Results of the 2014 Dyke Marsh Breeding Bird Survey
The 2014 survey was conducted between Saturday, May 24 and Sunday, July 6, but any data collected outside of this period that confirmed a breeding species was entered into the database. This permitted us to weed out most migrants that do not use the marsh to breed. I also included information provided from the Sunday morning walks and reliable individuals to supplement data reported by the survey teams. The survey tract encompassed the Belle Haven picnic area, the marina, the open marsh, the Potomac River from the shoreline to the channel, and the surrounding woodland from the mouth of Hunting Creek to Morningside Lane. Volunteers found 84 species at Dyke Marsh during the survey. By the completion of data collection, 44 species had been confirmed as breeders, six species were listed as probable breeders, and 17 species as possible breeders. An additional 17 species were identified in the survey tract during the reporting period, but were considered not to be in suitable breeding habitat.
Several confirmation misses are worthy of note. A Willow Flycatcher reported by multiple observers near the boardwalk from mid-May to early June apparently departed without attempting to breed. The now famous Eastern Screech-Owl pair put on quite a show in early March, copulating and giving every indication of preparing to breed, but we could not quite positively identify the nest cavity or locate young. A June 1 report of a Red-tailed Hawk pair near an empty nest in the south marsh was exciting news, but subsequent survey teams could not locate the pair or determine that the nest actually belonged to the hawks. Too bad, because Red-tailed Hawk has not been confirmed as a breeder in the 22 years that I have been compiler.
Ospreys had a highly successful breeding season in 2014. Survey teams discovered 10 Osprey nests and eight of these eventually contained nestlings. Of the successful endeavors, the platform nest near Porto Vecchio was the most productive, fledging four youngsters. That may be a new record for the Dyke Marsh breeding bird survey. Another observer reported a nest with four nestlings near the island in Pipeline Bay, but Iím not sure that all of them fledged.
There is a corollary to the marina Osprey nest story. A group of Purple Martins nested at the base of the platform of the marina nest during the 2012 and 2013 breeding season. On April 6, 2014 observers during a Sunday morning walk saw four Purple Martins flying around inspecting the platform, but the birds apparently decided that the lean was too great to try to nest there for a third year. So several found an alternative according to one report. They apparently nested in the masts of some of the inactive sailboats in the marina, and with some success. An adult was found feeding a fledged youngster in mid-July at the boardwalk. More fledglings were sighting in the following weeks.
There remains much concern about the future of the Marsh Wren breeding population at Dyke Marsh. As in previous years, Marsh Wrens in the northern portion of Dyke Marsh were concentrated in the marsh vegetation on the north side of the Haul Road peninsula and the larger of the adjacent islands. By late June a canoe team could clearly see perhaps a half dozen nests in the Narrow-leaf Cattails as the surveyors transited the channel separating the peninsula from the island. By plotting locations of singing Marsh Wrens, I calculated that there was a minimum of 16 males on territory at this location.
The pattern and concentration of the Least Bittern population at Dyke Marsh increasingly seems to parallel that of the Marsh Wren. I assess that Least Bitterns are starting to focus their breeding efforts on the marsh vegetation around the Haul Road peninsula, to include the Little Gut. A canoe team tallied five Least Bitterns within five minutes of entering a tributary of the Little Gut on a June 7 survey. That includes a definite breeding pair. Another breeding pair was found near the north end of the boardwalk and at least a territorial male maintained a constant presence at the southern tip of the peninsula just off the boardwalk. In contrast, Least Bitterns south of the Little Gut seemed to be found primarily in the extreme upper portion of the Big Gut. Survey teams in the Big Gut reported no definite breeding pairs. Sightings or heard vocalizations were all of single birds. It may be that the rapid erosion in the lower portion of the Big Gut is making the habitat unsuitable for Least Bitterns.
Unfortunately we were not able to confirm Least Bittern as a breeder anywhere in Dyke Marsh. Several light colored birds seen in flight along Haul Road towards the end of the survey could have passed as either adult females or fledged young. So Least Bittern went into the probable breeder category for 2014.
This survey would not be possible without the hard work and dedication of so many volunteers who collected breeding bird data in 2014 as part of a Dyke Marsh survey team or who provided information as leader of a Sunday morning bird walk. I want to thank all those who contributed to the survey. In alphabetical order, they are: Bob Beard, Dave Boltz, Ed Eder, Myriam Eder, Sandy Farkas, Kurt Gaskill, Susan Haskew, Gerry Hawkins, Ellen Kabat, Elizabeth Ketz-Robinson, Dorothy McManus, Ginny McNair, Larry Meade, Roger Miller, Nick Nichols, Patrice Nielson, Marc Ribaudo, Rich Rieger, Don Robinson, Peter Ross, Molly Ross, Trish Simmons, Ned Stone, Jessie Strother, Paula Sullivan, John Symington, Maggie Symington, Bill Whitacre, Margaret Wohler, Katherine Wychulis.
The 2014 Breeding Bird Survey Results:
Confirmed - 44 Species: Canada Goose, Wood Duck, Mallard,
Osprey, Bald Eagle, Mourning Dove, Red-bellied Woodpecker, Downy Woodpecker, Hairy Woodpecker,
Northern Flicker, Great
Crested Flycatcher, Eastern Kingbird, Warbling Vireo, Blue Jay, Fish Crow, Northern Rough-winged Swallow,
Purple Martin, Tree Swallow, Barn Swallow, Carolina Chickadee, Tufted
Titmouse, White-breasted Nuthatch, Marsh Wren, Carolina Wren, Blue-gray Gnatcatcher, American Robin, Gray
Catbird, Brown Thrasher, European Starling, Cedar Waxwing, Prothonotary Warbler,
Common Yellowthroat, Northern Parula, Yellow Warbler, Song Sparrow, Northern Cardinal, Red-winged Blackbird, Common Grackle, Brown-headed Cowbird, Orchard
Oriole, Baltimore Oriole, House Finch, American Goldfinck, House Sparrow.
Confirmed Breeder: Any species for which there is at minimum evidence of a nest. A species need not successfully fledge young to be placed in the confirmed category.
Probable Breeder: Any species engaged in pre-nesting activity, such as a male on territory, courtship behavior, or even the presence of a pair, but for which there is no evidence of a nest. Since birds can and do sing and display to females during migration, this category cannot be used until the safe dates are reached.
Possible Breeder: Any species, male or female, observed in suitable habitat, but giving no hard evidence of breeding. Unless actively breeding, all birds in suitable habitat before the start of the safe date are placed in this category.
Present: Any species observed that is not in suitable habitat or out of its breeding range.
Definition of Safe Dates: We use safe dates as a means of deciding if a bird can be considered a breeder or a migrant. Safe dates are simply defined as a period of time beginning when all members of a given species have ceased to migrate in the spring and ending when they begin to migrate in the fall. Unless a bird is engaged in behavior that confirms breeding, it will be placed no higher than in the possible breeder category if it is observed outside the safe dates assigned to that species.
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