Great Marsh Institute (GMI) focuses on the Great Marsh in Chester County, PA. The Great Marsh is primarily owned by the Moore family and French & Pickering Creeks Conservation Trust. The Great Marsh is a periglacial marsh and the largest marsh in Southeastern Pennsylvania, about 700 acres. Surrounding the marsh is shrub swamps, swamp forests, corridors of floodplain forest, upland forest, row crop farming and the PA turnpike.
The Great Marsh supports a large diversity of flora and fauna. Over 180 bird species and 160 plant species have been identified on the property. There are also large mammals, such as Whitetail deer, coyote, red and silver fox, muskrat and beaver that are present on the property. Many species of amphibians and reptiles can also be seen at the Great Marsh. The Great Marsh also has an IBA (Important Bird Area) designation of D3 from Audubon. D3: Sites that contain rare or unique habitat or are an exceptional representative of an ecological community type, and that hold important species or species assemblages largely restricted to a distinctive habitat or ecological community type.
will focus on the avian community along with the associated activities and
initiatives during 2019 and into the future.
2019 was a productive year for birding at GMI. Monthly public bird walks and the bluebird monitoring program greatly increased coverage throughout the year in the easily accessed areas of the property. A total of 133 species were confirmed this past year including the following new species: Glossy Ibis (April 21st), Little Blue Heron (July 28th), Blue Grosbeak (October 6th), Golden Eagle (October 13th), and American Pipit (December 27th). These additions bring the total number of species seen to 183 which ranks 10th for eBird hotspots in Chester County.
The Winter season (Dec-Feb) came in with a count of 49 species. Great Marsh hosts a wintering population of Rusty Blackbirds which are rare in Eastern Pennsylvania. Total populations of Rusty Blackbird have declined 85%-95% in the period between 1970-2010. Great Marsh has the unique habitat necessary to host wintering populations and favored areas include the NW sector of the Catfish pond and adjacent thickets and the wet woodlands south of the Spring pond. Other species of note include: Northern Harrier, Eastern Phoebe (late), Winter Wren, Gray Catbird (late), and American Pipit. A notable absence was a lack of Long-eared Owls of which wintering populations have been recorded annually. Habitat improvement efforts which would involve the planting of either an expanded or new White Pine grove may be needed to sustain this species in the future.
The Spring Migration period (Mar – May) had a total of 119 species reported. Great Marsh is one the most reliable locations to see Blue-winged Teal which is considered rare in Chester County. Starting in April, Virginia Rail and Sora return to the property and begin vocalizing and setting up territories. Wilson’s Snipe also migrate through during this period. There was a sighting of a Long-eared Owl in March in the Pine Grove adjacent to the nature center and it is assumed to be a migrant (see above). American Kestrel was reported for three consecutive weeks from mid-March to the first week in April. Kestrel nest boxes have been installed in two areas and we are hoping that this will lead to a breeding pair on the property. Other spring highlights include: Wild Turkey, Glossy Ibis, Common Raven, Purple Martin, Marsh Wren, Purple Finch, White-crowned Sparrow, Hooded Warble (across Rt 401 on Hillside), and Chestnut-sided Warbler.
The Breeding Period (Jun – Jul) had a total of 66 species recorded. This period needs greater study moving forward as summer vacations and activities limited coverage in 2019. Great Marsh hosts breeding populations of Great Blue and Green Herons and the Great Blue rookery at the lower edge of the marsh (technically not on GMI property) is probably the largest in Chester County. The last week of July saw a post-breeding Little Blue Heron visit the property.
Migration (Aug-Nov) hosted a count of 84 species. A post-breeding Great Egret
took up residence during September into the first week of October. An immature
Golden Eagle was spotted migrating overhead during the second week of October.
This is mainly a Western US species and is very rarely seen east of the
Appalachians during migration. November saw good numbers of Fox Sparrow and GMI
and is one of the most reliable locations to see this species. A notable
absence in October was Lincoln’s Sparrow which more than likely was present but
was missed. Rusty Blackbirds returned in good numbers in November for the
winter. A Blue Grosbeak was recorded the first week of October.
