Coliphages and indicator bacteria in birds around Boston Harbor

Droppings from feral populations of pigeons, geese and herring gulls from the urban/suburban environment around Boston Harbor, MA, USA contained up to 106 somatic coliphages, 108 enterococci, 109 thermotolerant coliforms and 102 F-specific coliphages per gram of feces. Somatic coliphages, enterococci and thermotolerant coliforms were common in the feces of all three kinds of birds but F-specific coliphages were found in droppings from only three of 32 gulls. Thus these sources of bacterial and viral indicators should be considered when dealing with the ecology of fecal pollution indicators. Moreover, microbial indicators of fecal or sewage pollution originating from bird droppings may be mistaken for indicators that come from humans. This may cause an overestimate of the hazard from human pathogens in water and confound attempts to locate sources of fecal or sewage pollution.