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Yellow
Warbler (Dendroica petechia) |
Seasonal
status at MBO:
| JAN
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FEB
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MAR
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APR
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MAY
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JUN
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JUL
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AUG
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SEP
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OCT
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NOV
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DEC
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QUICK TIPS:
| 1) Check
the primary coverts - on HY/SY birds they have
minimal greenish edging and are usually narrow,
pointed, and quite abraded by spring, while on AHY/ASY
birds they have yellow edging and are broader,
fairly rounded, and relatively fresh
2) Check the
secondaries - on HY/SY birds they have little
to no yellow edging, while on AHY/ASY birds they
have yellow edging similar to the primary coverts
3) Check
the shape of the outer rectrices - on HY/SY birds
they are fairly pointed and easily abraded, while
on AHY/ASY birds they are broader, fairly rounded,
and more likely to remain fresh; note that colour
pattern can be somewhat variable
4)
Identify sex only after age has been determined by
breast streaks - AHY/ASY males have extensive
reddish-brown streaking, HY/SY males and AHY/ASY
females have finer, less extensive streaking, and
HY/SY females have minimal streaking |
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Ageing and sexing guidelines:
Ageing and sexing details:
In
spring, ASY males are the easiest age/sex class to identify among Yellow
Warblers. The body plumage is uniformly yellow to golden, often with
a distinct orange tinge to the crown. The reddish streaks on the
breast are broad and extensive. Some individuals have a reddish
tinge to the crown, most noticeable in the third photo below.
Photo by Marie-Anne Hudson,
McGill Bird Observatory,
May 2007
Photo by Marcel Gahbauer,
McGill Bird Observatory,
May 2004
Photo by Marcel Gahbauer,
Dinosaur Provincial Park, May 2007
ASY Yellow Warblers have broad and rounded primary coverts with distinct
yellowish edging, as well as yellow edging to the primaries and
secondaries, not contrasting significantly in wear with the tertials.
Note that sometimes, as in the second photo below, there is a visible
moult limit among the greater coverts, but with the primary coverts and
outer greater coverts similar in wear, having both been replaced in an
adult prebasic moult.
Photo by Marie-Anne Hudson,
McGill Bird Observatory,
August 2007
Photo by Marcel Gahbauer,
McGill Bird Observatory,
May 2006
Photo by Marie-Anne Hudson,
McGill Bird Observatory,
May 2006
RETURN TO AGE/SEX
OVERVIEW
Compared
to ASY males, ASY females have noticeably less red streaking on the
breast, and the crown tends to have a greenish tinge, with at most a trace
of orange. ASY females are most similar to SY males, and are most
easily confirmed by looking at the wings for the absence of a molt
limit. Note that due to its exposure to the sun, the alula can look
brownish even on ASY birds by spring. The third bird below is a
known ATY bird, banded at MBO in 2005 and photographed in 2007.
Photo by Marcel Gahbauer,
McGill Bird Observatory,
May 2006
Photo by Marcel Gahbauer,
McGill Bird Observatory,
May 2005
Photo by Marie-Anne Hudson, McGill Bird Observatory,
May 2007
In
both sexes, ASY birds lack a clear molt limit. Note the narrow but
distinct yellow edging to the primary coverts, and the broad yellow edging
found on all of the greater coverts. The second photo is of a female
known to be at least 2 years old, showing that sometimes the edging
along the outer greater coverts and primary coverts can be quite thin
and pale.
Photo by Marcel Gahbauer,
McGill Bird Observatory,
May 2005
Photo by Marie-Anne
Hudson, McGill Bird Observatory,
May 2007
In
both sexes, the outer tail feathers of ASY birds are fairly broad and
rounded. With females, there is a fair amount of brown on the inner
web, though its shape and extent may vary somewhat, as shown by the three
birds below.
Photo by Marcel Gahbauer,
McGill Bird Observatory,
May 2006
Photo by Marcel Gahbauer,
McGill Bird Observatory,
May 2005
Photo by Marie-Anne
Hudson, McGill Bird Observatory,
May 2007
RETURN TO AGE/SEX
OVERVIEW
SY
males have a moderate amount of reddish streaking on the breast, quite
similar to that of ASY females. The crown tends to be more yellow
than on females, contrasting less with the face, but this can be variable. The tail
and/or wing usually need to be studied to bonfirm SY males.
