ML610278710

Age

Not specified

Sex

Not specified

Observation details

Two diagnostic characteristics stand out…First the bill color and second the central tail feather. The bill color of the bird on the right is pinkish/orange. The bill color of the bird on the left is greenish/yellow. According to the Pyle’s report comparing Nazca versus Masked, the pinkish/orange bill is Nazca. “….. Two distinct bill-color patterns emerged as the birds aged from juvenile to definitive plumage. Birds with dusky, horn color (medium-pale brownish, often tinged mustard or olive), orange, and/or pink in the bill base commonly had brighter orange-yellow or golden yellow but not green in the bill tip. By contrast, birds with dark blue, green, and/or yellow in the bill base commonly had green and/or yellow but not orange in the bill tip, and the tip was less often brighter than the base. I propose that the first category represents Nazca Boobies and the second represents Masked Boobies.…” From ‘Ocean Birds of the World’ by Howell … Nazca has a white central tail feather; Masked does not. Please see the pictures below…

Technical information

Model

Canon EOS 5D Mark IV

Lens

EF100-400mm f/4.5-5.6L IS II USM

ISO

100

Focal length

400 mm

Flash

Flash did not fire

f-stop

f/8.0

Shutter speed

1/500 sec

Dimensions

1740 pixels x 1466 pixels

Original file size

399.16 KB