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Investigation of shrubland migrants on the Eastern Shore of Virginia National Wildlife Refuge
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A blackpoll warbler caught in a mist net |
Along the Atlantic Coast, significant barriers such as large bodies of water act as migration bottlenecks funneling large numbers of birds onto relatively small land masses. For southbound migrants, the Chesapeake Bay is one of the largest physical barriers along the East Coast of North America. Migrants that reach the mouth of the Bay in the hours just before dawn land near the tip of the Delmarva Peninsula. Many of these birds depend on habitats found within the lower peninsula for rest and refueling before leaving on the next leg of their migration. Because of its unique geographic position, the lower Delmarva contains some of the most critical habitats for migrant birds within the Atlantic Flyway. The Eastern Shore of Virginia National Wildlife Refuge is particularly significant because of its position at the southern tip of the peninsula.
In the fall of 2009, the U.S. Fish and Wildlife Service initiated a study of shrubland migrants within a network of several refuges including the Eastern Shore of Virginia National Wildlife Refuge. The Eastern Shore Refuge is currently managing approximately 280 acres in an early successional grassland/shrub-scrub habitat. The primary goal of this study is to collect baseline data on the number and diversity of fall migrants using this habitat complex. The information will be used to better manage habitat for migrating songbirds on the lower Eastern Shore of Virginia. The study includes point counts, vegetation work, and banding. The Center for Conservation Biology partnered with the refuge to conduct field work with Shannon Ehlers doing point counts and vegetation work and master bander Jethro Runco operating the banding station.
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Bander in Charge, Jethro Runco, bands a grey catbird. |
Jethro releases a red-eyed vireo after banding it. |
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Birds hang in cloth holding bags waiting to be banded and processed. |
Bander, Shannon Ehlers, holds a black-throated green warbler. This species is primarily an inland migrant with very few passing through the outer Coastal Plain. |
In 2009, songbird banding was conducted on 57 days between 15 September and 30 November. The station included 15 mist nets situated in dense shrub habitat. A total of 7,860 birds were banded of 85 species (Table 1). Captures included 6086 (77.5%) nearctic migrants, 1683 (21.4%) neotropical migrants, and 91 (1.1%) resident birds. Average capture rate was 175 birds/100 net hours. Operation days included 17 days with greater than 200 captures, 8 with greater than 300 captures and 3 with greater than 400 captures. An incredible effort with such a small field crew and a testament to the banding experience of Jethro. Plans are in place for the project to continue during the fall of 2010.
