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I've been a Canberran since moving here from Adelaide on the first day of 1980. I now live in suburban Duffy with my partner Louise Maher, ABC 666 radio and on-line journalist. Among my early memories is following Sleepy Lizards (Shinglebacks) around the paddocks north of Adelaide, guarded by the faithful bull terrier. I have always been passionate about the natural world, trying to understand how it works, how the nature of Australia came to be, and sharing those understandings. My especial passions are birds, orchids and mammals. For much of my life I have been a full-time naturalist, running bush tours, writing books etc, doing consultancies, presenting a regular radio slot on local ABC, chairing a government environment advisory committee and running adult education classes. Recently I have eased back somewhat, but am still writing, teaching, doing some radio work and running overseas tours - as part of my fascination with our Gondwanan origins I've been running tours to South America for the past decade. I was awarded the Australian Plants Society Award in 2001 and the Australian Natural History Medallion in 2006, both for services to education and conservation.

Thursday, 2 February 2017

A World of Herons: #1

I've just noticed that I haven't offered a post focussing on birds since last September, so it's probably time to rectify that. Herons form a single family of some 64-72 species, depending on your preferred taxonomy. They are found in nearly all unfrozen parts of the world, other than the deepest deserts and highest mountains, and are familiar to most people who take an interest in such things. 

They are very interesting birds (but what bird isn't?!), so I'm going to spread this topic over two weeks; today I'll introduce the general characteristics and history of the family and next week look at the sub-groups and representative species of each. Regarding the latter, suffice it to say for now that the general opinion is that there are four recognisable subfamilies - day herons, night herons, bitterns and tiger herons.

It is an ancient group, traceable back at least 55 million years. They are essentially water birds, though some, and notably the two species of cattle egret, forage in dryland pastures. They are, with variations, long-legged and long-necked with a long straight bill; all are carnivores subsisting, naturally enough, mostly on aquatic animals. A characteristic is a strongly kinked or S-shaped neck, due to an elongated sixth vertebra, which enables the neck to be retracted and hurled forward like a harpoon.
Great Egret Ardea alba, Jerrabomberra Wetlands, Canberra,
displaying the typical heron characters including the neck kink.
(Pity about the shadow!)
Which leads us to the 'heron vs egret' issue, which is indeed a non-issue. We simply, by convention, use 'egret' for a heron which happens to be white. (Both words have related origins in old European languages, reflecting the harsh calls typical of the family; for instance when the French hayroun entered English in the early 1300s it replaced the related Old English hragra. 'Egret' was a diminutive (perhaps for the Little Egret) of older French aigron, again from the same root.)

There is no taxonomic relevance to the terms; consider the following pairs of birds. 
Great Egret Ardea alba and Little Egret Egretta garzetta Cairns, north Queensland;
two egrets, two genera.

Snowy Egret Egretta thula Arica, northern Chile (above) and
White-faced Heron Egretta novaehollandiae Canberra (below).
Egret and heron, same genus.
 
They hunt either from the bank...
White-faced Heron, National Botanic Gardens, Canberra.
... or standing in the water.
Capped Heron Pilherodius pileatus, Peruvian Amazonia.
Little Blue Heron Egretta caerulea, Arica, northern Chile, attacking fish.
They will often stand upright, like these three, to get a broader perspective, or crouch to be less conspicuous and closer to prey.

Striated Heron Butorides striata, Fraser Island, Queensland.
Most species are primarily fresh-water specialists, but others can also be found on the seashore, in addition to those like the Striated Heron and the reef herons which are nearly always seen there.
Pacific Reef Heron Egretta sacra, south coast New South Wales.
 The next two are definitely part-time beach-goers.
Great Egret in the sea, Cape Hillsborough NP, central Queensland.

Great Blue Heron Ardea herodias, Fernandina, Galápagos.
The Black Heron Egretta ardesiaca of Africa is famous (via documentaries) for 'mantling' its wings to shadow the water, either to attract prey into the shade, or to protect its vision from light reflecting off the water. However this is not the only species to adopt the practice, though it is not otherwise common.
Lava Heron Butorides sundevalli hunting, Isabela, Galápagos.
Flight is strong, with trailing legs but pulled-in neck, a distinctive pose. Compare the two herons below in flight with an example of both a crane and a stork, superficially similar birds to herons.

