Columbia subject headings:
Bird populations--North America.
Birds--Effect of pesticides on--North America.
Pesticides and wildlife--North America.
Harvard subject headings:
Bird populations--North America.
Birds--Effect of pesticides on--North America.
Pesticides and wildlife--North America.
Princeton subject headings:
Bird populations--North America.
Birds--Effect of pesticides on--North America.
Pesticides and wildlife--North America.