ML623635768

Age

Not specified

Sex

Not specified

Observation details

A juvenile found exhausted and unable to fly, handed over to the Department of Wildlife Conservation. Initially thought to be South Polar, but measurements confirmed it as Brown Skua. Measurments: Culmen: 55 mm Tarsi: 88 mm Wing: 420 mm Comments by Vincent Mourik regarding this bird is as followed. Quoted. ".....The measurements are somewhat on the bigger end of the Brown Skua range but well within, and well outside South Polar Skua range. It's probably a southern Indian ocean bird, but of course this is speculative. The location of the sighting is the first thing of note. This record, and a few earlier ones from India, are to my knowledge the only records of Brown Skua well north of the equator in the Indian ocean. No such records exist in the Pacific ocean, I believe. There may be a record from the northern Atlantic ocean, but if my memory serves me right it is contested. This should be contrasted to South Polar Skua which is a known long distance migrant between the hemispheres, and it was a strong reason for me to be biased towards South Polar. Species ID: the added photographs are also very helpful for understanding the species ID. The bird is very worn, but the colour tone of the plumage is warm brown, not the colder colour typical of South Polar. You can see remnants in the worn plumage of the rich rufous colour typical of Brown. The extensive scaling in the lesser coverts is very typical of the Brown Skuas juvenile plumage, especially after wear. The markings on the few fresh scapulars are a better fit for Brown Skua too, but they are rather minimal, as is typical for both species once they moult out of juvenile plumage. Only once older they get stronger markings on the back. As a sidenote, the very plain appearance of immature skuas is a major reason for ID confusion - because this bird is mostly in worn juvenile plumage its ID is a bit easier in my opinion. The light head feathers are entirely caused by wear, the contrast with the newer darker feathers shows this. The bill is indeed long and heavy, this is one of the first things that struck me in the pictures. Moult and wear: you can beautifully see a broad line of synchronous weaker feather growth running through all the secondaries and into the primaries as well, proving beyond doubt these are juvenile feathers. This bird must have had an extended period of poorer nutrition as a chick, around one or two weeks or so, to cause this. P1 is shed, meaning it has just begun its first primary moult. This moult timing is pretty typical for juvenile Brown and South Polar Skuas, since both species fledge around the same time and are out of sync with the adults, the young birds roughly moult in the same season, and you cannot use this to discriminate them. Overall a very interesting bird......" Bird is feeding in rehab (2024.09.12)

Technical information

Model

SM-A725F

ISO

40

Focal length

5.2 mm

Flash

Flash did not fire

f-stop

f/1.8

Shutter speed

1/718 sec

Dimensions

4624 pixels x 2604 pixels

Original file size

4.02 MB