2021 Fall Migration Summary

The 2021 fall migration banding season at the Kiawah Island Banding Station (KIBS) concluded on Tuesday, 30 November. Banding occurred at two sites on Kiawah Island:  Captain Sam's and Little Bear.  This was the 13th consecutive year of fall migration banding at the Captain Sam's site with banding occurring daily during the last 10 years.  It was the 7th 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 Sam's 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 7,808 birds and had 2,017 recaptures of 105 different species.  Captain Sam's had a small increase in the number of birds banded compared to last fall, while Little Bear experience a substantial increase. Combined, that increase translated into 8.5% more birds banded. August started off relatively slow with the typical hot and humid weather. The heat and humidity continued through September but that didn’t seem to slow down migration. Steady migration continued through October before experiencing a sharp decline over most of November. For the second year in a row, tropical weather did not affect the banding station.

CAPTAIN SAM'S

Nets were opened for a total of 103 days from 15 August - 30 November.  There were only 5 days when banding did not occur because of rain (9/9/, 9/20, 9/21, 11/6, 11/7). Unlike at Little Bear, Captain Sam’s can operate during windy conditions as there are some nets that are sheltered enough to open.  It is rare that wind alone will cause Captain Sam’s to completely shut down.

We banded 4,704 new birds of 94 different species.  The most commonly banded species were Common Yellowthroats (1,077), Gray Catbirds (959), and Yellow-rumped Warbler (688).  Those three species combined made up 58% of all the birds banded this season.  After a down year last year, Common Yellowthroats regained the number one spot this year after exhibiting a 22.4% increase from last fall.  However, Common Yellowthroats were still down 4.4% compared to the 10-year average. Gray Catbirds increased 6.9% from last year, and 24.8% over the 10-year average.  The 959 Gray Catbirds banded this year was the second highest total over the past 13 years. After several years of steady declines in Yellow-rumped Warbler numbers, they rebounded nicely with a 35.2% increase from last year.  However, their numbers were still down 7.8% over the last 10 years.   

Several species exhibited record high numbers this season:  Mourning Dove (9), Eastern Screech-Owl (4), Tree Swallow (62), Tufted Titmouse (6), House Finch (20), Savannah Sparrow (4), Canada Warbler (2), and Rose-breasted Grosbeak (3). Alternatively, we had a few species that had record low numbers:  Magnolia Warbler (4) and Northern Cardinal (20).   

The overall effort increased from 13,734.0 net-hours in 2020 to 15,023.9 net-hours this year despite banding on one less day.  The more favorable weather we experienced over the course of the season allowed us to keep our nets open longer each day.  We banded 138 more birds this year compared to last year, and 138 birds more than the average for the previous 10 years.  Interestingly, the 10-year average is the same as the total number of birds banded last year. The overall capture rate was 40.7 birds/100 net-hours. The capture rate decreased slightly by 0.9 birds/100 net-hours compared to last year but was 8.7 birds/100 net-hours lower than the 10-year average of 49.5 birds/100 net-hours.  Our capture rate has decreased every year starting in 2012 with exception to 2017 and 2019 when we experienced small increases from the previous year.  The capture rate of recaptures is very consistent from year to year; therefore, all decreases in the total capture rate can be attributed to new birds.  The capture rate of recaptures this fall was 9.5 birds/100 net-hours.

We had 1,418 recaptures which is much higher compared to the 1,166 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 1,191 repeats, 238 returns, and 1 foreign recapture.  The foreign recapture was a Tree Swallow that was originally banded as a nestling in Ontario, Canada on 6/10/2021.  We also had a recovery of a young Mourning Dove that we banded on 8/22.  This bird was shot by a hunter on 9/16 in Grover, SC which is about 45 miles north of Kiawah Island.  

There were 13 days this fall when over 100 birds were banded compared to only 9 days last fall.  The best day of the season was on 24 September when we banded 196 birds and had 10 recaptures.  The next two busiest days occurred 10 and 17 September when 180 and 144 birds were banded, respectively. Because of the lack of strong, fast moving cold fronts, we never experienced any extremely busy days like we do in most years.  Instead, favorable winds associated with smaller low-pressure systems (“cold fronts”) created good migration conditions spread over a longer period of time. 

