ALWAYS IN SEASON: Spring highlights the diversity of the bird world
It’s been a week for diversity in the bird world.
We’ve had big black birds, big white birds, big black-and-white birds.
We’ve had small brown birds, small gray birds, small orange birds and small yellow birds.
Plus, we’ve had middle-sized birds of various hues.
That’s what spring brings to the Red River Valley.
The big black birds that several readers reported soaring over Grand Forks were turkey vultures. Yes, I know that turkey vultures seem out of place here, but that is a human perception. For turkey vultures, Grand Forks is a convenient stopover en route to nesting areas farther north and west.
It’s true these birds were practically unknown here a quarter of a century ago, but in recent years, sightings of turkey vultures have increased. This reflects the success the vultures have met in establishing nesting territories in southern Manitoba and northeast North Dakota.
Earlier, the turkey vulture was regarded almost exclusively as a bird of the west. They occurred in good numbers everywhere west of the Missouri River, but it was considered surprising to see them very far east of there.
The turkey vulture is easily recognized. It is a dark bird overall, with a bare, red head. At rest, it is a hulking figure, with head pulled back and shoulders slumped.
In flight, the usual state for vultures — its wings appear two-toned, darker in front and lighter behind. Vultures fly with their wings held in a noticeable V-shape, a dihedral. Most other soaring birds fly with flatter wings. Vultures habitually circle while other soaring birds generally set a course and pursue it.
It’s quite usual for vultures to be confused with eagles, and this makes sense since vultures and eagles are large, black soaring birds.
But eagles have large, feathered heads, while the heads of vultures seem small in relationship to the body. Plus, vulture heads are naked, pretty much completely without feathers — an adaptation that allows them to eat carrion without staining their plumage.
Two kinds of eagles occur here.
Bald eagles have rebounded significantly since the pesticide scare of the 1980s. Every spring season brings reports of more nests in the Red River Valley.
The bald eagle is not really bald, of course. Adults have white heads, which distinguish them from any other large, soaring bird.
Golden eagles are much less common here, and as far as I know, there are no nests in the immediate area. Golden eagles do occur here in winter and in early spring, so it’s worth being alert for them.
Separating adult eagles doesn’t pose significant problems, but juvenile birds are a different story. Both eagle species are three-year birds, meaning they don’t acquire full adult plumage until they are in their third year of life. In the first two years, they can be frustratingly difficult to identify with certainty.
So here’s a rule of thumb: Any eagle encountered in the Red River Valley between March 1 and Dec. 31 is likely — probably 90 percent likely — to be a bald eagle. In winter, the percentage drops, perhaps to 60 percent for bald and 40 percent for golden eagles.
Now as for the big white birds: These are tundra swans, and they aren’t likely to be confused with any other species. The middle weeks of April are swan season in the Red River Valley. The valley lies pretty much astride the flyway that swans follow from their winter quarters on the mid-Atlantic coast and to nesting range in northwestern Canada and Alaska.
This year’s passage was especially concentrated, probably because of the late spring.
As for the small brown birds: These are varieties of sparrows. The sparrows pass through our area in late April, generally in a specific order: American tree sparrows first, then fox sparrows, then white-crowned and white-throated sparrows, then Harris’ sparrows. All of these are northern nesters hurrying to get about the business of reproduction. Nesting sparrow species generally arrive later. The most common of these and the only one likely to be encountered in Grand Forks city is the chipping sparrow. In open country, there are several other species to watch for: clay-colored, vesper and LeConte’s.
Then there are the yellow birds. These are American goldfinches taking on summer plumage. Their reddish (perhaps more properly called orange) counterparts, small birds with short, thick bills adapted to cracking seeds, are house finches.
Both species are abundant here.
Jacobs is a former publisher of the Herald. Reach him at firstname.lastname@example.org.