Thursday, December 14, 2023

2023 Fall Season Summary

 

The 2023 fall migration banding season at the Kiawah Island Banding Station (KIBS) concluded on Wednesday, 30 November. Banding occurred at two sites on Kiawah Island:  Captain Sams and Little Bear.  This was the 15th consecutive year of fall migration banding at the Captain Sams site with banding occurring daily during the last 12 years.  It was the 9th season for the Little Bear site which we initiated during the fall of 2015.  The two sites are located at each end of island about 8 miles apart (Captain Sams on the west end, Little Bear on the east end).  Both sites are situated in coastal scrub/shrub and high marsh habitats, however, the Little Bear site is in an earlier stage of succession.

Collectively, we banded 8,001 birds and had 2,021 recaptures of 100 different species.  Captain Sams had a substantial decrease in the number of birds banded compared to last fall, while Little Bear experienced a large increase. Combined, however, we banded 6.7 % less birds than last year.

Overall, temperatures were seasonally normal except for August which was 3.2 °F warmer than the average.  Compared to last year though, the mean monthly temperatures from August-November were much higher.  This season was also drier, and we experienced less rain (17.3”) than normal (19.6”).  In addition, we received 4.2” less rain compared to last year.  Cold fronts were few and far between for the first 5 weeks of the season.  The first significant front didn’t arrive until 19 September.  We experienced good movement of migrants through October with the passage of three stronger fronts.  As usual migration slowed down during November, but unlike last year, we did not experience a late season push of large numbers of Yellow-rumped Warblers. 

Hurricane Idalia came up from Florida on 31 August bringing with it 3” of rain, strong winds, and a 2.3 ft storm surge.  Tides crested at 9.2 ft which was enough water to flood both banding sites.  Because Captain Sams is tidal, most of the water receded quickly only leaving only 6-8” of water in the lower elevation areas of the station.  Little Bear on the other hand is situated in a basin that collects and holds water.  When the tide breached the dunes, it flooded Little Bear with 18-24” of water.  Between a handful of rain events and other king tides, Little Bear was flooded for most of the season only drying up completely at the end of the season.          

CAPTAIN SAMS

Nets were open for a total of 104 days from 15 August - 30 November.  There were 4 days when banding did not occur because of weather:  8/30 and 8/31 (Hurricane Idalia; rain and wind), 10/12 (rain), 11/22 (rain).   

We banded 4,621 new birds of 85 different species.  The most commonly banded species were Gray Catbird (936), Common Yellowthroat (833) and Yellow-rumped Warbler (525).  Those three species combined made up 49.6% of all the birds banded this season.  Gray Catbirds decreased 15.8% from last year but was still up 15.6% since 2012.  After falling to the number three spot last year, Common Yellowthroats climbed back into number two despite exhibiting a 20.4 % decrease from last fall and a 23.9 % decrease over the average since 2012.   After a strong 2022 fall season, Yellow-rumped Warbler numbers plummeted this year with a 48.8% decrease.  Since 2012, this fall was the second worst fall for Yellow-rumped Warblers with 2020 being the lowest with 509 banded.

The overall effort increased from 15,292.6 net-hours in 2022 to 17,178.3 net-hours this year.  This increase can be attributed to banding on three more days than last year, and the addition of 2 new nets (net 10 and net 35).  The additional three days added on average about 496 net-hours while the two new nets added 1081 net-hours.  Net 10 was used during the winter of 2009-2010 and spring 2010 and 2011 and has never been used during the fall before.  Net 35 was added to make checking the set of nets along the Kiawah River more efficient to avoid unnecessary triple-checking of some nets and to eliminate back-tracking to other nets.  Both nets performed well below the average in terms of capture rate.  

We banded 1,088 less birds this year compared to last year, but only 45 birds less than the average for the previous 12 years.  The capture rate of new birds was 26.9 birds/100 net-hours. The capture rate decreased by 10.4 birds/100 net-hours compared to last year and was 11.3 birds/100 net-hours lower than the 12-year average of 38.3 birds/100 net-hours.  Our capture rate has decreased every year starting in 2012 except for 2017, 2019, and 2022 when we experienced small increases from the previous year. The capture rate of recaptures is normally very consistent from year to year, however this year the capture rate was 7.5 birds/100 net-hours which is 2.4 birds/100 net-hours lower than the average since 2012. 


