Vancouver Avian Research Centre

.....Research - Conservation - Education

June - The first week of June is always exciting and in past years has produced some very rare birds like the Brown Thrasher in 2009 and the Brewer's Sparrow in 2010.

Very unsettled weather at the beginning of the month had us all thinking 2012 could be the same and we weren't to be disappointed when this absolutely stunning second year (SY) male INDIGO BUNTING turned up!

Funnily enough it was captured in one of two nets we set up for Mountain Bluebirds along a fence line to the south of the banding station which have since been christened the 'Bluebird Nets' and although we didn't catch any MOBLs this spring we were very happy to settle for this 'blue bird'!!

Buntings often have an extensive 1st prebasic molt including all lesser, median and greater coverts, carpal covert, alula, tertials, additional inner secondaries and outer primaries. Members of the Cardinalis family like Grosbeaks and Buntings where males have such contrasting and distinctive plumages are very helpful for learning molt patterns and especially helpful in looking for molt limits in females of the same species.

The wing of our SY male below shows distinctive contrasts between 3 generations of feathers; juvenile, first basic and first alternate and illustrates the eccentric pattern of replaced remiges common in this species.

In its 1st prebasic molt following the breeding season last year this bird replaced lesser and most median coverts, all but two of its greater coverts (GC 3 & 10 illustrated with the green arrows - GCs are numbered proximally towards the birds body with GC10 the innermost), the carpal covert, alula, the outermost primaries (pp 5-9 - primaries are numbered distally away from the birds body with p9 the outermost) but no secondaries or tertials. The 1st prebasic molt limit is indicated with the red arrows - notice the thick glossy, black rachis of the replaced outer primaries easily distinguishing them from the retained juvenile inner primaries and secondaries. In its 1st prealternate molt in the late winter early spring it replaced inner greater coverts 7-9, tertials and the innermost secondary (S6) indicated by the blue arrows.

Finally notice the washed out, worn and lightly pigmented appearance of the retained juvenile feathers especially the now very worn and tapered primary coverts.

Not quite as impressive but gorgeous nevertheless was this after second year (ASY) female Lazuli Bunting the iconic bird of Colony Farm completing our Bunting double day!

Next up was another rarity and first banded (for us) Least Flycatcher (LEFL) which was initially heard and seen on a Monday in the small deciduous woodland at the banding station.

As we all have 'real' jobs and are only able to band Thursday through Sunday we were chomping at the bit on the Thursday after the bird was first seen hoping that it would still be around. We rushed out to open our woodland nets pre-dawn and immediately heard our LEFL CHE-bekking away and captured the bird on the very first net round!

We've talked at length about Empid identification in the hand and the benefits banders have over birders in being able to separate these very similar species.

We always start by dividing these tricky flycatchers in to 3 main groups:

White throat, white belly and spotted crown - Traill's (Willow/Alder) and Least
Greyish throat, yellowy belly and narrow bill - Hammond's and Dusky
Yellow throat, yellow belly and greenish back - Pacific-slope (and Yellow-bellied!)

As can be seen in the photo above Least is the smallest Empid with a white throat, whitish belly, rounded head and almond shaped eyering. The bill is small but wide with convex sides and pale lower mandible.

Wing morphology is really the key to making definitive Empid identification in the hand. The photo below left shows the primary projection of Least which is short at just 11mm. Wing and tail measurements were 64mm and 53mm respectively giving us a wing minus tail measurement of 11mm and tail minus primary projection of 40mm. Primary tip spacing is another important consideration in Empid identification being evenly spaced in Least (photo below right) although this second year bird was showing lots of wear to the tips of the primaries making this feature more difficult to see.

Having now banded 6 species of Empidonax Flycatcher - Traill's (Willow and we're certain at least one Alder!), Hammond's, Dusky, Pacific-slope and Least we're definitely getting the hang of Empid ID in the hand!

We were all feeling very sorry for our Least Flycatcher singing away in the woodland thinking that all his efforts to attract a mate were going to be in vain! The constant singing was explained three days later when a SECOND LEFL was caught in the same location – although this second bird was not showing a brood patch the pair are clearly on territory and we now have fingers crossed for a successful nesting attempt in the park!

Another Empid with an almond-shaped eyering caught the same day in the very same net was this Pacific-slope Flycatcher (PSFL) which showed an unusual molt pattern.

