McGILL BIRD OBSERVATORY

PHOTO LIBRARY

Blue Jay / Geai bleu (Cyanocitta cristata)

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 alula and primary coverts - on HY/SY birds they are brownish/grayish and unbarred, and on AHY/ASY birds they are blue with prominent dark bars.

2) Check for moult limits among the greater coverts - HY/SY birds often retain dull grayish blue outer coverts contrasting with brighter blue inner coverts, while on AHY/ASY birds all greater coverts are bright blue with dark barring.

3) Look at the upper mandible lining - on HY/SY birds a mix of white and black, on AHY/ASY birds mostly to entirely black.

Species account updated April 2009

Ageing and sexing guidelines:

January - June:

ASY - U
Sexes identical.  Alula and primary coverts bright blue, with faint to distinct dark barring.

SY - U
Sexes identical.  Alula and primary coverts grayish-blue with little or no dark barring.

-

July - December:

AHY - U
Similar to ASY-U (see above); roof of the mouth black.

HY - U
Similar to SY-U (see above); roof of the mouth partly to mostly whitish.
 

Ageing and sexing details:

JAN - JUL:  after-second-year unknown

ASY Blue Jays are most easily separated from SY individuals by having distinctly blue coverts across the wing, including the alula.  Usually faint to distinct barring is also visible on the alula and primary coverts, as on the bird below.  Sex of Blue Jays can be determined only during the breeding season, via brood patch or cloacal protuberance.  


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


ASY Blue Jays are easily recognized by virtue of their blue primary coverts and alula, all of which have some dark barring, although sometimes it is relatively faint.


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


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



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

RETURN TO AGE/SEX OVERVIEW

 

JAN - JUL:  second-year unknown

SY Blue Jays have a visibly dull grayish alula and primary coverts.  To some extent this is visible on perched birds, as below, but it is usually much easier to see on the open wing.  Sex of Blue Jays cannot be determined by appearance outside of the breeding season.


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


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


The grayish-brown tinged alula and primary coverts of SY Blue Jays contrast sharply with the bright blue of the greater coverts and primaries.  A distinct molt limit may also be visible among the greater coverts, as in the third photo below.


Photo by Peter Pyle, MerryLea (IN), May 2005


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


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



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

RETURN TO AGE/SEX OVERVIEW

 

JUL - DEC:  after-hatch-year unknown

AHY Blue Jays in fall are most easily separated from HY individuals by having distinctly blue coverts across the wing, including the alula.  Usually faint to distinct barring is also visible on the alula and primary coverts, as on the bird below.  Additionally, the roof of the mouth is entirely black in after-hatch-year birds.  Sex of Blue Jays cannot be determined by appearance outside of the breeding season.


Photo by Marcel Gahbauer, McGill Bird Observatory (QC), October 2004
 


After-hatch-year Blue Jays lack any brownish colouration to the wing; rather, all the primary coverts are blue, and the greater coverts are uniformly bold blue and white.  The alula is also blue, and often has distinct dark bars across it, though this can be variable. The second example below shows the flight feathers in moult, which only after-hatch-year Blue Jays replace in fall.


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


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


The tail of Blue Jays is not particularly indicative of age, though on after-hatch-year birds the blue tends to be somewhat more vivid and the black bars more pronounced than on younger birds.


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

RETURN TO AGE/SEX OVERVIEW

JUL - DEC:  hatch-year unknown

In fall, Blue Jays cannot be sexed, but it is fairly straightforward to age them.  The moult pattern on the wings is the most useful feature, but in addition to the plumage characteristics noted below, a mottled white and black pattern on the roof of the mouth is indicative of a hatch-year bird.


Photo by Marie-Anne Hudson, Le Nichoir (QC), August 2007


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


Hatch-year Blue Jays have brownish-blue primary coverts, with minimal dark barring on the alula and primary coverts.  In addition, a moult limit may be evident among the greater coverts, as in the second photo below, where three dull outer greater coverts contrast noticeably with the replaced bright blue inner greater coverts. The first photo is of a younger bird, with none of the greater coverts yet replaced.


Photo by Marie-Anne Hudson, Le Nichoir (QC), August 2007


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


The tail of Blue Jays is not particularly indicative of age, though on hatch-year birds the blue tends to be somewhat duller than on older birds.


Photo by Marie-Anne Hudson, Le Nichoir (QC), August 2007


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

RETURN TO AGE/SEX OVERVIEW

 

2002- The Migration Research Foundation Inc.