As I reported to HMBirds that day, I found a Gray-cheeked/Bicknell’s Thrush at Normanskill Farm in Albany on Sunday morning, 5/17. I was able to get some photos and video of the bird (including an audio recording of the call but not the song), all of which I submitted with my eBird checklist.
I returned the next morning and was able to find what was presumably the same bird at the same location. This time, it wasn’t nearly as cooperative visually, but I was able to record it giving its song for over two minutes, which is generally considered the most reliable way to separate Gray-cheeked and Bicknell’s. I wasn’t sure my recording was of sufficient quality to nail down a species identification – nor did I trust my ears to discern the difference with absolute certainty - so I submitted it to eBird and the “Mysteries” section at xeno-canto.
As of today, I still haven’t gotten any responses at xeno-canto. But I finally had enough time yesterday at lunch to sit down with some field guides, process the audio file, and look at the spectrogram on my own. Not only does having this concrete visual representation on-screen really help in parsing out the sometimes ambiguous bits of birdsong on a lower-quality recording, it makes it easier to recognize patterns in a series. And, of course, it gives a better idea of duration, frequency, and other auditory characteristics.
After many listens, I began to feel confident that I could call the bird I recorded on 5/18 a Bicknell’s Thrush (I’ve left the 5/17 thrush identified as Gray-cheeked/Bicknell’s Thrush since it gave no diagnostic vocalizations). I’ve heard some agreement on the song fitting Bicknell’s Thrush and other have commented that the photographs from 5/17 (assuming it’s the same individual) present visual characteristics that lean toward the Bicknell’s side of this confusing species complex (though most field guides seem to caution against relying entirely on fieldmarks in separating these species).
Complete eBird checklist for the 5/18 thrush with photos, audio recordings, embedded video, and spectrogram screenshots at the link below:
It’s been an exciting May for rarities in Albany County: a Trumpeter Swan at Partridge Run, the Forster’s Tern Zach found at Coeymans Landing, two Golden-winged Warblers, and a Cerulean Warbler at Hollyhock Hollow.
Good birding —