We had 1,292 recaptures this season which is lower compared to the 1,529 recaptures from last year.  Recaptures can be divided into 3 categories:  repeats (birds recaptured in the same season in which they were banded), returns (birds recaptured in a different season in which they were banded), and foreign recaptures (birds recaptured that were banded elsewhere). We had 1,073 repeats, 216 returns, and 3 foreign recaptures.  One of the foreign recaptures was a Common Yellowthroat that we recaptured on 10/5/23 and was banded the previous day at the Little Bear site.  It is rare to catch birds between our two sites even though they are only 8.8 miles apart.  The other two (Gray Catbird and Yellow-rumped Warbler) have been submitted to the Bird Banding Lab but neither band has been reported by the bander yet therefore no information is available.  In addition, one bird that we banded this fall was recovered in Florida: a Gray Catbird that was banded on 10/02/23 was hit by a car on 10/19/23. We also were notified that a Mourning Dove that we banded last fall on 11/3/22 was shot by a hunter about 13 miles away on John’s Island on 9/16/23. 

There were 12 days this fall when over 100 birds were banded including 2 days with over 200 birds banded.  Last year we had 5 days with over 200 birds and 16 days with over 100 birds.  The best day of the season was on 19 September when we banded 230 birds and had 13 recaptures.  Of those 230 birds, 118 of them were Common Yellowthroats!  The next two busiest days occurred on 10 October and 7 October when 225 and 199 birds were banded, respectively. Forty percent of the birds banded this season (1,835) were banded on just 10 days following the passage of 3 major cold fronts between the end of September and mid-October. 

Several species exhibited record high numbers this season:  Northern Flicker (4), Eastern Phoebe (82), White-eyed Vireo (76*), Ruby-crowned Kinglet (179), Eastern Bluebird (2), White-crowned Sparrow (3*), Black-and-white Warbler (43*), Swainson’s Warbler (3), Northern Parula (53), Bay-breasted Warbler (4), Palm Warbler (300), Pine Warbler (4), Summer Tanager (6*) . Alternatively, we had a couple species that had record low numbers:  Carolina Wren (2), House Wren (27), Eastern Towhee (5*), Hooded Warbler (1).  The * indicates species that tied the record high or low.    

Some other rare and notable species that were banded this fall include:  Eastern Whip-poor-will (1; 5 previous), Virginia Rail (1; 1 previous), Ash-throated Flycatcher (1; 2 previous), Bell’s Vireo (2; 5 previous), Sedge Wren (1; 3 previous), Fox Sparrow (1; 2 previous), Lincoln’s Sparrow (1; 4 previous), MacGillivray’s Warbler (1; 1 previous).  Ash-throated Flycatcher and MacGillivray’s Warbler are rare birds for eastern North America.  The MacGillivray’s Warbler breeds west of the Rocky Mountains and spend the winter in Mexico and Central America.  Ash-throated Flycatchers breed in the western US and Mexico and winter in Mexico and Central America.  They are rare but regular vagrants to the East Coast.     

Species notably absent this year included:  Common Ground Dove (67 total, average 5.6/year), Cooper’s Hawk (12 total, average 1.0/year), Eastern Screech-Owl (15 total, average 1.3/year), Field Sparrow (23 total, average 1.9/year), Nashville Warbler (21 total, average 1.8/year), Blue Grosbeak (26 total, average 2.2/year).  Common Ground Doves populations on Kiawah were on a steady decline since 2012 and then crashed in 2018 following a rare winter storm that blanketed the area with snow and ice for several days.  There was some hope of a rebound when we banded 3 ground doves last year however none were even seen or heard this year. 



 No new species were banded in 2023.

We hosted 6 groups this year including a home school group from Athens, GA (8 September), the Kiawah Island Conservancy (22 and 26 September), the Kiawah Island Natural History Group (5 October), the SC Master Naturalist Program (10 October), and the naturalists from Camp St. Christopher on Seabrook Island (14 October). 

