At the last meeting of the Cowra Garden Club, members had the pleasure of hearing from Dr Joanne Lenehan, a Cowra-based ecologist who showcased how various waterbird species across the Lachlan Valley used different types of plants to successfully breed in the last year.
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"At first glance, it might appear that the most important ingredient for waterbird breeding is water," Dr Lenehan said.
"While large volumes of water for long periods of time at the right time of year is critical, for waterbirds, the 'process of breeding' often starts with vegetation.
"Both live and dead plant material is great nesting habitat."
One of the more striking but lesser known and shy herons discussed during the evening was the nankeen night-heron.
"More than 5,000 of these birds were recently estimated nesting in a small river red gum and lignum lagoon of around 20 ha between Hillston and Booligal," Dr Lenehan said.
"Juvenile night-herons are often mistaken as Australasian bitterns (Botaurus poiciloptilus).
"This rarely spotted species is listed as endangered in NSW, with estimates as few as between 660 and 1,660 mature individuals in natural habitats in NSW.
"Australasian bitterns are at the other end of the stratum - nesting on the ground floor, building a platform of reeds and rushes just above the water, in the deep cover of tall dense stands of species, such as cumbungi and common reed (Phragmites).
"The Australasian bittern was recorded for the first time since 1990 at the end of the Lachlan in the Great Cumbung Swamp for the last two springs, as well as Lake Cowal and in the creek systems around Booligal."
Diving fish eating waterbirds, such as Australasian darter, and cormorants, including great cormorant, pied cormorant and little black cormorants, seem to have a preference for nesting in tree limbs that branch laterally over the water.
"This is so when a predator approaches a cormorant nesting colony, for example, the chicks will jump into the water long before they can fly to escape being eaten," Dr Lenehan said.
"Amazingly, the young chicks are very good at climbing back up to the nest likely aided by a sharp hooked beak."
Then there are those who nest out on top of and float on larger, open water bodies, such as black swans, or near the vegetated margins, such as the great crested grebe.
"With its spiky, black crest and chestnut mane, the great crested grebe is unmistakable," Dr Lenehan said.
"Young grebes are capable of swimming and diving almost at hatching, but the adults keep them close by carrying them on their backs until they've taught them to dive and fish.
"If your lucky, you'll get to witness them perform their elegant and elaborate courtship display, which include activities such as the 'weed dance' and the elegant 'penguin dance'."
Other species include the straw-necked, glossy and Australian white ibis.
"Approximately 35,000 ibis nested in less than 50 ha in just one medium-sized Lower Lachlan colony in late 2021, with the majority now fledged come February 2022," Dr Lenehan said.
"These species lend themselves very well to Drone imagery analysis and are often picked up first by air."
The Garden Club were shown some video of how thermal drone imagery is being trialled to see if can machine learning can count individual chicks on nests.
For the waterbird species so far, vegetation has been the core habitat but there is always the exception, such as the Australian Pelican.
"This iconic bird prefers bare ground or banks or islands surrounded completely by water. Their nest, called a scrape is very minimalist," Dr Lenehan said.
"While the breeding shown during the Cowra Garden Club talks has taken place is being monitored in large, floodplain natural wetlands across the Lachlan Valley in response to these habitats being inundated for over six months - we've also had reports of some less common visitors, such as plumed whistling ducks, making good use of resources in the back yard and paddocks."
The Cowra Garden Club will hold a meeting on March 3, 2022 in the Senior Citizen Rooms, Railway Lane near Woolworths.
Special guest speaker will be Rachael Young who is working for the NSW Department of Primary Industries (DPI) in Orange.
Rachael is part of researching agricultural climate and clean energy, and how to adapt crops and farm activities, including carbon farming and bio energy.
Rachael's presentation makes for a very interesting talk for the Cowra Garden Club.
Supper will be served at the conclusion of the meeting.
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