Bicknell's Thrush
Catharus bicknelli · Thrushes
The song at dusk from inside the krummholz — a thin, spiralling, flute-like phrase that rises at the end, more nasal and more upward than a Swainson's or a Hermit.
Why it's hard: Range edge and a tiny footprint. New Hampshire is near the southern limit of a global range that's essentially six Northeastern states and Atlantic Canada; the bird only uses a sliver of habitat above 3,000 feet, sings for barely an hour a day, and stays hidden inside the shrubs while doing it.