ML64256601

Age

Not specified

Sex

Not specified

Observation details

I found Royal Tern again (same spot as yesterday morning) at about 6:22 AM. The large size and relatively long thick bill of this tern eliminates all of the small and medium-sized terns and we are left with Caspian Tern, Elegant Tern, and Royal Tern as candidates. The characteristics that eliminate Elegant tern are the large size of this tern, the head pattern, and the bill shape. The dark crest is shorter on this bird that on an Elegant Tern, which shows more black on the crown and the nape. The bill of this bird differs with the bill of an Elegant Tern by being thicker, not down-curved, and the gonydeal angle is closer to the end of the bill. This Tern is not a Caspian Tern because a Caspian Tern lacks the shaggy crest, and a Caspian Tern has a thicker bill. The bill of a Caspian Tern is usually reddish with a dark tip. The large white area of the forehead on this tern serves to rule out Caspian Tern. Also, in flight, a Caspian Tern shows broader wings than this bird.

Technical information

Model

Canon EOS 7D

Lens

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

ISO

400

Focal length

600 mm

Flash

Flash did not fire, auto

f-stop

f/10.0

Shutter speed

1/640 sec

Dimensions

1728 pixels x 1242 pixels

Original file size

1.57 MB