We might think that herons and similar waterbirds find their prey entirely by sight, but there's sometimes more to it than this.
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Although sight is the main sense used before the beak jabs down at aquatic creatures, the feet can play a part too.
A white-faced heron in the North Gardens Wetlands near Lake Wendouree has been seen stirring up the water just above the mud with its feet. It stretches one leg forward in the shallow water, then the foot is vibrated or “stirred” just above the mud.
The water there is clear enough for this action to be clearly seen, and the water is not greatly muddied in the process.
The action probably disturbs small creatures such as mudeyes, water beetles, aquatic worms and similar things, which the heron then sees and instantly catches.
Other observers elsewhere have described herons using raking motions, rather than vibrating, but the bird in the North Gardens Wetlands has not been observed doing this.
Silver gulls have been observed “paddling” in a somewhat similar manner, but in their case the leg and foot is moved up and down, rather than horizontally. Masked lapwings (plovers) and some dotterels have also been observed using their feet to similarly disturb prey.
White-faced and white-necked herons sometimes feed in dry paddocks away from water when grasshoppers and crickets are numerous.
By the way, blackbirds don’t use their feet at all when scratching – all the mess they cause in gardens is done by the beak. This is the same with white-winged choughs.
BADGE HUNTSMAN
A plain, cinnamon-brown spider like a huntsman is most likely a badge huntsman.
Like many spiders, it is active mostly at night. We found one during the day a week ago, in a forest environment at Canadian.
Its name comes from a striking black, white and tan marking underneath its abdomen. Our specimen was on thin foliage, so the mark was plainly visible.
Body length of a mature specimen is about 20mm, with the legspan being 40 to 50mm, so it is smaller than most other huntsman spiders. It spends most of its time on branches and treetrunks, rather than on the ground. The abdomen of this spider is not quite as flattened as those of other huntsmen.
Young ones are green, gradually moulting to become the uniform cinnamon-brown colour of the adults. Occasional adults are almost orange.
Like other huntsmen, it can give a painful bite, but it is reluctant to do so.
