Supporting scientific studies, educational opportunities, and protecting the unique Great Marsh in Northern Chester County

Supporting scientific studies, educational opportunities, and protecting the unique Great Marsh in Northern Chester County


February Bird Walk

A small group of three birders braved the snow covered marsh on February 10th. This is typically the “slowest” time of the year for the birds but we did manage to observe thirty-two species. 
Some of the highlights include: A pair of Wood Ducks circling the marsh adjacent to the catfish pond, 4 American Black Duck, 7 Ring-necked Duck, Northern Harrier, Bald Eagle and 3 American Tree Sparrow. 
As we move out of February and into March the activity and number of species should be on the rise as we move into the very beginnings of spring migration. Our next walk will be on Sunday, March 17th. With the days getting longer and sunrise at 7:10 AM, this walk is scheduled to start at 7:30 AM. 
It’s time to start thinking spring and time to start brushing up on bird songs! (yes, while I know there won’t be a whole lot of singing in the middle of March I like to get an early start; but that’s just me…)
See you soon

Photograph courtesy of Jim Moffett


January Bird Walk 2019

Our January bird walk took place on Sunday, January 13th. A small group of 5 birders braved the cold and were treated to a total of 27 species. 

As we move further into winter, the waters of the marsh have frozen and ducks and geese have largely moved on to seek open water. We were still able to record 38 Canada Geese and 3 Black Ducks as fly-overs. Despite the cold and frozen water we were able to see and hear some notable species including: Northern Harrier hunting low over the marsh, Pileated Woodpecker calling from the hillside, the first American Tree Sparrow of the season, White-crowned Sparrow working the feeders and three Rusty Blackbirds in the wet areas behind the catfish pond.

Our next walk will be held on Sunday, February 10th at 8:00AM.
See you then!

Photograph taken by Jim Moffett


December Bird Walk 2018

On Sunday, December 9th we had a group of thirteen birders and decided to bird as a single group. It was cold but clear and windless day and the largely frozen ground made for some easier walking this month in the lower areas. Although the marsh was largely ice covered, there were some spots of open water available for waterfowl. 

A total of thirty-seven species were seen and some of the highlights included: 200 Snow Geese migrating overhead, 50 Mallards along with 2 American Black Duck. An American Kestrel flew in behind the Catfish pond and offered the group extended views as it perched in the top of a tree while surveying it’s surroundings. A hermit thrush was spotted low in the brush next to the Little Bass pond. A Fox Sparrow popped up at the racetrack and a female Purple Finch was perched above the lane. 

Our January bird walk will be on Sunday, January 13th at 8:00AM EST.

See you then.


November Bird Walk

On Saturday November 18th, 2018 we had a group of 24 birders for our monthly walk. It was a cool but pleasant day and the birds were very cooperative. Due to the number of people that showed up, we decided to split into three groups. Thanks to BQ and Jim Moffett for volunteering to lead two of the groups!

In total, we had 48 species. Some of the highlights include: Bald Eagle, migrating Snow Geese, scores of Fox Sparrows that are settling in to their winter habitat, Northern Harrier, Hermit Thrush, a holdout Catbird, Purple Finch, White-crowned Sparrow, Savanah Sparrow, and Rusty Blackbird.

Many thanks to Jim, Lori and Joan for the coffee, banana bread and warmth of the Nature Center! Our next walk will be on Sunday, December 9th.

See you then.


The Marshlands Catwalk Repair Project

A group of five intrepid catwalk repair specialists set out on a chilly sunny morning to replace the rotted planks of the 500 foot long span that traverses the lower end of the Great Marsh. No easy undertaking by anyone’s standards. Jeff, the most experienced among us, had theoretically devised an ingenious way to detect the defective planks…by stepping on them. As evidenced by the broad smile on Jeff’s face the undeniable proof of his theory was apparent.

John, the fastidious keeper of tools for the day’s project, decided that after a hard morning’s work, it was time to clean and pack up the tools for the return trip. To that end he tossed the muddy and soiled crowbar into the clear water below. And in the selfless team spirit that John exudes, he then jumped into the icy water to retrieve the freshly washed tool.

Thanks to the mentoring and examples of both Jeff and John, both an inspiration to the other team members, the project was a resounding success. Jeff, Jordan and Joe gained some valuable experience for the next project. Our new team slogan… Watch and learn!”

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Jeff after testing an old section with a face plant!
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Great Marsh October Report

On October 14, 2018 we had a group of 10 ten birders show up for our bird walk. It was a much better weather day than our inaugural walk and the birds were very cooperative as we observed over 55 species throughout the morning.

Highlights included Blue-winged Teal, 13 Green-winged Teal, Northern Harrier, 5 Sharp-shinned Hawks, an Adult Bald Eagle, American Kestrel, Blue-headed Vireo, the first Brown Creepers of the season, 8 Purple Finches, White-Crowned Sparrow, Lincoln’s Sparrow, first of season Rusty Blackbird, and a first of season Pine Siskin was heard by members of the group.

