JOURNAL ARTICLES - continued

dead ducks collected at Eagle River Flats. For

Racine, C.H., M.E. Walsh, B.D. Roebuck, C.M.

dabbling ducks, P4 particle size is not as impor-

Collins, D.J. Calkins, L.R. Reitsma, P.J. Buchli,

and G. Goldfarb (1992) White phosphorus poi-

tant as the dose ingested. For predators, the P4

soning of waterfowl in an Alaskan salt marsh.

contents of the entire digestive tract is important

Journal of Wildlife Diseases, 28(4): 669673.

for assessment of the risk of poisoning.

The cause of the yearly death of an estimated

1000 to 2000 migrating dabbling ducks (Anas sp.)

Roebuck, B.D., M.E. Walsh, C.H. Racine, L.R.

and 10 to 50 swans (Cygnus buccinator and C.

Reitsma, B.B. Steele, and S.I. Nam (1994) Preda-

columbianus) has remained a mystery for the last 10

tion of ducks poisoned by white phosphorus:

years in Eagle River Flats (ERF), a 1000-ha estua-

Exposure and risk to predators. Environmental

rine salt marsh near Anchorage, Alaska, used for

Toxicology and Chemistry, 13(10): 16131618.

artillery training by the U.S. Army. We have gath-

White phosphorus (P4) has been identified as

ered evidence that the cause of this mortality is the

the cause of mortality for dabbling ducks and

highly toxic incendiary munition white phospho-

swans at an estuarine salt marsh in Alaska. Pre-

rus (P4). The symptoms of poisoning we observed

dation of ducks poisoned by P4 was monitored to

in wild ducks included lethargy, repeated drink-

assess the extent and range of predator exposures

ing, and head shaking and rolling. Death was pre-

to P4. Avian tissues were analyzed for P4 by gas

ceded by convulsions. Farm-reared mallards

chromatography. We observed that both sick and

dosed with white phosphorus showed nearly

dead dabbling ducks were common prey of bald

identical behavioral symptoms to those of wild

eagles (Haliaeetus Ieucocephalus), herring gulls

ducks that became sick in ERF. White phosphorus

(Larus argentatus), and common ravens (Corvus

does not occur in nature but was found in both the

corax). Frank signs of P4 intoxication attracted

sediments where dabbling ducks and swans feed

predators and rendered the ducks easy prey. White

and in the gizzards of all carcasses collected in

phosphorus was found in the tissue remains of

ERF. We hypothesize that feeding waterfowl are

ducks that had been preyed upon, thus providing

ingesting small particles of the highly toxic, incen-

positive evidence that predators were exposed to

diary munition P4 stored in the bottom anoxic sed-

P4. Although P4 varied widely among individu-

iments of shallow salt marsh ponds.

als, P4 was generally highest in the gizzard con-

tents followed by fatty tissues such as fat depots

and the skin. White phosphorus was identified in

Roebuck, B.D., S.I. Nam, D.L. MacMillan, K.J.

Baumgartner, and M.E. Walsh (1998) Toxicology

fatty tissues of one eagle and in one herring gull

of white phosphorus (P4) to ducks and risk for

egg, thus providing direct evidence of absorption

their predators: Effects of particle size. Environ-

of P4 by predators.

mental Toxicology and Chemistry, 17(3): 511518.

Particles of white phosphorus (P4) in pond sed-

Sparling, D.W., and N.E. Federfoff (1997) Sec-

iments at Eagle River Flats, Alaska, U.S.A., a mili-

ondary poisoning of kestrels by white phospho-

tary artillery range are acutely toxic to dabbling

rus. Ecotoxicology, 6: 239247.

ducks and swans. We determined if toxicity of P4

Since 1982, extensive waterfowl mortality

to ducks varied by its form (i.e., dissolved or par-

attributable to white phosphorus (P4) has been

ticulate) or particulate size. Residual P4 in the

observed at Eagle River Flats, a tidal marsh near

digestive tract of ducks was measured to assess

Anchorage, Alaska. Ducks and swans that ingest

risks posed to predators and scavengers of ducks.

P4 pellets become lethargic and may display

Farm-reared mallards were treated with 12 mg

severe convulsions. Intoxicated waterfowl attract

P4/kg body weight, either dissolved in oil, or as

raptors and gulls that feed on dead or dying

numerous small, or one to two large particles. At

birds. To determine if avian predators can be

the first major convulsion, ducks were euthanized

affected by secondary poisoning, we fed Ameri-

and the quantity and location of P4 in the digestive

can kestrels (Falco sparverius) 10-day old domestic

tract were determined. These data were compared

chickens that had been dosed with white phos-

to data from dead ducks collected from the artil-

phorus. Of 15 kestrels fed intact chicks with a

lery range. Dissolved P4, and small or large parti-

pellet of P4 implanted in their crops, 8 died within

cles of it produced similar acute toxicity. Residual

7 days. Of 15 kestrels fed chicks that had their

P4 in digestive tracts was greatest in ducks treated

upper digestive tracts removed to eliminate any

with small particles and was as great as 3.5 mg P4.

pellets of white phosphorus, 3 also died. Haemat-

Similar quantities of residual P4 were found in

ocrit and haomoglobin in kestrels decreased,

to contents

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