The grass-dwelling caterpillars are well-known to many people — brown and hairy with yellow and black markings — and are frequently collected by children. They curl into a circle when disturbed.

These caterpillars pupate in a hole in the ground from mid-spring and are emerging as adults now, with March being their main flying time.

Male caterpillars turn into the moth pictured here. Fawn-coloured with attractive black linear markings above and below, they are attracted to lights at night. The wingspan is about 30mm. Sometimes they are found either dead or dazed-looking on the ground under windows in the morning.

The moth is one of the grass anthelids. There are several similar moths, with ours sometimes called the lined grass anthelid because of its "lined" markings. Scientists know them as Pterolocera, with ours possibly being P. amplicornis.

A striking feature is the large, fern-like antennae. Male grass anthelid moths fly with rapid zig-zag flight, covering a wide area — perhaps 10 metres wide — as they go. They are thought to be sampling the air with their large antennae, searching for the scent of the wingless females on the ground below.

The females are completely different. Without wings, they resemble plump furry grubs, but with longer, finer legs. Their body length is about 20mm.

Both the males and females are smaller-bodied than the 40mm caterpillars they were before pupation. This reduction in body size is a common feature of moths.

Moths of many species with "ferny" antennae are very often males. Females of the same species often have simple linear antennae.

Local bird observers visited Werribee last weekend, listing 68 species at the Western Treatment Plant, which is an internationally renowned waterbird spot.

Highlights included 20 Cape Barren geese and 60 freckled ducks as well as zebra finch, little egret, banded lapwing, curlew sandpiper, white-bellied sea-eagle and banded stilt.

Migratory waders were disappointingly scarce on the day. Only curlew sandpipers, sharp-tailed sandpipers and red-necked stints were seen.  

Curlew sandpipers are classified as critically endangered in Australia, where numbers dropped by 80 per cent between 1983 and 2007.

This is due to habitat loss on their Asian migratory route, particularly around the Yellow Sea between China and Korea.

Unfortunately, this decline is continuing.