McGILL BIRD OBSERVATORY

PHOTO LIBRARY

Yellow-billed Cuckoo / Coulicou à bec jaune (Coccyzus americanus)

 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 yellow on HY/SY birds at least through winter, and grayish on older birds

2) Look at the underside of the outer rectrices - AHY/ASY birds have a distinct white and black contrast, on HY/SY birds the contrast is dark gray/off-white, and gradual

Species account updated April 2009

Ageing and sexing guidelines:

January - June:

ASY - U
Orbital ring grayish, rectrices truncate and with sharply contrasting black and white pattern

   
SY - U
Orbital ring usually yellow, rectrices tapered and dull with indistinctly defined white tips
     

-

June - December:

AHY - U
Orbital ring grayish, rectrices truncate and showing sharp contrast between black and white
   
HY - U
Orbital ring yellow, rectrices tapered and dull with indistinctly defined white tips 
 

Ageing and sexing details:

after-second-year unknown

ASY Yellow-billed Cuckoos have a gray orbital ring, but as it may also be gray in some SY birds by spring, this criterion alone is not sufficient for determining age.



ASY Yellow-billed Cuckoos show a distinct contrast between black and white spots on the underside of the tail.

RETURN TO AGE/SEX OVERVIEW

 

second-year unknown

SY Yellow-billed Cuckoos may retain a yellow orbital ring as late as spring. 



The contrast between light and dark on the undertail is gradual.

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after-hatch-year unknown

AHY Yellow-billed Cuckoos can be quickly and accurately recognized by a gray orbital ring.  Sex cannot be determined in fall.



 
Photo by Peter Pyle, Hermosillo (Mexico), July 2007


On the underside of AHY tails, there is a distinct contrast between black and white spots.

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hatch-year unknown

A quick and reliable way to determine age in Yellow-billed Cuckoos is by the orbital ring, which is yellow in HY/SY birds (until late winter or spring) and grayish in older individuals.  Sex cannot be determined for HY cuckoos.


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



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


The photo below illustrates a typical HY tail, with the whitish spots on the underside poorly defined, unlike in adults where there is an abrupt break between black and white.


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

RETURN TO AGE/SEX OVERVIEW

 

2002- The Migration Research Foundation Inc.