On Nature column: Enjoy the songs and beauty of White River warblers
Each year, the spring migration of songbirds to their summer breeding range reaches a peak when over 30 species of warblers pass through Indiana in early to mid-May.
Most North American warblers are neo-tropical migrants, wintering in the tropics of Central and South America and returning to North America each summer to breed. Their colorful plumage and active foraging habits make this group a favorite among birders.
While many species continue their migration north to Canada’s extensive boreal forests, over a dozen species breed in Indiana. Three of these local breeders may be heard and observed in the woodlands bordering White River. These three species, the northern parula, the yellow-throated warbler, and the Louisiana waterthrush arrive earlier than the migratory peak, typically reaching east central Indiana in the first three weeks of April.
The northern parula is a small colorful warbler that typically forages high in the canopy, preferring sycamore trees in our area. The male has bluish-gray wings and tail feathers with a yellow throat and breast interrupted by a black and a chestnut band. The female has only a hint of the darker breast bands. Both sexes have white wing bars, a yellow-green patch on their back and a white belly. The song of the northern parula consists of an ascending series of buzzy notes that drops to an abrupt ending note.
The yellow-throated warbler is also typically found in sycamores along White River. It has a bluish-gray back, white wing bars and a yellow throat but lacks the breast bands of the northern parula. The bold black and white facial pattern and the black streaks on the sides of the breast further differentiate this species from the previous one. This species has a distinctive foraging habit of creeping along large tree limbs, not unlike the white-breasted nuthatches that frequent our bird feeders. Their song consists of a series of similar slurred notes that descend and weaken toward the end.
The distinctive Louisiana waterthrush is found along clear wooded streams. They may be easily found along the spring-fed streams in the deep ravines at Mounds State Park. Their plumage is very thrush-like with a brown back and wings and a spotted white breast. Unlike our true thrushes, there is a prominent white line above the eye. The Louisiana waterthrush forages on the ground along streams, walking with a distinctive gait that includes incessant tail-bobbing. It feeds on aquatic invertebrates plucked from the shallow water. This foraging habit makes it easier to observe than the other two species. Its song starts with slurred notes resembling that of the yellow-throated warbler, but rather than weakening, it ends in an emphatic jumble of notes. All three of these species may be heard singing in their breeding territories from late April through July.