When songbirds fill the air with their melodious voices and raptors perform daring acrobatics in flight, you know spring is near and mating season has begun. Birds of all sorts are pairing up and building nests for their offspring. And when those nests are complete—humans be aware.

It’s important that we help ensure the perpetuation of our feathered friends and abide by the laws that have been put in place to protect birds and their nests, eggs, and young. “You can’t remove or damage their nests or eggs, or possess their eggs, nests, feathers, or parts. And you can’t harass the birds or their young,” said Sheri Mayta, a Senior Biologist at GPA Consulting. Harassment includes any action or behavior, especially those that appear predatory, that will stress or threaten the parenting birds. “Birds absolutely dislike anyone standing under their nests,” Mayta said. “If you stand there long enough, they get nervous. And they will let you know it!”

Many species of birds will try to drive away, or even attack, anyone near a nest; however, some species, if disturbed, may abandon their nests, leaving their eggs or young defenseless. Herons and egrets are especially sensitive to human disturbance, Mayta explained.

Nesting season typically begins in February but can begin as early as mid-January for raptors (also known as birds of prey). Mayta said a recent study prepared by scientists with the National Audubon found that many species of birds are adapting their lifestyles to breed earlier because of global warming. “Species are moving northward and to higher elevations,” Mayta said. “Warming could become problematic for many warmer climate species. The cool window [for breeding] may became too short for some species.”

Some species, like raptors, hummingbirds, and owls, will court and nest any time of the year.

As nesting begins, GPA’s biology team rises early in the morning and heads out into the field to conduct bird surveys, cataloging all species they see in the area and noting behavior that could clue them into the fact there may be a nest, like if a bird is carrying nest material or food. Birds prefer tree canopies and lush vegetation, but they can set up a nest anywhere; for example, underneath bridges or in spaces or openings in buildings. Some bird eggs look like rocks, Mayta said, so eggs may be hidden among rocks. Some nests are so tiny they are hard to spot by the untrained eye. “It’s good to do multiple surveys,” Mayta said.

Before construction or rehabilitation projects can begin, biologists try to determine whether there are nesting birds in the project area; any disturbance to them can negatively affect their young. “If an active nest is found, vegetation removal should be stopped,” Mayta said. If adult birds are observed flying to and from a nest, or sitting on a nest, it can be assumed that the nest is active. Crews must set up buffers (typically 300 feet for songbirds and 500 feet for raptors) and work around the nest. “Crews cannot work within the buffer,” Mayta added. Follow up surveys should be performed to determine when the nest is no longer active.

It's not just construction crews who have to be mindful of nesting birds; anyone wishing to remove or trim trees or shrubs need to be aware of the nesting season and the law. “It is illegal to remove nests,” Mayta said. “Tree and shrub removal should be done outside of the nesting season.”

Most birds are protected under a plethora of federal, state, and local laws. The largest blanket of protection is the Migratory Bird Treaty Act (MBTA), a federal law passed in 1918. It is one of the first pieces of environmental legislation enacted and it is still one of the most influential. It saved birds such as the heron, egret, and other waterfowl from extinction. One hundred years later, many bird species are still threatened or endangered. And, unfortunately for our feathered friends, the Act itself is threatened. Currently the U.S. House of Representatives is considering H.R.4239 – Secure American Energy Act, which, if passed, will eliminate protection for migratory birds that are victim to oil spills, wind turbines, or other energy infrastructure.