Bird of the Week: Black-capped Vireo

Black-capped Vireo
Vireo atricapilla

 By James Giroux

Along with the Golden-cheeked Warbler, the Black-capped Vireo is a “destination bird”, and many birders from around the nation travel to Texas to see it. It is a habitat specialist, nesting in short scrub oaks. From 1987 through 2018 it was on the endangered species list, and its current nesting population is only 11,000.

The male has a jet black cap and white spectacles while the female has a gray cap. It is the only vireo species that exhibits sexual dimorphism – a difference in appearance between male and female. It is also the only vireo species in which the male takes two years to reach adult plumage.  So, a gray-headed Black-capped Vireo could be a first year male or a female.  The bird pictured below is a presumed female because it was foraging with the male during nesting season.

Black-capped Vireo – Female                     Photo by James Giroux

If you are looking for this bird, you will probably hear it before you see it. Like most of the vireo species, it loves to “sing”, and will often sing well into the afternoon.  I put “sing” in quotation marks because its “song” is more of a series of non-musical trills, rattles and buzzes. It makes a wide variety of sounds, and uses about ten times more “syllables” than the other vireos.

Most Texans will tell you it’s a Texas specialty, but it also nests in Oklahoma.  It winters in western Mexico, and begins to show up here in Central Texas the last week of March. The map below shows its historic breeding range reaching up into Kansas, but the bird can no longer be found there.

Males arrive on breeding grounds first, and establish their territories by singing and chasing away other males. When the females arrive, they choose their mates based on territory suitability, singing ability and perhaps appearance of the male. The males perform a rarely-seen “dance” that displays an attractive black and yellow pattern underneath the wings. They also rear their head back, and rhythmically show each side of their face.

Like all vireos, they feed mostly on bugs, including adult and larval moths, butterflies, beetles, flies, katydids, and spiders. They will also consume small amounts of plant matter.

Photo by James Giroux