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McGILL BIRD OBSERVATORY

PHOTO LIBRARY

White-throated Sparrow / Bruant à gorge blanche (Zonotrichia albicollis)

Introductory notes:
A rather tricky species to age by plumage, since age-related differences in wing and tail patterns are often subtle. Until late fall, most can be aged by skull development, but in spring many cannot be reliably classified beyond AHY. Sex can generally be determined only in the hand, by brood patch / cloacal protuberance during the breeding season, or by particularly short or long wing chords (<67 mm = female, >74 mm = male).

QUICK TIPS:

1) Look at the tail - uniformly narrow and pointed rectrices are indicative of HY/SY, while broad and more rounded rectrices are typical of AHY/ASY, but beware that some individuals may replace their tail early, so this is less reliable for AHY/ASY

2) Check the wing for molt limits - HY/SY birds should show a contrast between darker/fresher greater coverts and the paler block of primary coverts, primaries, and secondaries, but this tends to be more apparent in spring and even then can sometimes be too subtle to distinguish from the pseudolimit typical of AHY/ASY birds

3) Look at the iris in good light - it is grayish-brown in HY birds and brown (sometimes with a slight reddish tinge) in AHY birds (criterion reliable only in fall)

Species account updated January 2011

Ageing and sexing guidelines:

Note: there are white-striped and tan-striped morphs of this species which look considerably different; while differences
in head colouration are to some degree related to age and sex, they should not be used to classify individuals in the field.

January - July:

ASY - U Age can be difficult to assess in spring. Broad and rounded rectrices, and broad dark outer primary coverts are the best indicators of ASY.
SY - U Age can be difficult to assess in spring. Narrow and tapered rectrices, and narrow pale outer primary coverts are the best indicators of SY.

July - December:

AHY - U Reddish-brown iris, unstreaked breast, dark primary coverts, and broad rectrices.
HY - U Gray-brown iris, sometimes lightly streaked breast, relatively pale primary coverts, and narrow pointed rectrices.
JUV - U Streaked breast, limited colouration to coverts, and narrow but fresh rectrices.

Ageing and sexing details:

JAN - JUL: after-second-year unknown

Age can be difficult to assess in spring. Broad and rounded rectrices in combination with uniformly dark wings are the best indicators of ASY.

Photo by Marie-Anne Hudson, McGill Bird Observatory (QC), May 2007

Photo by Marcel Gahbauer, McGill Bird Observatory (QC), May 2006

The wing is usually the most reliable clue to age in spring. ASY birds lack a molt limit, and have a dark brown wing relatively uniform in colour and wear, though note that in all ages there are pseudolimits between the darker tertials and adjacent secondaries, as well as between the greater coverts and primary coverts.

An ASY wing in particularly good condition, showing little wear on any feathers, and a rich
dark tone to all feathers.
Photo by Peter Pyle, Braddock Bay Bird Observatory (NY), May 2010

A somewhat more typical wing, showing a more faded overall appearance, but still
quite uniform in colour and wear across all feather tracts.
Photo by Marcel Gahbauer, McGill Bird Observatory (QC), May 2006

ASY birds have relatively broad and rounded rectrices. However, this should not be used as a sole criterion of age, as White-throated Sparrows seem particularly liable to lose and replace their tails prematurely.

A typical ASY tail, with relatively broad and rounded rectrices, showing only moderate wear.
Photo by Marcel Gahbauer, McGill Bird Observatory (QC), May 2006

RETURN TO AGE/SEX OVERVIEW

JAN - JUL: second-year unknown

Age can be difficult to assess in spring. Narrow, tapered, and worn rectrices in combination with a molt limit on the wing are the best indicators of SY

A typical SY white morph bird.
Photo by Marcel Gahbauer, McGill Bird Observatory (QC), April 2006

An SY tan morph bird, still with a somewhat grayish iris.
Photo by Marie-Anne Hudson, McGill Bird Observatory (QC), June 2006

The condition of the wing is typically the best clue to age in spring, but there are many intermediates where the presence or absence of a molt limit cannot be reliably determined.

