Bald Eagles and Hawks Compatible with Management

By Charlie Todd, IF&W Wildlife Biologist

Maine’s bald eagles were designated an Endangered or Threatened Species from 1978-2009. The special Essential Habitat rules adopted under Maine’s Endangered Species Act no longer apply after delisting. National Management Guidelines are in place, however, to help avoid liabilities under the Bald Eagle-Golden Eagle Protection Act, a federal law.

The guidelines promote the same concepts previously applied via regulation. The timing of activities in relation to the breeding cycle is always a concern within 10 chains and potentially extends to a radius of 20 chains (or 1,320 feet, about a quarter mile) for more intensive projects. Harvesting and new road construction may not be problematic in fall or winter, but could disrupt egg-laying, incubation, or eaglet development during the period from Feb. 15-Aug. 31 each year. Maine eagles may remain near a nest virtually any month of the year, but disturbance risks diminish outside the nesting cycle.

IF&W now monitors statewide nest distribution only once every five years, and 2013 will be the next complete inventory year. Research and surveys related to environmental permits provide some updates in interim years, and IF&W maintains a list of known nest locations.

We know from decades of cooperative management efforts, intensive population monitoring, and accumulated experience that forestry is a potentially compatible activity if timing safeguards are addressed. Forest practices mold the landscape and can either promote or reduce the suitability of a stand as eagle nesting habitat. More than 80% of all eagle nests in Maine are within 20 chains of an open water shoreline along lakes, rivers, expansive wetlands, or coastal waters. Except for offshore islands, the eastern white pine is highly favored as a nest tree.

The “typical” nest is built below the canopy of a live pine greater than 30 inches DBH within 250 feet of a shoreline in a rural setting, but increasingly diverse situations are observed if optimal habitat features remain. Eagles will use high-quality nest trees for decades, or find a replacement nearby if a replacement is needed. The stand around a nest not only provides replacement nest trees but also serves as a landscape buffer screen from potential disturbances such as blowdowns. The extreme site fidelity of nesting eagles rewards woodlot owners who accommodate their special needs.

IF&W will continue to notify owners of properties that support a newly found eagle nest or nearby parcels. Wildlife biologists can assist via site visits or reviewing forest management plans. If you discover a nest that you feel the agency is not aware of, please report that location. We learned long ago that sharing information early on is the best way to achieve mutual goals -- and bald eagle recovery as we currently enjoy it in Maine would not have been possible without private stewardship. Thank you!

Other raptor nests are protected when “active” (eggs or nestlings are present) by the Migratory Bird Treaty Act. Thus, fall and winter harvests are again implicitly safer. The breeding season is invariably shorter than that of bald eagles but the exact timing varies amongst species.

Ospreys usually do not lay eggs until late-April in Maine, but nestlings remain in nests through much of August. Their conspicuous nests are only a little smaller than an eagle’s, and usually are at the extreme top of a live pine, a snag in a flowage, or an electric transmission line pole.

Woodland hawks generally lay eggs in May across Maine, and most nestlings fledge in July. These nests are not as easily seen. Many foresters encounter territorial behavior, rather than the nest itself. Detectability varies greatly with the stage of the breeding cycle. A northern goshawk that may swoop at someone near a nest with young during June will sit quietly through similar intrusions while incubating in May. Nests are again built of sticks but vary greatly in size.

A red-tailed hawk nest is perhaps two feet across, but those of smaller buteos (red-shouldered hawks or broad-winged hawks) and accipiters (northern goshawk, Cooper’s hawk, and sharp-shinned hawk) may be only half that size. Great-horned owls, barred owls, and merlins often use the nest of a crow or another raptor rather than build their own. Contact IF&W if you have questions.


For more information:

National Management Guidelines: www.fws.gov/northeast/EcologicalServices/eagle.html
Maine nest locations:
www.fws.gov/mainefieldoffice/Project%20review4.html