Ruins of Old
Whether or not a kobold tribe enjoys prosperity, its numbers invariably swell. Tribes try to accommodate their growing populace by mining out additional living quarters and enduring cramped conditions, but eventually population overtakes space. The all-watcher then announces that the tribe must split. This decree marks a time of celebration for kobolds. It means that the tribe can expand into new lands, discovering more ruins of the old society and relieving overcrowding.
The tribe divides the population evenly, allocating representatives from every profession necessary to maintain a new kobold lair. The departing group includes a large number of young adults with the vigor to create a new living space from the ruins. Older and more experienced kobolds might join the new tribe later on, but only after excavation is well under way.
A new kobold lair must contain radioactive waste material or significant amounts of waste from the old society, preferably both. Not content to leave finding such a place to chance, kobolds rely on tinkerers to identify a suitable locale for a new warren.
Kobolds never start mining a new lair until a profitable site has been found. Such spots are scouted out well in advance of a wandering tribe embarking on their exodus. Scouts note potential competitors and other dangers, determining the need for war. Common locations include cities of the old society that fell to nuclear strikes during the apocalypse or ruins of old pre-apocalyptic nuclear power plants. Ruins of old subway systems are also good, especially if they can provide ample shelter without modification and connect to ruined cities above that can be excavated in search for numenera or other technological remains of the old society.