The 1st prebasic molt in PSFL is partial and normally includes lesser, median and some inner greater coverts, sometimes 1-3 tertials but no other flight feathers. This bird had replaced virtually no lesser coverts, some median coverts, 6 inner greater coverts (GCs 5-10) and unusually 4 outer primaries (PP6-9) all illustrated with the red arrows. The 1st prealternate molt included 5 inner greater coverts (GCs 6-10) and all 3 tertials illustrated with the blue arrows.

And we weren't finished with new species banded for the station this month when incredibly this quite stunning Red-breasted Sapsucker showed up in a net one morning!

Although not rare in the coniferous forests of BC the last place you might expect to find one is in the middle of the old field habitat at Colony Farm.

A fitting bird for our 90th species banded at the station!

 

Members of the Oreothlypis (ex Vermivora!) genus such as Orange-crowned Warblers (OCWA) have very thin, sharply pointed bills which they use to prise open small buds to extract spiders and insects which may be inside.

We are sometimes able to show visitors this reflex action with birds in the hand by asking them to gently place their forefinger and thumb on the upper and lower mandibles when the bird will often prise them apart as with this particularly cooperate OCWA in the photo below!

The final spring Bird Monitoring and Banding Workshop was held over the June 8th - 10th weekend where our 11 course participants (some from as far away as Washington and the Yukon!) sacrificed their entire weekend to learn all about molt and ageing of NA landbirds in the hand. The two field sessions although freezing cold (as you can see by coats, hats and gloves in June!!) were a lot of fun and it's always such a treat to see the look on people's faces as they band their first bird. It really is a unique experience and one which we hope will encourage them to get involved in banding and citizen science monitoring programs once they return home.

It was another excellent workshop and by the end of the weekend this group had again become like family to us. Thanks to all of them for their wonderful workshop evaluations which as always can be viewed on our testimonials page by clicking here:

June Workshop Evaluations
 

This after second year (ASY) Western Wood-Pewee (WEWP) of unknown sex was one of 3 WEWP banded this month.

Although the wing of this adult bird shows no discernible molt limits this bird abnormally had 4 alula feathers (indicated by the red arrow in the photo below left).

The tail of the same bird (photo below right) shows the very broad, truncate appearance of adult retrices with a distinct corner to the inner web of r4 indicated by the red arrow.

WEWPs are long distance migrants overwintering as far south as Bolivia in South America and like all long distance migrants have long wings as can be seen from the photo left which in WEWPs almost extends to the tip of the smudged undertail coverts.

Wing morphology refers to the shape of the wing and reflects 3 aspects of the primaries - the length and the occurrence of indentations to the inner and outer webs called notches and emarginations.

Longer, more pointed wings produce less air resistance in flight which is beneficial to birds making these incredible long distance migrations.

This second year (SY) female Black-throated Gray Warbler (BTYW) with a fully developed brood patch had us scratching our heads when we looked at the wing to age her (photo below right).

Unlike many of the Setophaga (formerly Dendroica) warblers BTYW have a very limited prealternate molt which is supposed to be limited to head feathers and the 1st prebasic molt is supposed to include all lesser, median and greater coverts and the greater alula covert.

In its 1st prebasic molt after the breeding season last year this bird had replaced all lesser and median coverts, the carpal covert and greater alula covert but only some outer greater coverts, the 1st prebasic molt limit between the outer greater covert and inner primary covert indicated by the red arrow. The green arrow points to the retained juvenal inner greater coverts. Strangely, in its 1st prealternate molt this year she replaced a single inner greater covert (GC 7), the glossy black feather indicated by the blue arrow (this feather may or may not have also been replaced in the 1st PB).

The only thing that was by the book was the white tips and small shaft streaks of the median coverts diagnostic of first year females (white arrow).

Another reminder and example that there is always something new and interesting to learn with molt and ageing of NA landbirds in the hand and that in many instances more study is needed with each species.

Hummingbird monitoring continued with the first hatch birds showing up this month and so did Dev with his fancy new super-macro lens!

Digital photography and super-macro technology takes us in to a whole new world where one can only further marvel at the miracle of birds.

The two super-macro shots below are courtesy of Devin Manky and should not be used without his permission.

Hummingbirds are Apodiformes which comes from the Greek word meaning 'no feet' and although they do of course have feet to perch they are too far back on their bodies to walk.

