DOVER — With a resident population of around 70, Delaware’s population of bald eagles is on the rise but there’s still a long way to go.

The National Fish and Wildlife Service reports that in 18th-century America there were more than 100,000 bald eagles but the population began declining in the late 19th century due to hunting. However, it was nearly wiped out due to the pesticide DDT introduced in the 1940s.

Bald eagle numbers declined to less than 1,000 by 1963. Although birds did not die from ingesting DDT, the chemical prevented eagles from producing strong egg shells so many eggs broke during incubation or failed to hatch.

But since the ban of DDT in 1972, numbers for the species has been rebounding and proof can be seen this time of year by the young chicks taking to the skies for the first time.

“Some chicks have fledged the nest already this year and we hope that when the time comes they choose to make their own nests here,” said Kate Fleming, a wildlife biologist at the Division of Natural Resources and Environmental Control.

Adult eagles nest between November and early February and lay their eggs between January and April.

Chicks first venture out of the nest between 10 and 12 weeks of age so the first ones of 2016 are already heading out of the nest. Others will continue to fledge as late as early July.

Although eagles are full-sized by the time they leave the nest, they are distinguishable from their parents by their all-brown color.

The white won’t grow in until they mature more and they won’t build a nest of their own until they reach sexual maturity and find a mate at about 5 years of age.

“We do anticipate many of the chicks to stay around and build their nests here, but it all comes down to personal preference,” Ms. Fleming said.

The birds tend to nest in large, tall trees but not just any tree will do. They search for the perfect spot and that could have them checking out real estate in nearby states.

According to The National Audubon Society, when an eagle finds the perfect tree, the male and female work together to build a nest they will most likely use for years to come because eagles typically mate for life.

Eagles prefer to nest high, choosing branches up to 180 feet from the ground and the branches have to be strong since eagle nests are the biggest of any other North American bird.

Eagles typically have two chicks so the nest must be large enough to accommodate four full-sized birds. The largest eagle nest in North America was found to be 8.2 feet wide.

For the most part, eagles choose to nest away from areas with lots of people and traffic.

“More and more eagles are getting used to human activity, but given the option, they’d prefer to have some distance from humans,” Ms. Fleming said.

If an eagle does nest close to your home, it’s important to give the nest plenty of space even if the birds don’t seem bothered by humans.

“It’s important to enjoy them from afar,” Ms. Fleming said. “If you have a nest on your property, don’t approach the nest. Or if you just want to get a better look at the birds, use binoculars.”