GCBO Bird of the Month
Olive Sparrow
by Mike Williams
Geography/Habitat:

The Olive Sparrow, (Arremonops rufivirgatus), sometimes called Schott’s, Texas, Pacific or Yucatan Sparrow is taxonomically poorly understood. First described by Lawrence in 1851 in Texas there are at least nine sub-species, of which some are considered distinct species by some authorities. Currently in a genus with 3 other Central/South American species, Green-backed, Tucuyo and Black Striped, many think it is more closely related to the Ammodramus genus. Almost certainly its classification will eventually change and is likely to become at least 3 different species.

Olive Sparrows form three distinct populations: the Texas group, the Yucatan group and the Pacific group. These are separated by tail length and overall brightness, but this is difficult to observe in the field. In the US, Olive Sparrows are only found in extreme South Texas and parts of the Texas Hill Country, where they are permanent residents, although their range appears to be moving slowly northwards. 

The Olive Sparrow is typically a ground dweller and as such prefers a wide variety of thickets and thorny scrub, including Mesquite, Texas Ebony and Live Oak. The species also likes streamside cane-breaks.

Olive Sparrows both seed and insect forage on the ground and in low shrubs. It often uses the “double scratch” technique to hunt, as do some other sparrows and towhees.

Olive Sparrows build a low nest close to the ground made of twigs, bark and leaves and lined with hair and moss. Two to five white eggs are laid and incubated for 10-12 days by the female alone. 

Identification

A medium-sized chunky sparrow with olive green-brown upperparts and light olive gray underparts, becoming whiter on the belly. The face is light with a black eye-stripe and a light-colored central stripe on the crown bordered by a chocolate-colored strips on either side. The nape is light brown before becoming olive on the back and wings. The tail is dark olive with light under tail coverts. The bill is cone shaped as for all sparrows, dark on the upper mandible but grading to light pink on the lower mandible. Of note is a tiny yellow green flash on the edge of the upper wing. The legs are pink. Its call is a rapidly repeated and descending “chip chip chip-chip-chip-speee tsik”.

Interesting Facts:

•Sometimes known as a Green Finch in Texas and is the only Sparrow with an olive back.

•A group of Olive Sparrows is known as a bunch.

•There are over 2 million Olive Sparrows and its status is of Least Concern.


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