McGILL BIRD OBSERVATORY

PHOTO LIBRARY

Chestnut-sided Warbler / Paruline à flancs marron (Dendroica pensylvanica)

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/7AB1229BD3F33F46 

QUICK TIPS:
1) Look at the primary coverts - on HY/SY birds they brownish-gray with little or no edging and paler than the adjacent greater coverts, while on AHY/ASY birds they are blackish with grayish edging in fall sometimes faded and indistinct by spring

2) Check the tail - outer rectrices are relatively narrow and tapered to a point on HY/SY birds, but broad and rounded on AHY/ASY birds

3) Examine the flanks - FALL:  AHY males have relatively distinct and extensive chestnut markings, limited and indistinct chestnut can be seen on some AHY females and some HY males, and an absence of any chestnut can occur on AHY females, HY males, and HY females ... SPRING:  on females the chestnut is relatively narrow and limited, and on males fairly broad and extensive

4) In spring, look at the lores and moustache - on males they are black, while on females they grayish with some black

5) In spring, look at the crown - typically it is yellow on males, and green on females, though the distinction is not always clear and may depend on lighting

Note that there is a fair amount of overlap in plumages, especially in fall, and multiple characteristics should be assessed; for some intermediate individuals age and especially sex may not be reliably determined

Species account updated April 2009

Ageing and sexing guidelines:

January - July:

ASY - M
Yellow crown; solid black lores and moustache; broad and extensive chestnut markings extending past the legs; blackish primary coverts; broad and rounded rectrices
ASY - F
Greenish-yellow crown; grayish lores and moustache with some black; moderate chestnut markings; blackish primary coverts; broad and rounded rectrices
SY - M
Yellow crown; mostly black lores and moustache; broad and extensive chestnut markings extending to near or beyond the legs; brownish primary coverts
SY - F
Greenish crown; grayish or even whitish lores; grayish moustache sometimes with black flecks; limited chestnut markings; brownish primary coverts

-

July - December:

AHY - M
Blackish primary coverts; fairly distinct chestnut markings; broad and rounded rectrices
AHY - F
Blackish primary coverts; chestnut limited to absent; broad and rounded rectrices
HY - M
Dark gray primary coverts; chestnut limited to absent; narrow and tapered rectrices
HY - F
Dark gray primary coverts; chestnut absent; narrow and tapered rectrices
 

Ageing and sexing details:

JAN - JUL:  after-second-year male

After-second-year males have extensive chestnut sides and a yellow crown.  They typically also have a black mask, though in some cases such as the example shown, it can be faded.


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


The wing of after-hatch-year males is for the most part uniformly dark, with contrast limited to the darker alternate plumage feathers in the greater coverts.


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


 


After-hatch-year Chestnut-sided Warblers have relatively broad and rounded rectrices; the extent of white is typically greater on males than on females.


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

RETURN TO AGE/SEX OVERVIEW

JAN - JUL:  after-second-year female

The combination of an indistinct grayish moustache and distinct chestnut streaking is strongly suggestive of an after-second-year female, but it is recommended to check the wings and tail for confirmation. The crown is typically more greenish than yellowish.


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


Note that while the primary coverts are slightly paler than the greater coverts, they are nonetheless quite dark, fresh, and rounded. Also, the primaries, secondaries and primary coverts do not differ appreciably in wear.


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


The outer rectrices on after-second-year birds are quite broad and rounded at the tip; the extent of white tends to be less on females than on males.


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

RETURN TO AGE/SEX OVERVIEW

JAN - JUL:  second-year male

The black moustache and moderate extent of chestnut markings suggest a second-year male, but this should be confirmed by looking at the wing and tail.


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


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


Note the distinct contrast between the dull and somewhat worn primary coverts, primaries, and secondaries, versus the much darker and fresher greater coverts.  Note also the contrast sometimes visible on second-year birds between the fresh and dark greater coverts and the somewhat worn, unreplaced secondaries (the tattered tertials often being the most apparent).


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


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


The rectrices on second-year birds are narrower and more pointed than those of after-second-year birds, and often show appreciably more wear (especially the central rectrices).


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


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

RETURN TO AGE/SEX OVERVIEW

JAN - JUL:  second-year female

Second-year females are the palest in spring, with only small traces of chestnut, pale and indistinct grayish moustaches, and greenish caps.


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


As with second-year males, second-year females show fresh greater coverts contrasting with a paler and more worn block of feathers comprising the primary coverts, primaries, and secondaries.  The contrast can be particularly evident when comparing the often tattered tertials with the adjacent greater coverts.


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


Rectrices of second-year warblers tend to be relatively narrower and more pointed than those of older birds.  In the photo below, the outer rectrices do not show this typical shape, but the central rectrices are closer to the expected shape, and also show some of the wear expected on a second-year bird.


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

RETURN TO AGE/SEX OVERVIEW

JUL - DEC:  after-hatch-year male

After-hatch-year males have the most distinct fall plumage, as they are the only age/sex class with moderately extensive chestnut streaking, as shown in the photo below.   Another distinctly after-hatch-year feature visible in this photo is the bluish-gray edging on the black primary coverts.


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


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


The primary coverts are only slightly paler than the greater coverts, and are broad and rounded, with narrow bluish-gray edging.


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


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


The rectrices are broad and rounded on after-hatch-year birds; after-hatch-year males have the greatest amount of white.


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


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

RETURN TO AGE/SEX OVERVIEW

JUL - DEC:  after-hatch-year female

After-hatch-year females are relatively recognizable by virtue of their blackish primary coverts with bluish-gray edging, combined with minimal or absent chestnut streaking.  However, they may be confused with hatch-year males and the open wing and tail should be checked to confirm age and sex.


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


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


The primary coverts are only slightly paler than the greater coverts, and are broad and rounded, with narrow bluish-gray edging.  in the second example below, the bird is just completing its prebasic moult, with the final two secondaries almost fully grown.


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


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


The rectrices are broad and rounded on after-hatch-year birds. Females tend to have less white on the tail than males, though the amount is variable as illustrated by the photos below.


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


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

RETURN TO AGE/SEX OVERVIEW

 

JUL - DEC:  hatch-year male

Hatch-year males have little to no chestnut streaking, like after-hatch-year females, but tend to have somewhat paler and more poorly-marked primary coverts.  However, as the second photo below (of a hatch-year male confirmed by skull condition) shows, the primary coverts may show some visible blue edging even on hatch-year birds, therefore looking at the open wing and tail is advised to be confident of age and sex.


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


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


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


The contrast between the primary coverts and greater coverts is somewhat greater than on after-hatch-year birds, and the primary coverts tend to have less blue edging.


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


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


The rectrices of hatch-year birds are relatively narrow and tapered to a point.


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

RETURN TO AGE/SEX OVERVIEW

JUL - DEC:  hatch-year female

Hatch-year females are the palest of the age/sex classes in fall.  They usually lack any chestnut markings, and the primary coverts on a perched bird appear grayish with minimal edging.


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


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


The contrast between the primary coverts and greater coverts is somewhat greater than on after-hatch-year birds, and the primary coverts tend to have little or no blue edging. 


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


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


The rectrices of hatch-year birds are relatively narrow and tapered to a point.


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


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

RETURN TO AGE/SEX OVERVIEW 

2002- The Migration Research Foundation Inc.