Late summer is a good time to study the young of local breeding birds. In some species,fledglings are identical to adults; in others, there is a dramatic difference in plumage. When they leave the nest, the young of common perching birds have a short tail, partially developed flight feathers, and beg for food for several weeks, so are relatively easy to spot.
Look for young Wood Ducks and adults in eclipse plumage on secluded ponds and rivers. The marshy end of Centennial Lake, Race Road Wetlands, and quiet sections of the Patapsco River or the Middle Patuxent River are possibilities.
Continue watching for vagrant egrets and herons on local lakes and rivers; many will be immature birds. Great Egret numbers often peak this month. During the summer, both of the night-herons may be detected at dusk along the edges of one or more of the three Columbia lakes. The Yellow-crowned Night-Heron is the more unusual of the two. It favors Lake Elkhorn, while the Black-crowned Night-Heron is most consistently seen at Wilde Lake.
Warm summer days, when thermals are strong, are a good time to view soaring hawks and vultures. Watching both species of vultures together is an effective way to learn the “jizz” of each. Although Black Vultures used to be less common than Turkey Vultures in the eastern part of the county, it is now possible to see them countywide. To see both species, try Alpha Ridge Park or Mt. Pleasant.
By mid-month, start watching mudflats and reservoir/lake edges for early shorebird migrants. Most of these early arrivals will be adults still in partial breeding plumage. Whether any particular site will be productive is unpredictable. If heavy rains have filled ponds, lakes, and reservoirs, there will be few muddy edges—and few shorebirds. On the other hand, too dry a season means that exposed mudflats will dry quickly and harden; worse, the empty expanses are soon covered with sprouting vegetation that holds little attraction for migrants. If the stars are aligned properly, flats will be exposed gradually as heat reduces water levels and brief showers will moisten the exposed mud. Check the mudflats at Browns Bridge, Pigtail, and Big Branch as well as the edges of Waverly Pond on MD 99 from now until late September.
From mid-July through August, watch extensive short-grass areas for the infrequently spotted Upland Sandpiper.
At dusk, listen for Eastern Screech-Owls this month and next. Families have fledged and are talkative. The diminutive owls have often been found at Daniels, and sometimes at the Big Branch parking lot.
Great Crested Flycatchers call at dusk, sometimes only briefly.
Late this month start checking reservoirs, as well as lakes and ponds, for flocking swallows.
In late July, juvenile Purple Martins gather in flocks, often on dead branches at the tops of tall deciduous trees. They have also been observed using light fixtures adjacent to the ballfields at Centennial Park.
Fruit-bearing trees, both wild and domestic, are magnets for family groups. Many species, besides Northern Mockingbirds, Gray Catbirds, and Brown Thrashers, gravitate to mulberry, cherry, chokecherry, and sour gum trees. Orioles, thrushes, woodpeckers, waxwings, tanagers, and blackbirds are among the groups that may be observed gorging on ripe fruit.
There is some early migration of songbirds this month. By month’s end, note the disappearance of most Orchard Orioles, many Yellow Warblers, and the majority of Louisiana Waterthrushes.
Check alfalfa fields or weedy expanses for Dickcissels singing from a weed or from a nearby utility line. The presence of this visitor from the Midwest is highly sporadic.
Those with a curious turn of mind should watch for fledgling Brown-headed Cowbirds and observe the host species. Young cowbirds usually announce themselves with an incessant call. All too frequently they are seen in association with a smaller host valiantly attempting to satisfy the demanding youngster.
The American Goldfinch is the county bird and can be seen almost anywhere in the county. Most nest in late July after thistle has gone to seed. Centennial Park, Schooley Mill Park, and Rockburn Branch Park, as well as the Middle Patuxent Environmental Area, all have extensive suitable habitat.