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Galls on a young wattle plant Photo: F Mangubhai |
The planned outing to Goombungee had to be cancelled because of the amount
of rain during the night. Instead, we were to meet at the James Byrne end of
the Highfields Falls Bushland. Ten members and a
visitor arrived by 9 a.m. on a sunny but cold morning.
It was an easy walk with a chorus of birds to keep us company. The stops made on the route were mainly to try to spot birds which were flitting about, quite often high in the canopy. These spots were where the sun broke through, as well as at the top of the waterfall, and again at the bottom of the Falls. Recent rains ensured that there was a good flow of water. Opposite the descent to the bottom of the Falls was a tree where Powerful Owls used to roost, but there was no sign of any owl, nor any giveaway signs on the ground to indicate they might have been there.
One of the non-avian things that caught our attention was some large galls on a quite small wattle tree (see photo). It was not the gall that poet Gerard Manley Hopkins was referring to in these few lines:
But
it is a bit of a curse for the wattle tree. The gall is a reaction to insects such as mites, thrips
and wasps, laying eggs in the plant tissue, and their larvae release chemicals
(like cecidotoxins) that stimulate abnormal cell growth, forming the
gall. The gall is essentially the tree’s defensive response - a kind of
botanical scar tissue - triggered by foreign substances or organisms. It walls
off the invader, but in doing so, creates a nutrient-rich shelter that
ironically benefits the pest. Gall shapes vary on different Acacias. [For more information on galls: gall
history in Aus.pdf.]
Straw-necked Ibis; Pacific Baza (probable sighting); Brown Quail; White-headed Pigeon; Galah; Sulphur-crested Cockatoo; Rainbow Lorikeet; Little Lorikeet; King Parrot; Pale-headed Rosella; Laughing Kookaburra; Black-faced Cuckoo-shrike; Eastern Yellow Robin; Grey Shrike-thrush; Grey Fantail; Eastern Whipbird; Superb Fairy-wren; White-browed Scrubwren; Brown Thornbill (probable sighting); Varied Sittella; White-throated Treecreeper; Noisy Miner; Lewin’s Honeyeater; White-naped Honeyeater; Brown Honeyeater; Mistletoebird; Spotted Pardalote; Red-browed Firetail; Olive-backed Oriole; Australian Figbird.
