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Q: What species of bird is this?

This is a female or immature magnolia warbler. This species’ notable identifying characteristics include the yellow feathers extending on the sides and belly; brown, faint, dark streaks along the sides below the wings; and the pale gray band between the throat and the belly. Other traits to look for include a gray head, a white eye ring, and two white wingbars. Both sexes have a unique tail pattern — white at the base and black at the tip. Adult males are bright yellow, have a black mask, a black neck band, black streaking on the chest and sides, and a bold white wingbar.

Fall warblers are a challenge for even seasoned birders to identify, so photo-documentation is helpful. The pattern under their tail is diagnostic, so keep an eye out for that. Also, listen for their short song, a whistled weta, weta, WETA, which generally becomes louder toward the end.

Magnolia warblers primarily eat caterpillars, insects, and spiders. They tend to forage on the outer edges of branches, searching the undersides of needles and leaves for prey. Because they are committed insectivores, they do not visit feeders and may only stop off in your yard during migration, but you can still provide habitat for them by landscaping with native trees and shrubs.

These birds breed in dense stands of conifers further north. As they migrate south to Latin America and the Caribbean, they forage along forest edges, woodlots, and parks. They often migrate in groups, but it’s unusual to see more than one warbler species flocked together in a tree.

Q. This is the first time I have ever witnessed black acorns falling from oak trees. Can you explain why this occurs?

Scientists aren’t completely certain why these acorns have a black appearance.

However, it’s possible the black coloration may have resulted from the drought conditions Missouri has experienced in recent years. It is conceivable dry weather intensified the tannins in the acorns, which otherwise look robust and not desiccated. And when confined in an envelope — a more-humid environment — these acorns returned to a normal brown, our forest entomologist reported.

Other observers note a tree producing black acorns likely is stressed. When an oak is struggling, immature seeds, darkly colored, die in mid-growth. These stunted acorns are shaken from the tree with high winds, but green, healthier acorns cling to the tree’s limbs and maintain their viability.

Q. What moth is this?

This is a white-lined sphinx moth (Hyles lineata). This moth has a narrow tan band running from the wing tip to the base on the upper side of its forewing, and white streaks along the veins.

This day-flying sphinx moth is a common site in gardens and natural areas. As caterpillars, they feed on a wide variety of plants including evening primrose, wild grape, elm, grape, tomato, and Virginia creeper. As adult moths, this species is even less selective, and will visit a variety of flowers to collect nectar. Learn more about these beautiful moths at short.mdc.mo.gov/4mc.