Closing In On The Lowest Count In 17 Years In A Remarkable Flower/Caterpillar Season

Leaders:March 21-March 28, 2019
Don White
Hal Cohen
Herb Stone
Laura Webb
Pam Albers
Rose Leong

Migration:
March 21-0
March 22-12 Swainson's Hawks
March 23-3 Swainson's Hawks
March 24-0
March 25-11 Swainson's Hawks
March 26-14 Swainson's Hawks; 10 Turkey Vultures
March 27-1 SW; 6 TV's
March 28-2 SW's

Discussion:
Since my last post we have had a total of 43 migrating Swainson's Hawks and 16 Turkey Vultures. This period of time traditionally yields thousands of migrants. This season we have had a remarkable flower bloom along with widespread caterpillars. The White-lined Sphinx Moth caterpillars can be found across several hundred square miles in Southern California and Northern Mexico. The Swainson's Hawks have most likely spread out to feed on the caterpillars. We should be grateful that the health of the hawks is probably pretty good with such an ample food source available.

Our evening watch has not been very exciting. Although occasionally we see a burst of activity to the east. A few nice kettles of hawks has been observed. Unfortunately the migrating hawks have moved much further away from the morning watch site. Will the hawks finally move through Borrego Valley after the caterpillar numbers dwindle? So far the number of caterpillars seems to be increasing and spreading throughout the region. Do not make the mistake of confusing the sphinx moth caterpillars with the huge number of Painted Lady Butterflies. Over 1 billion Painted Lady Butterflies have migrated through Southern California. The plant selection of the butterflies is different than that of the sphinx moths. The Swainson's Hawks evidently do not feed on the butterfly caterpillars as they are heavily armed with bristles and may not be appetizing.

Speaking of appetizing, a few hardy raptor watchers have finally participated in a traditional ritual that was very popular for hundreds of years by the native Cuhuilla Indians. Below is a narrative written by William Greenwood Wright in 1884.

“In an hour we came to the caterpillar pasture. The sand is dotted with mats and patches of a procumbent plant, much resembling in flower the common sand verbena, Abronia, on which vast armies of caterpillars are feeding; they are huge worms three and four inches long. Another small army of Indians—[men, women, and children]— are out gathering them as though they were huckleberries, for use as food. The Indians do not notice us, but go on with their gathering. Seizing a fat worm, they put off its head, and by a dexterous jerk the viscera are ejected, and the wriggling carcass is put into a small basket or bag, or strung upon strings and hung upon the arm or about the neck, till occasion is found to put them into a large receptacle.1 got three of these gathering baskets. One is funnel-shaped, holding a quart or two; another is like a large, flat saucer, and the third is similar but with a deep rim. At night, these Indians carry their prey home, where they have a great feast. Indians from a long distance come to these worm feasts, and it is a time of great rejoicing among them. The larvae that are not consumed at the time (and they eat incredible quantities), are put upon ground previously heated by a fire, and thoroughly dried, when they are packed away whole, or pulverized into a meal [Wright 1884:283].” 

We tried to perform the same ritual and found the worms to be very tasty. If I were served this delicacy in a restaurant, I would order more. 

Robin Roberts-White-lined Sphinx Moth Showing Proboscis

Sphinx Moth Caterpillar-Randy Lenon

Sphinx Moth Caterpillars Crowded Together-Randy Lenon

Sphinx Moth Caterpillars Cleaned, Broiled and Ready to Eat-HC

Painted Lady Chrysalis-HC

Painted Lady Butterfly-HC