McGILL BIRD OBSERVATORY

PHOTO LIBRARY

Black-billed Cuckoo / Coulicou à bec noir (Coccyzus erythropthalmus)

 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) Check the orbital ring - it is greenish/gray on HY/SY birds at least through winter, and red on older birds

2) Look at the underside of the outer rectrices - AHY/ASY birds have a distinct white tip, on HY/SY birds the pale tip is dull or absent

Species account updated April 2009

Ageing and sexing guidelines:

January - June:

ASY - U
Orbital ring red, dark rectrices with distinctly contrasting white tips

   
SY - U
Orbital ring greenish to gray, pale tips on rectrices indistinct or absent
     

-

June - December:

AHY - U
Orbital ring red, dark rectrices with distinctly contrasting white tips
     
HY - U
Orbital ring greenish to gray, pale tips on rectrices indistinct or absent
 

Ageing and sexing details:

after-second-year unknown

AHY (Jun-Dec) / ASY (Jan - Jun) Black-billed Cuckoos can be easily recognized by their red orbital ring.  It may be possible to differentiate ATY individuals based on molt patterns, but this requires further study.  There is no reliable way to differentiate sexes, as plumages are identical, and both males and females develop brood patches, while males rarely develop prominent cloacal protuberances.


Photo by Marcel Gahbauer, Innis Point Bird Observatory, May 2004
 



RETURN TO AGE/SEX OVERVIEW

 

second-year unknown

SY Black-billed Cuckoos usually have a greenish to gray orbital ring, and the pale tips on the rectrices typical of ASY birds are either indistinct or absent.  There is no reliable way to differentiate sexes as plumages are identical, and both males and females develop brood patches, while males rarely develop prominent cloacal protuberances.



 


RETURN TO AGE/SEX OVERVIEW

 

after-hatch-year unknown

AHY Black-billed Cuckoos can be identified by their red orbital ring, but there is no way to differentiate sexes in fall.


 



 


RETURN TO AGE/SEX OVERVIEW

hatch-year unknown

HY Black-billed Cuckoos can be easily recognized by their greenish to gray orbital ring.  Additionally, the pale tips of their rectrices are either indistinct or absent.  Sexes cannot be differentiated in fall.


Photo by Marcel Gahbauer, McGill Bird Observatory (QC), August 2007


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



 


Photo by Marcel Gahbauer, McGill Bird Observatory, August 2007


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



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

RETURN TO AGE/SEX OVERVIEW

 

2002- The Migration Research Foundation Inc.