Banding activity in early July slows down as migrants have all moved
through and most of our breeding birds are either on territory or
incubating eggs. Dawn in the park allows for some stunning photo
opportunities as the mist rises over the old field habitat where we
One thing that
definitely doesn't slow down is the grass which seems to grow while
you watch it and which presents a bit of a problem for our
'vertically challenged' volunteers like Celia who literally
disappear in the grass and have to be sent out with walkie-talkies
to make sure we can find them!
In addition to
being a good time to study the molts and plumages of local breeding
species July is an exciting time for banders as it produces a wide
array of plumages, from juvenal to fresh first basic, to worn
alternate, through the various sequences of molt leading to fresh
definitive basic (i.e. fall/winter non-breeding) plumage.
A very large part of our banding activities involve accurately
ageing and sexing the birds we catch in order to determine
population dynamics in terms of the changes in size and age
composition of avian populations and the biological and
environmental processes influencing those changes. A complete
understanding of the timing, sequence and extent of molt is
essential to the accurate ageing and sexing of birds in the hand
always remembering that young males look a lot like adult females.
In many species the prebasic molt is the only molt occurring
annually thus breeding occurs in the birds basic, winter
non-breeding plumage. But in many species of passerines there is a
second molt that occurs prior to the next prebasic molt - called the
prealternate molt it occurs in both first year birds and adults
during the late winter / early spring. In spring and summer first
year birds can show three generations of feathers but adults can
also show molt limits! An example and explanation of this is given
below on this second year (SY) female Yellow Warbler.
During its first prebasic molt last
fall, this bird replaced 8 inner greater coverts, the carpal covert
and greater alula covert, then stopped molting. The first molt
limits therefore (indicated with red arrows numbered 1) are
the molt limits between GCs 2 and 3, between the carpal covert (CC)
and retained juvenal primary coverts and between the greater alula
covert (A1) and the adjacent larger alula feather (A2) all replaced
in the 1st prebasic molt after the breeding season last year.
Many Dendroica (or should I say ex-Dendroica now they fall in
the new Setophaga classification!) warblers (both adults and
young) undergo a second molt in the late winter / early spring prior
to the next prebasic molt called the prealternate molt. This results
in a SECOND molt limit in the spring and, ultimately, three
generations of feathers on a second year (SY) bird. Here
greater coverts 5-10 were molted this spring i.e. the prealternate
molt limit is between GC 5 and 6 (indicated with red arrow numbered
2). Thus the three generations of feathers are: GC 5-10
which are first alternate feathers i.e. the most recently molted
feathers from the prealternate molt this spring; GC 1 and 2, the
carpal covert and greater alula covert which are first basic
feathers i.e. retained feathers from the first prebasic molt last
fall; and finally, the two larger alula feathers, primary coverts,
and primaries and visible secondaries (not including tertials) which
are retained juvenal feathers.
Note also how the retained juvenal feathers, particularly the
primaries are very worn and abraded now being close to 12 months old
and having been worn for one long Neotropical migration and for an
entire breeding season (indicated with red arrow 3)
And they say this molt stuff is complicated!!
We band a number of
Northern Flickers each year at Colony Farm and love their handsome
scalloped plumage and the bright red malars of males which are
lacking in females like the one in the photo below left. Like other
woodpeckers Flickers have very pointed and stiff retrices or tail
feathers (photo below right) which are used to support them as they
hitch their way up the trunks of trees. Unlike many other
woodpeckers Flickers prefer to find food on the ground eating mainly
ants and beetles which they dig up using their unusual slightly
non-passerines like woodpeckers is quite different from passerines.
Following their first prebasic molt, hatching year (HY) woodpeckers
retain all of their juvenal primary coverts. Second year (SY) birds
have all juvenal primary coverts until their second prebasic molt,
when they replace up to several outer juvenal primary coverts. Until
their third prebasic molt in their third year, third year (TY) birds
therefore show two distinct generations of primary coverts - very
worn and often abraded juvenal inner primary coverts and fresher
replaced second basic outer coverts.
