Count your plovers before their eggs hatch, once they hatch, and in each subsequent year.

This tailored adage will likely find its way into the report that Lincoln Park Zoo’s scientists submit to government officials following the completion of an “independent technical review” of the U.S. Army Corps of Engineers’ management strategy for the piping plover (Charadrius melodus).

Representatives from the Corps, the U.S. Fish & Wildlife Service (USFWS) and the Canadian Wildlife Service visited Chicago to meet with the zoo’s Steve Thompson, Ph.D., Vice President and Emily and John Alexander Chair of Conservation and Science; Joanne Earnhardt, Ph.D., director of conservation biology; and Megan Ross, Ph.D., the Hope B. McCormick Curator of Birds.

The group asked zoo scientists to create a population model that would assess the extinction risk to the Great Plains population of piping plovers. The plover is an endangered migratory shorebird whose primary nesting grounds are the gravel banks, sandbars, beaches and alkali wetlands along the Missouri River. The population in the region is estimated at fewer than 2,000 birds. It faces numerous threats, including predation, human disturbance and development, along with egg and chick mortality due to changes in the water flow and water levels on the Missouri River. The model, termed a Population Habitat Viability Analysis, is a quantitative analysis drawing upon factors such as a species’ life history, ecology and management that identifies threats to a population’s long-term survival. With the plover, zoo modelers rely on the work of field researchers to gather data such as number of eggs laid, number of eggs hatched and number of chicks that survive.

“Getting people on the ground in the field to count eggs and birds is always important if we are to make accurate projections for the population,” Earnhardt says.

The model becomes a valuable conservation tool when it’s used to assess a population’s probability of extinction under a variety of different scenarios, including biological and management strategies. The zoo’s model will be used by federal agencies to evaluate the role of the Corps’ captive-rearing center in South Dakota as a recovery tool. The plight of the plover has attracted considerable political attention due to the fact that it is one of three endangered species (the other two are the pallid sturgeon and least tern) determined by the USFWS to be sensitive to changes in the Corps’ operation of the dam system on the upper reaches of the Missouri River.