Wednesday, June 8, 2011

Metro Beach banding report - June 2 & 4, 2011

The first week of June is typically the last week of spring migration. The scarcity of migrants in the banding area definitely signalled the end of spring migration for this year. At least the rainy trend did not plague us this week and we got two full days of banding in, though a White-tailed Deer destroyed a brand new net on Thursday so our setup was one net short on Saturday.

Highlights of the 44 birds banded on Thursday, June 2 included two Ruby-throated Hummingbirds, plus a returning female banded in August 2010. This is only the second time since 2004 that a Ruby-throated Hummingbird has been recaptured in a different year; the first was in 2008 of a bird banded in August 2007 as an adult. This year's returnee was a hatch-year when banded, which is more unusual because of the high mortality rate of hatch year birds.

AHY-F Ruby-throated Hummingbird.

AHY-F Ruby-throated Hummingbird spread tail.

The swamp woods transitioning to herbaceous wetland and cattail marsh, with scattered dogwood patches is more favorable for nesting Willow Flycatchers but Alder has been noted here in summer as well. The bird in the photo below keyed out to Alder, based on several measurements, but it is unknown if it was a migrant or a bird that could remain to nest.

AHY-U Alder Flycatcher

Willow and Alder Flycatchers (known as "Traill's" before they were split many years ago, and sometimes humorously called "Walder" Flycatchers) tend to be brownish-olive on the upperparts with not much greenish tones, and a slightly grayer head. Both also have very clean white throats, where Least and Acadian tend to have grayish-white throats and Yellow-bellied always has yellow on the throat. Least tends to have a broad bright white eyering, and greener back and grayer head, while Acadian is more olive above and Yellow-bellied is brighter olive above. Some "Traill's" Flycatchers show a slight difference in coloration of the two wing bars, as this bird does. Alder's sometimes seem to have a more prominent, clean, complete eyering like the bird above, but there is much overlap making visual ID extremely challenging.

In most years, the last week of banding in early June produces the first hatch-year birds of the year, in the form of juvenile American Robins. The bird in the photo below had fully grown wing and tail feathers and was likely mostly independent of its parents.

HY-U American Robin

Yellow Warblers are usually fairly easy to determine the sex in spring, but in fall the young birds are mostly left unsexed. An individual recaptured today had been banded last August as a hatch-year of unknown sex, and when recaptured about 10 days ago I called it a male based on the chestnut streaks on the breast as can be seen in the photo below.

SY-F Yellow Warbler

But as the caption above indicates, this bird had to be called a female today when recaptured because she had a prominent brood patch, and a very clear egg forming in her abdomen! It is known that some females can show chestnut streaks, but I didn't expect it in a second-year bird. Perhaps two springs ago, there was a Yellow Warbler singing near the banding area that completely lacked chestnut streaks so it was either an unusually "dull" male, or a very unusual female that was singing. The lesson is that probably no "rules" in nature are 100%.

Bill deformities are fairly rare in birds, as they often prevent the bird from surviving very long. The Red-winged Blackbird in the photo below has apparently found a way to cope with its deformity as it was an after second-year bird, having survived at least 18 months from hatching.

ASY-M Red-winged Blackbird

Baltimore Orioles have been banded in record numbers this spring (13), in addition to record numbers of returning birds (8) being captured. It has been a joy handling so many of these beautiful birds this spring.

ASY-M Baltimore Oriole

Interesting birds observed but not banded included a Spotted Sandpiper out in a wet area near the Field Nets, a single Marsh Wren in the cattails, two Blue-gray Gnatcatchers (only occasionally nest here), a lingering Hermit Thrush that has been in the Swamp Nets area for about a week or so, and two singing American Redstarts (probably don't nest here).

Highlights of the 26 birds banded on Saturday June 4 included another Ruby-throated Hummingbird; this one had a slight bill deformity with the lower mandible slightly longer than the upper, and slightly upturned.

AHY-F Ruby-throated Hummingbird

The Hermit Thrush that has been lingering around the Swamp Nets for nearly two weeks was finally captured today, in the Willow Net adjacent to the swamp. Normally, this species departs for more northerly breeding areas by mid-May, so it is suspected that this individual might not be healthy. The abdomen may have shown the possible presence of an internal parasite, but I have no experience with such things so cannot be sure what I was looking at (and photos were not taken of the abdomen).

