Migration was in full swing this month with good numbers of wood
warblers moving through the park including this particularly
handsome hatch year (HY) male Wilson's Warbler (WIWA) which we
couldn't resist posting. It also reminded us of our friends from
Powdermill who joined us last month at the NAOC especially
Adrienne Leppold as WIWAs are her favourite
In addition to an obvious molt limit
between the replaced lesser, median, greater coverts, alula covert
and carpal covert (red arrows photo right) one of the additional
criteria which is helpful in ageing WIWAs is the variation in the
extent of the crown patch being glossy black on adults and extending
further forward and backward than on hatch year birds like the bird
above which is less extensive and shows greenish yellow mottling.
This after hatch year (AHY) female
Yellow Warbler (formerly alpha code YWAR now YEWA - we're not sure
why it's been changed!) has replaced all body and flight feathers in
her definitive, complete adult prebasic molt following the breeding
season. The wing (below right) is a prime example of what definitive
adult plumage, with no discernible molt limits among the coverts or
alula, looks like in fall.
This hatch year (HY) Orange-crowned
Warbler wing (photo below left) has replaced all lesser, median,
great coverts and carpal covert in its partial 1st prebasic molt and
the rectrices (photo below right) show the very pointed and tapered
shape diagnostic of first year (HY/SY) birds.
Birds in active molt are very helpful
to banders learning ageing strategies using molt and plumage
criteria. These 'molt limits in the making' allow us to see the
sequence of events unfold as birds go through the molting process
and to memorize the differences between retained and replaced
feathers to help us when looking at these same species later in the
fall and winter.
these photos are good examples of molt limits in the making. The top
photo shows a hatch year (HY) Purple Finch (PUFI) undertaking its
partial 1st prebasic molt with median (MCs) and greater coverts
(GCs) in sheath. GCs molt proximally (towards the birds body) and
when all GCs are molted, the innermost (GC10) is normally the last
of these feathers replaced. This however was not the case with this
bird which appeared to have replaced this feather first!
PUFIs often don't replace all their
GCs in their 1st PB with molt limits then appearing within the GCs
in which case this innermost feather (GC10) is often a retained or
The Black-capped Chickadee (BCCH) wing
(photo right) shows a typical partial 1st PB in this species with
all but the outermost greater covert (GC1) molted and the carpal
covert in sheath. Once the inner GCs have grown the molt limit will
be between GC1 and GC 2 and between the carpal covert and adjacent
primary covert. As molt limits can be difficult to see in BCCH due
to colour contrasts among the GCs (known as pseudolimits) knowing
this to be a retained feather is helpful in recalling differences in
shape and structure between replaced and retained feathers once molt
Although molt is vitally important to
birds as damaged, worn and broken feathers can only be replaced
during the molt cycle it definitely isn't a time when birds are at
their most attractive as this photo of a hatch year (HY) male
Spotted Towhee completing its 1st prebasic molt shows!
always pleased when we're notified of a recovered bird and always
hope that it's a bird retrapped in some distant foreign land to add
to our knowledge of winter destinations and important stopover
Unfortunately that wasn't the case when we received an email from
Bruce Lange on August 28th saying he had found a banded bird which
had died as a result of a window strike in New Westminster, BC.
which he thought may be one of our banded birds.
We tracked down the band from our records and 2571-00460 was indeed
one of our birds, a hatch year (HY) Swainson’s Thrush banded on
Bruce was as dismayed as we were
that this super long distance migrant overwintering as far south as
Argentina had fallen victim to a plate glass window just 10
kilometers from where it almost certainly hatched and was banded at
Window strikes are a huge cause of bird fatalities (up to 1 BILLION
a year in NA alone!) and it prompted us to post instructions how to
make window mobiles to help prevent them.
We use this as part of our public outreach and education program to
promote window strikes and what people can do to help prevent them.
These step by step instructions allow even kids to make a simple
mobile to prevent window strikes – there’s no cost, they’re esthetic
and work really well. Please take the time to pass this information
on – it’s too cruel that a long distance migrant like this SWTH ends
up hitting a window a few miles down the road!
