Annual Bird Report 2019
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.
Winter Season (December – February)
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.
Spring Season (March – May)
The Spring Migration period (Mar – May) had a total of 119 species reported. Great Marsh is one of 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 Warbler (across Rt 401 on Hillside), and Chestnut-sided Warbler.
Breeding Period (June – July)
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.
Fall Migration (August – November)
Fall 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.