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bobolink

bobolink (Dolichonyx oryzivorus) [female]
Photo © Mary Kay Rubey

bobolink (Dolichonyx oryzivorus) [male]
Photos © Mary Kay Rubey

Features and Behaviors

FEATURES
The bobolink averages six to eight inches in length (tail tip to bill tip in preserved specimen). The breeding male has black feathers on the ventral (lower) side and tan and white feathers on the back. The female has tan feathers with dark stripes on the head. In fall, the males look more like females, as they lose their bright colors. The thick bill is cone-shaped, pointed and sharp.

BEHAVIORS
The bobolink is a common migrant throughout Illinois and a common summer resident in the northern one-half of the state, decreasing southward. It lives in alfalfa fields, clover fields, hay fields and pastures as well as fence rows. Its bubbling song is produced while flying. Migrating in the day and sometimes at night as well, the bobolink begins arriving in Illinois in late April each year. The birds migrate in small flocks with the males arriving first. The breeding season occurs from late May through July. The nest is constructed on the ground in dense vegetation. The female finds or makes a shallow depression in the soil and lines it with grasses. Three to seven, light brown eggs with dark blotches are deposited by the female in the nest. She alone incubates for the entire 13-day incubation period. Nests are often parasitized by the brown-headed cowbird that deposits an egg that the bobolink will hatch and raise, taking food and care away from its own young. Bobolinks migrating south begin appearing in Illinois in mid-August. This bird eats insects, fruits, grains and seeds.

Reasons for Concern

​Loss of grassland habitat and the brown-headed cowbird’s (Molothrus ater) nest parasitism affect this species.

Illinois Range

Taxonomy

Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Passeriformes
Family: Icteridae

Illinois Status: common, native