|
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
|
|
|
|
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 |
|
|
|
|
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
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.
RETURN TO AGE/SEX
OVERVIEW
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.
RETURN TO AGE/SEX
OVERVIEW
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
|
