Monday, September 7, 2009

Metro Beach banding report - September 3, 5 & 6

There were some interesting lessons in variation and expectations provided by birds captured this past week.

Banding studies, among others, have collected much of the data that has shown that adult songbirds of many species depart for their wintering grounds earlier than their young. Local banders then form expectations of what age classes should be migrating through their area at given times. My own expectations regarding the migration of Tennessee Warblers was that the migration of adults was mainly earlier than I typically start the banding season since they're captured in late July around Kalamazoo, but also that perhaps adults may not pass through southeastern Michigan in large numbers as they are mainly a circum-Gulf migrant on their way to Central America. At Kalamazoo, these early adults are often found molting their flight and body feathers, and may be undergoing what is termed a "molt migration" where the adults migrate a short distance away from breeding grounds to an area where they finish molting (called "staging") before continuing south. One of these Tennessee Warblers is shown in the photo below.

Second-year female Tennessee Warbler

She was molting some of her body feathers which gives her the untidy appearance. She is also molting her wing feathers, which are a bit odd looking in this photo. Taking a closer look at her spread wing, below, we can see that she is growing in her inner secondaries and the outermost primary.

Same second-year female Tennessee Warbler

This is entirely what would be expected, as the typical molt pattern of many songbirds is to start with the outermost secondaries and innermost primaries, and molt outward from the center. This individual appears to have nearly completed its molt. Another second-year female Tennessee Warbler was somewhat different. As you can see from the photo below, her body feathers appear more disorderly, suggesting more extensive molt.

Another second-year female Tennessee Warbler

Now, my expectation might be for the molt to be occurring closer to the center of the wing...involving outer secondaries and inner primaries. But the photo of her wing, below, shows something I didn't expect.

Same second-year female Tennessee Warbler

While it is the outer secondaries that are molting, it is also the outer primaries that are molting! This points out very clearly that even things we understand fairly well are not always set in stone, can sometimes vary between individuals, and suggests there's more we can learn. The apparent lateness of the molt of these birds might be telling us something too.

So, on to this week's banding highlights. A total of 175 birds was banded on the three days covered in this report. This included 13 flycatchers of 4 species, 8 thrushes of 2 species, and 69 warblers of 12 species.

Banding highlights on Thursday, September 3 included 12 Ruby-throated Hummingbirds (though still very little Jewelweed blooming due to heavy deer browse), a single Marsh Wren, and two Mourning Warblers. Interesting birds observed but not banded included a Green Heron flying over, still-singing Warbling Vireo, and a Blue-gray Gnatcatcher continuing to tease me by not being captured. A single male Baltimore Oriole made a brief appearance in the tree at the center of the Field Nets.

Banding highlights on Saturday, September 5 included 8 Ruby-throated Hummingbirds, and 5 Least Flycatchers which oddly were the only flycatcher species captured today. The individual in the photo below is one of the more clearly marked, showing its big, grayish head contrasting with greenish-olive back, and bold white teardrop-shaped eyering.

Hatch-year Least Flycatcher

Two Red-eyed Vireos were also quite welcome, especially in light of the severe reduction in captures since 2004, compared with the 1989-2000 data. Shrub cover has changed not in height, but in species composition, and I fear that what's left (lots of Multiflora Rose) is not suitable for feeding and foraging songbirds, making the area less important for migrants stopping over. Banders can easily age Red-eyed Vireos by their eye color, bright red in adults and brown in hatch-years. This should also be possible by birders in the field.

After hatch-year Red-eyed Vireo

Hatch-year Red-eyed Vireo

Probably the highlight of the day was a hatch-year female Northern Parula, only the second I've banded at Metro Beach since 2004 (the first one was in spring 2005), and only the 10th one overall (between 1989-2000 there were 8 banded, 2 in spring, 6 in fall). They are beautiful little birds, even the "duller" young females.

Hatch-year female Northern Parula

Interesting birds observed, but not banded, included flyover flocks of Double-crested Cormorants, another flyover Green Heron, and a young Great Horned Owl calling briefly in the morning darkness.

Banding highlights on Sunday, September 6 included 8 more Ruby-throated Hummingbirds, an Eastern Wood-Pewee (4th for the season!), two Yellow-bellied Flycatchers, one more Red-eyed Vireo, and an adult male Mourning Warbler, which was unexpected as adults should have mostly moved through by now. Is this telling us something? With such a small sample size, there's no way to know. But in the fall season of 2007 I was noticing an unusually high proportion of adult (AHY) to young (HY) White-throated Sparrows. This was based on a much greater sample size, and was well-correlated with banding results at the Rouge River Bird Observatory that same fall.  Lower productivity? Changes in migration routes or timing?

After hatch-year male Mourning Warbler

And another surprise today, yet another hatch-year female Northern Parula. I've included a photo of her here as well, not just because they're cool, but to allow individual variations of these two same-age, same-sex birds to be compared.

Hatch-year female Northern Parula

American Goldfinches also staged a major influx, with the 23 banded today nearly tripling the season total to date. That will change significantly through the end of the month and into October.

Interesting birds observed but not banded included 2 flyover Green Herons, a Great Crested Flycatcher, and still-singing Warbling Vireos, while the flocks of Cedar Waxwings present through August seem to have departed.

Also today, an interesting insect encounter is worthy of note, especially as I got a photo of the critter! As we were closing up the nets, I noticed a large-ish black and yellow thing flopping around in one of them. On closer examination, I could see what it was. A Pigeon Horntail (Tremex columba), nearly two-inches in length. I managed to get it out of the net, and into a bird bag without injury to it, or me! Back at the car I took photos, the best of which is below.