Top 10 Species Banded at Captain Sams

1.  Gray Catbird (936)

2.  Common Yellowthroat (833)

3.  Yellow-rumped Warbler (525)

4.  Palm Warbler (300)

5.  American Redstart (297)

6. Ruby-crowned Kinglet (179)

7.  Red-eyed Vireo (150)

8.  Northern Waterthrush (130)

9.  Painted Bunting (129)

10.  Black-throated Blue Warbler (112)

LITTLE BEAR

Nets were open for a total of 79 days from 23 August - 15 November.  Little Bear opened and closed one day later than last year.  There were only 3 days cancelled due to weather:  8/30 and 8/31 (Hurricane Idalia; rain and wind), 10/12 (rain).  Little Bear was closed for an additional 3 days (9/26, 10/20, 10/30) to allow the crew to take a break and get some rest.     

We banded 3,380 new birds of 86 different species.  The most commonly banded species were Gray Catbird (762), Common Yellowthroat (528), and Palm Warbler (394).    Those three species combined made up 50% of all the birds banded this season.  Gray Catbird numbers exhibited only a 2.1% increase compared to last fall and a 15.1% increase since 2015.  Common Yellowthroat increased by 18.4% compared to last year but was 10.4% lower compared to the average of the last 8 years.  After a down year in 2022, Palm Warblers numbers were up 87.6% from last fall and 84.1% above the average since 2015.

We logged 9,260.1 net-hours at Little Bear this fall – a large increase from the 6,985.1 net-hours in 2022.  We averaged 25.3 more net-hours per day than in 2022.  We banded on three more days than last fall and added two new nets (net 24 and 25).  The additional 3 days added on average 351.6 net-hours while the new nets added 684.7 net-hours.  In addition, many fewer days were cut short due to excessive heat and/or wind this year compared to last.  The new nets were added to mitigate some of the loss of vegetation surrounding several of our wetland nets.  Excessive flooding and saltwater intrusion have reduced the vegetation in that area severely to the point where a couple nets have very little cover nearby. 

We banded 425 more birds this year compared to last year, and 408 more birds than the average since 2015.  Despite this, Little Bear’s capture rate decreased by 13.7% from 42.3 birds/100 net-hours in 2022 to 36.5 in 2023.  Similarly, the capture rate decreased by 18.5% compared to the average over the last 8 years.  


 

We had 729 recaptures this season which is slightly higher than the 701 recaptures from last year.  The average capture rate of recaptures, however, followed a similar pattern as the new birds decreasing by 21% from 2022 and by 15% compared to the average since 2015.  We had 621 repeats, 108 returns, and no foreign recaptures.

There were 10 days when over 100 birds were banded including 2 days with more than 200 birds banded.  Last year, we had 8 days over 100 birds and no 200-bird days.  The best day of the season was on 8 October when we banded 220 birds and had 11 recaptures.  Of the 220 birds, 98 of them were Palm Warblers!  The next two busiest days occurred on 15 October and 7 October when 208 and 177 birds were banded, respectively.  Like Captain Sams, 42% of the birds banded this season, were banded during these 10 days following 3 strong cold fronts between the end of September and mid-October.    

Several species exhibited record high numbers this season:  Mourning Dove (1*), Yellow-billed Cuckoo (46), Green Heron (7), Chuck-wills-widow (2*), Downy Woodpecker (8), Acadian Flycatcher (1*), Least Flycatcher (1*), Eastern Phoebe (45), Blue Jay (3), Veery (10), Swainson’s Thrush (30*), House Finch (4*), White-throated Sparrow (6), Saltmarsh Sparrow (5), Savannah Sparrow (6), Black-and-White Warbler (28), American Redstart (187), Northern Parula (27), Bay-breasted Warbler (3*), Blackburnian Warbler (3), Chestnut-sided Warbler (4*), Blackpoll Warbler (28), Palm Warbler (394), Yellow-throated Warbler (2*).  Species that had record low numbers included:  Hermit Thrush (4*).  The * indicates species that tied the record high or low.  

