the animals and their habitats. Here we
map the digitized banding data by location and season, revealing the relative number and diver sity of birds
banded at each point in space and time from 1960 through 2016.HOW TO READ THE MAPS
The size of each square represents the number of individual
birds banded in the location of its center point. (Latitude and
longitude coordinates were rounded to the nearest degree.)The color of each square is guided by
the Shannon Wiener Diversity Index.
One species dominatesReasonably even distribution
of species, but some
are more prevalent
than othersRelatively even
distribution
of species56 Scientific American, March 20211,000 50,000 500,000White circles mark the location with
most birds banded per season. Just west
of Niagara Falls in Ontario, 436,875 birds
were banded between 1960 and 2016.Blue circles mark
the location with most
blue-winged teals
banded per season.Declining Songbird
The golden-winged warbler, a neotropical migrant
songbird, has declined by more than 70 percent since the
1960s. Banding data have helped reveal the present-day
distribution of the species—which breeds mainly in the
regions of the Great Lakes and Appalachian Mountains and
winters in Central and South America—and identify popula-
tion concentrations that could be targets for conservation.Blue-W inge d Te alTracking Disease
Blue-winged teals are thought to play a role in spreading
avian influenza viruses, which have health consequences
for not only birds but also other animals, including humans.
Scientists are tracking the movements of teals to identify
areas where they may be transmitting viruses to other
wild birds as well as domestic poultry. Golden-Winged
Warbler
© 2021 Scientific American © 2021 Scientific American