In Australia here, and I knew exactly what he meant.

I guess it just depends on whether you've done much tree-work. (I'm ex-SES in an area with lots of National Parks/State Recreation Areas)

Widowmaker was also the name used for the hammer drills used in the Australian goldfields. The dust from the drilled rock got into the miners lungs and killed them prematurely.

Or any number of dangerous mammals. ;)