CONTENTS 
Young Barn Owls Photo by //. T. Bohlman Frontispiece 
The Barn Owl and its Economic Value 
Win. L. Finley (5 photos by H. T. Bohlman ) 83 
The Percentage of Error in Bird Migration Records Witmer Slone 88 
Land Birds of San Onofre, California Joseph Dixon 91 
Notes on Birds Observed while Traveling from Yokohama to Manila (with one 
line cut) Richard C. McGregor 98 
“ A tratus versus Megalonyx” Robert Ridgway 100 
NOTES AND NEWS 101 
Directory of Cooper Club Members 101 
Entered as second-class matter May 4, 1906, at the post office at Pasadena, California, 
under Act of Congress of March 3, 1879, 
Issued from The Office of The Condor, 871 No. I.ake Ave., Pasadena, Cal. 
Boys and Girls 
Magazine 
A. Nature Magazine 
For Home and School 
Beautifully Illustrated 
Contains Live, Interesting Nature 
Stories. 
FIFTY CENTS A YEAR 
Send for sample copy 
Address, 
Boys and Girls Magazine 
ITHACA, N. Y. 
Camp Agassiz 
At Glen Alpine, above 
Lake Tahoe, Cal. 
In the Lake Tahoe Forest Reserve 
Is the key to a region unequalled for 
fishing and natural history pursuits. 
Ninth season. For beautiful booklet 
address the directors: 
W. W. Price, or Walter K. Fisher, j 
Tallac, Lake Tahoe, Cal. 
When replying to advertisements please mention THE CONDOR 