Photo by Marie-Anne Hudson,
McGill Bird Observatory,
May 2007
Photo by Marcel Gahbauer,
McGill Bird Observatory,
May 2005
The
pattern of molt on the wing is often the easiest way to distinguish SY
male and ASY female Yellow Warblers. Two key features are
characteristic of the SY male; many individuals show only one clearly, but
some have both. Most commonly visible, and present in both photos
below, are worn and tapered primary coverts with only faint
yellowish-green edging. Occasionally, as in the first photo, there
is also a distinct contrast between new, yellow-edged, tertials and adjacent unreplaced
secondaries without edging. A third way to identify a Yellow Warbler as
SY is to recognize three distinct generations of feathers among the
coverts, as in the first photo below: brownish juvenile primary coverts,
somewhat faded outer greater coverts with narrow edging from the preformative (first prebasic) moult, and fresh inner greater coverts from the first
prealternate moult. The abraded tips to the primaries, visible
especially in the second and third photos, are also a good SY indicator.
Photo by Marie-Anne Hudson,
McGill Bird Observatory,
August 2007
Photo by Marcel Gahbauer,
McGill Bird Observatory,
May 2005
Photo by Marcel Gahbauer,
McGill Bird Observatory,
May 2005
As
with SY females, the tail feathers of SY males are typically quite worn
and tapered. However, the brown on the inner web is comparatively
limited, usually extending no more than 1 cm from the tip.
Occasionally new and old feathers are mixed. In the first photo
below, it appears that r5 and r6 (the two outermost feathers on the right)
are older than the adjacent yellow-edged r4, and that r3 is again an
older, browner feather. The contrast is more plainly visible in the
third photo, where the two central rectrices and all of those on the right
side have been replaced, while r2-r6 on the left side remain old.
Photo by Marcel Gahbauer,
McGill Bird Observatory,
May 2005
Photo by Marie-Anne Hudson,
McGill Bird Observatory,
August 2007
RETURN TO AGE/SEX
OVERVIEW
SY
females are generally quite easy to recognize by their overall appearance,
which is generally more greenish-yellow than other age/sex combinations,
and with hardly any reddish streaks present on the breast.
Photo by Marcel Gahbauer,
McGill Bird Observatory,
May 2005
SY females have
worn and
tapered primary coverts with only faint yellowish-green edging.
Occasionally there is also a distinct contrast between new,
yellow-edged, tertials and adjacent unreplaced
secondaries without yellow edging. Another way to identify a Yellow
Warbler as SY is to recognize three distinct generations of feathers
among the coverts, as in the second photo below: brownish juvenile
primary coverts, somewhat faded outer greater coverts with narrow edging
from the first prebasic moult, and fresh inner greater coverts from the
first prealternate moult.
Photo by Marcel Gahbauer,
McGill Bird Observatory,
May 2005
Photo by Marcel Gahbauer,
McGill Bird Observatory,
May 2005
SY
females typically have more brown on the inner web of the outer tail
feathers than other age/sex combinations. Often it extends at least
halfway up the feather, as in the photo below, but in some
individuals it is more restricted toward the tip. In all cases, the tail feathers are relatively narrow and
fairly worn; usually at least some of them appear pointed as well.
Photo by Marcel Gahbauer,
McGill Bird Observatory,
May 2005
RETURN TO AGE/SEX
OVERVIEW
AHY males
are the only age/sex class to have distinct reddish streaks on the
breast during fall migration.
Photo by Marcel Gahbauer,
McGill Bird Observatory,
September 2005
The wing appears similar for AHY birds of
both sexes. They lack a molt limit, have
distinct yellow edging to the primary coverts, and broad yellow edging
on all of the greater coverts. An individual replacing its primaries
or secondaries, as in the second photo below, is recognizable as AHY,
since HY birds do not molt these feathers.
Photo by Marcel Gahbauer,
McGill Bird Observatory,
September 2005
Photo by Marcel Gahbauer, McGill Bird Observatory,
July 2006
In
both sexes, the outer tail feathers of AHY birds are usually fairly broad and
rounded. With males, almost the entire inner web is yellow, with
usually only a small amount of brown near the tip, extending up the
shaft much less than on females. Note that the third photo is of a
male at least 3 years old, showing unusually narrow and pointed
rectrices, though the colour pattern is consistent with that of an older
male.
Photo by Marcel Gahbauer,
McGill Bird Observatory,
August 2005
Photo by Marcel Gahbauer,
McGill Bird Observatory,
August 2005
Photo by Marie-Anne Hudson,
McGill Bird Observatory,
August 2007
RETURN TO AGE/SEX
OVERVIEW
Compared
to AHY males, AHY females have little to no reddish streaking on the
breast, and a more green tinge to the crown.
Photo by Marcel Gahbauer,
McGill Bird Observatory,
September 2005
Photo by Marcel Gahbauer,
McGill Bird Observatory,
September 2005
In
both sexes, AHY birds lack a clear molt limit. Note the narrow but
distinct yellow edging to the primary coverts, and the broad yellow edging
found on all of the greater coverts.
