McGILL BIRD OBSERVATORY

PHOTO LIBRARY

Eastern Bluebird / Merlebleu de l'est (Sialia sialis)


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/A8347C7DF99F44B5

 

 Introductory notes:
A distinctive species in all plumages.  Most individuals can be sexed by overall appearance as males are always more blue than females of the same age, even as juveniles.  Ageing is also often possible based on body plumage.  However, in case of doubt, the wing and/or tail generally allow for easy confirmation of age.


QUICK TIPS:
1) Look at the greater coverts - the presence of a molt limit between fresh blue and older brownish feathers indicates a HY/SY bird, however uniformly blue greater coverts are NOT an entirely reliable indicator of AHY/ASY, as some HY/SY may have replaced all their greater coverts, in which case a molt limit between the greater coverts and primary coverts should show a similar contrast

2) Consider overall plumage - only AHY/ASY males are solid bright blue above, HY/SY males are mostly blue with a grayish tinge, AHY/ASY females are mostly grayish with a bluish tinge, and HY/SY females are largely grayish with limited blue

3) Look at the shape of the rectrices - if all are relatively narrow or there is a mix of narrow and fresher, broader rectrices this indicates an HY/SY individual, but note that some HY/SY bluebirds have uniformly broad rectrices similar to those of AHY/ASY individuals, as a result of a more extensive preformative molt

Species account updated February 2011

Ageing and sexing overview:

January - July:

ASY - M
Bright blue above, and with extensive orange below; wing uniformly blue; rectrices blue, broad, and rounded.
ASY - F
Grayish-blue above, and with pale orange on upper breast; wing uniformly grayish-blue; rectrices blue, broad, and rounded.
     
SY - M
Blue above, and with fairly extensive orange below; wing partly blue with contrasting brownish primary and (sometimes) greater coverts; rectrices bluish, but often relatively narrow and tapered.
     
SY - F
Largely gray above, with some orange on upper breast; wing grayish-blue with contrasting brownish primary and (sometimes) greater coverts; rectrices brownish-blue, but often relatively narrow and tapered.
     

-

June - December:

AHY - M
Bright blue above, and with extensive orange below; wing uniformly blue; rectrices blue, broad, and rounded.
     
AHY - F
Grayish-blue above, and with pale orange on upper breast; wing uniformly grayish-blue; rectrices blue, broad, and rounded.
     
HY - M
Bluish above, and with fairly extensive orange below; wing partly blue with contrasting brownish primary and (sometimes) greater coverts; rectrices bluish, but often relatively narrow and tapered.
HY - F
Largely gray above, with some orange on upper breast; wing grayish-blue with contrasting brownish primary and (sometimes) greater coverts; rectrices brownish-blue, but often relatively narrow and tapered.
JUV - M/F
Largely grayish above with back and shoulders mottled with white; males have blue primaries and secondaries while on females they are grayish-blue.
 

Ageing and sexing details:

JAN - JUL: after-second-year male

  ASY male Eastern Bluebirds can be recognized by their bright blue upperparts and solid dark orange breast. 


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


ASY Eastern Bluebirds have wings that are uniform in colour and quality; males are bright blue, while females show a similar pattern buy are somewhat more grayish.


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


ASY Eastern Bluebirds have relatively broad and rounded rectrices, but note that some SY individuals will have replaced their entire tail during their preformative molt and will therefore be inseparable from ASY individuals with respect to the tail.


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

RETURN TO AGE/SEX OVERVIEW

JAN - JUL: after-second-year female

  ASY female Eastern Bluebirds have largely grayish upperparts with bluish tinges to the wing and tail, and a fairly orange upper breast.



The wing of ASY Eastern Bluebirds is uniform in colour and quality; females are grayish-blue, noticeably paler than males.



ASY female Eastern Bluebirds have broad and rounded rectrices similar to those of males, but usually somewhat duller blue in colour. but note that some SY individuals will have replaced their entire tail during their preformative molt and will therefore be inseparable from ASY individuals with respect to the tail


RETURN TO AGE/SEX OVERVIEW

 

JAN - JUL: second-year male

SY male Eastern Bluebirds are dull blue above, with a fairly extensive orange breast.  Although they are often distinctly paler than AHY males, the wing may need to be viewed to confirm age.


SY Eastern Bluebirds usually have a molt limit among the greater coverts, though in some individuals all greater coverts are replaced during the preformative molt, and the limit is instead between the greater coverts and the primary coverts.  In either case, males usually show a moderately distinct contrast between the replaced blue inner feathers and the retained brownish-blue outer feathers.

 


Since HY Eastern Bluebirds may replace none, some, or all of their rectrices during their preformative molt, the tail can either be very useful or useless for ageing SY individuals.  If all rectrices have been replaced, the tail will look identical to that of ASY bluebirds, and cannot be used to determine age.  However, a mix of juvenile (narrow and relatively pointed) and formative (broad and fairly rounded) rectrices is unique to SY bluebirds, and a tail comprising entirely juvenile rectrices can also be used to identify a bluebird as SY.

