Take Home Message
For Herring Gull eggs
Eggs from Channel-Shelter I. (Saginaw Bay) had the highest or among
the highest levels of PCBs, TCDD, HCB and DDE of all sites on the Great
17 of 21 contaminant trends (81%) from 3 Annual Monitor Colonies in
Lake Huron have declined since 1974-80; 62% of them at a constant rate;
19% have slowed in recent years.
For Colonial Waterbirds on Lake Huron
Over 400,000 colonial waterbirds breed on Lake Huron, mostly Ring-
billed and Herring Gulls and cormorants.
Approximately 73% of these occur in Canadian waters and 27% in U.S.
Trends over 23 years indicate cormorant and black-backed gulls are
increasing steadily, Common Terns and Herring Gulls have declined
steadily and night-herons and Ring-billed Gulls have fluctuated.