We captured one species that has never been banded at the Captain Sam's site during the fall:  White Ibis. A flock of White Ibis had been feeding in the marsh near the banding table for several days at the beginning of November.  We noticed that these birds were not bothered by our presence and would not flush if we were nearby. We came up with a plan to attempt to catch them and were successful. 

Some other rare and notable species that were banded this fall include:  Black-billed Cuckoo (1; 1 previous), Eastern Whip-poor-will (1, 4 previous), Clapper Rail (1, 1 previous), Red-shouldered Hawk (1, 1 previous), Winter Wren (2, 4 previous), Eastern Bluebird (1, 2 previous), Fox Sparrow (1, 1 previous), Lincoln’s Sparrow (1, 2 previous), Red-winged Blackbird (1, 2 previous), Louisiana Waterthrush (1, 4 previous), Mourning Warbler (1, 3 previous), and Canada Warbler (2, 3 previous).

Species notably absent this year included:  Common Ground Dove, Yellow-bellied Flycatcher, American Goldfinch, Swainson’s Warbler, Blackpoll Warbler, Yellow-throated Warbler, and Wilson’s Warbler. After a record high of 19 last fall, no Blackpoll Warbler were captured.  This is only the 2^nd fall since 2012 where that has occurred.

Top 10 Species Banded at Captain Sam's

1.  Common Yellowthroat (1,077)

2.  Gray Catbird (959)

3.  Yellow-rumped Warbler (688)

4.  American Redstart (202)

5.  Red-eyed Vireo (195)

6. Palm Warbler (142)

7.  Black-throated Blue Warbler (124)

8.  Painted Bunting (116)

9.  Northern Waterthrush (113)

10.  Ruby-crowned Kinglet (101)

LITTLE BEAR

Nets were opened for a total of 78 days from 21 August - 15 November.  Little Bear opened three days earlier than lasts year but only one day earlier than normal.  There were 9 days cancelled due to bad weather (rain and/or wind).  Because the habitat at Little Bear is more open than at Captain Sam’s, wind has a much bigger effect on the operation of the nets there.  As a result, 3 days were cancelled due to wind alone (10/29, 11/4, 11/5) at Little Bear this year with the other 6 due to rain (9/9, 9/20, 9/21, 10/25, 11/6, 11/7).   

We banded 3,104 new birds of 79 different species.  The most commonly banded species were Gray Catbirds (752), Common Yellowthroat (645), and Palm Warblers (249).    Those three species combined made up 53% of all the birds banded this season.  Gray Catbird numbers exhibited a 32.4% increase compared to last fall and 16.2% increase over the last 6 years.  Common Yellowthroat were up by 21.5% compared to last year but slightly down (0.9%) compared to the average of the last 6 years.  After a down year in 2020, Palm Warblers made a big comeback with a 70.5% increase from last fall.  This year’s numbers were also up 19.1% over the 6-year average.  Yellow-rumped Warblers increased by 12.8% this year compared to last but are still down 23% over the last 6 years.   At Little Bear, the long-term negative trend for Yellow-rumped Warblers can partly be attributed to saltwater intrusion that killed many of the mature wax myrtles in 2015 and 2016.  It’s encouraging to see Yellow-rumped Warbler number continue to increase over the last couple of years.  Hopefully, this is a sign that the wax myrtles are beginning to rebound.   

Several species exhibited record high numbers this season:  Green Heron (3), Copper’s Hawk (2), Downy Woodpecker (7), Eastern Kingbird (7), House Wren (97), Bobolink (2), Worm-eating Warbler (5), Prothonotary Warbler (9), Black-and-white Warbler (20), and Pine Warbler (3).  Species that had record low numbers included:  Eastern Screech-Owl (1), “Traill’s” Flycatcher (12), Swainson’s Thrush (15), Northern Mockingbird (6), and Song Sparrow (16).   

We logged 8,332.6 net-hours out at Little Bear this fall – a moderate increase from the 7836.82 net-hours in 2020.  More favorable weather conditions this fall allowed the nets to be kept open longer each day.  Last year, excessive heat and/or wind caused the nets to be shut down earlier in the morning.  This was also the first full season with the three new nets that were added in September last year.   

