These traps may be used legally only in farm dams and estuaries and require a fishing licence.

Unfortunately, a platypus was found drowned a few months ago in a crab trap at Maroota near Richmond, which is in the upper reaches of the tidal section of the Hawkesbury River, where crab traps can be legally used.

Once caught in a trap, platypuses have only two minutes to escape before they drown.

So people wanting to catch yabbies, should use the old manual methods.

The platypus is the world's most unique mammal and we have it in our local bushland; let's not risk its survival for the sake of a few yabbies.

See http://branches.npansw.org.au/br- macarthur/News_Campaigns/2011/pla typus_kentlyn.shtml.

■More bad news is that Peter, a mature male koala from Peter Meadows Creek that had infected bite wounds, had to be euthanised.

The infection had degraded the cartilage of one shoulder joint leaving bone rubbing on bone.

So any arm movement would have been painful.

Moreover, he had a heart condition that seriously affected blood flow.

Another koala, from Minto Heights, also had to be euthanised.

This animal was brought in to the Wildlife Health and Conservation Centre at Cobbitty looking very dishevelled and we feared that it might have chlamydia.

This would have been a major calamity for Campbelltown's koalas because we are yet to see clinical signs of this painful and devastating disease.

Fortunately, the symptoms were not caused by chlamydia bacteria.

It was the work of a tiny mite, an eight-legged arthropod that causes mange.

This mite causes immense suffering among wombats, occurs occasionally on captive koalas, but is seldom seen on koalas in the wild.

■On a happier note, a koala has been visiting St Helens Park Primary School over the past two weeks and has fascinated the students who love to find him every morning.

Not so pleased is the owner of an adjoining house who discovered that the koala likes to drop its faecal pellets on to her trampoline from an overhanging branch.

Koalas produce 70-130 pellets per day so this koala reaps the rewards of practice.

Please report koala sightings on UWS pager 9962 9996.