This was the case with the above female (wing photo below) showing
replaced outer primary coverts from the birds second prebasic molt
last year now making her a third year (TY) bird.
During their third prebasic molt, TY woodpeckers normally replace
most if not all of their primary coverts and at this molt any
retained juvenal coverts will almost always be replaced.
hatching year Downy Woodpeckers (DOWOs) were in full juvenal
plumage, the male (photo above right) showing an extensive red
juvenal crown patch. Peter Pyle's excellent book the
Identification Guide to North American Birds Part I suggests that
both male and female DOWO juveniles have a red juvenal crown but it
has been proven that DOWOs with an extensively red juvenal crown
are, in fact, males, while those with a black, or mostly black,
juvenal crown are young females (photo below right). The same is
apparently true of Hairy Woodpeckers.
During this males first prebasic molt, its red juvenal crown will be
lost and a red nuchal patch (on the back of the head) characteristic
of 'adult' males will molt in.
Despite quiet and
vacant boxes being available along the edge of the old field habitat
one pair of Tree Swallows chose the box under the eaves of our
Banding Pagoda to nest and despite the comings and goings of banding
personnel, film crews and lots of visitors produced 5 nestlings.
The adults kept us amused with their constant scolding every time we
entered the Pagoda and the nestlings kept us all entertained as we
monitored their progress from impossibly tiny nestlings to 10 day
olds (photo top left below) ready for banding and then watched as
first beaks then heads appeared at the entrance hole until they
finally fledged at 19 days (photo below right)
Swallows are part of the guild of aerial insectivores which have
suffered precipitous declines and their plight has gained increasing
attention. Research has shown that in the last 20 years the
population of Barn Swallow and Bank Swallow has fallen by 70% and
Cliff Swallow, Northern Rough-winged Swallow and Purple Martin by
over 50%. Without solid insights into the mechanisms that are
driving population changes, it is difficult to imagine how the
current decline of aerial insectivores can be forestalled, let alone
reversed. VARC’s banding data from 2010 showed a huge decline in the
capture of swallow species and their numbers compared to 2009 which
made our 2011 TRES babies even more special!
Speaking of the
plight of aerial insectivores we were contacted by the Western
Canada Wilderness Committee who wanted to film a documentary on Barn
Swallows, a species of special concern in BC and a species upgraded
to threatened in 2011 by the Committee on the Status of Endangered
Wildlife in Canada (COSEWIC).
Some serious equipment was brought in to photograph and film our
swallows and the crew got some excellent shots and footage of adults
and nestlings at various stages of development.
filming sessions they pitched the story to Global TV who in turn
came out to film and interview and the story was aired on Global TV
News Hour on July 22nd!
Our catch in July
is dominated by hatch year birds in juvenal plumage. A definitive
characteristic of juvenal plumage is loosely textured feathers.
Juvenal feathers have many fewer interlocking barbules and,
therefore, looser barbs, giving them a very wispy appearance.
This is especially noticeable on the nape and back feathers, and
also on the undertail coverts, as shown in the photo (below right)
of this hatch year Black-capped Chickadee.
This hatch year
(HY) Song Sparrow showed all of the characteristics of a bird in
juvenal plumage - the streaked, spotted plumage, dull eye colour and
prominent gape. In addition the feathers of the tibiotarsus (photo
below right) and underwing (photo below left) develop later in
juvenile birds and these areas are often devoid of feathers as can
clearly be seen in these photos.
characteristics of juvenile birds are displayed by this hatching
year Savannah Sparrow showing very buffy plumage, a prominent,
fleshy, brightly coloured gape, a nesting trait often retained for
several weeks following fledging and bright mouth lining.
