Migration Research Foundation - McGill Bird Observatory - Photo Library

McGILL BIRD OBSERVATORY

PHOTO LIBRARY

Northern Waterthrush / Paruline des ruisseaux (Seiurus noveboracensis)

Seasonal status at MBO:

JAN

FEB

MAR

APR

MAY

JUN

JUL

AUG

SEP

OCT

NOV

DEC

common

fairly common

uncommon

rare

occasional

no records

QUICK TIPS:

1) Look at the tertials - on HY/SY birds they are relatively worn and faded with narrow rusty or pale tips in fall, while on AHY/ASY birds they are uniform with the rest of the wing

2) Examine the rectrices - on HY/SY birds they are relatively narrow and tapered to a point, while on AHY/ASY birds they are more broad and rounded toward the tip and may have small patches of white at the tip

Note that the pale tips of the tertials are a good clue in fall; by mid-winter they are typically absent and as a result many individuals cannot be aged reliably during spring

Species account updated May 2009

Ageing and sexing guidelines:

January - July:

ASY - U Wing uniform in appearance; rectrices broad and rounded, sometimes with narrow white tips to the outer feathers (r5 and r6)
SY - U Tertials more worn and faded than rest of wing; rectrices somewhat narrow and tapered, uniformly brown

July - December:

AHY - U Wing uniformly dark brown; rectrices broad and rounded, sometimes with narrow white tips to the outer feathers (r5 and r6)
HY - U Tertials often (but not always) with narrow rusty or pale tips; rectrices somewhat narrow and tapered, uniformly brown

Ageing and sexing details:

JAN - JUL: after-second-year unknown

Overall appearance rarely provides any clues to age for waterthrushes, and sex can be determined only in the hand by looking for brood patches (females) or cloacal protuberances (males).

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

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

After-second-year waterthrushes have a relatively uniform appearance to the wing, with the tertials in particular not appearing significantly more pale or worn than adjacent feathers.

Photo by Marie-Anne Hudson, McGill Bird Observatory (QC), May 2008

Photo by Peter Pyle, Howell Woods (NC), May 2006

Rectrices are useful for ageing waterthrushes, since adult feathers are typically much broader and rounder at the tip than juvenile feathers. In some cases, as in the second example below, there can be a bit of white near the tip on after-second-year birds.

Photo by Marie-Anne Hudson, McGill Bird Observatory (QC), May 2008

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

RETURN TO AGE/SEX OVERVIEW

JAN - JUL: second-year unknown

Overall plumage is rarely useful for ageing waterthrushes, though on occasion very worn tertials on a second-year bird can be visible while perched.

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

Second-year waterthrushes often have particularly worn or pale tertials; the example below shows this only to a moderate extent.

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

Rectrices can be helpful for ageing waterthrushes, with second-year birds typically having narrower and more pointed tail feathers.

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

RETURN TO AGE/SEX OVERVIEW

JUL - DEC: after-hatch-year unknown

Overall plumage is rarely of use in identifying after-hatch-year waterthrushes; sex cannot be determined outside of the breeding season.

Photo by Barbara Frei, McGill Bird Observatory (QC), August 2008

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

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

The wing of after-hatch-year waterthrushes is uniform in colour and wear, with no pale tips to the tertials or any other feathers. Note, however, that in late summer to early fall, individuals may be moulting their primaries and secondaries as in the third photo below; any individual seen replacing these feathers can immediately be recognized as after-hatch-year, as hatch-year birds do not replace any of these feathers during their preformative moult.

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

Photo by Barbara Frei, McGill Bird Observatory (QC), August 2007

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

After-hatch-year waterthrushes have relatively broad and rounded rectrices, sometimes with a bit of white on the outermost two feathers (r5 and r6).

Photo by Barbara Frei, McGill Bird Observatory (QC), August 2008

Photo by Barbara Frei, McGill Bird Observatory (QC), August 2007

RETURN TO AGE/SEX OVERVIEW

JUL - DEC: hatch-year unknown

Hatch-year waterthrushes can occasionally be aged while perched, if pale tips of the tertials or other wing feathers are visible, but in most cases the open wing and/or tail need to be viewed to determine age.

Photo by Marie-Anne Hudson, McGill Bird Observatory (QC), August 2008

Juvenile tertials typically have narrow rusty or pale tips; occasionally (as in the first photo below) these may also be present on other coverts.

Photo by Seabrooke Leckie, McGill Bird Observatory (QC), August 2006

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

Photo by Seabrooke Leckie, McGill Bird Observatory (QC), August 2006

Hatch-year waterthrushes tend to have somewhat narrower and more tapered rectrices than after-hatch-year individuals, though the difference is less pronounced in fall than spring, therefore the pale-tipped tertials are the best feature to look for in fall.

Photo by Marie-Anne Hudson, McGill Bird Observatory (QC), August 2008

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

RETURN TO AGE/SEX OVERVIEW