A 'Widow Maker' in Humboldt and Del Norte county is not a spider. It is an old 'logging term' that is very appropriate to Redwood Trees.
Redwoods are very stable trees. However their tops and branches are prone to breaking off in windstorms. When that event occurs, the piece of the falling redwood becomes know as a 'widow maker'. When they fall on your head your wife becomes a widow!
If you have large Redwoods on your property, the best advice is to stay away from them during storms and periods of high winds. You do not want the top of a Redwood or a large branch falling on you.
The same goes if you hear strange sounds in your Redwoods on days of light wind. If your Redwoods are growing close together, it may be the case of branches rubbing together. Something will give when they do. If in doubt, contact a local tree service for their advice.