Heavy metal and selenium levels in feathers of known-aged common terns (Sterna hirundo)

Abstract

Concentrations of five metals and selenium in the breast feathers of known-aged common terns (Sterna hirundo) were examined at a breeding colony in Massachusetts, USA. Concentrations of selenium, chromium, and manganese increased significantly with age among adults (2-21 years old), whereas concentrations of mercury, cadmium, and lead did not. Concentrations of cadmium, selenium and manganese were lower in fledglings (20-23 days old) than in adults. Concentrations of mercury, however, were higher in fledglings than in adults, and concentrations of chromium were higher in fledglings than in young adults, probably reflecting higher exposure to these metals in the breeding area than in the winter quarters where the adults' feathers were grown. At least for mercury, excretion of metals into the feathers at each molt was an efficient protective mechanism, preventing continued accumulation in the body with increasing age.

Feather mercury levels in seabirds at South Georgia: influence of trophic position, sex and age

“…We did not find significant effects of adult age on mercury feather levels in any of the 4 species studied. This accords with earlier results from black-browed, grey-headed and wandering albatrosses (Thompson et al 1993b), which moult infrequently and irregularly (Furness 1988, Weimerskirch 1991, and from other species such as red-billed gulls Larus novaehollandiae scopulinus (Furness et al 1990), great skuas Catharacta skua (Thompson et al 1991) and common terns Sterna hirundo (Burger et al 1994), which moult more regularly. The independence between feather mercury levels and bird age may be explained by the (usually annual) moult being an effective way of decontaminating the body mercury burden (see 'Introduction').…”

Arsenic, cadmium, chromium, lead, manganese, mercury, and selenium in feathers of Black-legged Kittiwake (Rissa tridactyla) and Black Oystercatcher (Haematopus bachmani) from Prince William Sound, Alaska

“…We expected that older kittiwakes would have higher levels of metals than younger birds, based on the principle of bioaccumulation with age, although Monteiro and Furness (1995) noted that mercury in body feathers did not accumulate with adult age in their studies. Burger and Gochfeld (1994) found age-related differences for chromium, manganese and selenium, but not mercury, cadmium and lead for known-aged common terns (Sterna hirundo). In birds, age-related differences have generally been examined between young of the year and adults, mainly because these age classes are easily distinguished by plumage patterns, especially in seabirds (Burger, 1993).…”

“…Monteiro and Furness (1995) noted that mercury in body feathers did not accumulate with adult age in these studies. Since then, Burger and Gochfeld (1994) found age-related differences in the feathers of known-aged common terns (S. hirundo) for chromium, manganese and selenium, but not in mercury, cadmium and lead. Donaldson et al (1997) reported age-related increased in cadmium, but no significant differences for lead, mercury and selenium in breast muscle of thick-billed murres (Uria lomvia).…”

Influence of species, age and diet on mercury concentrations in Shetland seabirds

“…2) and therefore it must be concluded that physiological differences do play an important role. In particular it seems that terns have an unusual and distinct pattern of mercury accumulation (Gochfeld & Burger 1987, Burger et al 1994, Monteiro & Furness 1995. Therefore, this suggests that invoking dietary differences to be the principle factor influencing interspecific variation in metal concentrations in chicks may in many cases be overly simplistic, and other sources of variation must be considered (Walsh 1990(Walsh , blonteiro et al 1994.…”