ML32093111

Age and sex

Adult, Unknown sex - 1; Immature Unknown sex - 1

Media notes

This photo nicely shows the head and bill of this Thick-billed Murre; here, unlike in photo ML32090111, the faux reddish color produced by chromatic aberration has been electronically removed. Discussion of differentiating this individual from other murre species and, more broadly, Alcidae species will be provided in association with photo ML32090101.

Observation details

Two individuals of this species are documented here, via photographs, an adult (long slender bill) and an immature individual (short, less slender bill). Three different photos are provided herewith, but each is provided in two different versions (but both versions involve some cropping from the full frame). One version of each shows it without any electronic correction to remove the bothersome and potentially misleading reddish color in the originals that was due to chromatic aberration (i.e., differential diffraction of wavelengths). The chromatic aberration presumably was due, in large part, if not entirely, to the fact that in all of the photos--but in some much more than in others--the optical axis of the camera lens had inadvertently been tilted a bit relative to that of the spotting scope. This was possible because the camera's lens was simply hand-held up to the eyepiece of the scope, and it was easy to displace it a bit, especially when triggering the shot by pressing a button on the camera. Nonetheless, this technique made possible photos adequate both for species identification and determination of age of both of the Thick-billed Murres. One was an adult and the other, a first-winter bird.

Technical information

Model

Canon EOS 10D

ISO

400

Focal length

50 mm

Flash

Flash did not fire

f-stop

f/2.8

Shutter speed

1/125 sec

Dimensions

2150 pixels x 1434 pixels

Original file size

391.12 KB