SY-U Hermit Thrush

The lone Baltimore Oriole banded today was the 13th of the season, and was a second-year male. It isn't very easy to age this bird from the photo below, but the flight feathers, especially the tail, made the age quite obvious.

SY-M Baltimore Oriole

Note the adult tail feathers in the center of this bird's tail, as well as a single adult-type male outer left (bottom) tail feather. The remaining tail feathers are juvenile-type, confirming this as a second-year male. Adult females show tails similar to juveniles, and some older individuals can show fairly extensive black hoods.

SY-M Baltimore Oriole

Interesting birds observed but not banded included a Pied-billed Grebe calling from north of the road, which has been determined is a bird at least 200 yards away so technically not in the banding area but certainly audible from there. Wood Ducks and a Green Heron flew over, and both Willow and Alder Flycatchers were heard singing in the area; Alder from the shrub-swamp north of the road, Willow from the more open area south of the road. Two Marsh Wrens were singing from the cattails near the Field Nets, and a single Blue-gray Gnatcatcher continued calling near the Upland Nets.

Banding could not have been conducted this week without the help of very dedicated volunteers including John Bieganowski, Dave Lancaster, Jerry McHale, Jeremy Miller, and Tom Schlack. Also, special thanks to volunteer Larry McCullough who provided a cart on the last day greatly reducing the time and effort required to take everything down. Thank you everyone!

Banding Data
THURSDAY, June 2, 2011
Sunrise (E.S.T.): 4:58
Time Open (E.S.T.): 5:45
Time Closed (E.S.T.): 13:30
Hours Open: 7.75
No. of Nets: 4.25-13.25
Net Hours: 96.938
Temperature (F): 54-66
Cloud Cover: 5%
Wind: NW @ 5-7-12 mph
Barometer: 30.24-30.30
Precipitation: None
No. Banded: 44 (plus 36 recaptured and 3 released unbanded)
No. of Species: 16
Capture Rate: 85.6 birds per 100 net hours
Volunteers (worked 10.0 hours, 6:00-16:00): John Bieganowski, Dave Lancaster, Jeremy Miller, Tom Schlack.

Ruby-throated Hummingbird - 2 (plus 1 recaptured)
Downy Woodpecker - 1
Alder Flycatcher - 1
Willow Flycatcher - 1
Black-capped Chickadee - 1
American Robin - 4 (plus 4 recaptured and 1 released unbanded)
Yellow Warbler - 2 (plus 9 recaptured)
Common Yellowthroat - 1 (plus 3 recaptured)
Song Sparrow - 2 (plus 4 recaptured)
Swamp Sparrow - 2
Northern Cardinal - 1 (plus 1 recaptured)
Red-winged Blackbird - 9 (plus 9 recaptured and 2 released unbanded)
Common Grackle - 7
Brown-headed Cowbird - 1
Baltimore Oriole - 2 (plus 3 recaptured)
American Goldfinch - 7 (plus 2 recaptured)

SATURDAY, June 4, 2011
Sunrise (E.S.T.): 4:57
Time Open (E.S.T.): 5:45
Time Closed (E.S.T.): 12:45
Hours Open: 7.00
No. of Nets: 4.25-12.25
Net Hours: 79.25
Temperature (F): 63-84
Cloud Cover: 80-100%
Wind: S @ 3-5-7 mph
Barometer: 30.12-29.98
Precipitation: None
No. Banded: 26 (plus 26 recaptures)
No. of Species: 15
Capture Rate: 65.6 birds per 100 net hours
Volunteers (worked 9.5 hours, 6:00-15:30): Larry McCullough (2 hrs), Jerry McHale, Tom Schlack.

Ruby-throated Hummingbird - 1
Downy Woodpecker - 1 (plus 2 recaptured)
[Willow Flycatcher - 2 recaptured]
Hermit Thrush - 1
American Robin - 2 (plus 2 recaptured)
[Gray Catbird - 2 recaptured]
Yellow Warbler - 1 (plus 4 recaptured)
Common Yellowthroat - 1 (plus 1 recaptured)
Song Sparrow - 1 (plus 1 recaptured)
[Swamp Sparrow -  recaptured]
Northern Cardinal - 1
Red-winged Blackbird - 5 (plus 4 recaptured)
Common Grackle - 6
Baltimore Oriole - 1
American Goldfinch - 5 (plus 7 recaptured)

No comments: