ML616731021

Age

Not specified

Sex

Not specified

Observation details

A loose group of swifts with fast direct flight foraging at canopy height along river edge forest. I could never discern any hint of a pale rump through my binoculars in 10 minutes of careful study but light wasn’t great. My mediocre photos also don't suggest any pale coloration on rump. The most distinctive notes in these recordings are the burry/buzzy descending calls (example right at and a little before 0:05). Based on correspondence with Dan Lane, these seem to line up well with Chaetura cinereiventris. Unclear if the swifts I photographed were the ones in the recording. Even in the poor lighting, I would imagine the pale gray rump of C. cinereiventris would have come out in the photos so it might be that the individuals in the photos are not the ones in the recording or that it is really impossible to get diagnostic photos of Chaetura with such poor lighting conditions.

Technical information

Model

Canon EOS R7

Lens

RF100-400mm F5.6-8 IS USM

ISO

5000

Focal length

400 mm

Flash

Flash did not fire

f-stop

f/8.0

Shutter speed

1/640 sec

Dimensions

2754 pixels x 1492 pixels

Original file size

736.01 KB