We banded 470 more birds this year compared to last year and 95.5 birds more than the 6-year average.  Little Bear’s capture rate increased 10.5% from 40.1 birds/100 net-hours in 2020 to 44.3 in 2021.  Alternatively, the capture rate decreased 21.2% compared to the 6-year average.  Again, the wax myrtle die off due to saltwater intrusion after 2017 appears to have severely affected capture rates and maybe the uptick in capture rate this year means the habitat is starting to recovery a bit.

A substantial decrease in the number of recaptures occurred each year from 2016-2019.  Last year the number of recaptures had increased from 460 in 2019 to 508 in 2020.  The number of recaptures increased again this year with a total of 588, however the capture rate remained very similar and only increased by 0.6 recaptures/100 net-hours.     

There were 5 days when over 100 birds were banded.  The best day of the season was on 10 October when we banded 140 birds and had 9 recaptures.  The next two busiest days occurred 17 October and 24 September when 123 and 112 birds were banded, respectively.

We captured five species never banded at Little Bear during the fall:  Barn Swallow (1), Red-bellied Woodpecker (2), Merlin (1), Great Crested Flycatcher (1), Brown Creeper (2).  Barn Swallow, Red-bellied Woodpecker, and Merlin have never been banded at either site during the fall before. I was surprised to see that Little Bear had never captured a Great Crested Flycatcher before considering Captain Sam’s has banded 55 of them.  

Some other rare and notable species banded included:  Green Heron (3; 2 previous), Least Flycatcher (1; 5 previous), Tufted Titmouse (18; 31 previous), Blue Jay (1; 1 previous), Lincoln’s Sparrow (2; 5 previous), Bobolink (2, 3 previous), Louisiana Waterthrush (1, 1 previous), Swainson’s Warbler (1, 3 previous), Mourning Warbler (1, 3 previous), and Wilson’s Warbler (1, 1 previous).

Species notably absent: Marsh Wren.  After banding 2 each of Chuck-will’s-widow and Eastern Whip-poor-will last year, neither species was captured even though both were present around the banding the site.

Top 10 Species Banded at Little Bear

1.  Gray Catbird (752)

2.  Common Yellowthroat (645)

3.  Palm Warbler (249)

4.  Yellow-rumped Warbler (194)

5.  Painted Bunting (142)

5.  American Redstart (115)

7.  House Wren (97)

8.  Red-eyed Vireo (89)

9.  Northern Waterthrush (83)

10. Prairie Warbler (69)

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. 

First, I'd like to thank my awesome team of banding assistants (Kristin Attinger, Josh Lefever, Kandace Glanville, Ben Stalheim, and Nate Watkins).  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:  Ben Stalheim, Kandace Glanville, Kristin Attinger, Josh Lefever, Nate Watkins, Aaron Given

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

Volunteers were welcomed back to the banding station this year, albeit to a much lesser degree.  David McLean, Chris Snook, Cathy Miller, Michael Gamble, Nancy Raginski, Alex Sharp, Brendan Wang, Amy Given, and Aidan Given all donated a considerable amount of their time (more than 10 hours each) to help out.  We also had several others 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.

