Effects of Petroleum on Birds

Oil pollution is in the forefront ofpublic attention because of the recent series of oil spills from tankers such as the Argo Merchant. Oil spillage frequently destroys the marine flora and fauna; the most striking single effect is the oiling of large numbers of marine birds. For example, as many as 30,000 birds died after the grounding of the Torrey Canyon at Seven Stones Reef, Great Britain in 1967 (Bourne, Parrack and Potts 1967). Moreover, between 1967 and 1971 at least 250,000 seabirds died worldwide as a direct result of oil spillage (Clark 1973). More recent oil spills have had equally 'devastating effects on marine birds. Oil spillage resulting from the transportation of oil accounts for only 35 percent of the 6.1 million metric tons of petroleum hydrocarbons introduced into the oceans each year (Wilson and Hunt 1975). Most of the oil in the environment results from the countless discharges of petroleum occurring during normal usage, Most of these discharges are small enough to go uncataloged, but their global impact may in the long run be determined by the total amount of oil rather than by the size of the individual spills (Storrs 1973). Thus, the overall effect of oil pollution on aquatic bird populations must be examined from two points of view: (1) the disastrous effects of oil spills and (2) the sublethal and indirect effects of chronic exposure to low levels of petroleum hydrocarbons in the environment