ML571196291

Age

Not specified

Sex

Not specified

Observation details

5/19/23 Update: Changing from BITH/GCTH to BITH. I came across this bird at the North End west of the Salt Pond just as morning flight was calming down. Overall, the bird visibly ticked all the boxes for BITH. It was overall browner with a reddish wash to the wings and tail, a very rich yellow mandible that extended 3/4 of the way up the bill, purplish feet, and a slightly more extensive eye ring compared to GCTH. The bird was silent the entire observation even when BITH playback was used. However, the bird did react to the playback and moved closer to me when played. Although I felt this bird was a strong contender for a BITH, I left the ID as BITH/GCTH without any audio to ID it. I knew that BITH can be differentiated from GCTH in the hand by wing chord and other measurements (though there is overlap) and looked through records of BITH in NJ based on these. Although these were mainly from banding stations, I did find Milton Collin's 2020 Losen Slote Creek park record of BITH, which was a silent bird. He had sent photos to Tom Brown, who IDed the bird as a BITH based on the wing formula and other plumage features. After looking at photos taken of the BITH/GCTH in question, and seeing I had gotten pretty good shots showing the primaries that could be potentially used in ID, I sent them to Tom Brown. He IDed the bird as a BITH based on the primaries and field marks mentioned above. Here is his exact response: “I'm usually skeptical on id's of bith by sight alone, and most photo's don't help. HOWEVER, i think this bird is perfect for BITH. It has overall brownish tones, not olive, it looks slight and compact, the photo showing the wing is great. On GCTH the length-extension of primaries is long (because they are a longer distant migrant), and there isn't very much overlap in the outer primaries, especially p6 though p8. On this bird i can't even distinguish where p6 through p9 are because the overlap is so close. Another factor (although there is overlap with gcth) is the amount of yellow on the lower mandible. BITH has more extensive yellow (often more intense as well) than GCTH, and the lower mandible on this bird is actually more than 3/4 yellow, more than i would expect or have observed on a GCTh. Be careful with Catharus thrushes and playback, they will respond to each others calls/songs. At times i'll play SWTH at nets and will get GCTH right at the speaker where SWTH is playing, and vice versa. I've played bicknell's just standing in woods and have had swth respond vocally and fly in to playback. I do think this bird was likely responding to the playback though since i'm entirely sure it is a BITH. For me the third week of may into memorial day weekend is peak (not that i band a ton...a few a year, 5 in one year, so this bird is right when i'd expect them to start showing up.” I know this is ultimately not the preferred way for BITH to be IDed during migration when not in the hand, but feel confident in the ID of this bird as a BITH.

Technical information

Model

Canon EOS Rebel T7

Lens

150-600mm F5-6.3 DG OS HSM | Contemporary 015

ISO

3200

Focal length

421 mm

Flash

Flash did not fire

f-stop

f/10.0

Shutter speed

1/800 sec

Dimensions

5393 pixels x 3693 pixels

Original file size

7.29 MB