Yesterday while I was in my backyard I noticed five small red spiders crawling across the sidewalk in a single-file line. I took a closer look and realized that they were newly hatched trapdoor spiderlings. I ran back inside and grabbed my camera. When I got back I saw even more spiderlings. I watched them for about 45 minutes. During that time I saw between 30-50 spiderlings. They were following a trail of silk that went from the grass, across the sidewalk, and then up my cottonwood tree. I watched them crawl about 12 feet up the tree before disappearing around a thick branch.

I'm not positive, but I'm pretty sure what I saw was pre-ballooning behavior, although I never saw any actual ballooning. What I observed was similar to what is described in this paper. Apparently, ballooning is a rare behavior in mygalomorph spiders. I'm not sure what species these spiderlings are, though, so I don't know if ballooning is known in this species.