Week 6:  September 5 - 11, 2009

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Although not as abundant as at this time last year, Magnolia Warblers were still the
most abundant warbler at MBO this week. This handsome young male is further
featured below with a photo of his unusually boldly marked tail.

(Photo by Marcel Gahbauer)

MBO gratefully acknowledges the financial support provided for the 2009 Fall Migration Monitoring Program by TD Friends of the Environment Foundation






2009 TOTAL


# birds (and species) banded

109 (33)

1024 (59)

2028 (79)

20949 (105)

# birds (and species) repeat

29 (11)

208 (26)

487 (41)

3834 (66)

# birds (and species) return

4 (4)

25 (16)

143 (32)

597 (37)

# species observed





# net hours





# birds banded / 100 net hours





Note: table does not include nocturnal banding (owls)

Banders-in-charge: Simon Duval, Marcel Gahbauer, Gay Gruner
Assistants: Christine Barrie, Jean Beaudreault, Isabelle-Anne Bisson, Jean Demers, Nicki Fleming, Barbara Frei, Chloe Gendre, Tiffany Gilchrist, Kristen Keyes, Meg Langley,  Barbara MacDuff, Francine Marcoux, Chris Murphy, Clémence Soulard, Alex Stone, Carine Touma

Notes:  At times this week it almost seemed like the birds had read last week's report and were determined to show us what a REALLY slow fall week is like.  Only on Friday did we finally band more than 15 birds in a day, and even then the total of 25 was rather slow for this time of year.  For comparison, last year during this week we banded 343 birds, and in the previous three years our range had been from 162 to 279.   Diversity was also quite low, with daily estimated totals often in the 35 to 40 species range, and the weekly total of 75 the fewest we've ever had at this time of year.

Why such a slow week?  It's hard to say, as various factors could be at play.  As noted last week, a poor breeding season in much of the boreal forest could be at least partly to blame.  However, it was also a rather warm week (temperatures a few degrees above the seasonal norm) with remarkably consistent conditions, so the lack of distinct weather fronts might have held back some birds longer than usual.  Again, all we can do is wait and watch how the rest of the season unfolds.

Despite how quiet the week was compared to our expectations, we added some species to our seasonal and yearly totals as usual.  A Black-billed Cuckoo detected while opening nets one morning was our first observed at MBO this year; other species seen for the first time this fall were Spotted Sandpiper, Ruby-crowned Kinglet, Western Palm Warbler, and Cape May Warbler.  The Palm Warbler was our first to be banded this year, as was the Philadelphia Vireo featured lower down on this page.  We also had our first Rose-breasted Grosbeak return of the year (i.e. a previously banded bird not recaptured for at least 3 months), a male we banded two years ago.

This week our supplemental research on warbler plumages transitioned from American Redstart to Magnolia Warbler.  With them, we're interested (among other things) in the extent of white on the tail.  Shown above and below are two individuals that nicely illustrate the range of variation that exists.  The pattern above is typically associated with after-hatch-year Magnolia Warblers, but in this case both the moult limit on the wing and the presence of an incompletely ossified skull indicated it to be hatch-year (and a male based on the extent of white, as well as being overall boldly marked).

In contrast, the tail below is much grayer, and also the uppertail coverts are largely greenish with minimal black centre spots. Even on pale birds, there is usually at least some white on all of r2 to r6 (the outermost five rectrices on either side).  In this case, the outermost feather on the right side is hidden from view, but what is evident is that there is no white at all on r2, and even r3 has just a small spot, so we can probably be quite certain this is a hatch-year female.
(Photos by Marcel Gahbauer)

In the first two weeks of August we banded 20 White-throated Sparrows, almost all juveniles that must have come from nests rather nearby.  Since then though, we've banded relatively few additional ones, so the sudden appearance of the species at the top of our list of species banded this week is a sure sign that the migrants from further north have started to arrive ... and we expect them to remain among the most dominant species for the next few weeks.  Magnolia Warbler and Song Sparrow remained near the top of the list this week; of note, we banded 109 Magnolia Warblers during this week last year, so that is a significant factor explaining this year's lower total.  American Redstart dropped to fourth place this week, marking the sixth week in a row that it has ranked at least that high, an impressive streak of consistency.  They dropped off noticeably though as week 6 progressed, so it's possible they will fall off the list next week as more northern species arrive in (hopefully) larger numbers.  The "blue birds" (Indigo Bunting, Black-throated Blue Warbler, and Blue Jay) all had a good showing this week.  Although remaining numerous, Black-capped Chickadees continued to largely elude the nets this week.

This week’s top 10   [last week's rank in brackets]

# individuals banded

mean # individuals observed daily

1. White-throated Sparrow (18) [-]

1. Canada Goose (42.7) [1]

2. Magnolia Warbler (10) [1]

2. American Crow (31.0) [3]

2. Song Sparrow (10) [1]

3. Cedar Waxwing (25.4) [4]

4. American Redstart (7) [2]

4. Black-capped Chickadee (22.7) [2]

5. Common Yellowthroat (6) [4]

5. Common Grackle (21.0) [6]

5. Indigo Bunting (6) [8] 

6. American Goldfinch (15.6) [5]

7. Red-eyed Vireo (5) [-]

7. Blue Jay (12.9) [8]

7. Black-throated Blue Warbler (5) [4]

8. American Robin (12.7) [-]

9. Black-capped Chickadee (4) [6]

9. White-throated Sparrow (10.1) [-]

10. Blue Jay (3) [-]
10. Blackpoll Warbler (3) [-]
10. Northern Waterthrush (3) [10]
10. Ovenbird (3) [-]

10. Song Sparrow (9.9) [-]

The Canada Goose flocks continue to grow slowly, putting them on top of our list of most observed species for a second week in a row.  The rest of the top seven is also awfully similar to last week, with only Common Grackle and American Goldfinch switching between fifth and sixth place, and Black-capped Chickadee being pushed down by increases in the number of American Crows and Cedar Waxwings.  The bottom three spots are occupied by American Robin, White-throated Sparrow, and Song Sparrow, the first two of which are likely to increase substantially in prominence over the coming weeks.

Extra thanks this week to Ryan Young for organizing the annual Ecology Day in Ste-Anne-de-Bellevue and offering MBO a prominent booth there, as well as to Tiffany Gilchrist and Marcel Gahbauer for staffing the booth.  If you're reading this as a result of having stopped by to chat, we look forward to having you out at MBO as volunteers!

Like many other boreal-nesting songbirds, Philadelphia Vireos have been scarcer than unusual so far this fall.  This one graced our nets this week, our first of the season.
(Photo by Gay Gruner)

While not a particularly eye-catching bird, this hatch-year female Cape May Warbler was arguably the highlight of this week's captures, as we've only banded 10 of them at MBO previously, making them our third-scarcest of the 25 warbler species we've caught here (only the slightly out-of-range Golden-winged and Blue-winged Warblers have a lower count).

(Photo by Marcel Gahbauer)

Another relatively scarce bird this week (we've banded an average of 6 per year) was this Brown Thrasher, which kindly showed up just in time to be seen by the entire McGill ornithology class, making their first visit to the site on Wednesday morning.
(Photo by Marcel Gahbauer)



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