White phosphorus (P4) has been identified as the cause of mortality for dabbling ducks and swans at an estuarine salt marsh in Alaska Predation of ducks poisoned by P, was monitored to assess the extent and range of predator exposures to P, Avian tissues were analyzed for P, by gas chromatography We observed that both sick and dead dabbling ducks were common prey of bald eagles (Haliaeetus leucocephalus), herring gulls (Larus argentatus), and common ravens (Corvus corax) Frank signs of P, intoxication attracted predators and rendered the ducks easy prey White phosphorus was found in the tis sue remains of ducks that had been preyed upon, thus providing positive evidence that predators were exposed to P, Although P, varied widely among individuals, P, was generally highest in the gizzard contents followed by fatty tissues such as fat de pots and the skin White phosphorus was identified in fatty tissues of one eagle and in one herring gull egg, thus providing di rect evidence of absorption of P, by predators

American kestrels (Falco sparverius) exposed to a diet containing white phosphorus (P4) had detectable quantities of P4 only in their fatty tissues. As early as 24 h postdosing, P4 was found in the fat depots and skin but not in other tissues such as the brain, heart, intestine, liver, kidney, and muscle. After 7 d of continuous exposure to P4‐containing diet (6.4 μg P4 per gram of diet), the skin but not fat depots showed significant accumulation of P4. When P4‐containing diet (6.4 μg P4 per gram of diet) was fed for 2 d followed by 3 d of feeding a diet containing less P4 (0.7 μg P4 per gram of diet), P4 was not detectable in the tissues. Upon refeeding with the higher dietary concentration of P4, P4 was again detectable in skin and fat. This cyclic dosing regimen indicates that tissue levels are sensitive to dietary levels of P4.

Abstract-Thousands of waterfowl deaths occurring at Eagle River Flats (ERF), Anchorage, Alaska, USA, have been attributed to the ingestion of white phosphorus (P 4 ) particles. White phosphorus has been found in the egg of one herring gull (Larus argentatus) and in the yolks of some shorebirds at ERF. The presence of P 4 in eggs suggests potential toxic consequences for avian reproduction. This study was undertaken to determine the magnitude and potential importance of P 4 translocation from the hen to the egg. Egglaying hens (Gallus domesticus) were gavaged with a single dose of 1, 3, or 5 mg P 4 /kg body weight or dosed with 1 mg P 4 /kg body weight for 5 consecutive d. Eggs of dosed hens were collected daily. White phosphorus was extracted from the yolk and the white, individually, with isooctane and analyzed by gas chromatography. White phosphorus had no significant effect on chicken weight, egg weight, or shell thickness. However, laying frequency was significantly reduced (p Ͻ 0.05) in chickens receiving 1 mg P 4 /kg body weight for 5 d. For all treatments, P 4 was detected in the yolk and not in the white. It was first detected in the yolk approx. 1 to 2 d after P 4 exposure and became nondetectable 6 to 10 d after P 4 exposure. The total P 4 recovered from eggs of chickens treated with P 4 was less than 0.01% of the administered dose.

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White phosphorus (P4) has been identified as the cause of mortality for dabbling ducks and swans at an estuanne salt marsh in Alaska Predation of ducks poisoned by P4 was monitored to assess the extent and range of predator exposures to P4 Avian tissues were analyzed for P4 by gas chromatography We observed that both sick and dead dabbling ducks were common prey of bald eagles (Hahaeetus leucocephalus), herring gulls (Larus argentatus), and common ravens (Corvus corax) Frank signs of P4 intoxication attracted predators and rendered the ducks easy prey White phosphorus was found in the tis sue remains of ducks that had been preyed upon, thus providing positive evidence that predators were exposed to P4 Although P4 varied widely among individuals, P4 was generally highest in the gizzard contents followed by fatty tissues such as fat depots and the skin White phosphorus was identified in fatty tissues of one eagle and in one herring gull egg, thus providing direct evidence of absorption of P4 by predators