The word of the day: “Kettling”

Autumn is a wonderful time of year to visit the Monadnock Region to see the fall foliage and other sights.  One of those wondrous sights is the annual migration of the raptors (hawks, eagles, falcons, vultures, etc) from New England and Canada heading South.

Pack Monadnock, also known as Miller State Park, just four miles East of downtown Peterborough is considered one of the best places in New England from which to view this spectacular event.  Its such a great spot that the Audobon Society sets up a monitoring station at the top of the mountain from which to count them.
Counting hawks 🙂  I saw hundreds overhead that afternoon
Why is Pack such an ideal spot?
It was explained to us by one of the society’s volunteers.  When migrating, raptors will travel as much as 50-60 miles a day.  To conserve their energy, the birds prefer to glide as much as they can…and fly as little as necessary.  The way the birds do this is that they “kettle”.
“Kettling” is when the birds fly into a stream of air current that is pushing upward (updraft), ride it as high as it will take them (in a spiraling motion), and then shoot out of the upward spiral and glide as far as it will take them.  They will then repeat this system any chance they can.  Those vertical streams occur when horizontal air streams hit the side of a mountain and are deflected.  
Pack is near the very Northern terminus of a twenty-two mile ridge line called the Wapack Trail.  The ridge line creates a lot of updraft giving the birds a lot of opportunity to “kettle” and glide.  This means the birds can glide for nearly twenty-two miles without flying too much saving their energy…that’s why they like it so much.
So why is it called kettling?  When a mass of birds hit these upward flowing winds, they spiral upwards en masse and look like steam coming out of a tea kettle.  Thus…”kettling” 🙂
For the record, the site usually counts about 10,000 raptors each season.  This season they are already over 18,000 and there is plenty of counting left to be done!  Over a two day period last month they counted over 7,000!