Orange-crowned Warblers (OCWA) moved through this month, some of
them causing momentary double takes as they can easily be confused
with other members of the oreothlypis genus. We commonly see
three of the four subspecies at Colony Farm especially in the fall
and plumage colour differs quite dramatically between them. The
Pacific Coast form, (lutescens), is bright yellow (bottom
photo below), the celata
subspecies is found in Alaska and across Canada, and is the dullest
and grayest and the orestera subspecies intermediate in
appearance (top photo below).
The bird below came under close scrutiny as it looked more like a
Tennessee Warbler (TEWA) than an OCWA but in addition to yellowish
undertail coverts (compared to whitish in TEWA) OCWA always has a
yellowish ‘face’ and blurry grey breast streaking always lacking on
Still it goes to show it's worth
carefully checking out those fall warblers!
of visitors again this month and it was nice to welcome back British
'A' Ringer and Trainer Tim Ball from the Reading and Basingstoke
We managed to get Tim's Canadian ringing life list up to 24 of which
11 are on the British list so when that Swainson's Thrush shows up
on Lundy Island Tim you'll be well prepared!
It was a real pleasure to have Tim
back especially as he came with TWO packs of Cadbury's Boost Bars
this time AND he's promised us a Red Kite when we're next over
Sussmann, PhD an Instructor in the Department of Biology at Kwantlen
Polytechnic University brought 24 students and teachers for a field
trip to the banding station. Everyone had a great time and Andrea
intends to make the visit a permanent field trip as part of the
course she teaches.
And people following the blog may
remember Lily helping us to band Tree Swallow nestlings last year
(photo below left) when she was just 6 and a half years old. Well
what a difference a year makes! Lily is now 7 and a half and has a
full set of teeth! (photo below right)
Lily is amazingly connected with wild
birds and has become an advocate for bird conservation. Her
experiences with birds in the hand at the banding station has
fostered a unique awareness and appreciation of birds and the
environment and for anyone who doesn't think that raising awareness
of environmental issues with children really can make a difference
they should take a moment to read this letter from her Mum!
We also had a visit from Jeff and
Michelle Clay and their daughter Elena. Jeff and Michelle are strong
supporters of the educational work VARC is doing with kids and very
kind and generous donors.
Elena had a really terrific time as you can see from the following
sequence of photos which just goes to show that it's never too soon
to start teaching children about birds and the environment!
"I'm not too sure about this whole
'banders grip' thing!"
"Maybe if I use both hands!"
"Wow! That was so cool!"
The 31st annual Vancouver
International Film Festival (VIFF) is being held from September 27th
to October 12th. As one of the largest film festivals in North
America, VIFF brings Vancouver audiences some of the best films from
around the globe.
in association with the World Wildlife Foundation (WWF) VARC is very
pleased to sponsor a film entitled 'Birders: The Central Park
Effect' documenting the importance of urban oases like Central
Park in New York for breeding and migratory birds.
More information on venues and show
times can be found online by clicking the link below:
The Central Park Effect
Swallows are part of the guild of aerial insectivores which have
suffered precipitous declines in recent years with research showing
that populations of Barn Swallow and Bank Swallow have fallen by 70%
and Cliff Swallow, Northern Rough-winged Swallow and Purple Martin
by over 50%.
Researchers at Cornell University and elsewhere have launched a
continent-wide research program called Golondrinas de Las Americas
(Swallows of the Americas), an international community of biologists
studying swallows in the genus Tachycineta (including our
Tree and Violet-green Swallows) from northern Canada to Argentina.
Seven of the eight species of North
American swallow occur at Colony Farm, sometimes in large numbers
and the old field habitat provides an excellent opportunity to
contribute to these nationwide monitoring studies.
This hatch year (HY) Barn Swallow
(BARS) showing a very prominent gape and the short tail streamers
characteristic of first year (HY/SY) birds, the tail notch generally
measuring less than 20mm (photo right).
lots of Empidonax Flycatchers banded this month this very
fresh plumaged hatch year (HY) Dusky Flycatcher was a nice surprise.
Although DUFL appear in small numbers in the spring, fall records
are less common for us at Colony Farm.
||By far our most
numerous species this month was Lincoln's Sparrow (LISP) and on some
mornings the grass was literally alive with them as we drove in to
the banding station. LISP are one of our favourite sparrows with
such intricate tortoiseshell patterning on the upperparts and fine
buffy streaking on the breast.