Eye color is
another useful criterion for ageing certain species and has been
mentioned in previous blogs. It's especially useful for those
species with dark or brightly colored eyes as adults. In these
species the eye color of the juveniles usually is duller and browner
or grayer than that of adults.
is shown in this locally hatched Ring-necked Pheasant which was
flushed one morning while making our net rounds. As we are not able
to band game birds we ran back to the banding station for a camera,
took a few quick photographs and released this baby which ran off to
join its scolding Mother. Although somewhat prehistoric looking it
drew lots of oohs and ahhs from the banding team!
gratuitous baby photos - Common Yellowthroat (top left),
Orange-crowned Warbler (top right), Spotted Towhee (bottom left) and
Cedar Waxwing (bottom right)
hatch year wrens were a surprise for us this month as neither
species would readily be associated with the old field habitat where
we band proving once again the value of this unique habitat. We'll
leave it to you to guess the identity of these two species, one of
which was a new species banded for the site! (Answers at the end of
very fortunate to have a banding station in the heart of an urban
area like Vancouver as it affords us the luxury of lots of visitors
which gives us an opportunity to talk about the importance of
preserving habitat for breeding and migratory birds.
In addition to using birds in the hand as teaching tools to raise
awareness of environmental issues we teach visitors how to hold a
bird gently in the 'banders grip' which is a unique experience and
one they will never forget. We've always said that once you place a
songbird in to anyone's hand you have a convert for life and that
can clearly be seen in the faces of a couple of our visitors this
||That is especially
true of children and we have lots of kids visit us and love their
energy and enthusiasm for birds and that was certainly the case with
10 year old Lily who visited with her Mum.
Both Tree Swallow nestling and Lily scored a 10 on the cuteness
|Some 20 plus kids
from the Catching the Spirit youth group came out to learn more
about the birds and habitats of the Vancouver area.
Catching the Spirit is an outdoor environmental stewardship and
learning program that encourages leadership development and social
responsibility for youth in the Metro Vancouver area.
Everyone had a great time and said that the trip to the banding
station was the highlight of their weekend!
gorgeous second year (SY) female Eastern Kingbird was a first banded
for the season. Molt is not well known in this Tyrant
Flycatcher and Pyle indicates more study is needed. This bird showed
an incomplete 'eccentric' 1st prebasic molt pattern with retained
primaries 1-3 and a clear molt limit between the replaced greater
alula covert (A1) and retained alula feathers (A2 & A3).
EAKIs are sexually
monomorphic both male and females show the bright red crown patch
(which are normally concealed) shown in the photo above left.
The shape of the outer primary P10 (indicated by the red arrow in
photo on the left) is helpful in separating males from females (and
juveniles from adults) the indentation on the inner web of the
feather (called a notch) being shorter in adult females than adult
Our female EAKI also had a fully developed brood patch leaving us in
no doubt as to her sex.
By the middle of
the month many hatch year birds have already started their first
prebasic molt. The juvenal plumage of many wood warblers, like this
very recently fledged Orange-crowned Warbler replaces the juvenal
plumage within just a few weeks after fledging.
This second year
(SY) male Lazuli Bunting pleased one of our volunteers Mum's who
came for a visit - she wanted a 'Bluebird' and although it's a bit
late in the season for Mountain Bluebirds we did manage this
beautiful 'blue bird' a second year (SY) male showing clear molt
limits between retained and replaced feathers.
Members of the Cardinalis family (Grosbeaks & Buntings) often
have an extensive molt including all greater coverts, carpal covert,
alula, tertials, additional inner secondaries and outer primaries as
can be seen in the photo below right. These species, where males
have such contrasting and distinctive plumages are helpful for
learning molt patterns and this can be particularly helpful in
looking for molt limits in females of the same species.
And finally an
enormous thank you to Saskia Wischnewski who left us to return home
to Germany before heading back to university in Scotland to
continue her studies. Saskia was such a great addition to the
banding team for the past 9 months and we'll really miss her. Make
sure you keep in touch Sask!
Thanks to Mark
Habdas, Kerry Kenwood, Carol Matthews, Jason Jones, Saskia
Wischnewski, Marg Anderson, Jerry Rolls, Debbie Wheeler, Sarah Gray,
Marguerite Sans, Marianne Dawson, Mike Nutter and Gabriel Jamie for
their help with banding this month.
Answer: Bewick's Wren (left photo)
MARSH WREN (right photo) Marsh Wren was the new species banded for
the site. Although common in the tall reeds of the pond adjacent to
the banding area this secretive and difficult to see wren rarely
strays in to the old field habitat where our nets are located.