Lincoln’s Sparrow
Based on data available for Salter Grove from 2002 to 2022, the Lincoln's Sparrow has only been documented once in October 2020.
It is by no means a rare migrant in the Northeast and it is quite possible that more birds have come through the park but may have been misidentified as the resident and more common Song Sparrow. The two species belong to the same genus, have similar plumages and both frequent dense shrubbery in moist habitats such as the vegetation along the causeway and Marsh Trail.
Sparrows are notoriously difficult to tell apart and are sometimes listed simply as LBJs (little brown jobs) by exasperated birders. Paying attention to the following plumage details may increase sightings of the Lincoln's Sparrow as well as other migrant sparrows. However, be forewarned that it will be challenging because LBJ's prefer to stay hidden in the brush.
Overall, the Lincoln's Sparrow is somewhat smaller than the Song Sparrow and has a shorter and grayer tail. It is lightish gray and olive-brown above with buffy areas below, whereas the Song Sparrow is reddish brown above and grayish cream below. The Lincoln's Sparrow has fine dark streaks on a buffy breast but in comparison, the Song Sparrow has thicker and messier streaks on a grayish cream breast.
The thin but clear buffy eyering of the Lincoln's Sparrow contrasts with the indistinct eyering of the Song Sparrow. The eyebrow is gray in the Lincoln's Sparrow but light grayish cream in the Song Sparrow. The submoustachial stripe of the Lincoln's Sparrow is buffy and bordered by thin dark lines, but in the Song Sparrow, it is light grayish cream with reddish brown borders. Lincoln's Sparrow has a more slender, often two-tone bill compared to the Song Sparrow's stouter and darker bill.
Lincoln's Sparrow breeds in the northern quarter of North America as well as in the montane regions of western North America. It is active within willow and aspen thickets as well as dense shrubbery in moist habitat. Its nest is placed on the ground and hidden beneath vegetation. The same type of habitat is favored during migration, and on the wintering grounds which extend from the southern states to northern Central America.
For more information:
https://www.allaboutbirds.org/guide/Lincolns_Sparrow
https://www.audubon.org/field-guide/bird/lincolns-sparrow
https://en.wikipedia.org/wiki/Lincoln's_sparrow
https://www.flockingaround.com/post/song-sparrow-or-lincoln-s-sparrow
https://www.birdzilla.com/birds/Lincolns-Sparrow/bent-life-history.html
https://www.youtube.com/watch?v=7rDGa28BrrY