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Shrub-scrub layer mast crops on the lower Delmarva Peninsula provide cover and food for fall songbird migrants. Common shrub-scrub level plants on the Delmarva include: |
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Figure 1. Temporal distribution of landbird captures during the 2009 fall trapping season |
Summary table for 2009 songbird banding
| Species | Total Number | Percent of Total | First Capture | Last Capture | High Date | High Count |
| Sharp-shinned Hawk | 33 | 0.3 | 19-Sep | 25-Nov | 20-Oct | 4 |
| Cooper's Hawk | 6 | 0.08 | 1-Oct | 19-Oct | 6 Days | 1 |
| American Woodcock | 4 | 0.05 | 4-Nov | 6-Nov | 4-Nov | 3 |
| Mourning Dove | 2 | 0.03 | 17-Sep | 18-Sep | 2 Days | 1 |
| Yellow-billed Cuckoo | 13 | 0.17 | 15-Sep | 3-Nov | 5-Oct | 5 |
| Eastern Screech-Owl | 2 | 0.03 | 16-Sep | 17-Sep | 2 Days | 1 |
| Yellow-bellied Sapsucker | 3 | 0.04 | 5-Oct | 7-Nov | 3 Days | 1 |
| Downy Woodpecker | 1 | 0.01 | 29-Sep | 29-Sep | 1 Day | 1 |
| Yellow-shafted Flicker | 3 | 0.04 | 16-Sep | 22-Sep | 3 Days | 1 |
| Flicker Intergrade | 1 | 0.01 | 24-Nov | 24-Nov | 1 Day | 1 |
| Eastern Wood-Pewee | 3 | 0.04 | 30-Sep | 5-Oct | 3 Days | 1 |
| Acadian Flycatcher | 1 | 0.01 | 29-Sep | 29-Sep | 1 Day | 1 |
| Traill's Flycatcher | 8 | 0.1 | 15-Sep | 30-Sep | 16-Sep | 3 |
| Eastern Phoebe | 13 | 0.17 | 30-Sep | 29-Oct | 3 Days | 2 |
| White-eyed Vireo | 3 | 0.04 | 16-Sep | 9-Oct | 3 Days | 1 |
| Blue-headed Vireo | 2 | 0.03 | 5-Oct | 16-Nov | 2 Days | 1 |
| Philadelphia Vireo | 2 | 0.03 | 15-Sep | 16-Sep | 2 Days | 1 |
| Red-eyed Vireo | 35 | 0.45 | 15-Sep | 20-Oct | 4-Oct | 4 |
| Blue Jay | 5 | 0.06 | 15-Sep | 10-Nov | 11-Oct | 2 |
| Tree Swallow | 1 | 0.01 | 30-Sep | 30-Sep | 1 Day | 1 |
| Carolina Chickadee | 9 | 0.11 | 17-Sep | 3-Nov | 18-Sep | 6 |
| Red-breasted Nuthatch | 1 | 0.01 | 25-Oct | 25-Oct | 1 Day | 1 |
| Brown Creeper | 4 | 0.05 | 13-Oct | 19-Oct | 19-Oct | 2 |
| Carolina Wren | 16 | 0.2 | 15-Sep | 16-Nov | 15-Sep | 3 |
| House Wren | 69 | 0.88 | 19-Sep | 17-Nov | 8-Oct | 11 |
| Winter Wren | 22 | 0.28 | 5-Oct | 20-Nov | 19-Oct | 5 |
| Golden-crowned Kinglet | 69 | 0.88 | 11-Oct | 16-Nov | 19-Oct | 37 |
| Ruby-crowned Kinglet | 54 | 0.69 | 5-Oct | 29-Nov | 19-Oct | 26 |
| Blue-gray Gnatcatcher | 2 | 0.03 | 16-Sep | 18-Sep | 2 Days | 1 |
| Veery | 12 | 0.15 | 15-Sep | 1-Oct | 15-Sep | 3 |
| Gray-cheeked Thrush | 6 | 0.08 | 1-Oct | 19-Oct | 6 Days | 1 |
| Swainson's Thrush | 5 | 0.06 | 15-Sep | 14-Oct | 5 Days | 1 |
| Hermit Thrush | 56 | 0.71 | 11-Oct | 25-Nov | 19-Oct | 10 |
| American Robin | 53 | 0.67 | 19-Oct | 23-Nov | 6-Nov | 17 |
| Gray Catbird | 625 | 7.95 | 16-Sep | 30-Nov | 5-Oct | 165 |
| Northern Mockingbird | 13 | 0.17 | 15-Sep | 18-Nov | 3 Days | 2 |
| Brown Thrasher | 15 | 0.19 | 1-Oct | 7-Nov | 1-Oct | 3 |
| Cedar Waxwing | 2 | 0.03 | 15-Sep | 12-Oct | 2 Days | 1 |
| Tennessee Warbler | 2 | 0.03 | 5-Oct | 9-Oct | 2 Days | 1 |
| Orange-crowned Warbler | 7 | 0.09 | 19-Oct | 8-Nov | 25-Oct | 2 |
| Nashville Warbler | 4 | 0.05 | 15-Sep | 11-Oct | 4 Days | 1 |
| Northern Parula | 122 | 1.55 | 15-Sep | 14-Oct | 5-Oct | 45 |
| Yellow Warbler | 18 | 0.23 | 15-Sep | 20-Sep | 15-Sep | 7 |
| Chestnut-sided Warbler | 2 | 0.03 | 5-Oct | 6-Oct | 2 Days | 1 |
