As I had observed that same creek bank at 9 am, I knew that the predation had occurred during the day as it was 3 pm when I observed the claws. At night the forests are stalked by the Australian water rat (Hydromys chrysogaster), which is a voracious predator of crustaceans and is like a tiny otter rather than a rat. Their footprints can often be seen in the mud and on the beach. So what preys on crabs in the middle of the day. It was not people – no fresh footprints and people did crabs up which makes a mess. In fact their were no footprints which made me thing that the predator was a bird. Birds can carry their victims away from the site of capture before processing their prey and swallowing it. In this case the large claw was removed.
Without footprints the only way to check out suspects was to photograph birds and look for mud on their beaks. In the patch of mangrove forest where the crabs were taken were kookaburras, black butcher birds and scrub fowl. On the sand flats next to the mangroves were several more candidates including a beach stone-curlew and various herons.
|Beach stone-curlew, white-faced heron and great heron|
|Beach stone-curlew - Esacus magnirostris|
|Kookaburra with mud on its beak a few metres from the crab remains|