While the discovery that many migratory songbirds can thrive in deforested wintering spots ..., the fact remains that these birds are dying at unusual rates.
it is heartening
hearten
heartening
is heartening
Pembahasan: Concordance
Pastikan kesejajaran S + P sesuai jumlahnya (singular/plural).
Bandingkan pilihanmu dengan sobat pembelajar yang lain.