The first of our collared females near Churchill swam ashore on July 7th. For perspective, this is a month earlier than the 1980s. Other bears have trickled to land since. On the break-up side of things, it looks like 2012 is fairly similar to other years since 1998.
The downside is that the frequency of the early break-ups is occurring much more often. Because polar bears “remember” good and bad years by either storing or depleting fat stores over several years, a run of bad years can run down a population. This happens because adult females deplete the fat stores needed to either produce cubs when they’re pregnant or to produce milk when they have cubs. Based on the aerial survey conducted last summer, recruitment of new polar bears in the Churchill area is well below normal now.