Summary

Description

Table 1 provides the results of organochlorine and mercury analysis on plasma and whole blood samples respectively collected from 20 sharpshinned hawks at HMS Little Gap station and Cape May Observatory. Note that mercury and organochlorine analysis were run on different birds to minimize the amount of blood collected from one animal. No significant levels of oxychlordane, heptachlor epoxide, transnonachloro, p,pDDT, or mirex were detected in plasma from any of the birds. However, DDE was detected in the blood plasma of every bird sampled from both the Little Gap and Cape May stations, at concentrations ranging from 0.02 to 0.49 ppm wet weight. The mean DDE concentration for all of the birds was 0.12 ppm. Viewing Little Gap and Cape May as two separate data sets, the mean for Little Gap was 0.18 ppm n 5; range 0.040.49 ppm, and the mean for Cape May was 0.06 ppm n 5; range 0.020.13 ppm. Three out of the five Little Gap samples were from secondyear SY birds, while all five Cape May samples were from hatchyear HY birds, leading to the higher mean value at Little Gap. The mean DDE concentration for the three SY sharpshinned hawk blood plasma samples collected at Little Gap was 0.26 ppm, vs. 0 06 ppm for all HY birds from both stations. Although it is tempting to conclude that SY birds must have picked up their DDE burden on their wintering grounds, the explanation for their higher blood DDE may be simply that these birds are older, and hence have had more time to accumulate this persistent compound. Although we are unaware of any other studies on contaminant levels in sharpshinned hawk blood, similar work has been conducted on other species. The DDE levels reported from our samples are generally much lower than levels reported by Court et al. 1990 in adult male peregrine falcons at Rankin Inlet, Northwest Territories, Canada geometric mean from 22 samples 0.93 ppm, but somewhat higher than values they reported from nestlings geometric mean for 19 samples 0.02 ppm. Interestingly, the sharpshinned hawk HY DDE mean of 0.06 ppm closely matches the mean values reported for HY males and females collected from 1976 through 1979 from Assateague Island, MarylandVirginia and Padre Island, Texas means ranging from 0.05 to 0.07 ppm Henny et al., 1982. The sharpshinned hawk SY DDE mean of 0.26 ppm is considerably lower than Henny et al. 1982 reported from SY birds collected at Padre Island from 19761980 means ranging from 0.60 to 0.67 ppm. Mercury was present in low concentrations in whole blood samples from only two of the sharp shinned hawks. Both were HY birds captured at Cape May one male and one female. The small sample size precludes any further interpretation of the data.