Sunday, September 30, 2012

Sunday's Results

We did a little better than yesterday with 30 new birds and had 10 recaptures of 10 different species.  The "cold" front seemed to have brought in some new birds even though the front had not yet passed at the time we opened the nets.  We'll see if we do any better tomorrow now that front has pushed into the Atlantic. 


It was neat to band 3 Swainson's Thrushes today because it is unusual for us to band more than 1 or 2 during a morning.  Thrushes typically follow the same molt pattern as Gray Catbirds (see the September 27 post) with hatch-years showing distinct molt limits within the greater coverts.  They usually only replace a couple of inner greater coverts which contrast with the unreplaced outer greater coverts.  The outer greater coverts usually have distinct buffy teardrops or tips to them when fresh and the replaced inner greater coverts will be darker, fresher, and about the same color as the back feathers.  Now, that being said . . . the following individual was much more difficult to age.  It appeared that all of the greater coverts had been replaced leading us to originally call it an after hatch-year.  However, upon a closer look at the greater coverts, they just didn't look right to me for an adult bird.  We ended up skulling the bird and found out that it was indeed a hatch-year bird.   Skulling is a process in which banders spread apart the feathers on the head and look through the skin for areas of the skull that have not been ossified yet.  This bird showed two small windows (spots that have not fully ossified) at the back of the skull.  In addition, if you look very closely you can kind of make out the very thin and indistinct buffy tips on the greater coverts.

Swainson's Thrush (hatch-year, sex unknown)

Swainson's Thrush (not showing the obvious molt limit in the greater coverts typical of hatch-years)

Painted Buntings undergo an "extra" molt during their 1st molt cycle. This molt typically begins within a week of fledging and only replaces the body feathers.  Later in the fall and before they migrate, they undergo another molt called the presupplemental molt which is eccentric meaning that the wing molt is incomplete.  Typically the outer primaries and the inner secondaries are replaced leaving a block of juvenile feathers in between.  Additionally, they will molt the rectrices (tail feathers), greater coverts, and their body plumage again.  The resulting plumage is female-like in both sexes with males retaining their female-like plumage through next year's breeding season.  Today we captured a Painted Bunting that had almost completed its 1st prebasic molt, and showed the eccentric molt pattern discussed above.  We have captured several Painted Buntings lately that have almost complete or complete prebasic molts which means that they will be leaving Kiawah Island soon. 

Painted Bunting (hatch-year, sex unknown)


2 Red-eyed Vireo

2 House Wren

3 Swainson's Thrush

5 Gray Catbird

2 Black-throated Blue Warbler

5 Palm Warbler

2 American Redstart

8 Common Yellowthroat



1 Carolina Chickadee

3 House Wren

2 Gray Catbird

1 Common Yellowthroat

1 Northern Cardinal

2 Painted Bunting



# of Birds Banded:  30

# of Recaptures:  10

# of Species:  10

Effort:  80.75 net-hours

Capture Rate:  49.5 birds/100 net-hours

# of Nets:  17

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