COMMENTARY: Migrating birds return, but are their northern homes safe?

By Christine Hepburn, New Jersey Hills Media Group Editor

Wood Thrushes are one of many migratory bird species that rely on habitats like the Drew University Forest Preserve in Madison.

Photo by Blaine Rothauser

Spring is here and the “snowbirds” are returning to New Jersey. These are the people who migrate south to avoid the winters at home (disclosure: I’m one of them).

In the winter, the state of Florida alone plays host to about a million people from the icy north. We fortunate snowbirds go south by choice, aided by powerful machines, and don’t worry about having a home when we return.

Many of the real birds we enjoy all summer also head south for the winter – way south, to southern Mexico, and Central, or even South, America. It isn’t a choice, it’s what they must do to survive. They are now due to journey back to their northern breeding grounds and will be arriving in New Jersey from March through the month of May. These real birds, however, are not necessarily going to find their northern habitats intact.

I lived next to the Drew Forest in Madison for years and enjoyed Wood Thrushes and other neotropical migrants nesting. The Drew Forest is now at risk of being sold for development.

Please imagine that you are a Wood Thrush from the Drew Forest. You have spent the winter months in Belize. You’re fortunate that the forest where you ‘winter’ has not been replaced by farmland. You’ve rested and had plenty to eat and now the longer days mean that it’s time to set off on the 2000-mile journey to your breeding home in New Jersey.

You travel at night and fly nonstop over the Gulf of Mexico, hoping that no major storm throws you off-course or even drowns you. You make it over the gulf and keep on flying, heading northeast night after night, resting and feeding during the day in patches of green. You’re lucky to not get hit by a car or fly into a tall, dark building in the night, as so many others do. You’re getting closer – the Jersey shoreline is attracting a lot of birds, but it’s not the place for you. You keep flying.

You are aiming, as you do every spring, for a specific patch of woods where you were born. It isn’t large – only 53 acres, versus the 250 acres considered optimal, but it has enough of what you need. Its deciduous trees include large, old ones that provide a high tree canopy and lots of moist leaf litter on the ground. Moist leaf litter is where you find the worms and insects that you feed upon.

The rich understory of shrubs and plants helps protect your young from predators when they are new to flying and foraging on their own.

You are exhausted from your arduous five-day journey and have lost a noticeable amount of body weight that was under two ounces to begin with. Soon, though, you will rest, eat, and look for a mate, perhaps the gal from last summer.

But wait, did you make a wrong turn? Impossible – you unerringly arrive at your forest every spring! But where is it? You search but there are only a few tree tops; the full, green canopy is gone.

Perched in one of the few trees, you see that the world has changed catastrophically. Countless trees are gone and large machines lurk. The leaf litter where your food lives? It is gone; mud and concrete have taken its place. Even if you built a nest in a remaining tree, you can not survive here and certainly couldn’t feed a family.

Though weakened, you must take to the skies again and look for a new home. There aren’t many places in the vicinity that meet your needs and you won’t find your mate from last year. If you do find a good place, another Wood Thrush is likely to already be there and will defend his territory against a bird who occupies the exact same food niche. You are in trouble.

This scenario has played out countless times in the southern as well as northern forests. Not surprisingly, the numbers of ‘neotropical migrants’ have declined alarmingly in recent decades. This spring, the Wood Thrushes and other species will find the intact Drew Forest that they need.

I hope that we can say that in the years to come.

The writer was a founder of Madison Matters and the original chair of Madison's Open Space, Recreation, and Historic Preservation Advisory Committee. She now lives in the woods in Hardwick, and is active with the Friends of the Drew Forest. She can be reached at christinehepburn@me.com.