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The weird case of the bagworm
(Not a bird, but most likely something that a bird would find interesting!)
Bagworms, sometimes called case moths, are interesting creatures. The larvae of the moth surround themselves with a case made of silk for protection. Then they go one step further: they attach leaves and sticks to the case, making a home that looks quite weird. Some of the cases can be large: up to 12 centimetres long.
I came across just such a case recently, when walking through a burnt area of bush. (The cases are hard to spot when the bush is lush and healthy.) I guess this larva was travelling around looking for food, and found itself exposed on a black tree trunk.
This particular case was quite large, at 11 centimetres long. At the top is the patch of silk that the larva uses to attach the case to the tree. When moving around, the larva detaches from the tree, pokes its legs out at the top of the case, and drags the case around with it.
I think is is most likely a Saunders’ case moth, also called the large bagworm (Metura elongatus), which is found in eastern Australia where I live.
Here’s a view from another angle:
In the zoomed-out view, the bagworm is half way up the blackened tree trunk in the middle of the picture:
Spotted at this location in Manly Dam park, on the east coast of Australia. I’ve posted recently about other bagworms that I’ve encountered.
Case moth caterpillar or bagworm in Sydney
Occasionally we see strange little caterpillars dragging what looks to be some kind of shell or case around with them. Here’s one moving precariously across a wall:
The clothes peg at start and end of the video is for scale. The caterpillar and its case are just a few millimetres long. The head and thorax of the caterpillar stick out at the top of the case, with the rest of the body inside the case. There’s nothing holding the case against the wall except the caterpillar’s six tiny legs at the top!
After seeing the above caterpillar yesterday, I searched the internet to find out what it was. It looks to be a caterpillar of a case moth (Psychidae), also called a bagworm.
Then I remembered another odd case that I’d seen on the wall of our house a year or so ago. That turns out to be a case moth’s case too. This one is more decorative than the one above:
Evidently the caterpillar pupates within the case, and sometimes the female moth even lives her entire live within the case.
The Butterfly House has more pictures of the decorative cases of the case moth.
Sydney Birder 