FAIR USE NOTICE - This website may contain copyrighted material the use of which has not been specifically authorized by the copyright owner. We are making such material available in our efforts to advance understanding of the Endangered Species Act and its implementation. We believe this constitutes a 'fair use' of any such copyrighted material as provided for in section 107 of the US Copyright Law. In accordance with Title 17 U.S.C. Section 107, the material contained in this document is distributed without profit for educational and research purposes. For more information go to this site. If you wish to use copyrighted material for purposes of your own that go beyond 'fair use', you must obtain permission from the copyright owner.
This video describes how biologists use science to estimate populations of this endangered butterfly.