Mormon crickets and birds

[DAVID A LEATHERMAN]

I did a little research this morning.  A lot of birds from many different families are recorded as eating them.  One article alone, written in 1941 in Nevada, mentions the following species (in no formal order): turkey vulture, sharp-shinned hawk, red-tailed hawk, Swainson's hawk, rough-legged hawk (must have been spring before hawk headed north), golden eagle, northern harrier, merlin, American kestrel, sharp-tailed grouse, greater sage-grouse, ring-necked pheasant, burrowing owl, northern flicker, Lewis's woodpecker, western kingbird, horned lark, American crow, pinyon jay (Doug, please note), black-billed magpie, American robin, sage thrasher, American pipit, loggerhead shrike, house sparrow, western meadowlark, yellow-headed blackbird, red-winged blackbird, Brewer's blackbird, brown-headed cowbird, lark sparrow, fox sparrow and green-tailed towhee.

It is doubtful any of these birds are able to truly regulate huge Mormon cricket population upticks.  But they certainly include them in their diet opportunistically.  I suspect when sagebrush is a major food item of the omnivorous crickets (they eat basically all plants in their path, plus other insects including dead cohorts), the breadth of bird species eating them, and the number of crickets consumed per encounter would decrease.  Sagebrush contains some problematic chemistry.  

The smaller birds that eat Mormon crickets are probably selectively consuming smaller individuals, mostly early-instar immatures, or just eating softer, juicier parts of the crickets that are easier to digest.  

As for California gulls "saving the day" by eating all the Mormon crickets ravaging crops in 1848, yes, gulls of more than one species (but perhaps dominated by California gulls) did opportunistically respond to the insect invasion.  Did they have a big impact?  Probably not, but they tried and for that and the "fish story" that ensued which gets better with time, they will always be revered in the Great Basin.  One aspect of the 1848 "miracle of the gulls" that was apparently misinterpreted was the casting of pellets by the gulls.  Contrary to contemporary thinking that the gulls were regurgitating so they could eat more crickets and be more helpful, they were simply getting rid of excess undigestible chitin and other materials similar to all birds that produce pellets.  Cherry growers in the same region do not share warm fuzzies for California gulls, as they have a definite soft spot for cherries.

Dave Leatherman

Fort Collins