McGILL BIRD OBSERVATORY

FALL MIGRATION MONITORING PROGRAM

Week 11:  October 10 - 16, 2009

Welcome to the McGill Bird Observatory weekly report.  Click here for a complete listing of our archives.
Comments or questions are welcome at "mbo AT migrationresearch.org".

PICTURE OF THE WEEK:




While Northern Saw-whet Owls technically aren't part of our Fall Migration Monitoring
Program, their unprecedented abundance at MBO in recent days nonetheless merits
top billing in this week's report (see below for details).  The photo is a bit fuzzy since
we avoid using flash photography with owls, and focus is trickier in the dark.

(
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

 

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THIS WEEK

THIS FALL

2009 TOTAL

SITE TOTAL

# birds (and species) banded

257 (22)

2680 (72)

3684 (82)

22605 (105)

# birds (and species) repeat

38 (8)

483 (35)

762 (46)

4109 (66)

# birds (and species) return

1 (1)

35 (16)

153 (32)

607 (37)

# species observed

65

132

163

198

# net hours

225.5

5153.0

8511.5

38976.8

# birds banded / 100 net hours

114.0

52.0

43.2

58.0

Note: table does not include nocturnal banding (owls)

Banders-in-charge:  Simon Duval, Marcel Gahbauer, Gay Gruner
Assistants:
Jessica Adams, Shawn Craik, Jean Demers, Matthew Emrich, Nicki Fleming, Tiffany Gilchrist, Jeff Harrison, Marie-Anne Hudson, Marie Melissa Kalamaras, Meg Langley, Francine Marcoux, Dan McDonough, Chris Murphy, Clémence Soulard, Alex Stone, Alexis Thorbecke, Rodger Titman, Carine Touma

Notes:  As is sometimes the case in later fall, weather was the story of the week.  For the first three days we had close to seasonal temperatures, but lost nearly half our normal net hours to rain and/or wind.  However, the site was teeming with birds - an average of over 40 species observed each day, and 190 birds banded in just 136 net hours.  Then on Tuesday a cold front came through, accompanied by rain, wiping out everything but census.  For the remainder of the week it remained 6 - 8 degrees Celsius colder than usual for this time of year, to the extent that we had to severely curtail the opening of nets.  During this part of the week our average daily count of species was down to around 30, and we banded just 66 birds in 92.5 net hours. The 22 species banded this week is a sharp drop in diversity from last week's 37, but this is actually quite typical of weeks 10 and 11 at MBO ... there is usually a big change in the bird community right around Thanksgiving.

Before going on to the rest of this week's regular news, a brief tangent on the subject of owls is in order.  In 2004, 2005, 2007, and again this fall we have supplemented our standardized migration monitoring program with a bit of nocturnal effort to catch and band Northern Saw-whet Owls.  For various reasons, but largely due to a limited availability of qualified banders, we haven't been able to operate the owl banding program as consistently as we'd like.  However, we've always felt the effort is worthwhile since there is much yet to be learned about these birds and the relatively high rate of recaptures for this species improves our chances of connecting some dots on the landscape over time (e.g. one of the birds we caught in 2004 had been banded near Kingston, Ontario three years earlier).  During our three previous owl banding attempts at MBO we had modest results at best, with season totals ranging from 15 to 17 individuals banded. 

This fall, largely thanks to the determination of our BIC Simon Duval, we decided to give the owling another chance, but we moved the nets to a new location, near the existing E1 net, and going around and through a small fir/spruce stand.  We hoped this would improve our results, but never expected the change to be as dramatic as it has been.  On Tuesday night alone we banded 17 saw-whets - as many in one night as our previous best season!  We also had 12 the night before, and 13 over the rest of the week, for a total of 42 (which would put them as #3 on the weekly chart below if they counted toward it).  For the season we are now at 50, and we expect at least a few are yet to come.  Perhaps most intriguing is that most other saw-whet banders in the northeast are reporting this to be a below average year in terms of numbers (saw-whets have quite a dramatic four-year population cycle), so we are very excited to see how our new site will fare when we have a "good" year!


It would be an exaggeration to say we've been experiencing an invasion of Red-breasted Nuthatches, but given that we've never before banded more than one in a season (and a grand total of three before this fall), the fact that this hatch-year female was our fourth individual of the season is impressive.
(Photo by Marcel Gahbauer)


Slate-coloured Juncos are one of our dominant species in the late part of fall, and sure enough they have been among the most numerous birds at MBO this week, eclipsed in the nets only by American Robins.  This after-hatch-year male shows just how dark and solid gray juncos can be, a contrast to the much more numerous hatch-year birds with their patches of brown on their wings and back.

(Photos by Marcel Gahbauer)

Additions to our seasonal and annual lists were sparse this week.  American Tree Sparrow was observed and banded for the first time this wall, while Wilson's Snipe was observed for the first time this year.  We also had our first junco recapture of the year this week.  Other late season species such as Northern Shrike and "winter finches" have yet to make an appearance despite the cold weather in the second half of this week, but we expect them soon.


