White-Lined Sphinx Moth Caterpillars
(aka hummingbird hawk moth, Hyles lineata):
Favorite Food for Swainson’s Hawks’ Borrego Springs Migration
Prepared by Dr. John V. Richardson Jr., Ecological Informatician
Besides flying ants or dragonflies, these hawks love caterpillars which may explain why the hawks stop overnight outside Borrego Springs! This year (2016) the wildflowers are better than they have been in many years, so maybe the hawk count will be up, too? The peak years for Swainson’s were 2004 (1,406), 2007 (1,365), and 2011 (1,851). The caterpillars seem to vary widely in color—“from black with stripes to green with red spots,” according to Wikipedia.
Primary and Secondary Sources:
Borrego Valley Hawkwatch at http://borregohawkwatch.blogspot.com/ (accessed 21 March 2016).
Christopher W. Briggs, “Survival and Nesting Ecology of the Swainson’s Hawk in Butte Valley, California,” MS Thesis, University of Nevada, Reno, 2007. 99 pages.
Michael M. Collins, Moth Catcher: An Evolutionist’s Journey Through Canyon and Pass (Reno: University of Nevada Press, 2007).
“Hyles lineata” at https://scholar.google.com/scholar?q=hyles+lineata&btnG=&hl=en&as_sdt=0%2C5
(accessed 21 March 2016).
J. Harry Jones, “Swainson’s Hawk Migration in Full Swing,” San Diego Union-Tribune, 17 March 2016 (online)—see photo gallery “Nancy and John Richardson, of Los Angeles, arrive with others at a spot along Di Giorgio Road in Borrego Springs…”and “Nancy Richardson, of Los Angeles, watches in awe as a large group of hawks in the distance takes flight.”
Marci R. Tarre, “Harvesting Hyles lineata in the Sonoran Desert: A Larval Legacy,” In Les "insectes" dans la tradition orale [Insects in Oral Literature and Traditions], edited by Élisabeth Motte-Florac (Leuven: Peeters, 2003).
Created: 21 March 2016