Vancouver Avian Research Centre

.....Research - Conservation - Education

September: 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 birds!

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.

Both of 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 skipped feather.

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 has completed.


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!
We're 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 sites.

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 August 17th.

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 Colony Farm.

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!

Window Mobile

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 TEWA.

Still it goes to show it's worth carefully checking out those fall warblers!

Plenty of visitors again this month and it was nice to welcome back British 'A' Ringer and Trainer Tim Ball from the Reading and Basingstoke Ringing Group.

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 there!

Andrea 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.

This year 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).

Amidst 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: September 2011 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 habitats.


Anna's 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.

Other 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 Ruby-crowned 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.





Red-breasted Sapsucker (photo left) was our second for the year!







And White-throated Sparrow an annual but uncommon winter bird of the coast and our 4th banding record for the station.






And finally (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!
Thanks 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.

The Vancouver Avian Research Centre Society is a Registered Canadian Charity (# 82118 2656 RR0001)

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