Over the past 205 years, the lake has frozen over 162 times and remained open 43 times. Though the 43 open years aren’t even distributed – 65% of these have occurred within the last 50 years, 90% in the last 100 years. And this has had a significant impact on our resident birds. For many birds that depend on wetlands for food and shelter (herons, egrets, bitterns, rails, ducks, terns, sandpipers, etc), the impending freeze up of their habitat in the fall signals that it’s time to migrate to more favorable habitats either on the coast or farther south. This is particularly true for shore birds that rely on the shallow parts of rivers, ponds, and lakes which freeze up first and more reliably. These birds tend to be more synced up with the calendar (day length change) than the weather for coordinating migration times.