Pigeon Horntail (Tremex columba)

This is perhaps only the 5th Pigeon Horntail I've ever seen in my life. The first was when I was maybe 10 years old and one of the other neighborhood kids got stung by one. I only remember that he'd killed it, and I took the dead thing home and identified it using my little Golden Guide insect book by Herbert S. Zim. After a few photos, it awkwardly took off and flew back into the swamp. This is generally a solitary species, and the "horn" at the end of the abdomen assists the female in laying her eggs in decaying wood which is how they feed until they're adult. Cool bug!

I would like to thank all the very helpful banding assistants who came out on these three days. It was a delight having more than two people helping each day as it lightened the load for everyone. Thanks to Barb Adams, John Bieganowski, Terri Chapdelaine, Chris Goulart, Amanda Grimm, Dave Lancaster, Harry Lau, Rose Lau, Ava Lau, Tessa Lau, Tom Schlack, and Joan Tisdale.


Banding Data
THURSDAY, September 3, 2009
Sunrise (E.S.T.): 5:59
Time Open (E.S.T.): 6:00
Time Closed (E.S.T.): 12:00
Hours Open: 6.00
No. of Nets: 5.50-13.75
Net Hours: 77.438
Temperature (F): 54-70
Cloud Cover: 0-10%
Wind: Calm-SE @ 0-5 mph
Barometer: 30.27-30.25
Precipitation: None
No. Banded: 42 (plus 16 recaptured and 3 released unbanded)
No. of Species: 19
Capture Rate: 78.8 birds per 100 net hours
Volunteers: John Bieganowski, Dave Lancaster, Tom Schlack, Joan Tisdale

Ruby-throated Hummingbird - 12
Willow Flycatcher - 1
Least Flycatcher - 2
[House Wren - 1 recaptured and 1 released unbanded]
Marsh Wren - 1
Veery - 1
Swainson's Thrush - 2
[Gray Catbird - 1 released unbanded]
Cedar Waxwing - 1
Tennessee Warbler - 1
Chestnut-sided Warbler - 1
Black-throated Blue Warbler - 2
American Redstart - 1
Mourning Warbler - 2
Common Yellowthroat - 6 (plus 5 recaptured and 1 released unbanded)
Wilson's Warbler - 2
Song Sparrow - 3 (plus 9 recaptured)
Swamp Sparrow - 2 (plus 1 recaptured)
American Goldfinch - 2
SATURDAY, September 5, 2009
Sunrise (E.S.T.): 6:01
Time Open (E.S.T.): 6:00
Time Closed (E.S.T.): 13:00
Hours Open: 7.00
No. of Nets: 5.00-13.25
Net Hours: 87.313
Temperature (F): 57-76
Cloud Cover: 0-20%
Wind: Calm-SE @ 0-5 mph
Barometer: 30.30-30.31
Precipitation: None
No. Banded: 55 (plus 9 recaptured and 1 released unbanded)
No. of Species: 20
Capture Rate: 74.4 birds per 100 net hours
Volunteers: Lau Family (Harry, Rose, Ava, and Tessa)

Ruby-throated Hummingbird - 8 (plus 1 released unbanded)
Least Flycatcher - 5
Red-eyed Vireo - 2
House Wren - 2
Swainson's Thrush - 4
Gray Catbird - 1
Tennessee Warbler - 1
Nashville Warbler - 4
Chestnut-sided Warbler - 1
Magnolia Warbler - 2
Black-throated Blue Warbler - 6
American Redstart - 2
Ovenbird - 1
Mourning Warbler - 2 (plus 1 recaptured)
Common Yellowthroat - 3 (plus 4 recaptured)
Wilson's Warbler - 1
Song Sparrow - 6 (plus 4 recaptured)
Swamp Sparrow - 2
American Goldfinch - 1


SUNDAY, September 6, 2009
Sunrise (E.S.T.): 6:02
Time Open (E.S.T.): 6:00
Time Closed (E.S.T.): 13:00
Hours Open: 7.00
No. of Nets: 5.00-13.25
Net Hours: 86.375
Temperature (F): 57-77
Cloud Cover: 20%
Wind: Calm-E @ 0-5 mph
Barometer: 30.35-30.32
Precipitation: None
No. Banded: 78 (plus 7 recaptured and 1 released unbanded)
No. of Species: 22
Capture Rate: 99.6 birds per 100 net hours
Volunteers: Barb Adams, Terri Chapdelaine, Chris Goulart, Amanda Grimm.

Ruby-throated Hummingbird - 8
Downy Woodpecker - 1
Eastern Wood-Pewee - 1
Yellow-bellied Flycatcher - 2
"Traill's" Flycatcher - 1
Least Flycatcher - 1
Red-eyed Vireo - 1
Black-capped Chickadee - 1
House Wren - 3
Swainson's Thrush - 1
[American Robin - 1 recaptured]
Nashville Warbler - 12 (plus 1 released unbanded)
Magnolia Warbler - 2
Black-throated Blue Warbler - 2
Northern Waterthrush - 2
Mourning Warbler - 1
Common Yellowthroat - 7 (plus 4 recaptured)
Wilson's Warbler - 3
Song Sparrow - 2 (plus 1 recaptured)
Swamp Sparrow - 3 (plus 1 recaptured)
American Goldfinch - 23

1 comment:

Jerry said...

Great report, Allen! Thanks for the lesson. Nasty little horntail...