Tag Archives: Guilfoyle’s Volcano

Weekdays outing to the Royal Botanic Gardens, Melbourne

16 February 2016
Azolla and floating island
Azolla and floating island

Sporadic rain did not deter 18 people assembling near Gate H. Newcomers joined long-term members being led by David Plant as Bell Miners called in the surrounding trees. Early arrivals were met by a young Willie Wagtail confidently foraging nearby. The water levels in all lakes had plummeted since the rains stopped over the previous six weeks or more. The gardens do not receive tap water but are wholly watered by purified road run-off. No run-off, no water. When the rain does fall, the surrounding gutters flow into a series of ponds where pollutants are removed or sequestered by vegetation, often on floating islands. Partially cleaned water is then pumped up to Guilfoyle’s ‘Volcano’ where the final purification proceeds (via more floating islands of vegetation) before it is gravity-fed down to the garden beds where it is distributed where needed by means of a computer-controlled system.

Floating islands on Guilfoyle's Floating islands on Guilfoyle's "Volcano"
Floating islands on Guilfoyle’s ‘Volcano’

Today the lack of recent rain meant that lake levels were about a meter below normal and birds were walking on mud rather than paddling on water. Another problem is the proliferation of Azolla, a water plant whose dense surface growth blocks all light from deeper-growing vegetation.

Floating island and Azolla
Floating island and Azolla

Still, the gardens hosted numerous Silver Gulls, Pacific Black Ducks, Eurasian Coots and Purple Swamphens. There were fewer Dusky Moorhens, which included several well-grown young, and one male Chestnut Teal foraged close to a stripy youngster. Each of the three Black Swans seen was banded on the neck for identification during the ongoing research on breeding patterns. David mentioned that a population of foxes lived among the rockery and had effectively eliminated cats from the gardens, resulting in much less overall predation on the garden wildlife. Several original trees were pointed out, among them a Melaleuca liniariifolia and a swamp gum or ‘kanuka’. Cushiony green lawns are planted with kikuyu which needs no water and resists the wear of heavy traffic.

Azolla
Azolla and a couple of Eurasian Coots and a Dusky Moorhen

Only a couple of other individual waterbirds were recorded – Little Pied and Little Black Cormorants, a Hardhead seen by only a few and a pair of Grey Teal seen by all. A highlight was at least one Nankeen Night-Heron initially in flight then later by a lake. Bush birds were not numerous. White-browed Scrubwrens and Brown Thornbills were heard, Red and Little Wattlebirds were occasionally seen and many had a fleeting glimpse of an Eastern Spinebill. Little Ravens and Australian Magpies called and a Magpie-lark was initially heard before being seen. A still slightly fuzzy young magpie beside an adult elicited ‘Aaww’ all round.

Some of the group
Some of the group

The final bird count was 33 species, continuing a trend of loss of the garden’s birds. David had shared with us his enthusiasm and encyclopaedic knowledge of the garden’s history and treasures and we thanked him wholeheartedly.

Diane Tweeddale, Coordinator BirdLife Melbourne Weekdays Outings; all photographs by Diane Tweeddale