Species	Captain Sam's		Little Bear
	New	Recapture	New	Recapture
Mourning Dove	9	2	-	-
Yellow-billed Cuckoo	17	1	26	-
Black-billed Cuckoo	1	-	-	-
Green Heron	-	-	3	-
White Ibis	1	-	-	-
Chuck-will's-widow	1	-	-	-
Eastern Whip-poor-will	1	-	-	-
Clapper Rail	1	-	-	-
Sharp-shinned Hawk	4	1	1	-
Cooper's Hawk	1	-	2	1
Red-shouldered Hawk	1	2	-	-
Eastern Screech-Owl	4	-	1	-
Yellow-bellied Sapsucker	8	7	2	-
Red-bellied Woodpecker	-	-	2	-
Downy Woodpecker	8	35	7	8
Northern Flicker	1	-	-	-
Merlin	-	-	1	-
Eastern Wood-Pewee	11	-	2	-
Acadian Flycatcher	2	-	-	-
"Traill's" Flycatcher	18	1	12	3
Least Flycatcher	1	-	1	-
Eastern Phoebe	43	-	32	1
Great Crested Flycatcher	5	4	1	-
Eastern Kingbird	1	-	7	-
White-eyed Vireo	47	38	31	9
Blue-headed vireo	2	-	3	-
Red-eyed Vireo	195	8	89	1
Blue Jay	-	-	1	-
Carolina Chickadee	6	30	7	8
Tufted Titmouse	6	-	18	2
Barn Swallow	-	-	1	-
Tree Swallow	62	1	-	-
Golden-crowned Kinglet	14	1	6	-
Ruby-crowned Kinglet	101	31	52	2
Red-breasted Nuthatch	1	-	-	-
Brown Creeper	2	-	2	-
Blue-gray Gnatcatcher	1	-	3	-
House Wren	67	30	97	25
Winter Wren	2	-	-	-
Marsh Wren	2	-	-	-
Carolina Wren	13	44	14	36
Gray Catbird	959	638	752	233
Brown Thrasher	8	12	9	1
Northern Mockingbird	15	4	6	1
Eastern Bluebird	1	-	-	-
Veery	16	-	5	-
Gray-cheeked Thrush	7	-	2	-
Swainson's Thrush	38	-	15	-
Hermit Thrush	49	29	6	1
Wood Thrush	4	-	3	-
American Robin	1	-	-	-
House Finch	20	1	-	-
Chipping Sparrow	-	-	2	-
Clay-colored Sparrow	2	-	-	-
Field Sparrow	4	2	-	-
Fox Sparrow	1	-	-	-
White-crowned Sparrow	1	-	2	1
White-throated Sparrow	10	4	3	-
Saltmarsh Sparrow	5	1	-	-
Savannah Sparrow	4	2	3	-
Song Sparrow	35	23	16	8
Lincoln's Sparrow	1	-	2	-
Swamp Sparrow	36	27	44	10
Eastern Towhee	9	9	10	2
Yellow-breasted Chat	9	2	7	3
Bobolink	-	-	2	-
Baltimore Oriole	2	-	2	-
Red-winged Blackbird	1	-	-	-
Ovenbird	31	9	23	7
Worm-eating Warbler	3	-	5	-
Louisiana Waterthrush	1	-	1	-
Northern Waterthrush	113	6	83	6
Black-and-white Warbler	39	-	20	1
Prothonotary Warbler	8	-	9	-
Swainson's Warbler	-	-	1	-
Tennessee Warbler	1	-	2	-
Orange-crowned Warbler	13	17	10	-
Nashville Warbler	1	-	1	-
Mourning Warbler	1	-	1	-
Common Yellowthroat	1077	58	645	65
Hooded Warbler	7	-	2	-
American Redstart	202	10	115	7
Cape May Warbler	18	1	19	2
Northern Parula	25	-	17	-
Magnolia Warbler	4	1	3	-
Bay-breasted Warbler	1	-	-	-
Yellow Warbler	28	-	47	1
Chestnut-sided Warbler	3	-	1	-
Blackpoll Warbler	-	-	4	1
Black-throated Blue Warbler	124	3	51	2
Palm Warbler	142	2	249	1
Pine Warbler	2	2	3	-
Yellow-rumped Warbler (Myrtle)	688	197	194	13
Yellow-throated Warbler	-	-	2	-
Prairie Warbler	97	3	69	-
Black-throated Green Warbler	1	-	-	-
Canada Warbler	2	-	-	-
Wilson's Warbler	-	-	1	-
Summer Tanager	3	-	1	-
Scarlet Tanager	3	-	-	-
Northern Cardinal	20	58	42	65
Rose-breasted Grosbeak	3	-	-	-
Blue Grosbeak	2	1	1	-
Indigo Bunting	27	-	25	2
Painted Bunting	116	60	142	59

BANDING STATISTICS	CAPTAIN SAM'S	LITTLE BEAR	TOTAL
# of Birds Banded	4,704	3,104	7,808
# of Recaptures	1,418	588	2,006
# of Species	94	79	105
Effort (net-hours)	15,023.9	8,332.6	23,356.5
Capture Rate (birds/100 net-hours)	40.7	44.3	42.0
# of Nets	30	23	53
# of Days Operated	103	78	-
Dates of Operation	8/15-11/30	8/21-11/15	-

Please note that these numbers are preliminary and may change after the date has been thoroughly proofed.