Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock ( ) or https://
means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
Body mass in overwintering waterfowl is an important fitness attribute as it affects winter survival, timing of spring migration, and subsequent reproductive success. Recent research in Europe and...
data.gov
An official website of the GSA's Technology Transformation Services