Barn Owls began breeding on Nantucket in 1968. These birds do not like very cold weather and prior to 2002, the population was only about 15 to 20 pairs. During the severe winters of 2002 and 2003, however, the population crashed to a low of only one known owl in 2005. In 2006 we knew of one successful nest and the population has been increasing since then, helped perhaps by the construction of many nesting boxes.
Inside a Nantucket Barn Owl box:
2014 Update- Winters are hard on Barn Owls
From Dr. Bob Kennedy: “Though Barn Owls live on every continent except Antarctica, they are restricted to the warmer regions of Earth. They do not do well in extreme cold and when snow covers the ground for extended periods limiting access to prey.
“Nantucket and Martha’s Vineyard are essentially at the northern limit of the Barn Owl range in North America. They have been recorded nesting further north but in the most recent Breeding Bird Atlas for Massachusetts, there are no known breeding birds outside of the islands. During the winters of 2002/2003 and 2003/2004 the seemingly very healthy population of Barn Owls on Nantucket plummeted from around 20 pair to one known bird. The first successful nesting after 2004 was of a pair along Polpis Harbor in 2005. Fortunately, Barn Owls disperse up to 500 miles once they leave the nest, and a few birds probably made it to Nantucket to get things started again. We do have one bird that we know came from Rhode Island. In 2012, Maria Mitchell Association Collection Manager Julia Blyth located 23 active Barn Owl nest boxes, the highest population ever recorded for Nantucket. It took 14 nesting seasons to build up to this population. Last winter was tough for Barn Owls and we lost about half the population. Fortunately we found 12 nest boxes with young in June of 2013 and they produced 46 young.
“The way this winter is shaping up, it could be a repeat of the winters earlier that devastated the population. There is not much we can do to help the Barn Owls as this is a natural phenomenon – a process that happens with all wild species at the limits of their range. We can just hope that some make it through the winter to help restore the population this summer.”
How do we band Barn Owls?
- We temporarily take the young out of the box to measure them.
To band Barn Owls, we use a ladder to access the elevated nesting boxes. The adults typically fly away, though sometimes we are able to catch them and collect important measurement data. There can be up to eight young owls in a box. We check the boxes after the babies hatch, but before they can fly. We measure the young and then loosely attach an aluminum band to their leg. This lightweight band has a unique number and will be with the bird its entire life.