White-faced Heron, James River, Barkly Tablelands, Northern Territory.

Great Egret, Cairns, north Queensland.
Brolga Grus rubicundus, Clermont, central Queensland.

Black-necked Stork Ephippiorhynchus asiaticus, Cobbold Gorge, north Queensland.
Nests may be in colonies (often) or solitary, but are mostly built over water.
White-necked Heron Ardea pacifica chicks, near Cunnamulla, southern Queensland.
And while nesting, some herons take on breeding hues, both of feathers and of soft body parts.
Great Egret, Kakadu NP,  with breeding flush to face, and black bill.
When non-breeding (see top photo) face and bill are yellow.
But it was the long filamentous back and head plumes grown during breeding that almost brought them undone, thanks to the brutal whimsies of the fashion industry. Heron feathers have been sought for centuries; Maoris used Great Egret plumes for chieftain’s head-dresses – but they kept captive birds for plucking. The French army used them for colonel’s hats (not from captive birds!). In New Zealand in the 19th century Bitterns were slaughtered by trout fishers for fishing flies. 

Snowy Egret with plumes, Arica, northern Chile
All this however was unimportant relative to the trade in breeding plumes in the 19th and early 20th centuries. They became fashionable for ladies’ hats in Europe and North America; the trade also used gulls, albatrosses, condors, owls, parrots and hummingbirds, but egrets were the favourites. To provide a kilogram of plumes required the death of up to 300 Great Egrets or 1000 Little Egrets – and of course thus their eggs and chicks. 

Great Egret with breeding plumes, Canberra.
From 1899 to 1912, fifteen tonnes of feathers were exported from Brazil, Argentina and Venezuela (ie between 5 and 15 million dead birds). At the height of the industry 10,000 people were employed in the industry in the Paris area alone. One London dealer handled 2 million skins in 1887. By 1877 in New Zealand, only six Great Egret nests were known! In 1903, the price to the hunter in North America was $30 per ounce – twice the value of gold; later it was $80 per ounce. Snares and scatter guns wiped out whole colonies in Burma, Malaysia and Indonesia. It led directly to the formation of the British Royal Society for the Protection of Birds in 1898 and the American Ornithologists’ Union in 1883 and the Audubon Society in 1886; campaigns were intense – two Audubon Society guards were murdered by poachers. 
Intermediate Egret with breeding plumes, only just visible on the back, Canberra.
(Note too the colour of the face and bill, which are both yellow when not breeding.)
In 1910 after intense campaigning the sale of feathers was declared illegal in New York State, and imports to the US were banned in 1913, and to Britain finally in 1920. An illegal trade continued until the whims of fashion finally ended the slaughter in the 1920s. I don’t have evidence of much of an official trade in Australia, though Japanese hunters operated in the north, and through the western Pacific. However, there were certainly raids on colonies in the Riverina, and photographs of starving chicks here were influential in the growing opposition in London.

I don't like dwelling on such dark thoughts, but we can only do things better if we learn from the past - unlikely as that prospect may seem at times. Overall the persecuted heron species have recovered and can readily be appreciated for their intrinsic values now.


BACK ON THURSDAY
(to complete the heron story)


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2 comments:

Susan said...

I think I read somewhere that so many herons and egrets were eaten in France during medieval times that the populations are only now recovering. I'll see if I can find a source for that or if I just made it up :-)

Ian Fraser said...

Making it up's OK, as long as it's plausible... :-)
I have some problems with it though, unless they were entirely wiped out. The egret populations in the main Sth American hunting areas have recovered pretty well in about 100 years, whereas mediaeval times were centuries ago. See what you can find out though. I know that hunting herons with falcons was widespread in Europe until recently - in the Netherlands until the 1960s. I'm not sure how intensive it was though.