Brown Thornbill
Acanthiza pusilla
The brown thornbill is warm brown to olive-brown above, with flanks of olive-buff to yellowish white. It has buff scallops on the forehead and large dark red eyes. There are blackish streaks on a grey throat and breast, a tawny rump and tail base, and a black subterminal band with paler tips on the tail. The brown thornbill ranges in size from 9 to 10 cm (3.5 to 3.9 in), making it relatively small. It typically weighs 7 g (0.25 oz). Voice: Brown thornbills are skilled mimics and also respond to humans imitating their calls. The calls have been described as "rich, musical warble". Their calls vary from a mellow baritone pee-orr, high whistles with rapid cascading trills, to many squeaks and churrs.
ID text from Wikipedia, CC BY-SA 4.0
Yellow Thornbill
Acanthiza nana
Although similar to the striated thornbill and brown thornbill in both size and shape, the yellow colour of the yellow thornbill is more prominent. There is no sexual dimorphism, so that males and females look alike. They are around 9 cm (3.5 in) in length, with an average wing span of 14 cm (5.5 in), and weighing between 6–7 g (0.21–0.25 oz). Voice: The yellow thornbill has a loud, two-note tzid-id call, notably different from calls of the closely related striated thornbill by its harsher, less insect-like sound. The call is repeated at various intervals throughout the day and is associated with contact between birds while foraging, as defence, or as a territorial advertisement.
ID text from Wikipedia, CC BY-SA 4.0
Where you might meet both
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