Recently, Patterson and Patterson (2010) documented a single Glaucomys sabrinus (Northern Flying Squirrel) having two litters in a single year in southern Ontario, Canada. We confi rm this record and provide evidence for two new observations; 1) Northern Flying Squirrels will attempt a second litter after raising a successful fi rst litter; and 2) Northern Flying Squirrels can be lactating and pregnant at the same time. We also present data on the frequency of polyestry in a single year. In 2008, 3 of 10 radio-collared flying squirrels in southern New Brunswick, Canada attempted two litters. The first litter was born in early June, and the second litter in mid-August. Our data suggest that polyestry in Northern Flying Squirrels may be relatively common in some years.

Model forest, Adaptatation, Canada