Like songbirds Hummingbirds have one toe (the hind toe or hallux) back and three toes forward in a toe configuration termed anisodactyl.

Ageing Hummingbirds is relatively easy as all species can be aged for the first 5 to 9 months after fledging by the extent of grooves called corrugations along the lateral portions of the upper mandible.

When Hummingbirds are born the bill is soft and these deep grooves are easily seen under magnification (red arrow photo below left) whereas adult bills are smooth, hard and shiny along the entire length of the upper mandible (photo below right)

NA Hummingbirds have 10 primaries (the tenth full in length), 6 secondaries and 10 retrices.

Rufous Hummingbirds (RUHU) can be reliably aged and sexed by differences in the shape and width of primary 10 (p10 - the outermost primary), and by the pattern of the central retrices.

P10 is broader and blunter (photo below left) in hatch year RUHU and narrower and curved (photo below right) in after hatch year (AHY) birds, especially in adult males.

The central retrices of hatch year (HY) males (photo below left) have substantial rufous at the base while those of after hatch year (AHY) males (photo below right) are almost entirely rufous, narrower and more pointed and the outer retrices (r3-r5) are usually without white tips.

The central retrices of females are primarily green without rufous or with limited rufous at the base of the feathers as can be seen in the photo left of a hatch (HY) female.

Baby birds were much in evidence this month all showing the characteristics of recently fledged birds with streaked/spotted plumages, prominent gapes, loosely textured feathers and bright mouth linings like our Orange-crowned Warbler, Black-capped Chickadee, Downy Woodpecker and Red-winged Blackbird in the photos below.

June was an ugly month for weather in Vancouver and went down as one of the coldest on record with lots of rain.

We feared for our Tree Swallow nestlings and wondered whether they could possibly make it. Like all aerial insectivores. cold, wet weather is their worse enemy as adults try to find enough insects to feed hungry babies.

Temperatures first thing in the morning were sometimes only just above freezing and it seemed impossible that one or two day old nestlings (top photo) could possibly survive but survive they did as we monitored their progress and and all but one of our occupied boxes successfully fledged young!

 

By late spring many birds are showing extensive wear to flight feathers. Retained juvenile feathers by now almost 12 months old and which have been worn for one long neotropical migration are sometimes so worn that only the rachis remains with all the interlocking barbs and barbules worn away. Such was the case with this second year (SY) male Black-headed Grosbeak (BHGR).

This emphasizes the importance of molt to birds as worn or damaged feathers like these can only be replaced during the annual molt cycle.

Conversely, this after second year (ASY) male was showing very little flight feather wear having replaced all of its feathers in its definitive adult prebasic molt after the breeding season last year.

Also notice the extensive white wing patch and tail spots diagnostic of adult BHGRs.

 

 

Eastern Kingbirds (EAKI) are another species where more study is needed regarding molt patterns and ageing.

EAKIs are sexually monomorphic meaning males and females cannot be separated by their markings or the colour of their feathers; both males and females display the red central crown feathers shown in our after hatch year (AHY) female photo right.

 



 

Males and females can be separated in the hand by the indentations to the inner web of the outermost primaries (p9 & p10) called notches.

This notch is less pronounced (<8mm from the tip) in females and longer and more elongated (>8mm from the tip) in males.

The prebasic molt in EAKI is thought to be complete or nearly complete although much is still not known of molt patterns in this species and more study needed.

This bird had replaced some lesser coverts, the alula covert, carpal covert and outer primaries (p5-p10) illustrated by the red arrows. The inner 4 greater coverts (blue arrow) had been replaced presumably in this birds prealternate molt this winter/spring.

So despite horrible weather for the entire month that severely hampered our banding effort June was an exciting month with lots of diversity, an eastern rarity and two new species banded for the station!

Thanks to Mark Habdas, Kerry Kenwood, Carol Matthews, Jason Jones, Jerry Rolls, Debbie Wheeler, Sarah Gray, Mike Nutter, Kyle Norris, Eric Demers, Celia Chui, Louise Routledge, Monica Nugent, Todd Heakes, Dev Manky, Marianne Dawson, Vinci Au, Sara Legros, Christine Bishop, Kathy Elwood. Marg Anderson and Hummer volunteers Marguerite Sans, Alida Faurie and Erin O'Connor  for their help with banding this month.

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