Photo by Marcel Gahbauer,
McGill Bird Observatory,
September 2005
In
both sexes, the outer tail feathers of AHY birds are fairly broad and
rounded. With females, there is a fair amount of brown on the inner
web, in comparison to males, where the inner web is almost entirely yellow.
Photo by Marcel Gahbauer,
McGill Bird Observatory,
September 2005
RETURN TO AGE/SEX
OVERVIEW
HY
Yellow Warblers are generally greenish above and yellow below, with few
prominent markings. Some males already show faint reddish streaks on
the breast in this plumage, thus if these are present sex can be
determined easily. If they are absent, it may be possible to
determine sex using the tail, but most often it will be unknown.
Photo by Marcel Gahbauer,
McGill Bird Observatory,
August 2005
HY
Yellow Warblers show minimal pale edging on the primary coverts, and these
become increasingly narrow, tapered, and worn over the course of the fall. The
wing does not provide any information to assist in determining sex.
Photo by Marcel Gahbauer,
McGill Bird Observatory,
August 2005
HY
Yellow Warblers have pointed rectrices. The photo below shows fresh
feathers in early August; they become noticeably paler and more tattered
over time, as can be seen on SY birds in spring. Males typically
show a relatively small amount of brown on the inner web of the outer
rectrices. This can be used as an aid to determining sex, but should
be used with caution and preferably not as the only identifying
characteristic.
Photo by Marie-Anne Hudson,
McGill Bird Observatory, August 2007
RETURN TO AGE/SEX
OVERVIEW
Female HY
Yellow Warblers are generally greenish-yellow with a grayish tinge, and with
reddish streaks on the breast often absent, or at most faint. The
alula of HY individuals may appear distinctly browner than adjacent
feathers.
Photo by Marcel Gahbauer,
McGill Bird Observatory,
August 2005
HY
Yellow Warblers show minimal pale edging on the primary coverts, and these
become increasingly narrow, tapered, and worn over the course of the fall. The
wing does not provide any information to assist in determining sex.
Photo by Marcel Gahbauer,
McGill Bird Observatory,
August 2005
HY
Yellow Warblers have pointed rectrices. The photo below shows fresh
feathers in early August; they become noticeably paler and more tattered
over time, as can be seen on SY birds in spring. Females typically
show a relatively large amount of brown on the inner web of the outer rectrices. This can an aid to determining sex, but should
be used with caution and preferably not as the only identifying
characteristic.
Photo by Marcel Gahbauer,
McGill Bird Observatory,
August 2005
RETURN TO AGE/SEX
OVERVIEW
HY
Yellow Warblers are generally greenish above and yellow below, with few
prominent markings. Males may already have faint reddish streaks on
the breast at this age, but many do not. Therefore, a bird such as
the one below could be either a male or a female. In general the
males are a bit more yellowish and females somewhat more gray, and by that
criterion this would likely be a female. However, this can be a
subjective assessment and very dependent on light conditions, therefore it
is preferable to have additional features (such as the tail) to confirm
sex.
Photo by Marcel Gahbauer,
McGill Bird Observatory,
August 2005
HY
Yellow Warblers show minimal pale edging on the primary coverts, and these
become increasingly narrow, tapered, and worn over the course of the fall. The
wing does not provide any information to assist in determining sex.
Photo by Marcel Gahbauer,
McGill Bird Observatory,
August 2005
HY
Yellow Warblers have pointed rectrices. The photo below shows fresh
feathers in early August; they become noticeably paler and more tattered
over time, as can be seen on SY birds in spring. Males typically
show a relatively small amount of brown on the inner web of the outer
rectrices, while on females it is more extesive. This can be used as
an aid to determining sex, but should be used with caution and preferably
not as the only identifying characteristic. The photo below is of an
individual considered to be a probable female.
Photo by Marcel Gahbauer,
McGill Bird Observatory,
August 2005
RETURN TO AGE/SEX
OVERVIEW
Juvenile
Yellow Warblers are predominantly gray. Small patches of yellow are
usually visible on the face, and there is greenish-yellow edging on the
wings and tail.
Photo by Marcel Gahbauer,
McGill Bird Observatory,
July 2005
The
wing of juvenile Yellow Warblers is predominantly brown/gray, with dull
yellowish-green edging to the primary coverts and flight
feathers.
Photo by Marcel Gahbauer,
McGill Bird Observatory,
July 2005
Fledgling
Yellow Warblers leave the nest before their tails are fully grown, thus it
is fairly common to see juveniles with short tails, such as the one shown
below. Note that the feathers are pointed and largely brown, but
with distinct yellow edging.
Photo by Marcel Gahbauer,
McGill Bird Observatory,
July 2005
RETURN TO AGE/SEX
OVERVIEW
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