Some other rare and notable species banded included:  Mourning Dove (1; 2 previous), Solitary Sandpiper (1; 1 previous), Tricolored Heron (1; 0 previous), Great Crested Flycatcher (1; 1 previous), Yellow-green Vireo (1; 1 previous), Blue-winged Warbler (1; 1 previous), Connecticut Warbler (1; 3 previous).  KIBS’s second Yellow-green Vireo was a complete surprise.  Yellow-green Vireos breed in Mexico and Central America and spend the winter in northwest South America. There are only 6 records of this species on the East Coast north of Florida with two of those being birds banded on Kiawah Island.    

Species notably absent include Common Ground Dove (29 total; 3.2/year), Sharp-shinned Hawk (11 total; average 1.2/year), Chipping Sparrow (8 total; 0.9/year), Scarlet Tanager (8 total; 0.9/year).

We captured 1 species never banded at Little Bear during the fall:  Tricolored Heron.

Top 10 Species Banded at Little Bear

1.  Gray Catbird (762)

2.  Common Yellowthroat (528)

3.  Palm Warbler (394)

4.  Yellow-rumped Warbler (289)

5. American Redstart (187)

6.  Northern Waterthrush (114)

7.  Painted Bunting (100)

8.  Red-eyed Vireo (81)

9.  Ruby-crowned Kinglet (67)

10. Black-throated Blue Warbler (61)

ACKNOWLEDGEMENTS

Without the cooperation of many people and entities, this work would not be possible.  The success of this project relies on their commitment, and I am in a debt of gratitude to everyone involved. 

I'd like to thank my awesome team of banding assistants (Kristin Attinger, Camille Blose, Matt Hixson, Brittany Holliker, Natalie Miller, and Wentao Yang).  Their hard work over the course of this long season was outstanding.  It was a great season, and I would like to wish them all the very best of luck in the future. 

From left to right:  Camille Blose, Matt Hixson, Wentao Yang, Kristin Attinger, Aaron Given, Natalie Miller, Brittany Holliker


I'd like to acknowledge the Town of Kiawah Island for providing funding for equipment and the stipends for the banding assistants.  In addition, The Town of Kiawah Island and the Kiawah Island Conservancy provided funding for the housing of the banding assistants.  Thanks to the Kiawah Partners and the Bear Island Holding Trust for allowing access to their property for banding.

David McLean (69.7), Sean Dowd (65.3), Aidan Given (43.2), Chris Snook (29.6), Violet Wu (21.7), Michael Gamble (19.6), Nancy Raginski (19.6), John Rushton (14.3), Sierra Tompkins (11.5) all donated a considerable amount of their time (more than 10 hours) to help at the banding station.  We also had several volunteers that came out for just the day. I’d like to thank all the volunteers that made it out this year. Because of their help, we can operate a more efficient banding station.

BANDING STATISTICS

CAPTAIN SAMS

LITTLE BEAR

TOTAL

# of Birds Banded

4,621

3,380

8,001

# of Recaptures

1,292

729

2,021

# of Species

85

86

100

Effort (net-hours)

17,178.3

9,260.1

26,438.4

Capture Rate (birds/100 net-hours)

34.4

44.4

37.9

Capture Rate of New Birds (birds/100 nh)

26.9

36.5

30.3

Capture Rate of Recaptures (birds/100 nh)