Volunteers at MBO often hear the banders talking about "molt limits", but unfortunately some of them are rather subtle and difficult to point out.  Not so with the wing of this hatch-year Eastern Phoebe!  In this case there is a highly visible contrast among the greater coverts - the outermost five are retained juvenile feathers, clearly shorter than the replaced formative greater coverts closer to the body, and also more brownish, with distinct buffy tips.  If only all molt limits were so easy to spot!
(Photo by Marcel Gahbauer)


Whereas most adult passerines undergo a complete molt annually, this is not necessarily the case for other birds.  For example, even though they are small, Northern Saw-whet Owls may have as many as four generations of feathers among their primaries and secondaries, recognizable by their different shades of brown (since the feathers fade and become more worn over time).  In the case of the bird above, there are three distinct generations just among the primaries:  the innermost two feathers (the broad feathers in the middle of the photo) are two years old, the three to the right are newly replaced from this year's moult, the two to the right of them are one year old, and then the outermost three (not well visible) are again new.  Contrast is also visible among the secondaries; of note, s1 (adjacent to the first primary) is particularly pale and frayed along the edge - it is at least two years old, and possibly three, in which case this owl would very likely be a fourth-year individual.
(Photo by Marcel Gahbauer)

As mentioned earlier, there tends to be quite a significant turnover of birds at MBO around mid-October, and the list of species banded most frequently this week reflects those changes. Our two late-fall specialists, American Robin and Slate-coloured Junco, have settled into the top two spots, and it would be not surprising to see them remain there (or at least close to the top) for the remaining two weeks as well. The biggest surprise this week is the continuing abundance of Hermit Thrushes, bringing our seasonal total to 80 individuals, more than double our count from any previous season (and of note we also had 19 repeats this week, many of birds we banded last week, so some are clearly hanging around and enjoying the feeding opportunities at MBO).  Ruby-crowned Kinglet, White-throated Sparrow, and White-crowned Sparrow were all still reasonably numerous early in the week, but are sliding down the list as most of them moved out when the cold front arrived.  Black-capped Chickadees were banded in good numbers this week, suggesting that there may be somewhat of a migration underway after all (we have seen substantial movements in "odd" years previously, but no big push of birds yet this fall).  Song Sparrows continue to move in decent numbers, with this week's 12 birds bringing our season to 301, far above our normal count for them, and just one shy of the record we set in 2006.

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

# individuals banded

mean # individuals observed daily

1.  American Robin (51) [7]

1.  American Robin (403.0) [2]

2.  Slate-coloured Junco (46) [8]

2.  Canada Goose (168.9) [1]

3.  Hermit Thrush (34) [5]

3.  Red-winged Blackbird (153.0) [5]

4.  Ruby-crowned Kinglet (33) [1]

4.  American Crow (112.6) [7]

5.  White-throated Sparrow (32) [2]

5.  White-throated Sparrow (62.9) [3]

6.  Black-capped Chickadee (15) [-]

6.  European Starling (53.1) [4]

7.  Song Sparrow (12) [6]

7.  Slate-coloured Junco (33.7) [-]

8.  White-crowned Sparrow (9) [4]

8.  Black-capped Chickadee (18.1) [-]

9.  Swamp Sparrow (6) [-]

9.  White-crowned Sparrow (17.6) [6]

10.  Blue-headed Vireo (3) [9]

10.  Ruby-crowned Kinglet (15.0) [8]

Like last year at this time, Canada Goose numbers have tapered off a bit, while clouds of swirling American Robins have taken over the site and the top spot on the list of species most frequently observed for the week.  In the second half of the week Red-winged Blackbirds were nearly as abundant as the robins, bringing them to third place for the week.  The local American Crow roost appears to be building in size again, and we continued to have flocks of European Starlings fly over the site most days this week, occasionally even stopping to perch in some of the taller trees on occasion.  Thanks largely to phenomenal numbers over the first couple of days of the week, White-throated and White-crowned Sparrows remain in the top 10, but are likely to drop out next week unless a large number of late migrants are waiting to move south through MBO.  The surge in the arrival of Slate-coloured Juncos resulted in them being added to this week's list, and Black-capped Chickadees returned after an absence of one week, boosted a bit by the arrival of apparent migrants.  Common Grackle and Yellow-rumped Warbler were the two species on the list last week that fell off this week as their numbers dropped.

We have just two weeks left in this year's Fall Migration Monitoring Program, and with the cold weather of the past few days it feels in some ways like the end of the season should be coming even sooner!  But we take heart in the warming trend shown in the long-range weather forecast, and hope that we'll have a good finish to the season ... no doubt with many more robins and juncos, but perhaps also a few surprises still.  After all, some very northern breeders have yet to put in an appearance at MBO this fall, and with the early cold snap there may be increased opportunities to spot some of them, whether in the nets (e.g. shrikes or finches) or overhead (e.g. raptors and waterfowl). 


The birding may have slowed down later in week 11 due to the cold, but it was still a beautiful time to be out at MBO, with the sumac groves flaming red, the forest behind a mix of yellow and green, and some carpets of red maple leaves in the woods too.

(Photos by Marcel Gahbauer)


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