Our winter migrants are all settled in, and our year-round species are flocking right along with them.
With the breeding season behind them, territoriality pretty much goes out the window, and they find more safety by traveling in mixed flocks.
They are so busy! But what on Earth are they doing out there?
Well, eating, of course!
Birds are small animals with fast metabolisms. When the weather turns cold, they spend every waking moment in search of the calories that will literally keep them alive through the night.
This is especially true of the really small birds, like chickadees and kinglets (incidentally, when it turns really cold, kinglets go into a state of torpor to stay alive).
We often don't give the birds much thought, even though we enjoy watching them and listening to them sing. It's really quite miraculous how they can survive the bitterly cold winters.
One interesting method of survival, is simply a matter of taste.
Just like humans, birds have their favorite foods. This varies depending on the species and the region they live in.
Around here, the big winter food sources are hard mast like acorns, hickory nuts and beech nuts, seeds from Elms and Maples, as well as over-wintering moths and caterpillars.
But what about fruit? We tend to think of fruit as a warm season food source that perishes quickly, but it is also crucial for winter.
Fruits like blackberries, raspberries and black cherries are big favorites, and usually get eaten up as soon as they're ripe. They are juicy, and full of fats and sugars. While this makes them really nutritious, it also means that they spoil quickly; offering a feeding bonanza for a short period of time.
You may notice, however, some types of fruit are left untouched, and seem to just rot on the plant.
A few examples around here are Viburnums, Buckthorn (Rhamnus sp.), Pokeberry (Phytolacca americana) and Virginia Creeper (Parthenocissus quinquefoloia).
If you pay attention, you'll see these are all eaten in turn, depending on the birds' preferences.
They save the least tasty fruits for last, and may not even eat them if the winter isn't harsh enough.
Coralberry (Symphoricarpos orbiculatus) comes to mind.
Even though it looks similar to American Beautyberry, it must not taste very good because we have NEVER seen anything eat it. Does that mean it's useless? Of course not! It's, quite simply, insurance.
If the cold weather drags on longer than usual, they will still have a food source to depend on.
While these emergency rations aren't very tasty or nutritious, their low water content means that they stay preserved much longer, sometimes even into early Spring.
In some cases, the ripening fruit of a certain plant coincides with groups of migrating birds, fueling them for the rest of their journey. Some species come to depend on this food source, and plan their entire migration routes around these crucial locations. Each new generation of birds is taught where to find them. If the food source becomes unavailable for whatever reason, they adapt and try to find another one.
In late fall, we get mixed flocks of thrushes: Veerys, Wood, Swainson's, Hermit and Gray-cheeked have all been recorded in these groups.
|Hermit Thrushes are another winter resident. When they begin to sing in early spring, their song will make your heart skip a beat|
They seem to fly through when the fruit of the Black Gum tree (Nyssa sylvatica) is ripe. All of those thrushes feeding, flitting and singing in one tree is a sight to behold!
|Nyssa sylvatica heavy with fruit. If you zoom in, you can see at least 4 thrushes in this photo|
|A closeup of a foraging Wood Thrush and below him a Tennessee Warbler|
|Robins feeding on sumac berries|
Another little-known important food source came as a bit of a revelation for me.
Yellow-rumped Warblers are the only warbler species that stay in the park throughout the winter. Warblers are primarily insectivores, but insects can be pretty hard to come by, this time of the year.
One day I saw a flock of Yellow-rumps flitting around a tree trunk, flipping upside down eating the fruit of of a plant a lot of us wish didn't exist: poison ivy!
It's not like I'm the first person to ever see this; it's well documented. It was just exciting to discover it for myself!
Nature is full of surprises, and these little discoveries never lose their luster.
If you are looking for a good book to curl up with this winter, I would highly recommend this one:
|You can see it's suffered its share of abuse|
It is such a fascinating read, and it will blow your mind. You can find it for a good price on Amazon, here (by the way, I'm not affiliated with Amazon in any way).
Watching the birds throughout the winter is a great way to pass the time!
Here's to the birds of winter!