Metal concentrations in the eggs of endangered Florida scrub-jays from central Florida

We analyzed metal levels in the eggs of the endangered Florida scrub-jay (A phelocoma coerulescens), an extremely sedentary and modestly long-lived pas serine bird. Eggs were obtained as part of the long-term study of this spec ies at the Archbold Biological Station, located in south central Florida. F ollowing a brief and usually short dispersal, Florida scrub-jays remain in a permanent territory in their scrub oak habitat, where they feed mainly on insects and acorns. As they are low on the food chain and sedentary, we ex pected levels of contaminants to be comparatively low and to reflect the lo cal environment. No significant yearly differences existed for any metal be tween eggs collected in 1997 (n = 11) and 1998 (n = 5). Arithmetic mean met al concentrations (whole egg, dry weight) were low for arsenic (34 ppb), ca dmium (25 ppb), mercury (74 ppb), and lead (66 ppb), intermediate for chrom ium (226 ppb), and higher for selenium (1,470 ppb) and manganese (2,230 ppb ). Except for the low mercury value, all these means were within the range of mean values reported for a wide range of nonpasserine species, including those at high trophic levels, but are lower than concentrations associated with abnormalities in birds. The three essential elements (chromium, selen ium, and manganese) were approximately normally distributed, whereas arseni c, cadmium, lead, and mercury were highly skewed (arithmetic mean much high er than geometric mean).