Ian’s Bird of the Week – Grey Goshawk

Grey Goshawk ( novaehollandiae) by Ian 1

Ian’s Bird of the Week – Grey Goshawk ~ by Ian Montgomery

Newsletter ~ 5-24-12

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Here is an uncommon and beautiful raptor, the Grey or Variable Goshawk. It is usually called the Grey Goshawk in Australia but the moniker Variable is more accurate as it occurs in both grey and white morphs. The first photo shows a white morph bird perched in a dead tree near mangroves at Bushland Beach near Townsville, photographed in 2002.

It is the only completely white raptor worldwide, though white morph birds may show some grey on the tail – as this one does – and on the head. These are large hawks, with the females being 50-55cm/20-22in in length with a wingspan to 1.1m/43in. The smaller males are 38-42/15-16.5in. By way of comparison – the choice is deliberate – the Sulphur-crested Cockatoo is 44-51cm with a comparable wingspan of about 1m. Despite their size, they are difficult to see (and to photograph) as they inhabit mainly dense forest, or forest edges and are shy, so it would be another ten years before I got an even vaguely respectable photo of a grey morph bird, second photo.

Grey Goshawk ( novaehollandiae) by Ian 2

Here you can see how broad and rounded the wings are. This shape is ideal for short glides and rapid braking and is an adaptation for the preferred hunting strategy of this species, called ‘still hunting’ – perching on a well-hidden perch and making short, devastating swoops on unsuspecting prey feeding on the ground or in trees. Prey includes birds, mammals and reptiles and a female can take prey up to the size of herons, rabbits and possums. Goshawks are subject to mobbing by small birds, and the when the individual in the second photo landed on a tree stump several seconds later (12 to be exact) it immediately attracted the attention of a Willie-wagtail visible in flight near the goshawk in the third photo.

Grey Goshawk ( novaehollandiae) by Ian 3

You might recall that pied plumage is often the hallmark of aggressiveness – the reverse of camouflage – and this Willie-wagtail actually landed on the tree stump as in the third photo. The Goshawk gives the appearance of having lost interest in the Willie-wagtail, but I suspect that it was more concerned with preparing to take flight as I approached it trying to get a closer shot, which it did very shortly afterwards.

Grey Goshawk ( novaehollandiae) by Ian 4

I mentioned Sulphur-crested Cockatoos before as it has been suggested that the white morph has evolved to mimic Cockatoos to escape detection, but this theory has never been proven. It is thought that genetically the white morph is simply a single recessive gene, like Mendel’s sweet peas, as white-white mating produces white offspring, while white-grey and grey-grey can produce either. There is supposed to be geographical variation in the proportion of the morphs, with the white one being predominant in northern Australia, Tasmania and western Victoria and the grey morph being predominant in eastern Australia. Despite the specific name novaehollandiae, it isn’t an Australian endemic and also occurs in New Guinea and neighbouring islands, though the island races are sometimes treated as separate species.

Best wishes

Ian

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Ian Montgomery, Birdway Pty Ltd,
454 Forestry Road, Bluewater, Qld 4818
Tel 0411 602 737 ian@birdway.com.au
Check the latest website updates:
http://www.birdway.com.au/#updates
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Lee’s Addition:

Wow! Another beautiful bird! I really enjoy Ian’s Newsletters. They tell about birds that many of us never see or even hear about. Then again, we tell about American birds and to others, those are probably just as fantastic to hear about. Ian has managed to travel around the world in search of birds to photograph. Check out his website, Birdway, to enjoy his photos.

The Goshawk is one of the Birds of the Bible and was not to be eaten, but this one is such a beauty, I wouldn’t dream of eating it or hurting it anyway.

the ostrich, the short-eared owl, the sea gull, and the hawk after its kind; (Leviticus 11:16 NKJV)

The Goshawks are part of the Accipitridae – Hawks & Allies Family. Check out Ian’s 47 members of the Hawks, Eagles & Allies and then the whole list of 255 species in the family listed here.

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