Please join us on November 18th at 8am for our next bird walk.

See you then!


MOTUS at the Great Marsh

As some of you may know I have been working on a technical project to support a program of deploying automated receivers across the country to pick up coded signals from bird tags. I felt they could use some technical guidance from a retired electrical engineer and Ham radio hobbyist (W3ASA) since most of the folks involved are biologists and ornithologists. I have been working with Willistown Conservation Trust who are spearheading this effort in Pennsylvania. They recently received a $500K grant from US Fish and Wildlife which will be used to deploy more automated receivers throughout the mid Atlantic region. My role in this will be to advise on appropriate antennas that will be mounted on towers which will provide good directional information, be cost effective, and relatively easy to install in remote locations.

As part of GMI’s science mission we are supporting a test facility that will enable field testing of various antenna combinations and bird tags. The tags currently in use operate at 166 MHz. Cornell has developed a new tag which operates at 432 MHz in addition to allowing smaller antennas they have orders of magnitude more code combinations than the 166 MHz tags currently in use. We have antennas set up for these tags as well and are currently running tests on them.

Since Great Marsh has been designated as an Audubon Important Bird Area(IBA) it is appropriate that GMI support new technologies that will enable ornithologists and biologists to gather new information that was not possible without the support of this technology. See for more information. This link shows receiver locations worldwide and if you zoom in far enough you will see the two Marshlands deployments

Jim Moore, October 4, 2018


Great Marsh Bird Walks

A group of ten adventurous birders braved the rainy conditions on Sunday September 23, 2018 for the inaugural monthly birdwalk program at Great Marsh.

Although the rain washed away any raptor migration, the group did get a good mix of fall migrants including 7 species of warbler: Tennessee, Black-throated Green, Blackburnian, Common Yellowthroat, American Redstart, Magnolia, and Northern Parula. Other much enjoyed migrants included Scarlet Tanager and Rose-breasted Grosbeak.

This is shaping up to be an impressive invasion year from the north due to poor food supplies in Canada and the birds are already moving in. The group observed at least one Red-breasted Nuthatch and six female Purple Finches.

A total of 43 species were observed.

Our next walk will be on October 14th and we will hope to see good numbers of wintering birds moving in along with some lingering migrants. Hawk migration will still be going on overhead as well.

See you then…


The Birds of the Great Marsh

Due to its size and unique combination of habitats, the Great Marsh hosts a diverse array of avian life. To date, over 170 species of birds have been identified on the property.
The Great Marsh hosts several rare and uncommon species throughout the entire year and often in numbers not seen in other locations in Southeastern Pennsylvania.
The winter season (December – February) is the quietest time of year but still offers opportunities to see rare species such as Rough-legged Hawk, Black-capped Chickadees, Rusty Blackbirds and large numbers of wintering sparrows.

Spring migration (March – May) is one of the best seasons to find a variety of uncommon and rare species. March and early April start with waterfowl migration and opportunities exist to see flocks of Tundra Swan and Snow Geese flying overhead. American Black Ducks can be common along with scores of Wood Ducks arriving to breed. Blue-winged Teal are regular visitors. With some luck you might catch Sandhill Cranes stopping in during their migration and American Bittern are usually present although they can be hard to spot and Common Gallinule have been spotted. Virginia Rails and Soras are commonly heard especially early in the morning. Early May also brings many species of Warbler to Great Marsh including: Golden-winged, Nashville, Cape May and Hooded (which set up to breed in the upland forest areas). The middle of May heralds the end of migration, at which time Gray-cheeked Thrush can be found.

The summer months (June – August) sees the number of species diminish but there are a number of breeding species that can be difficult to find elsewhere in Chester County. Confirmed and suspected breeding species include: Hooded Merganser, Great Blue and Green Heron, Virginia Rail, Black-billed Cuckoo, Bald Eagle, Blue-winged Warbler, Hooded Warbler, Chestnut-sided Warbler, and Scarlet Tanager.

Fall Migration (September – November) brings back a number of spring migrants along with a few birds that do not typically migrate east of the Allegheny mountains in the spring. September skies can be filled with hundreds of Broad-winged hawks moving south with Sharp-shinned Hawks and Northern Harriers following in October. Common Nighthawks can be easily seen at dusk in early September. Least Flycatchers are a possibility from the end of August through the middle of September. Philadelphia Vireos are possible in September as well. September is also a good time to look for Connecticut Warblers. October and early November brings the sparrows and the Great Marsh is an especially good spot to see Lincoln’s Sparrows. White-crowned, Vesper, Savannah and returning Fox Sparrows are all possibilities as well.

With the ongoing generous and carefully planned conservation efforts of the Moore family, the Brandywine Conservancy and the French & Pickering Creeks Conservation Trust, the Great Marsh will continue to be an extremely valuable laboratory for ornithological research and educational activities long into the future.