Spot­ting winged war­riors

Sunday Tasmanian - Tassie Living - - BOOKS - DON KNOWLER

FROM the time mankind fi rst gazed into the skies, birds of prey have been viewed with won­der and awe. It’s no sur­prise that ea­gles have al­ways been sym­bols of power and fal­cons a metaphor for speed and agility.

People who might not nec­es­sar­ily be in­ter­ested in birds still fi nd the sight of rap­tors ir­re­sistible. But the prob­lem with study­ing our rap­tors – for both the avid bird- watcher and the ca­sual ob­server – is that dif­fer­ent species can of­ten look the same.

The wedge- tailed ea­gle is pretty dis­tinc­tive with its long wedge- shaped tail and gi­ant size but what of smaller ea­gle species, and hawks, goshawks and fal­cons? High in the sky – where they are gen­er­ally spotted soar­ing on ther­mals – it can be diffi cult to de­ter­mine dis­tin­guish­ing fea­tures, such as colour and wing and tail shape.

Here, Birds of Prey of Aus­tralia comes into its own. It is billed in its sec­ondary ti­tle as a fi eld guide and it is eas­ily the most com­pre­hen­sive book on raptor iden­tifi cation pro­duced in Aus­tralia.

But the book is more than a mere fi eld guide, a sec­ond sec­tion forms a hand­book that goes into great de­tail about each of the di­ur­nal birds of prey found in Aus­tralia.

Once upon a time, a com­pre­hen­sive and specialist book such as this would have had a limited au­di­ence, but there is a grow­ing in­ter­est among the gen­eral pub­lic not just in rap­tors but the en­vi­ron­ments they in­habit.

There is even a re­cently re­leased Aus­tralian fi lm, Heal­ing, which fea­tures an in­jured wed­getailed ea­gle and its pris­oner- carer as its stars.

The re­ha­bil­i­ta­tion of in­jured ea­gles is also a sub­ject cov­ered in Birds of Prey of Aus­tralia, a sec­tion of it out­lin­ing the threats rap­tors still face in hu­mankind’s world.

While per­se­cu­tion, poi­son­ing and even the new threat of wind­farms are sub­jects cov­ered in other books about rap­tors, this one con­cen­trates fi rmly on what makes Aus­tralia’s birds of prey spe­cial and how our en­joy­ment of them can be max­imised.

In this re­gard, Birds of Prey of Aus­tralia has come up with an in­ge­nious so­lu­tion to end fi eld iden­tifi cation con­fu­sion.

Among many changes from the fi rst edi­tion pub­lished 15 years ago, the lat­est work pro­duces split im­ages of the most diffi cult species to iden­tify, so plumage and wing shape can be com­pared di­rectly.

The il­lus­tra­tion show­ing split views of the wedge- tailed ea­gle and the white- bel­lied sea- ea­gle clearly show the more prom­i­nent “fi ngers” of feath­ers at the wing- tips of the sea-ea­gle and the shorter tail.

Along with the beau­ti­ful colour il­lus­tra­tions and pho­to­graphs show­ing birds both perched and in fl ight, there are also head- on di­a­grams that show the an­gle of the wings.

The swamp har­rier, com­mon in Tas­ma­nia in the sum­mer months, has an up­swept wing pat­tern, which the book shows head- on as a shal­low V- shape.

The book also in­forms us that an­other sure way to iden­tify a swamp har­rier from other sim­i­larly sized birds of prey is the patch of light- coloured feath­ers on its rump.

In true fi eld guide style, brief de­tail is given about species, the em­pha­sis be­ing on iden­tifi cation, but in the hand­book sec­tion, there is much fas­ci­nat­ing in­for­ma­tion about the swamp har­rier as a species.

I didn’t know, for in­stance, that when the har­ri­ers – the only Tas­ma­nian raptor to cross Bass Strait – re­turn to the main­land af­ter the breed­ing sea­son they form com­mu­nal roosts.

It is be­lieved such roosts “might func­tion as in­for­ma­tion cen­tres at which some birds learn where oth­ers are hunt­ing suc­cess­fully”.

And in the same sec­tion, light is shed on the won­der­ful aerial dis­plays of wedge- tailed ea­gles.

“At all times of the year, but par­tic­u­larly in the breed­ing sea­son, pairs spi­ral up in a mu­tual soar­ing dis­play that might cul­mi­nate in rolling and foot- touch­ing when the male dives at the fe­male.

“The pair then de­scends to mate on a branch near the nest,” writes au­thor Stephen De­bus, who also de­scribes aerial passes in which the male pre­sents the fe­male with food, and courtship in which “mated birds perch to­gether, ex­tend their necks and touch bills”.

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