White-throated Sparrow

The White-throated Sparrow is a familiar songbird and is found at one season or another throughout much of North America south of the tree line and principally east of the Rocky Mountains. It breeds primarily in the boreal coniferous and mixed forest and, a short-distance migrant, winters mainly in the southeastern US as well as the pacific coastal regions of North America.

Adult Male (spring/summer)

Head has white median crown-stripe, black lateral crown-stripe, white supercilium, yellow lores, black eye-line, gray auricular, white malar and white throat bordered by black malar stripe. Breast is gray unstreaked or with coarse mottled streaks and always shows strong contrast with white throat. Belly and undertail coverts are white. Flanks dull tan with faint streaks. Tan nape with streaks and rufous streaked back. Rump, uppertail coverts and tail dull tan. Wings are streaked brown-rufous with white wing bars, which appear to be white drops. Bill is gray. Legs and feet are pale pink.

The White-throated Sparrow comes in two color forms: white-crowned and tan-crowned. The two forms are genetically determined, and they persist because individuals almost always mate with a bird of the opposite morph. Males of both color types prefer females with white stripes, but both kinds of females prefer tan-striped males. White-striped birds are more aggressive than tan-striped ones, and white-striped females may be able to outcompete their tan-striped sisters for tan-striped males.

Adult Female (spring/summer)

Similar to males.

Juvenile

Median crown stripe indistinct, yellow lores dull to absent and breast and flanks heavily streaked with dark brown.

General:

Stocky fairly large sparrow. Length: 16-18cm. Wing: 20-23cm. Weight: 22-32grams.

Behaviour:

This sparrow typically travels in small flocks and is frequently spotted on the ground, scratching through the leaf litter foraging for seeds and insects. White-throated Sparrows eat the fruit of dogwoods, elder, cedar, apple, maple, and oak trees. During migration and throughout its winter range, this species is a common visitor at feeding stations.

Habitat:

The White-throated Sparrow is a brushland bird of all seasons. They are common in wooded areas, along forest edges, in logged or burned regenerating areas, and along pond, swamp, or creek edges. In winter it is often found in dense deciduous thickets or brush piles, often at woodland edge or in woodland clearings and, in urban areas ground feeding under backyard feeders in mixed flocks.

Information:

This sparrow species builds a cup nest in concealed wet thickets. Nests are composed of grass and twigs and are lined with deer hair, feathers, and grasses. 4-6 eggs are laid between May and August. Eggs are creamy to light green in colour with rust markings. Chicks fledge seven to 12 days after hatching.

Similar species:

White-crowned Sparrow, Song Sparrow, Golden-crowned Sparrow.

Conservation Status:

Listed as Least Concern but declining in much of its breeding range.

White-throated Sparrow breeding range includes the more northern and interior areas of British Columbia. At Colony Farm, hosting ideal habitat for stop-over of these medium distant migrants, we capture a few individuals each spring and fall on migration.

Molt Summary:

PF: HY partial (Jul-Sep); PB: AHY complete (Jul-Sep); PA limited (Mar-May). PBs occur on the summer grounds.
Preformative molt usually includes all med and gr covs, but no terts or rects. Beware of pseudolimits between richer brown terts/inner gr covs and the duller brown middle ss/outer gr covs.
PAs: limited to body feathers, primarily the head region.

Note: Zonotrichia sparrows have strong colour contrasts (or pseudolimits) within the greater coverts which simulate molt limits but are in fact not true molt limits. These pseudolimits are present in both HY/SY and AHY/ASY birds. Examine the extent of wear to the feather tips to see if it is a true molt limit.

This HY in October has completed its preformative molt and replaced all lesser, median, greater coverts and carpal covert but nothing else – no tertials or central retrices – the molt limit shown with the red arrow between the replaced outer greater covert and retained inner primary covert. Notice the contrast between the replaced greater alula covert (A1) and lower main alula feather (A2) also indicated with a red arrow. White-throated Sparrows are among the Emberizid family which often show this key alula covert (A1) molt limit.

Notice the thin, narrow and tapered outer primary coverts and main lower alula feathers (A2 & A3) lacking any brownish edging and the contrast between them and the fresher replaced greater coverts.

Notice also the ‘pseudolimit’ mentioned above (green arrow) within the greater coverts, a natural colour contrast simulating a molt limit when in fact all greater coverts have been replaced. This ‘pseudolimit’ is also shown between the richer brown tertials and duller brownish middle secondaries (green arrow) causing the tertials to appear more recently replaced.

Tail shape is helpful in ageing many species being tapered and more abraded on retained juvenal feathers in first year birds (HY/SY) and broad and truncate with a corner to the inner web and relatively fresh in adults (AHY/ASY). The outer retrices (R4-R6) generally show the greatest age specific differences. The tail of the bird above is showing a very tapered outermost rectrix (R6) although R4 and R5 are more rounded. For this reason and the fact that tail feathers are frequently lost and replaced between normal molts tail feather shape must be used with great caution by banders, and only with other supporting characters (e.g., molt limits), when determining the ages of birds in hand.

A similar example of a HY in October – the molt limit shown with the red arrow between the replaced outer greater covert and retained inner primary covert. Notice the contrast between the replaced greater alula covert (A1) and lower main alula feather (A2) and thin, narrow and tapered outer primary coverts and main lower alula feathers (A2 & A3) with indistinct pale brown edging, the primary coverts already showing some wear to the tips, and the contrast between them and the fresher replaced greater coverts.

Notice again the ‘pseudolimit’ (green arrow) within the greater coverts and between the richer brown innermost tertials and duller brownish middle secondaries causing the tertials to again appear more recently replaced.