7.5

7.9

7.6

# of Nets

32

25

57

# of Days Operated

104

79

104

Dates of Operation

8/15-11/30

8/23-11/15

-


Species

Captain Sam's

Little Bear

New

Recapture

New

 Recapture

Mouning Dove

1

-

1

-

Yellow-billed Cuckoo

19

-

46

1

Solitary Sandpiper

-

-

1

-

Tricolored Heron

-

-

1

1

Green Heron

-

-

7

-

Chuck-will's-widow

2

-

2

-

Eastern Whip-poor-will

1

-

-

-

Virginia Rail

1

-

-

-

Sharp-shinned Hawk

4

1

-

-

Cooper's Hawk

-

-

1

-

Eastern Screech-Owl

-

-

1

2

Belted Kingfisher

-

-

4

-

Yellow-bellied Sapsucker

8

-

3

-

Downy Woodpecker

6

16

8

14

Northern Flicker

4

1

-

-

Eastern Wood-Pewee

6

-

3

-

Acadian Flycatcher

3

1

1

-

"Traill's" Flycatcher

23

1

14

1

Least Flycatcher

3

-

1

-

Eastern Phoebe

82

6

45

-

Ash-throated Flycatcher

1

-

-

-

Great Crested Flycatcher

6

-

1

-

Eastern Kingbird

6

-

2

-

White-eyed Vireo

76

85

58

24

Bell's Vireo

2

2

-

-

Blue-headed vireo

8

-

3

-

Red-eyed Vireo

150

11

81

-

Yellow-green Vireo

-

-

1

-

Blue Jay

-

-

3

-

Carolina Chickadee

6

25

5

11

Tufted Titmouse

-

-

3

-

Tree Swallow

4

-

-

-

Golden-crowned Kinglet

5

2

6

1

Ruby-crowned Kinglet

179

34

67

2

Brown Creeper

2

1

-

-

Blue-gray Gnatcatcher

11

2

7

-

House Wren

27

23

53

10

Sedge Wren

1

-

-

-

Marsh Wren

3

-

5

-

Carolina Wren

2

12

13

66

Gray Catbird

936

405

762

323

Brown Thrasher

7

5

9

5

Northern Mockingbird

23

7

5

1

Eastern Bluebird

2

-

-

-

Veery

23

-

10

-

Gray-cheeked Thrush

6

-

3

-

Swainson's Thrush

79

4

30

2

Hermit Thrush

26

41

4

-

Wood Thrush

8

2

2

-

American Robin

1

-

-

-

House Finch

7

-

4

-

Clay-colored Sparrow

1

-

1

-

Field Sparrow

-

-

1

-

Fox Sparrow

1

-

-

-

White-crowned Sparrow

3

2

3

-

White-throated Sparrow

16

4

6

-

Saltmarsh Sparrow

3

4

5

-

Savannah Sparrow

2

1

6

-

Song Sparrow

26

12

19

2

Lincoln's Sparrow

1

-

1

1

Swamp Sparrow

42

10

26

5

Eastern Towhee

5

4

8

11

Yellow-breasted Chat

8

3

5

-

Baltimore Oriole

2

-

3

-

Ovenbird

41

21

20

2

Worm-eating Warbler

3

3

4

-

Northern Waterthrush

130

38

114

49

Blue-winged Warbler

-

-

1

-

Black-and-white Warbler

43

11

28

-

Prothonotary Warbler

9

-

2

-

Swainson's Warbler

3

5

1

-

Tennessee Warbler

5

-

2

1

Orange-crowned Warbler

8

5

13

2

Nashville Warbler

-

-

1

-

MacGillivray's Warbler

1

-

-

-

Connecticut Warbler

-

-

1

-

Common Yellowthroat

833

89

528

49

Hooded Warbler

1

-

4

-

American Redstart

297

55

187

14

Cape May Warbler

11

2

25

-

Northern Parula

53

4

27

-

Magnolia Warbler

12

-

7

-

Bay-breasted Warbler

4

-

3

-

Blackburnian Warbler

-

-

3

4

Yellow Warbler

24

-

49

1

Chestnut-sided Warbler

1

-

4

-

Blackpoll Warbler

6

-

28

1

Black-throated Blue Warbler

112

5

61

2

Palm Warbler

300

1

394

1

Pine Warbler

4

1

1

-

Yellow-rumped Warbler (Myrtle)

525

131

289

15

Yellow-throated Warbler

1

-

2

-

Prairie Warbler

97

12

53

2

Black-throated Green Warbler

1

-

2

-

Summer Tanager

6

-

1

-

Scarlet Tanager

2

-

-

-

Northern Cardinal

42

139

34

76

Blue Grosbeak

-

-

1

-

Indigo Bunting

37

-

30

3

Painted Bunting

129

43

100

24


Please note that all data is preliminary until the data set can be thoroughly proofed.