Food Habits of the California Gull in Utah

Clifton M. Greenhalgh
1952 The Condor  
The California Gull (Lurus califurnicus) is generally revered in Utah for its well known role during pioneer times in helping to save the crops of the first settlers of Great Salt Lake Valley from crickets. Subsequently an interesting social taboo developed whereby the bird was rarely killed (Young, 1928) . The famous Seagull Monument, erected on the Temple grounds at Salt Lake City to commemorate the role of the gull, has helped to keep the taboo alive. The first change in local feelings
more » ... ocal feelings toward the gulls came with complaints against them because of their depredations on cherry crops in Davis County (Cottam, 193 5 ; Sugden, 193 7 ) . Similar charges have come from Boxelder and Utah counties. These birds have long been known to nest on several islands in Great Salt Lake (Behle, 1935 (Behle, ,1949 . New colonies of gulls have of recent years been established at three waterfowl refuges on the east side of Great Salt Lake, namely Farmington Bay, Ogden Bay, and the Bear River Refuge. This has brought them in close contact with nesting waterfowl and the gulls are being accused of predations on ducks. With attention being focused on these new problems, it seemed desirable to make a general study of the food habits of the California Gull. Little specific information was on record. Kalmbach (1914: 6) reported on the contents of five stomachs and Cottam and-Williams ( 1939: 153 ) listed the contents of six stomachs of birds taken in the Great Salt Lake region but these were small samples. Accordingly a study was started by the writer in 1940. This was interrupted by the war but was resumed in June of 1946 when arrangements were made with the personnel at Bear River Migratory Bird Refuge to spend the summer working on the refuge and at the laboratory of the research division at the refuge headquarters. In addition to field observations, food items in the stomachs of California Gulls previously collected on the refuge were identified and further samples were taken. The results are presented here supplemented with occasional notes from the literature and interviews with farmers. Thanks are due William H. Behle of the University of Utah for guidance in this study. I am indebted to several men at the Bear River Migratory Bird Refuge: Cecil Williams and Vanez Wilson were generous in providing facilities for me in 1946; Cecil Williams, Charles Sperry, Hortin Jensen, and Ralph Hervey were helpful in giving advice, collecting, and identifying food items. In my initial collecting around Salt Lake City I was helped by Jack Berryman, Rex Edward, Dan Gardiner, and Nathan Riser to whom I also express my thanks. MATERIALS AND METHODS The results herein presented are based mainly on an, analysis of 529 stomachs. Of these, 132 were collected at Bear River Refuge in 1939 by the personnel at the refuge. The writer collected 47 in the Salt Lake City area in 1940, and 166 in 1941. These were taken either on Antelope Island in Great Salt Lake or west of Salt Lake City. Ten stomachs were taken each week from March 30 to August 10. By this time most of the gulls had migrated and specimens were difficult to obtain. In. 1946, 184 stomachs were collected at the Bear River Refuge. Fifteen gulls were taken each time, again at weekly intervals. The usual techniques were followed in preserving and handling the stomach contents whereby they were sorted, dried and measured v9lumetrically in terms of cubic centimeters. First, the entire stomach contents, including debris and gravel, were considered on the basis of 100 per cent. After the gravel and debris had been measured Sept., 1952 FOOD OF THE CALIFORNIA GULL 303
doi:10.2307/1364946 fatcat:bge66et6wbd7tgv4dynk5qrleq