  RETURN TO AGE/SEX OVERVIEW

JAN - JUL: second-year female

SY female Eastern Bluebirds are largely gray above with only traces of dull blue, and with relatively limited dull orange on the breast.  Although they are somewhat paler than AHY females, the open wing may need to be examined to be confident of age.

 


SY Eastern Bluebirds usually have a molt limit among the greater coverts, though in some individuals all greater coverts are replaced during the preformative molt, and the limit is instead between the greater coverts and the primary coverts.  In either case, females usually show a distinct contrast between the replaced blue inner feathers and the retained grayish-brown outer feathers that usually only have a trace of blue.


Since HY Eastern Bluebirds may replace none, some, or all of their rectrices during their preformative molt, the tail can either be very useful or useless for ageing SY individuals.  If all rectrices have been replaced, the tail will look identical to that of ASY bluebirds, and cannot be used to determine age.  However, a mix of juvenile (narrow and relatively pointed) and formative (broad and fairly rounded) rectrices is unique to SY bluebirds, and a tail comprising entirely juvenile rectrices can also be sued to identify a bluebird as SY.

RETURN TO AGE/SEX OVERVIEW

JUL - DEC: after-hatch-year male

   AHY male Eastern Bluebirds can be recognized by their bright blue upperparts and solid dark orange breast.
 


AHY male Eastern Bluebirds have uniformly bright blue wings.
 


AHY male Eastern Bluebirds have bright blue tails with broad and relatively rounded outer rectrices.

RETURN TO AGE/SEX OVERVIEW

JUL - DEC: after-hatch-year female

   AHY female Eastern Bluebirds have largely grayish upperparts with bluish tinges to the wing and tail, and a fairly orange upper breast.
 


AHY female Eastern Bluebirds have uniformly grayish-blue wings.
 


AHY female Eastern Bluebirds have blue tails with broad and relatively rounded outer rectrices.

RETURN TO AGE/SEX OVERVIEW

JUL - DEC: hatch-year male

HY male Eastern Bluebirds are dull grayish-blue above, with a fairly extensive orange breast, with overall plumage intermediate between that of AHY males and AHY females.


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


HY Eastern Bluebirds usually have a molt limit among the greater coverts, though in some individuals all greater coverts are replaced during the preformative molt, and the limit is instead between the greater coverts and the primary coverts.  In either case, males usually show a moderate contrast between the replaced darker blue inner feathers and the somewhat more brownish retained feathers.


A typical HY male wing, largely blue, but note the contrast between the dark blue
formative inner greater coverts and the more brownish retained juvenile outer greater
coverts, which also may show pale tips, as is the case for one of the feathers here.

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


HY male Eastern Bluebirds have a blue tail with relatively narrow outer rectrices.


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

RETURN TO AGE/SEX OVERVIEW

 

JUL - DEC: hatch-year female

   HY female Eastern Bluebirds are largely grayish above, with orange limited to the upper breast; overall they are the palest age/sex class.


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


HY Eastern Bluebirds usually have a molt limit among the greater coverts, though in some individuals all greater coverts are replaced during the preformative molt, and the limit is instead between the greater coverts and the primary coverts.  In either case, females usually show a fairly distinct contrast between the replaced blue feathers and the retained brownish-gray outer feathers.


This HY female wing is typically grayish and dull; the innermost four greater coverts have
been replaced, and although their bluish centres are largely concealed from view, they
contrast with the outer greater coverts not only in colour, but also by being longer. Note
also the pale shaft streak on the innermost retained greater covert, a trait common to
juvenile greater coverts of most North American thrushes.

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


HY female Eastern Bluebirds have a dull brownish-blue tail with relatively narrow outer rectrices.  


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

RETURN TO AGE/SEX OVERVIEW

JUL - SEP: juvenile unknown

  Juvenile Eastern Bluebirds are largely grayish, lacking orange on the breast and with moderate to heavy white spotting on the back.


Photo by Gay Gruner, Montreal (QC), July 2009


Juvenile Eastern Bluebirds show extensive white spotting on the lesser, median, and greater coverts and back.  Those with largely blue primaries and secondaries can already be sexed as males at this age, while those that have dull grayish-blue primaries and secondaries are females.


A typical juvenile male wing.
Photo by Gay Gruner, Montreal (QC), July 2009


Juveniles of both sexes have bluish tails, but males have minimal pale edging on the outer rectrices while on females it is distinct and fairly broad.


Photo by Gay Gruner, Montreal (QC), July 2009

RETURN TO AGE/SEX OVERVIEW

2002- The Migration Research Foundation Inc.