to measure liver function in the mallard drakes 

 fed the RAM. Plasma clearance rates were 

 enhanced in the drakes fed the RAM at 0.4% of 

 the diet, suggesting that adult waterfowl may 

 be able to increase liver function to eliminate 

 high concentrations of petroleum hydro- 

 carbons. Although several plasma enzymes 

 (enzymes that appear in the blood because of 

 damage to specific organs) and electrolytes were 

 monitored monthly in both studies, none were 

 elevated above control levels. Adult waterfowl 

 are apparently able to adapt to and tolerate 

 high concentrations of petroleum hydro- 

 carbons in their diet when not otherwise 

 stressed. However, other adult mallards, given 

 seawater as drinking water and subjected to 

 mild cold stress (3° C) while being fed food 

 contaminated with 3% Kuwait or South Loui- 

 siana crude oil, died (table 5). 



Mallard ducklings survived from hatching 

 to 8 weeks of age on diets containing 0.025% 

 to 5% South Louisiana crude oil or No. 2 fuel 

 oil. Those fed 2.5% and 5% oil, however, were 

 stunted and failed to develop flight feathers 

 (fig. 3). Subtle biochemical and behavioral 

 changes were detected in ducklings fed as little 

 as 0.25% oil. It is not surprising that young 

 birds would be more seriously affected than 

 adults because they are in the critical rapid 

 growth phase. 



I able 5. The effects of petroleum-contaminated diets 



on the mortalities of scawatcr-adaptcd ducks main- 



tained for 50 days at 27° C followed bj a 50-day period 



of continuous mild cold stress at 3° C (adapted from 



Holmes et al. 1978). 



EFFECTS OF OIL INGESTION ON 

 REPRODUCTION IN BIRDS 



Mallard hens fed diets containing 2.5% 

 South Louisiana crude oil (25,000 ppm) for a 

 6-month period produced 50% as manv eggs as 

 controls. Over a 90-day period, the oil-dosed 

 birds laid an average of 35 eggs per hen, com- 

 pared with 69 for controls (table 6). Although 

 fewer eggs were laid by the oil-dosed birds, 

 those that were laid hatched as well as control 

 eggs when artificially incubated, and the hatch- 

 lings weighed as much as control hatchlings. In 

 contrast, hens on diets containing 0.25% (2,500 

 ppm) of oil performed nearly as well as controls. 



Dr. W. Holmes (under contract to the Patux- 

 ent Wildlife Research Center) reported similar 

 results in studies with South Louisiana and Ku- 

 wait crude oils. Egg laying was not affected In 

 1% of either oil in the diet. Egg laying decreased 

 by 75% on a diet containing 3% South Louisiana 

 crude oils and completely ceased on a diet con- 

 taining 3% Kuwait crude oils. 



Paired mallards were fed vanadium, a metal 

 contaminant of crude oils. The vanadium accu- 

 mulated to higher concentrations in the bone 

 and liver than in other tissues. Concentrations in 

 the bones of hens were five times those in the 

 bones of drakes, suggesting an interaction be- 

 tween vanadium and calcium mobilization in 

 laying hens. Lipid metabolism was altered within 

 3 weeks in laying hens fed 100 ppm vanadium 

 and within 12 weeks in hens fed 10 ppm vana- 

 dium. Vanadium concentrations in crude oil can 

 range up to 1,400 ppm. 



'Means followed b\ different letters are significant!) 

 different for a given sampling period, Scheffe's test. 

 P<0.05. 



