Heron Studies with Manomet Center for
Conservation Sciences
I've been working with scientists at the Manomet Center for Conservation Sciences for
several years, with a focus on the health status of heron colonies in the northeastern US
coast. Katherine Parsons at Manomet has led up these studies - more information on
her work can be found at the link below:

Environmental Toxicology and Chemistry: Vol. 19, No. 5, pp. 13171323.
MONITORING WADING BIRD EXPOSURE TO AGRICULTURAL CHEMICALS USING SERUM CHOLINESTERASE
ACTIVITY
Katharine C. Parsons and Angela C. Matz
Manomet Center for Conservation Sciences, Manomet, Massachusetts 02345, USA
Michael J. Hooper
The Institute for Environmental and Human Health, Texas Tech University, Lubbock, Texas
79416, USA
Mark A. Pokras
Tufts University School of Veterinary Medicine, North Grafton, Massachusetts 01536, USA
AbstractOrganophosphorus (OP) and carbamate (CB) insecticides are widely used and
have a variety of lethal and sublethal effects on nontarget wildlife, primarily through
cholinesterase (ChE) inhibition. To assess possible exposure to anti-ChE compounds in
wading birds, we monitored breeding colonies in northeast U.S. estuaries (Boston Harbor,
MA; New York Harbor, NY; Nantucket Sound, MA; Delaware Bay, DE; and Rehoboth Bay, DE) from
1991 to 1996. We documented serum ChE activities in black-crowned night-heron (Nycticorax
nyticorax), cattle egret (Bubulcus ibis), snowy egret (Egretta thula), little blue heron
(E. caerulea), and glossy ibis (Plegadis falcinellus), and we investigated factors known
to affect ChE, including age, nutritional and immune status, location of the colony
(estuary), and exposure to ChE-inhibiting compounds. Exposure to anti-ChE compounds in all
species was supported by at least one of the following: positive pyridine-2-aldoxime
methochloride (2-PAM; OP) and/or spontaneous (CB) ChE reactivations, negative or
nonsignificant age correlations in most species, or regional land-use patterns. We
observed negative or nonsignificant relationships between ChE and age in most species.
Only glossy ibis showed the age-related patterns of ChE activity observed in other
altricial species. Of the remaining potential explanatory factors, location (estuary) but
not nutritional or immune status was the only one having a significant relationship with
ChE activity (p < 0.024). Significant differences among colonies were consistent with
surrounding land uses, specifically active agriculture. We conclude that extensive
monitoring of serum ChE in wildlife can identify locations of exposure and provide
reference data for wildlife pesticide-risk assessment.