Following this thread with interest, I might point out that weeds (in
the sense of their spread being a process threatening some bird
populations) are not necessarily imports from abroad. I seem to recall
reading that wiregrass is spreading in Sherbrooke thus reducing foraging
effectiveness of lyrebirds. The spread is apparently facilitated by a
lack of grazing wombats.
Re Grey-crowned Babbler, on the Mornington Peninsula, due to excessive
fires and human disturbance, there has been a spread of (at least) two
native species (weeds?) namely Leptospermum laevigatum and Acacia
longifolia var. sophorae (forgive me if my taxonomy is out of date), in
areas which were formerly open grassy woodland more suitable for g-c
babblers, e.g. Mt Eliza, Baxter/Pearcedale.
I emphasise that I agree that habitat destruction through clearance and
activities of introduced predators are more important generally but that
weeds should not be discounted as having an effect.
Peter <>
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