The common belief of the lynx-related zoologists is that parturition in lynxes takes place in a thicket somewhere under treefall. Sometimes, it really happens. However, for more than twenty years of searching for wolf dens in Paazierre Forest and Naliboki Forest in Belarus in April-June I have found almost two thousand of wolf dens under treefalls (mostly without pups, former ones etc), but only a few lynx denning sites (easily recognisable by presence of lynx hair) have been found under treefalls.
At the same time when I worked in the regions, there were, at least, the same or double number of lynx litters compared to the number of wolf litters. So, if female lynxes give birth under treefall and in thickets, I could discover markedly more lynx dens there, perhaps, hundreds of former lynx denning sites, too (i.e. similar as in the wolf case).
At the same time, we (together with Wild Naliboki team) already got many pieces of evidence that in Belarus parturition in lynxes and raising of early day kits are going on in burrows such as former wolf burrows, abandoned badger setts and beaver burrow network.
Concerning the timing of giving birth by lynxes, it appears to be prolonged in Belarus; it happens starting from the last decade of April and perhaps until mid-June or until the end of May. Births in lynxes mainly happen during the first and second decades of May.