Watching out for sentinel species

Volunteers throughout Delaware are doing what state scientists simply cannot: spreading out over the three counties to gather vital information on some of the state’s most fascinating creatures.

Learning more about the First State’s wildlife helps with everything from making land management decisions to helping ensure the survival of some animal species. These include the horseshoe crab, a 450-million-year old living fossil and the osprey, a bird of prey that migrates to Delaware from winter grounds in the southeast United States and Caribbean.

The state Department of Natural Resources and Environmental Control (DNREC) is looking for volunteers for this year’s Citizen Osprey Monitoring Project, which will run from mid-March until August. DNREC also wants to sign up volunteers for its other wildlife monitoring programs throughout the year.

Delaware’s osprey are a sentinel species considered very sensitive to variations in their surroundings, DNREC wildlife biologist Kate Fleming said.

Because it feeds exclusively on fish, biologists can tie the general condition of the waters surrounding their nesting grounds to the number of osprey, Fleming said.

“If there were some kind of change in the environment, we might see it reflected in the population health of the osprey,” she said. “By looking at the osprey, their population and their success at reproduction, we find there is an indicator for the ecosystem’s health.”

That’s a main reason to find out how many osprey nest in Delaware over the summer, she said, and leads to why DNREC needs volunteers to document the birds’ population.

“They osprey population has been increasing, and it would be logistically impossible for us to monitor the birds at the same level our volunteers do,” Fleming said.

The number of birds nesting in Delaware has been on the rise since 1971, when only 25 nests were found, mostly around the state’s inland bays, Fleming said. In 2014, DNREC volunteers documented about 200 active nests in all three counties.

“We probably would not have been able to collect information on their population status without the volunteers,” she said.

Delaware’s heritage

Volunteers also are vital to success of the state’s horseshoe crab survey, which has been carried out annually since 1990, noted Maggie Pletta, volunteer coordinator at the Delaware National Estuarine Research Reserve near Kitts Hummock.

It is considered one of the most successful volunteer-based wildlife surveys in the country.

“These animals are a part of Delaware’s heritage,” Pletta said. “They’re a part of who we are and of our history. We want to make sure that we keep that heritage for future generations.”

The horseshoe crab is a vital part of Delaware’s environment, as its eggs serve as the primary food for the red knot, a bird species that uses the state as a migratory rest stop. The crab’s blood also is collected – usually without causing harm to the animal – for use as an anti-toxin in humans.

The information volunteer horseshoe crab counters gather is important in making sure they are not over-harvested, Pletta said. Those volunteers are vital to that program, she added.

“Honestly, we don’t have the staff, we don’t have the resources, we don’t have the manpower,” she said. “Without them to help, we could not complete the surveys and get the information we need.”

Keep coming back

In addition to horseshoe crabs and the osprey, DNREC also sponsors efforts to survey shorebirds, frogs, the endangered piping plover, and even bats, the latter as an effort to help stem a deadly disease that has killed millions of the nocturnal animals.

Training sessions help familiarize volunteers with what they need to observe and record, Pletta said. For horseshoe crabs, monitors usually work during high tides in May and June, wading into masses of the hard-shelled creatures.

“To see that many horseshoe crabs in one place, it’s really hard to explain how phenomenal it is to see,” Pletta said. “You can’t even see the ground; I’ve never seen anything else quite like it.”

Osprey observers monitor assigned nests, usually found atop tall poles, Fleming said. They look for adults arriving at the nest, how many eggs are laid and how many hatch, plus when the chicks are able to leave the nest, she said. It only takes a few minutes a day, every couple of days, to gather this information, and even can be done from the comfort of one’s car, she said.

The numbers of people taking part in the osprey monitoring has risen steadily, from just a handful to 15 in 2014. Some people even adopt a nest, monitored the same one, year after year, Fleming said.

Overall, those who volunteer for wildlife surveys do so because they want to get involved, they want to be part of a special community and they feel it’s important to help the environment.

“People get excited about it,” Fleming said. “There always are people who come in and later drop out, but it’s been increasing steadily each year, where we’ve had more and more volunteers stay with the program and provide some valuable information.”