A pair of great cormorants not at all threatened by a plastic owl
I think I’m slowly overcoming my prejudice against ducks. My duckism, if you like. There’s a sudden movement on the waterline, I fumble for my camera, then I realise it’s “just a duck”.
But slowly I’ve been persuaded that ducks are worth the effort. There’s the crazy goitre of the musk duck. The hardhead, gruesomely named after the challenges taxidermists faced stuffing its cranium. The nest-thieving pinkeared eared duck, with its black and white stripes and hints of neon. The good-looking but possibly feckless chestnut teal, said to engage in “dump laying” – dropping eggs in other teals’ nests to be raised. Even shooters participating in the autumnal “kill a duck in a national park” festival aren’t allowed to blow away the increasingly rare blue winged Australasian shoveler. (Field and Game Australia chair was said to be “disappointed” about this).
In the same way, I’m slowly starting to come around to the shag . It’s not that I’ve got a particular prejudice against them. It’s just that they’re always there. Whatever the time of day, season or weather conditions. Familiarity breeds not so much contempt as slight indifference.
But these foggy winter mornings have shown cormorants in a new (filtered) light.
Post-apocalyptic stillness and deep chill don’t deter them. When there’s nothing moving – maybe just a single sea-eagle enveloped in the mist – the cormorants are the silhouettes that make that gloomy snap worthwhile.
Four of the five species of Australasian cormorants can be found on my bit of the Hawkesbury. Only the black-faced cormorant, which only lives on the south coasts – in Tassie, Victoria, South Australia and Western Australia – has never made an appearance around here.
My favourite is the biggest, the great cormorant, Phalacrocarax carbo (or the black shag in New Zealand). It’s the world’s most widespread cormorant, found across Europe, India, Africa and South East Asia.
The little black cormorant is lovely too, with its jade green eyes and black-on-black pattern. I’ll never forget the feathered hush of a huge flock of them passing overhead as I paddled in in Myall Lakes National Park a few years back. Like other cormorants, they usually nest colonially, with lots of other waterbirds. These little black cormorants sometimes combine in flocks of hundreds to feed cooperatively as well, a line of birds trapping fish in inlets as the tide retreats. But I’ve never seen them flying or feeding en masse on the Hawkesbury or its tributaries.
The pied cormorant is a regular sight around here too. I haven’t seen them nesting though, even in the mangroves of Big Bay or Spectacle Island, though flooded forests – along with coastal islands – are apparently the sites they pick to raise their young. In the past, the pied, along with the great cormorant, were suspected by fishermen of raiding nets and at times licences were distributed to cull them. But mostly, along with crustaceans and molluscs, they eat the small fry, too insignificant to interest human fisherfolk.
I’m not so keen on the little pied cormorants – no glamorous green eye! I see fewer of them, though apparently they do congregate in large flocks in coastal areas. Along with the little blacks, they’re also found right across Australia’s inland waterways and dams, feeding on crustaceans, especially freshwater yabbies, as well as little fish.
Little pied cormorant drying its wings at Donnybrook Bay
I say cormorants are everywhere – from the turbid shallows at the top of Berowra Creek to the open water where the Hawkesbury meets the sea. But that’s not strictly true. Cormorants prefer fishing over seagrass – there’s a better range of things to eat there. And seagrass beds are under threat all over the place. A study tracking of numbers of coastal birds at a tidal bay in Victoria for over 40 years found that not only migratory birds but the year-round residents, including cormorants, had reduced in numbers:
The marked decline in some (predominantly) fish-eating birds (Australian pelican, great cormorant, little pied cormorant, white-face heron and grey-tailed tattler) around the early 1980s closely matches the beginning of a decline in commercial fish catch… Decreases in fish-eating birds and fish coincide with substantial losses of seagrass in the bay (Hansen et al 2015 524)
Cormorant avoiding a shark at Dusty Hole in Berowra Creek
And it seems, cormorants tend to steer clear of shallow water, no matter how good the spread, if there’s sharks about. Just another reason for a kayaker to love a shag!
Egg the ancient kayak at Twin Beaches
Additional references:
Dorfman, E.J. and Kingsman, M.J. “Environmental determinants of distribution and foraging behaviour of cormorants (Phalacrocorax spp.) in temperate estuarine habitats” Marine Biology 2001 138 1-10
Hansen, B., Menkhorst, P., Moloney, P and Loyn, R. “Long-term declines in multiple waterbird species in a tidal embayment, south-east Australia” Austral Ecology (2015) 40, 515–527
Heithaus, M.R. “Habitat use and group size of pied cormorants (Phalacrocorax varius) in a seagrass ecosystem: possible effects of food abundance and predation risk” Marine Biology (2005) 147: 27–35
Traylerd, K.M., Brothers, D.J., Woollera, R.D., and Potter, I.C. 1989 “Opportunistic foraging by three species of cormorants in an Australian estuary” Journal of Zoology (1989) 218, 87-98
