Summer slips away

Its officially fall, and not just because the leaves are changing or because of an arbitrary date on the calendar. No, for myself and thousands of other bird minded people, it's the birds that tipped the balance from summer to fall.

Since mid August, millions of birds great and small have been winging there way south, unnoticed by most, moving under cover of darkness, tirelessly aiming for some remembered wintering grounds or following and instinctual pull to go a specific direction for a specific distance. As they fly by they proclaim the ending of summer not with song and vigor as they welcomed spring but with silence broken only by a few faint call notes, heard overhead on nights with good winds, or the morning after as they frantically seek to replace lost energy.

But now at ling last the guard is changing. Still the neotropical migrants slip south, but they decrease as the vanguard of the fall birds increase. White-throated sparrows sing all year long as they move down from the boreal swamps, kinglets and red-breasted nuthatches annuounce their presence, oft heard but hard to see in the spruce and pines they prefer. Purple finches start to mingle with the house finches and goldfinches.

More obvious to everyone else is the clarion call of Canada Geese overhead, long sinuous V shapes lines winging high overhead. Soon great kettles of turkey vultures will be visible as the more northerly breeders head towards South America, leaving behind the brave resident vultures to subsist on roadkill and winterkill. All across the country, the birds of summer are heading south, back to their real homes, some biologists would say, as they may spend more time in the tropics then they do in the states.

And we are left with the brave birds of fall and winter, who view the chilling winds and snows that lay but a few months off as mild compared to what they flee from, and whom will keep is company as the days grow shorter and lives frantic pace slows. They give us something to look forward to as the mercury plunges, for the colder it gets, the better the chance of those denizens of the high arctic gracing us; goshawks and gyrfalcons, ross's and ivory gulls, hoary redpolls and boreal owls.

Actually to be honest, it's not the cold they flee but starvation. With adequate food supplies, any one of those birds would be at home in the fiercest of winters. But when the temperatures drop, they need more and more food just to survive, and if they can't find it they make venture down to comparatively warmer and hopefully more plentiful lands. And we'll be waiting, for by then the birds of fall will be commonplace, and the birds of winter will dance in our minds.

Wanderlust

I suppose my first post should include a bit of an explanation into the name of my blog. The word comes from German, and is a combination of Zug (move, migration) and Unruhe (anxiety, restlessness). It describes the instinctive restlessness that migratory birds experience before the onset of migration. It's often characterized by restlessness, changes in sleep pattern and practice flights in the direction of intended migration.


It seems a particularly apt title to the blog of a seasonal field biologist, though I suppose I'd fall more under the category of nomadic rather than truly migratory, since I don't return to the same area. My wanderings are largely tied to changing of the season, as when the birds I'm studying leave it's time for me to move on and find a new job.

My current employment has me gathering data on what has been described as the greatest migration of carnivores in the world; fall hawk migration. Working with the New Jersey Audubon Society, I am carrying on a long-standing tradition of recording migrating raptors, this being the 54th year of the Montclair Hawk Watch. The 2nd oldest hawk watch in the country, and indeed, the world, Montclair, NJ is an unlikely location for a hawk watch. Surrounded by million dollar homes and suburban development in all directions sits the NJAS's smallest sanctuary, a gravel covered platform barely an acre in size is all that's needed to view the over 10,000 hawks recorded here on average.

This week is a special time in hawk watching, the big Broad-winged Hawk push. Soon, with the next big cold front, thousands of Broad-wings will simultaneously feel the urge to migrate culminate when the right conditions are present. Good winds out of the north to push them on their journey south, a sunny day to heat the land and create those rising pockets of warm air called thermals that will drastically reduce the effort needed to gain lift. Indeed, on a good day, the hawks barely need to flap to stay aloft, instead rely on that rising air to push them upwards, then sailing down towards the next thermal with only a few flaps to steady them. On a good day, several thousand Broad-wings will be seen from the ridge moving by in groups called kettles, ranging in size from dozens to hundreds. As the first birds to reach the top of the column of rising air peal off and head south, the appearance is of a kettle boiling over and spilling out, a river of raptors being carried along on currents of air.

It's a spectacular sight that one has to see to appreciate, occurring every year right over our heads, unnoticed and unremarked by all but a few.