| Magnolia Warbler | 34 | 0.43 | 15-Sep | 12-Oct | 5-Oct | 12 |
| Cape May Warbler | 2 | 0.03 | 5-Oct | 5-Oct | 5-Oct | 2 |
| Black-throated Blue Warbler | 29 | 0.37 | 19-Sep | 25-Oct | 11-Oct | 6 |
| Myrtle Warbler | 5032 | 64.02 | 5-Oct | 30-Nov | 12-Oct | 384 |
| Black-throated Green Warbler | 4 | 0.05 | 30-Sep | 14-Oct | 4 Days | 1 |
| Prairie Warbler | 4 | 0.05 | 16-Sep | 30-Sep | 4 Days | 1 |
| Yellow Palm Warbler | 34 | 0.43 | 18-Sep | 5-Nov | 11-Oct | 6 |
| Palm Warbler | 59 | 0.75 | 19-Sep | 26-Oct | 25-Sep | 11 |
| Bay-breasted Warbler | 2 | 0.03 | 4-Oct | 4-Oct | 4-Oct | 2 |
| Blackpoll Warbler | 51 | 0.65 | 19-Sep | 25-Oct | 5-Oct | 9 |
| Black-and-white Warbler | 23 | 0.29 | 15-Sep | 21-Oct | 5-Oct | 4 |
| American Redstart | 161 | 2.05 | 15-Sep | 29-Oct | 5-Oct | 35 |
| Ovenbird | 9 | 0.11 | 16-Sep | 6-Oct | 17-Sep | 2 |
| Northern Waterthrush | 40 | 0.51 | 15-Sep | 13-Oct | 15-Sep | 12 |
| Connecticut Warbler | 1 | 0.01 | 5-Oct | 5-Oct | 1 Day | 1 |
| Common Yellowthroat | 218 | 2.77 | 15-Sep | 3-Nov | 29-Sep | 38 |
| Hooded Warbler | 2 | 0.03 | 30-Sep | 1-Oct | 2 Days | 1 |
| Wilson's Warbler | 1 | 0.01 | 29-Sep | 29-Sep | 1 Day | 1 |
| Yellow-breasted Chat | 3 | 0.04 | 15-Sep | 18-Nov | 3 Days | 1 |
| Scarlet Tanager | 1 | 0.01 | 18-Sep | 18-Sep | 1 Day | 1 |
| Eastern Towhee | 15 | 0.19 | 11-Oct | 29-Nov | 4-Nov | 3 |
| Chipping Sparrow | 22 | 0.28 | 11-Oct | 25-Nov | 4-Nov | 5 |
| Clay-colored Sparrow | 2 | 0.03 | 8-Oct | 11-Oct | 2 Days | 1 |
| Field Sparrow | 18 | 0.23 | 20-Oct | 30-Nov | 2 Days | 3 |
| Savannah Sparrow | 1 | 0.01 | 17-Nov | 17-Nov | 1 Day | 1 |
| Grasshopper Sparrow | 1 | 0.01 | 7-Nov | 7-Nov | 1 Day | 1 |
| Seaside Sparrow | 1 | 0.01 | 26-Sep | 26-Sep | 1 Day | 1 |
| Fox Sparrow | 7 | 0.09 | 3-Nov | 29-Nov | 20-Nov | 3 |
| Song Sparrow | 120 | 1.53 | 26-Sep | 30-Nov | 19-Oct | 20 |
| Swamp Sparrow | 229 | 2.91 | 29-Sep | 26-Nov | 26-Oct | 27 |
| White-throated Sparrow | 298 | 3.79 | 11-Oct | 30-Nov | 3-Nov | 67 |
| Slate-colored Junco | 20 | 0.25 | 11-Oct | 17-Nov | 16-Nov | 5 |
| White-crowned Sparrow | 3 | 0.04 | 12-Oct | 23-Oct | 3 Days | 1 |
| Northern Cardinal | 47 | 0.6 | 15-Sep | 29-Nov | 3-Nov | 5 |
| Rose-breasted Grosbeak | 2 | 0.03 | 25-Sep | 5-Oct | 2 Days | 1 |
| Blue Grosbeak | 3 | 0.04 | 18-Sep | 18-Sep | 18-Sep | 3 |
| Indigo Bunting | 23 | 0.29 | 22-Sep | 14-Oct | 2 Days | 4 |
| Baltimore Oriole | 3 | 0.04 | 20-Sep | 23-Nov | 3 Days | 1 |
| Purple Finch | 2 | 0.03 | 5-Nov | 8-Nov | 2 Days | 1 |
| House Finch | 1 | 0.01 | 20-Sep | 20-Sep | 1 Day | 1 |
| American Goldfinch | 3 | 0.04 | 10-Nov | 20-Nov | 10-Nov | 2 |
| Total | 7860 | 100 | 15-Sep | 30-Nov | 12-Oct | 427 |
| Total Number | Percent of Total | First Capture | Last Capture | High Date | High Day |
This study was conducted in conjunction with the staff of the Eastern Shore of Virginia National Wildlife Refuge. It is part of a larger study focusing on assessing population trends of fall migrant landbirds utilizing shrub-scrub habitat.
Project sponsored by The Center for Conservation Biology (CCB) and the U.S. Fish & Wildlife Service (USFWS) Refuge Program.
CCB USFWS
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