2019 SPECIES LIST
Great Horned Owl (Bubo Virginianus)
2019 PROGRAMS AND PROJECTS
GMI hosted public bird walks in each month of the year. Scores of visitors were able to enjoy GMI’s unique habitat and avian diversity. This is a program is effective at promoting GMI’s mission. This program was started in 2018 and we are looking forward to continuing it in the future.
In March 2019, volunteers gathered and helped construct and place 12 Bluebird nest boxes around the property to create Great Marsh Institute’s Bluebird trail. The trail was registered with Project NestWatch, which was created by Cornell Lab of Ornithology. NestWatch is a nationwide monitoring program designed to track status and trends in the reproductive biology of birds, including when nesting occurs, number of eggs laid, how many eggs hatch, and how many hatchlings survive. The database is intended to be used to study the current condition of breeding bird populations and how they may be changing over time as a result of climate change, habitat degradation and loss, expansion of urban areas, and the introduction of non-native plants and animals. To become a certified Nestwatch monitor, volunteers must read and review Cornell’s nest box monitoring guide and pass a test to register.
The Motus Wildlife Tracking System is an international collaborative research network that uses a coordinated automated radio telemetry array to track the movement and behaviour of small flying animals. Motus is used to track birds, bats, and large insects affixed with digitally-encoded radio transmitters that broadcast signals several times each minute. These signals are detected by receiving stations that scan for signals 24 hours a day, 7 days a week, 365 days a year, depending on the site. When results from many stations are combined, the array can track animals across a diversity of landscapes covering thousands of kilometers.
GMI hosts a MOTUS antenna and Jim Moore has been instrumental in testing and developing the associated technologies. Results can be found here: https://motus.org/data/receiverDeploymentDetections?id=4721
American Kestrel Nest Boxes
Two nest boxes were installed in 2019 to attract breeding American Kestrels to the property. GMI has appropriate habitat and it is hopped that these installations will be successful in 2020.
experimenting with acoustic monitoring systems in the marsh in 2019. GMI was in
possession of a Wildlife Acoustics SM-4 recording device as well as an
AudioMoth acoustic logger. Deployments were made in various locations and
programed to produce audio recordings at predetermined times throughout the
day. Results were analyzed using Wildlife Acoustics Kaleidoscope software which
produced sonograms that were then reviewed to detect various species
vocalizations. In late 2019 we launched a fundraiser that enabled us to
purchased five AudioMoth devices that will be deployed in set locations in the
marsh in 2020.
With the purchase of additional monitoring devices, there will be a focus on a better understanding the presence and distribution of species in the more remote areas of Great Marsh. A total of six devices are available for deployment starting in April and lasting into May. Some of the target species include known inhabitants such as Virginia Rail, Sora, American Bittern, and Common Gallinule and efforts to detect yet to be recorded species such as King Rail, Least Bittern and Black Rail. While there is no guarantee that the yet to be recorded species will be present, there is appropriate habitat that suggests they are possible. The installation of remote recording devices enables us to record data in some of the remote areas of the marsh on a daily basis.
Purple Martin Houses
Purple Martins have been recorded at Great Marsh in migration periods. The lack of appropriate nesting sites may limit their ability to gain residence during the breeding season. Purple Martins readily accept martin homes and GMI has appropriate habitat to support their presence.
Chimney Swift Tower
The Chimney Swift population has been in rapid decline over the last few decades. These swifts utilize man-made industrial and residential chimneys for roosting and nesting. As industry has changed and more residential chimneys are capped, habitat is rapidly disappearing for this species. Audubon has building plans posted for Chimney Swift towers that this species will readily take to. GMI’s upland open areas can provide a resource to help stabilize their decline.
Long-eared Owl Habitat Improvement
Wintering Long-eared Owls have been present at Great Marsh since at least the 1990’s. The Long-eared Owl population has been showing signs of decline in recent years most likely due to the degradation of the White Pine plantation which is their preferred habitat in this area. This is a species which is considered rare in Chester County and efforts should be made to provide a successional habitat. Ideally a new planting of White Pines of significant size (5 Ft. range) over an area of at least the current pine grove area should be sufficient to ensure the continuation of this rare species at GMI. With that being said, this will require a potentially significant financial investment and a need for fundraising and/or grant money.