Beak of the Week – Black-and-white Warbler

Black-and-white Warbler (Mniotilta varia)

Family: Parulidae

The Black-and-white Warbler is a medium-sized warbler with a long, slightly downcurved bill. They are boldly striped in black and white and their black wings have two wide, white wing bars. The males of this species have more pronounced black streaking on their underparts and cheeks. Females and immatures are paler, have less streaking and large black spots on their undertail coverts. They can easily be identified by their call which resembles a squeaky wheel. It is a high-pitched, monotonous weesy-weesy-weesy-weesy.

In the summer the Black-and-white Warbler can be found in deciduous and mixed forests. The trees are usually mixed ages, which gives the warblers a large variety of foraging substrates. During the winter they prefer forest and forest edges from Florida to Colombia. While foraging in these areas they look for hidden insects in the bark of trees. To find these insects they act similar to a nuthatch and creep up and down the tree. They have extra-long hind claws and heavier legs that help to support them as they look for food. Their diet mainly consists of caterpillars, beetles, ants, flies, leafhoppers, aphids, spiders, and daddy longlegs.

These warblers begin their migrations early and the males tend to arrive at their breeding grounds in late April. Once the female arrive and courtship begins the males will chase the females around while singing and fluttering. The female will build the nest on the ground under dead leaves or limbs, against a shrub, rock, log, or tree. Nest can also be found in a cavity at the top of a stump. The nest is an open cup made of leaves, coarse grass stems, bark strips, pine needles, rootlets. It is also lined with fine grass or hair. The eggs are only incubated by the female for 10-12 days. Once hatched the young are fed by both parents and leave the nest before they are able to fly well at around 8-12 days. It is common for the Black-and-white Warblers nest to be parasitized by a cowbirds.

We have been seeing these bold warblers at our sanctuaries! Come by and see if you can find them yourself.

Greg Lavaty
Greg Lavaty
 Visit our Bird Gallery to read about other Texas birds! 

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