Ian’s Bird of the Week ~ by Ian Montgomery
Newsletter – 10/14/16
Masked Booby was bird of the week in May 2011, but here it is again to acknowledge the recent use of one of my photos in an Australian, or more specifically, Norfolk Island, stamp.
Here is the original photo taken on Philip Island just off Norfolk Island in 2012. The differences between the sexes in Masked Boobies are subtle, with the main difference being in the colour of the bill: yellower in males than in females which have a bluish tint to the bill.
Here is another male Booby from the 2011 bird of the week, taken on an island in the Coral Sea east of Townsville. Note the difference in the colour of the eye. Masked Boobies generally have yellow irises, but those breeding on Norfolk Island, Lord Howe Island and Kermadec Island (off New Zealand) have dark brown irises and are sufficiently different in other less obvious respects to be treated as a separate race, sometimes known as the Tasman Booby (Sula dactylatra tasmani).
The next photo shows an adult female Masked Booby on Norfolk Island itself. Here you can see another difference characteristic of the tasmani subspecies: the legs and feet are khaki (those of the race personata found in the Coral Sea, off Western Australia and elsewhere across the Pacific have dark, almost black legs and feet.
Here is a juvenile at the same site on Norfolk Island as the female bird. The juveniles are somewhat similar in appearance to adult Brown Boobies and the best distinguishing field mark is the complete white collar of the juvenile Masked Booby. In Brown Boobies the brown of the head and neck is contiguous with the brown of the back and, in front, extends as far down as level with the wings and is sharply demarcated from the white breast.
Here is another photo of a juvenile Masked Booby, this time in flight and at Lord Howe Island, the other Australian breeding colony of the Tasman subspecies. The white collar is clear visible in flight too, as is the extensive amount of white on the breast.
Masked Boobies breed on isolated islands throughout the tropics and sub-tropics. As well as occurring across the Pacific, they breed in the eastern and western Indian Ocean, the Red Sea and in the western and central Atlantic. The adults normally stay close to the breeding colonies, though young birds and some adults do range farther afield. So, they do occur occasional along the coast of mainland Australia.
The largest colony is found on an uninhabited coral cay called Clipperton Island or Ile de al Passion – it’s a French territory – off the coast of Mexico, with a population of perhaps 100,000 birds.
It was visited in 1958 by an American ornithologist called Kenneth Stager who was shocked to find that feral pigs had reduced the population of Masked Boobies to a mere 150 birds. Being an old-fashioned ornithologist, he had a gun with him to collect specimens so he singlehandedly shot all of the pigs, 58 in number, restoring the cay to to its pre-human state.
Other animals to benefit were the local red crabs and other nesting seabirds. It has the second largest colony of Brown Boobies and one of the relatively few colonies of the eastern Pacific Nazca Booby, very similar in appearance to the Masked, but better known on the Galapagos island and Isla de al Plata off the coast of Ecuador.
Ian Montgomery – Birdway – Photos
It has been well over a month since Ian produced one of his articles for us to enjoy. I wrote to Ian to see if he was okay, and here is part of his response. I trust he doesn’t mind, but this will help us think about and pray for his recovery.
“I did have problems with the second cataract operation as an interruption to the blood supply to the retina caused some loss of sight to the central part of the field of view – cloudiness, blurriness and lack of colour vision. Naturally that was a bit of a shock and for a while it made me reluctant to do anything which made me more conscious of it, particularly photography and working with images on the computer.
Anyway, the eye is gradually improving, though whether it will recover completely over the next six months or so is uncertain. Your email prompted me to stop vacillating about the bird of the week and get me into action, so thank you for that.”