(2) If the regular operation of jet aircraft is contemplated 
at. Midway, experiments should be conducted to determine the effects 
of tern ingestion on jet engines. Also, the necessity for such opera- 
tions should be carefully weighed against any hazards that might result, 
especially in view of the fact that elimination of sooty terns cannot 
be accomplished in a single season. (Another factor which warrants 
serious consideration is the presence of several other species of 
small birds, particularly the extremely abundant petrels and shear- 
waters, for which no practical control means have been developed.) 
The use of screens on jet intakes appears to be the only method 
known at present of eliminating’ the possible hazards of small bird 
ingestion. 
(3) If the elimination of the sooty tern colony on Sand 
Island should become necessary, .it is recommended that a killing and 
harassment program, as conducted during the 1958 season, should be - 
continued on an annual basis as long as the birds continue to return 
to the island. The program should be started as soon as, but not 
before, egg-laying is well underway (early June). Birds should be 
clubbed or shot and their eggs broken as long as they remain in the 
area. : 
45 