In the fall our catch is dominated by hatch year (HY) birds
emphasizing the importance of the old field habitat as nursery
habitat for these young birds.
Molt limits are relatively easy to see on LISP with all lesser,
median, greater coverts, normally one or two tertials and often
central retrices replaced in the 1st PB (photos below)
LISP are among the Emberizid family
which often show an alula covert (A1) molt limit (macro photo
below). The differences between this tiny feather and the adjacent
main alula feather (A2) can be very subtle but here there is a clear
A1 limit - note the darker rachis of the molted A1 feather.
|A further reminder
that fall migration was in full force was illustrated by fat
scores on migrants caught for banding with many birds scoring
maximum fat scores like this hatch year (HY) Black-headed Grosbeak.
Where birds store fat and how we score fat deposits was explained in
a photo essay in last September's blog:
Bird banding data provides a very
important category of evidence for assessing and confirming the
value of areas and habitats for migratory birds. By recording a
measure of visible fat on migrants caught for banding and
documenting changes in body mass and fat deposits through subsequent
recaptures allows us to directly assess the quality of sites and/or
Hummingbirds (ANHU) have appeared in record numbers at Colony Farm
this year and now seem to be well dispersed and abundant throughout
the lower mainland. Its range has increased dramatically since the
1930s, when it was found only in California and Baja California. Due
to the widespread use of backyard nectar feeders and the planting of
exotic flowering trees it has greatly expanded its breeding range as
far north as the Comox Valley on the east coast of Vancouver Island.
This molting hatch year (HY) male was
attaining the iridescent red spots on the head which will turn in to
the unmistakable magenta-rose helmet diagnostic of adult males.
migrants included a good number of Fox Sparrows of both the Sooty
and Slate-colored forms. Pacific coast Sooty Fox Sparrows (below
left) have little if any gray in the plumage, have browner backs and
are darker overall compared to the interior Slate-colored Fox
Sparrows (below right) which have brownish-gray heads with thickly
spotted and streaked whitish underparts.
And finally three 'good' species for us, two of
which were unexpected visitors to the old field habitat.
Hutton's Vireo (HUVI) photo left was a first banding record for the
station and our 93rd species banded!
HUVI's are resident birds of oak and
mixed oak/pine woodlands and montane foothills. Although in the
field they can be strikingly similar to
Kinglets (RCKI) as the photo left shows in the
hand they are very different.
The upperwing pattern is different in the two species - on HUVI
there are two bold white wingbars on RCKI the lower wingbar is much
bolder than the upper wingbar. Both species have bills roughly
equal in length but the HUVI bill is broad and hooked slightly at
the tip while the RCKI is narrow and pointed. HUVIs look
"big-headed" while RCKI looks small-headed and the leg proportions
are different - HUVIs having stout blue-gray legs with matching
coloured feet; on RCKI the legs are matchstick thin and blackish
with yellow soles of the feet.
Sapsucker (photo left) was our second for the year!
White-throated Sparrow an annual but uncommon winter bird of the
coast and our 4th banding record for the station.
(finally!) an enormous thank you to Michaela Hofmann (sitting on the
tailgate) who left us to return home to Germany before heading back
to university to continue her studies. Michi was such a great
addition to the banding team for the past couple of months and we'll
really miss her. Thanks again Michi and make sure you keep in touch!
to Mark Habdas, Kerry Kenwood, Carol Matthews, Jason Jones, Debbie
Wheeler, Sarah Gray, Mike Nutter, Kyle Norris, Eric Demers, Celia
Chui, Louise Routledge, Monica Nugent, Todd Heakes, Michaela
Hofmann, Sara Legros, Olga Lansdorp, Christine Bishop, Kathy Elwood,
Rufus Macintyre, Erin O'Connor and Marg Anderson for their help with
banding this month.
Avian Research Centre Society is a Registered Canadian Charity (#
82118 2656 RR0001)
Donations to a registered charity are of course tax deductible and
we hope that people concerned about avian environmental issues in
Vancouver will consider making a donation to further VARC’s work.
This can be done by simply clicking on the link below to make an
immediate donation. Thank you for your generous support – it really
is very much appreciated!