ML619205998

Age and sex

Adult, Unknown sex - 1

Behaviors

Vocalizing

Observation details

Honestly, I wouldn't have felt comfortable calling this to a species level if I hadn't snagged a recording of it singing. That said, I still welcome thoughts on this ID. I would say this is my first actual attempt at parsing between the two species since this has been my first opportunity to do so. Bear with me. Here are my thoughts. Sure, the final upslur in the song should, in theory, be one of the most helpful ID tricks between GCTH and BITH. Without this recording and careful tabs on the location of this vocal individual, I don't think I would have started with BITH and gone straight to GCTH. Color tones/Lighting: • There are slightly warmer hues that can be detected along the dorsal side of the bird, but it appeared better under certain light. I added some photos to show how light can create highlights that ultimately lose this rusty appearance. It has a yellow lower mandible... The spotted breast is fairly bold, but there are a few photos on eBird that show others have found an individual with subdued markings. Not sure if this is due to the variability in photo quality, different individuals, and/or mis-ID (myself included). • It should be noted that it was an overcast day, unlike other checklists that have provided warmer images. Vocal tones: • Call. Since the "beer/veer" calls heavily vary between GCBT types, I decided not to rely on this feature. There might be something I am missing and still need to look into, but frequencies between the two species overlap dramatically. Maybe there is something in the shape of the overslur that I haven't unlocked yet. • Song. Due to the complexity of Catharus songs, I fixated on the end note since that seemed to be a decent tell between species. In my recording, you can see the hint of the upslur note that is heard at the end of the song, which is frequently used to point towards BITH. It is fairly difficult to detect between all the other thrushes singing in the area, but once I honed in on this detail, I started to detect this feature in the field and noticed it well in the recording. The upslur element of the song is best seen/heard after the 23-second mark of the recording. • Playback. I played GCTH and BITH songs once when I finally felt that I could keep good tabs on the individual. I started with BITH, and it had a slight reaction and more of a curious/bold behavior when I released the GCTH song... Do with that as you will. Morphometrics “tones”: • I took a gander at Pyle’s 2022 part 1 second edition to look at the wing/primary measurements and morphology. Hard to say anything based on the photos I got, but maybe a more experienced eye can detect these subtleties. Tail measurements seem to have a lot of overlap, so I can’t imagine that being helpful here. In conclusion, overall drab but slightly rusty, and has an upslur to the end of the song. Is this enough for a BITH? Found immediately behind wood pile (36.889631,-76.178343). Moved around the trails but easy to locate, and was able to spend a fair amount of time with it in open areas.

Technical information

Model

Canon EOS 7D Mark II

ISO

2000

Focal length

400 mm

Flash

Flash did not fire

f-stop

f/6.3

Shutter speed

1/200 sec

Dimensions

2440 pixels x 1627 pixels

Original file size

656.05 KB