Backyard WildlifeMonday, 20 March 2017
I regularly comment on the wildlife that appears in my backyard (or my internal courtyard) and in 2015 I wrote about the Gippsland Water Dragon which had taken up residence. Again this year there has been no nesting activity in the courtyard, but there certainly has been plenty of other activity.
▲ A couple of curious little cigar-shaped mud cylinders turned up on a garden wall. When I broke one open 18 little spiders spilt out, but didn’t run away. What on earth was this? The answer is a mud dauber wasp builds these mud cylinders and stocks them full of little jumping spiders which it has paralysed and stores there as living food for its larvae. Beauty is only a garden sideline the website I consult suggests, basically it’s just ‘sex and death.’
It was a mud dauber that caused the Dominican Republic 757 crash which killed 189 crew and passengers in 1996, it is believed a wasp nest had blocked a pitot tube (airspeed indicator) which had been left uncovered. After that accident there was some discussion about how long a pitot tube could be left uncovered before a wasp could block it. My experience, since another cigar full of paralysed spiders quickly reappeared, less than 48 hours. Blocked instrument ports (tape) led to another 757 crash in Peru (70 deaths) also in 1996 and ice-blocked pitot tubes led to the crash of an Air France A330 (228 deaths) in 2009.
▲ My handsome water dragon has now been in residence for nearly two years and seems quite unbothered by my presence. I can sit outside having a sundowner beer and the dragon will mosey over and stretch out nearby. In 2015 I estimated it was more than 40cm long, today I’d say it was more like 70cm. It’s easy to measure because it poses for photographs stretched out across paving tiles, which are 500mm across, not 400mm as I previously suggested. Plus there’s another, possibly two, more water dragons in our garden. I’ve never seen all three together, but I’m fairly certain they now come in small, medium and large sizes.