6 Vol. XX 



THE DESTRUCTION OF BIRDS AT THE LIGHTHOUSES 

 ON THE COAST OF CALIFORNIA 



By WALTER ALBION SQUIRES and HAROLD E. HANSON 



WITH TWO PHOTOS AND MAP 



(Contribution from the Audubon Association of the Pacific) 



FROM time to time we hear accounts of the destruction of migrating birds 

 at government lighthouses. Such rumors concerning the destruction of 

 birds on the California coast reached the Audubon Association of the Pa- 

 cific last spring, and led C. B. Lastreto, president of the Association, to under- 

 take a systematic investigation. The data obtained was turned over to the two 

 authors of the present paper, forming the basis of the report which they here- 

 with present. Mr. Lastreto was fortunate enough to secure the cooperation of 

 Captain R. N. Rhodes, lighthouse inspector for the district covering California. 

 The following questionnaire was prepared by the Association and sent out 

 under the supervision of Captain Rhodes. 



1. Give such estimates as you can concerning the number of birds found dead 

 about your lighthouse. 



2. At what season of the year is such mortality greatest? 



3. During what kind of weather does mortality seem to be greatest? 



4. Are there more dead birds on one particular side of the lighthouse than on the 

 other sides? 



5. Does the destruction of the birds seem to you to be due to their flying violent- 

 ly against the glass, or do they become confused and fly around and against the glass un- 

 til they become exhausted and fall to the earth? 



6. Have you noted any injury in such birds as you have picked up about your 

 lighthouse? 



7. Is there a railing around your lighthouse, or any other support on which birds 

 might perch? 



8. Name as many birds as you can which have been found dead at your light- 

 house. 



9. Give location of your lighthouse; is it on an island or on the mainland; at 

 what elevation is it? 



10. Is the number of birds killed at lighthouse stations increasing or is it de- 

 creasing, in your opinion? 



Thirty-seven letters were received in answer to the above questions. A 

 study of the contents of these letters points to the following conclusions. 



I. The destruction of birds at the lighthouses of the California coast is 

 slight. Only ten of the stations reporting tell of any destruction at all, and at 

 some of these ten the number of birds killed is very small. Many keepers, in- 

 cluding one who has been at the same lighthouse forty years, state positively 

 that no birds are ever killed at their station. It is of course possible that birds 

 are killed at some stations and escape notice, but this could hardly be the case 

 if they were destroyed in any considerable numbers, and, moreover, careful 

 count has apparently been made at several of the lighthouses of all birds found 

 dead. One keeper reports ninety-one birds killed in three years, another four 

 birds in three years. 



At two or three stations the destruction is evidently more serious. 



The keeper at the Point Arena light states that after "calm dark nights" 

 from ten to thirty birds are found dead at his lighthouse. Another says that at 

 his station the average is about six a night; still another reports an average 