This wing is quite intermediate in appearance, with only a slight contrast between the greater
coverts and the block of primary coverts, primaries, and secondaries, making it difficult to
determine whether this is a true molt limit, or just a pseudolimit. Such a bird should be
considered AHY unless the tail provides distinct evidence for it being SY.
Photo by Marcel Gahbauer, McGill Bird Observatory (QC), April 2006

A narrow, tapered, and worn tail is a fairly reliable indicator of an SY White-throated Sparrow.

Although not particularly pointed, the rectrices are somewhat narrow, and all show a
considerable amount of fraying, as expected on juvenile feathers by spring.
Photo by Marcel Gahbauer, McGill Bird Observatory (QC), April 2006

An example featuring somewhat narrower and more pointed rectrices.
Photo by Marie-Anne Hudson, McGill Bird Observatory (QC), June 2006

RETURN TO AGE/SEX OVERVIEW

JUL - DEC: after-hatch-year unknown

After-hatch-year birds have a reddish-brown iris and a breast lacking streaks. While eye colour is quite reliable, it can be difficult to assess accurately under some light conditions, and so both wing and tail should be examined too.

An AHY bird of the white morph.
Photo by Marie-Anne Hudson, McGill Bird Observatory (QC), September 2005

An AHY bird of the tan morph.
Photo by James Junda, McGill Bird Observatory (QC), September 2008

Primary coverts are broad and rounded, and fairly similar in colour to the adjacent greater coverts.

Photo by James Junda, McGill Bird Observatory (QC), September 2008

Photo by Marie-Anne Hudson, McGill Bird Observatory, September 2005

The rectrices of AHY White-throated Sparrows are broad and fairly rounded.

Photo by Marie-Anne Hudson, McGill Bird Observatory, September 2005

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JUL - DEC: hatch-year unknown

HY birds have a more grayish iris, and may retain traces of juvenile streaking on the breast. While eye colour is quite reliable in fall, it can be difficult to assess accurately under some light conditions, and so both wing and tail should be examined too.

A typical HY bird, with a bit of streaking retained on the breast.
Photo by Marcel Gahbauer, McGill Bird Observatory (QC), October 2009

While there is no streaking on the breast of this individual, the angle of the photo
provides a good look at the gray iris.
Photo by Marie-Anne Hudson, McGill Bird Observatory (QC), September 2005

A subtle molt limit may be visible in fall, with the replaced greater coverts contrasting with the somewhat paler retained juvenile feathers of the primary coverts, primaries, and secondaries.

Although the entire wing is fairly dark, note the molt limit, including the difference between
the dark alula covert compared to the rest of the alula and primary coverts.
Photo by Marcel Gahbauer, McGill Bird Observatory (QC), October 2009

HY White-throated Sparrows have relatively narrow and pointed rectrices.

A typical HY tail, showing somewhat pointed rectrices and also with faint growth
bars across the tail.
Photo by Marcel Gahbauer, McGill Bird Observatory (QC), October 2010

A similar example, but already beginning to show a bit of fraying at the tips of the feathers.
Photo by James Junda, McGill Bird Observatory (QC), September 2008

RETURN TO AGE/SEX OVERVIEW

JUL - DEC: juvenile unknown

Juvenile White-throated Sparrows are most easily recognized by the indistinct streaking across the upper breast. Note that in this plumage, White-throated Sparrows may be easily confused with Song Sparrows - White-throats average slightly larger, but the facial patterns should be examined carefully to ensure correct identification.

Photo by Marcel Gahbauer, McGill Bird Observatory (QC), August 2005

Photo by Marcel Gahbauer, McGill Bird Observatory (QC), August 2009

Body plumage alone is usually enough to recognize juveniles, but the very small pale tips on the juvenile greater coverts are another useful character.

Photo by Marcel Gahbauer, McGill Bird Observatory (QC), August 2009

Photo by Marcel Gahbauer, McGill Bird Observatory (QC), September 2008

The rectrices of juveniles are relatively narrow, though usually in fairly good condition because they are fresh. Distinct growth bars are often visible.

Photo by Marcel Gahbauer, McGill Bird Observatory (QC), August 2009

Photo by Marcel Gahbauer, McGill Bird Observatory (QC), August 2005

RETURN TO AGE/SEX OVERVIEW