BLACKBIRD ROOST DYNAMICS AT MILLERS LAKE, LOUISIANA - IMPLICATIONS FOR DAMAGE CONTROL IN RICE

Ecological data are needed to develop management plans related to bird damage to sprouting and ripening rice in the southern United States. Thus, we studied the blackbird roost at Millers Lake, Evangeline Parish, Louisiana, each spring from 1986 to 1988 to document roost size, species composition, and distribution patterns of foraging flocks in nearby rice fields. We report on the final year of study and discuss the relationship of roost size to options for controlling bird damage in spring-planted rice. The number of birds roosting at Millers Lake declined from 18 million in mid-February to 6,300 in late April 1988. In March and April, female red-winged blackbirds (Agelaius phoeniceus) were proportionally more abundant than male red-winged blackbirds or other species of blackbirds or European starlings (Sturnus vulgaris). The mean number of birds, flock size, and number of flocks that foraged in fields were not correlated with roost size. Evaluation of the cost-effectiveness of various control measures is needed.