Detroit River Hawk Watch Partners
Hawk Migration Websites
Visit HMANA's "Hawkwatch Site Selection" page to find a site near you.
Thermals - explanation of thermals and birds
https://en.wikipedia.org/wiki/Lift_(soaring)#Thermals: Discussion of types of lift from different thermal initiators (ridge, waves, dynamic). Mostly from the view point of glider pilots, with a passing mention of birds.
Aerospaceweb.org: Combines discussion of thermal formation and how birds and glider pilots use them, with nice graphics.
RC-Soar.com: Article "What Do Thermals Look Like?" discusses the shape and behavior of thermals.
https://web.stanford.edu/group/stanfordbirds/text/essays/Soaring.html: Brief discussion of how vultures and hawks soar from an aerodynamic perspective. Focus on aspect ratio of wings, drag coefficient, etc. Additional mention of albatross and other seabirds. Further links to discussion of wing shapes vs function and separately hovering flight.
Careau, V., J.F. Therrien, P. Porras, D. Thomas, K. Bildstein. 2006. Soaring and gliding flight of migrating Broad-winged Hawks: behavior in the Arctic and Neotropics compared. Wilson Journal of Ornithology 118(4): 471-477. Abstract and bibliography available free at www.bioone.org/doi/abs/10.1676/05-140.1 (full text available with a BioOne account).
Hawk Identification Books
A Field Guide to Hawks of North America by William S. Clark and Brian K. Wheeler, Houghton Mifflin, Second Edition (2001)
Hawks from Every Angle: How to Identify Raptors in Flight by Jerry Liguori, Princeton University Press (2005)
Hawks in Flight by Pete Dunne, David Sibley, and Clay Sutton, Houghton Mifflin (2012)
Hawk Watch: A Guide for Beginners by Pete Dunne, Debbie Keller, and Rene Kochenberger, Cape May Bird Observatory (2002)
A Photographic Guide to North American Raptors by Brian K. Wheeler and William S. Clark, Academic Press (2003)
The Crossley ID Guide: Raptors by Richard Crossley, Jerry Liguori, and Brian L. Sullivan, Princeton University Press (2013)
Hawks at a Distance: Identification of Migrant Raptors by Jerry Liguori with a foreword by Pete Dunne, Princeton University Press (2011)
Facebook Hawk ID Group
The Birder's Library has nice posts reviewing the above references.
Hawks on the Wing by Joshua Haas - Video describing Hawk ID, by one of Michigan's own - available on DVD and Blu-ray, and by digital download.
See Publications in sidebar at left.