McGILL BIRD OBSERVATORY

PHOTO LIBRARY

Wilson's Warbler / Paruline à calotte noire (Wilsonia pusilla)

 NOTE: This species account has been moved to Piranga to allow for improved comparison among examples.  
The updated profile is located at:  http://www.natureinstruct.org/piranga/view.php/Canada/1F09CCCCBD97B861
 

QUICK TIPS:
1) Examine the crown - AHY/ASY males have an extensive solid black cap, HY/SY males and AHY/ASY females have a limited black cap with flecks of yellow (note - glossier on males) , and HY/SY females have a mottled yellow/green crown with flecks of black

2) Look at the rectrices - on HY/SY birds they are relatively narrow and pointed, and on AHY/ASY birds they are relatively broad and rounded, though the contrast is not as great as on some other warblers

3) Look at the outer primary coverts - on HY/SY birds they are narrow and tapered with little or no dull olive edging, while on AHY/ASY birds they are broad and rounded with fairly distinct olive edging - but note that many individuals show intermediate characteristics and this feature is therefore often unreliable

4) Examine the throat and face - on males it is golden yellow, on females it tends to be paler yellow

Species account updated March 2009

Ageing and sexing guidelines:

January - July:

ASY - M
Solid black cap and golden throat; broad and rounded outer primary coverts and rectrices
ASY - F
Partial black cap and yellow throat; broad and rounded outer primary coverts and rectrices
SY - M
Partial black cap and golden throat; narrow and tapered outer primary coverts and rectrices
SY - F
Primarily yellow-green crown and yellow throat; narrow and tapered outer primary coverts and rectrices

-

July - December:

AHY - M
Solid black cap; broad and rounded outer primary coverts and rectrices
AHY - F
Partial black cap; broad and rounded outer primary coverts and rectrices
HY - M
Partial black cap; narrow and tapered outer primary coverts and rectrices
HY - F
Primarily yellow-green crown; narrow and tapered outer primary coverts and rectrices
 

Ageing and sexing details:

JAN - JUL:  after-second-year male

The solid black cap and golden throat shown in the photos below is indicative of an after-second-year male, but to confirm age and sex it is advisable to consider the wing and tail too.


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


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


After-second-year birds have greenish edging on the primary coverts, but it is often fairly dull and narrow.


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


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


The rectrices are broad and fairly rounded on after-second-year Wilson's Warblers.


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


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

RETURN TO AGE/SEX OVERVIEW

JAN - JUL:  after-second-year female

The extent of black on the crown is intermediate for after-second-year females and second-year males (generally more restricted for females); wing and tail need to be examined to determine age and sex, though typically females have a duller yellow throat.


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


Photo by Marie-Anne Hudson, McGill Bird Observatory (QC), May 2006

 
Photo by Marie-Anne Hudson, McGill Bird Observatory (QC), May 2006


Photo by Marie-Anne Hudson, McGill Bird Observatory (QC), May 2006


After-second-year Wilson's Warblers have green edging on the primary coverts; using them to determine age, the crown can then be used to identify sex.


 Photo by Marie-Anne Hudson, McGill Bird Observatory (QC), May 2006


The outer rectrices are usually relatively broad and often fairly rounded, though not always; wing is more reliable.


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

RETURN TO AGE/SEX OVERVIEW

JAN - JUL:  second-year male

The extent of black on the crown is intermediate for after-second-year females and second-year males (generally more extensive for females); wing and tail need to be examined to determine age and sex, though males tend to have a richer golden tone to the throat.


Photo by Marie-Anne Hudson, McGill Bird Observatory (QC), May 2006


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


The primary coverts lack edging and are brownish, contrasting with the greater coverts; the primaries and secondaries may be quite pale and worn by spring, as int he first photo below.


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


Photo by Peter Pyle, Big Sur Ornithology Lab (CA), May 2007


The rectrices tend to be relatively narrow and pointed, but in general their shape is much less reliable than the wing characteristics.


Photo by Marie-Anne Hudson, McGill Bird Observatory (QC), May 2006


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

RETURN TO AGE/SEX OVERVIEW

JAN - JUL:  second-year female

Individuals with minimal black on the crown, such as in the photos below, are almost always second-year females, but the wing should be checked to confirm age.


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


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


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


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


The primary coverts lack edging and are brownish, contrasting with the greater coverts, and the primaries and secondaries may be quite pale and worn.


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


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


 
Photo by Peter Pyle, MerryLea (IN), May 2007


The rectrices tend to be relatively narrow and pointed, but in general their shape is much less reliable than the wing characteristics.  Note, however, that the central rectrices may be extremely worn by spring in SY birds, much more so than would be expected in ASY birds.  This is especially evident in the first photo below, but absence of such wear should not be taken as indicative of ASY.


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


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

RETURN TO AGE/SEX OVERVIEW

JUL - DEC:  after-hatch-year male

The solid black cap shown in the photo below is indicative of an after-hatch-year male, but to confirm age and sex it is advisable to consider the wing and tail too.


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


After-hatch-year birds have distinct greenish edging on the primary coverts.


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


The rectrices are broad and fairly rounded on after-hatch-year Wilson's Warblers.


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


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

RETURN TO AGE/SEX OVERVIEW

JUL - DEC:  after-hatch-year female

The extent of black on the crown is intermediate and very similar for after-hatch-year females and hatch-year males; wing and tail need to be examined to determine age and sex. 


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


After-hatch-year Wilson's Warblers have green edging on the primary coverts; using them to determine age, the crown can then be used to identify sex.


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


The rectrices are typically broad and fairly rounded on after-hatch-year Wilson's Warblers.


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

RETURN TO AGE/SEX OVERVIEW

 

JUL - DEC:  hatch-year male

The extent of black on the crown is intermediate and very similar for after-hatch-year females and hatch-year males (generally more extensive for females); wing and tail need to be examined to determine age and sex. 


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


Hatch-year Wilson's Warblers typically have minimal edging on the primary coverts, though when fresh, they may show some greenish.


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


Rectrices are relatively narrow, and generally taper toward a point.


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

RETURN TO AGE/SEX OVERVIEW

JUL - DEC:  hatch-year female

Hatch-year females are easily recognizable by having little to no black on the crown.


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


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


The primary coverts have minimal edging and are brownish, contrasting with the darker greater coverts.


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


Rectrices are relatively narrow, and generally taper toward a point.


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

RETURN TO AGE/SEX OVERVIEW 

2002- The Migration Research Foundation Inc.