As we enter November, migratory raptor flights through the Lower Susquehanna River Watershed transition to the bigger birds. Whether you’re on the river, on a mountain, or just outside your humble abode, persistent alertness to soaring avians can yield rewarding views of a number of late-season specialties.
Red-tailed Hawks dominate the southbound raptor flights in November.Juvenile (hatch-year) Red-tailed Hawks are generally less wary and more inquisitive than the more experienced adult birds. Their curiosity frequently gets them into trouble, particularly when they try to hunt small rodents in traffic along busy roadways.Far fewer in number are migratory Red-shouldered Hawks. In our region, these denizens of bottomland forests more commonly migrate along the southern edge of the Piedmont and through the upper Atlantic Coastal Plain.A southbound hatch-year (juvenile) Red-shouldered Hawk.Mixed-race Peregrine Falcons, the descendants of birds reintroduced into the Mid-Atlantic States during the late twentieth century, often roam our region during the late-fall and winter months before settling into their nesting territories with the approach of spring. We spotted this one along a local ridge, but you may be more likely to see them in the city or near a bridge or dam on the river.As this adult peregrine passed the lookout, we noted its full crop. A sign it just completed a successful hunt.
A visit to a ridgetop on a breezy day—particularly after passage of a cold front—may give you the chance to see numerous eagles as well.
A second-year (Basic I) Bald Eagle barrel rolls while pursuing an adult Bald Eagle.
This afternoon, we got lucky and were treated to a bit of an aging clinic presented by the Bald Eagles we observed and photographed. Careful determination of the age classes of raptors counted by hawkwatchers can provide an early warning of problems in the ecosystems that support populations of these top-of-the-food-chain predators. For example: during the 1950s and early 1960s, a progressively lower percentage of juvenile and other non-adult age classes among the Bald Eagles being observed forewarned of the dangers of dichlorodiphenyltrichloroethane (DDT) pesticide in the environment. The principle effect of accumulations of the DDT toxins in eagles, Ospreys, Peregrine Falcons, and other predatory birds that consumed waterfowl and/or fish was to thin their eggs shells. The result was widespread brood failure and a near total loss of new generations of offspring. Eventually, nearly all Bald Eagles being seen in areas impacted by DDT were progressively older adults, most of which failed as nesting pairs. As the adult birds began dying off, the Bald Eagle population dwindled to numbers that raised fears of the species’ extinction. Implementation of the DDT cancellation order and the Clean Water Act in 1972, and the Endangered Species Act in 1973, helped save the Bald Eagle. But our regional “Eastern Peregrine Falcon”, a bird with a shorter life span than the Bald Eagle, was unable to endure the years of DDT use, dioxin pollution, and illegal hunting and egg collecting. Its population is gone.
A hatch-year (juvenile) Bald Eagle is typically dark headed and in a fresh set of juvenile flight feathers that exhibit no signs of molt. If the reproduction season and the months that followed were favorable for this year’s brood of new eagles, there should be nearly as many hatch-year birds as there are adults in an overall population.By November, second-year (Basic I) Bald Eagles are replacing many of their flight feathers and often show ragged trailing edges in the wings due to the retention of some of the well-worn and notably longer juvenile feathers. Varying amounts of white mottling are visible on the breast, belly, and underwing coverts. Due to mortality, there are usually fewer second-year Bald Eagles than there are hatch-year or adult birds.Another example of a second-year (Basic I) Bald Eagle.Third-year (Basic II) Bald Eagles show more yellow in the bill and an “osprey face”, a white head with a wide dark line through the eye. Most of the juvenile flight feathers have been replaced, so the wing edges appear more uniform. Like the second-year eagles, there is a varying amount of white in the breast, belly, and underwing coverts. In an overall population of eagles, birds in this age class are usually less common than those that are younger or those that are adults.Composite image of Bald Eagles in typical November plumage during their first three years. To see more images like this, be certain to click the “Hawkwatcher’s Helper: Identifying Bald Eagles and other Diurnal Raptors” tab at the top of this page.A fourth year (Basic III) Bald Eagle will often be seen with a black-bordered tail and a thin dark line through the eye. In some birds, traces of these traits can linger into the fifth year and beyond. These plumage types are usually the least frequently observed among an overall population of Bald Eagles. (Note: In these older birds, there develops significant variation in the timing of feather molt. In rare cases, fourth-year Bald Eagles may show minimal dark color in the tail or eye line and may appear to be in near definitive adult plumage.)A possible fifth-year (Basic IV) Bald Eagle.Adult Bald Eagles in definitive plumage. Birds in this plumage class are often the most frequently observed because the group includes all eagles five or six years of age and older.
While the Bald Eagles are still stealing the show, cold and gusty weather should bring an increasing number of Golden Eagles our way during the remainder of the month. Some are already trickling through…
This “before-third-year” Golden Eagle shows no visible signs of molt in its juvenile (hatch-year) plumage, but a look at the upperwing coverts is needed to properly age the bird. To learn more about the molt sequence in Golden Eagles, be sure to click the “Golden Eagle Aging Chart” tab at the top of this page.A “before-third-year” Golden Eagle (top) passing the lookout along with a second-year Bald Eagle (bottom).Another “before-third-year” Golden Eagle. More are on the way!
Later this month, Bald Eagle numbers on the lower Susquehanna below Conowingo Dam (U.S. 1) near Rising Sun, Maryland, will begin to grow. Fisherman’s Park, located along the west shoreline below the dam, is an excellent place to observe and photograph scores of these regal birds. And few places provide a better opportunity to learn to differentiate Bald Eagle age classes. If you’re really lucky, a Golden Eagle or two may drop in as well. So plan to make the trip. The best time to visit is on a weekday. The parking lot can become overcrowded on weekends and will be closed under such circumstances. It’s best to avoid the long Thanksgiving weekend as well.
