The song of several sparrows and warblers is a trill. To tell them apart note the length of the trill, if it is steady or accelerating, on one pitch or rising, and if there is a distinct final note.

Black and white warbler

Trill formed with couplets

April 18, 2023 – Hanging Rock State Park

Chipping sparrow

mechanical, 2-3 second trill

April 8, 2020 – Stout Farm Rd., Tobaccoville

Field sparrow

Accelerating trill

May 11, 2021 – Long Creek Park

Pine warbler

Musical 1.5-2 second trill at one frequency

April 20, 2023 – Shallowford Rd, Lewisville

Northern parula

Rising trill ending with a separate zip note

May 11, 2021 – Long Creek Park

Prairie warbler

Rising trill sometimes ending in a buzz

April 24, 2021 – Long Creek Park

Swamp sparrow

Irregular musical trill all on one pitch

April 10, 2023 (2) -Long Creek Park

Worm-eating warbler

Very fast unmusical trill lasting about 2 seconds