It’s no wonder the International Migratory Bird Day is held in the month of May. This is the time when trees leaf out and provide a welcome habitat to birds returning from their southern dwelling spots. The Great Lakes Radio Consortium’s Jim Blum ventures beyond the backyard to see who’s back:
Transcript
It’s no wonder the International Migratory Bird Day is held in the month of May. This is the time
when trees in the Great Lakes states leaf out and provide a welcome habitat to birds returning
from their southern dwelling spots. The Great Lakes Radio Consortium’s Jim Blum decided to
venture beyond the backyard to see who’s back:
Blum: Take a stroll into a forest and you may notice that trees have greened out this month.
There are thick canopies overhead that weren’t there just a week or two ago. Naturalist Dan Best
says, that times out very nicely for returning migratory birds.
Best: That’s right. A few warm days and the leaves just explode out of the buds. And we have
full leaf-out already. May is just an amazing month. You still have the wildflowers, lots of
wildflowers. And well, Jim, what do you hear?
Blum: Well, certainly a parade of birds that I didn’t hear a month ago. The nuthatches and the
chickadees are still here, but who’s joined them?
Best: Lots and lots of birds. New arrivals here. We have thrushes and warblers and vireos and
tanagers, flycatchers – a tremendous variety of birds that have come to us from their wintering
areas in Latin America. That is South America, Central America, the Caribbean nations. These
birds have made their way, many of them traveling at night, using amazing means of navigation.
They’re using celestial navigation, that is, using the stars. They’re using perhaps the earth’s
magnetism, sensitivity to polarized light, a variety of different means to make their way
thousands of miles over land and ocean to return here to our forests to nest.
Blum: Why May, why now, why so many?
Best: Well, let’s take a walk over to some of these leaves, and no matter what kind of tree you’re
looking at here, what do you notice on these leaves?
Blum: Well, it seems as if several of them have little chew marks or holes.
Best: That’s right, holes. And no sooner does a leaf out, then the salad bar is served for
hundreds of different kinds of caterpillars, whether they be butterflies or especially moths. Their
hatching of these eggs of these caterpillars is synchronized with this leaf-out.
Blum: So, apparently there are many visitors to this buffet, but who, what, and where?
Best: Well, ok. Let’s listen here. (bird chirps) Hear that over there? That’s a hooded warbler.
(bird chirps again) Yeah, there it goes. Now that one will tend to stay low. Oh, the male might
go up a little higher to sing to announce its territory, but generally it’s gonna forge in this shrub
layer in the lower part of the forest.
Blum: (another bird chirps) Now what was that?
Best: Well, I can hear a nice warble up there. That’s the rose-breasted grosbeak. They all
spend most of their time in the understory – that’s about halfway up in this mature forest we’re in.
And then listening a little higher above us, I can hear that nice hoarse, robin-like song of the
scarlet tanager. And I’m even picking up the cerulian warbler, and a little bit of the hoarser vireo
sound, as well as the yellow-throated vireo, and those birds like to stay high up in the canopy.
Blum: So in order for this forest restaurant, if you will, to accommodate so many different
customers, it needs different stories.
Best: That’s right. These birds are here because of the big insect menu that the forest has to
offer. And they’re not fighting for the same seat at the same table because they’re distributed in
these different levels of the forest.
Blum: So if you’re talking about a canopy, an understory, and a shrub layer, you’re indicating a
mature forest.
Best: That’s right. That’s a characteristic of a mature and old growth forest is it has these defined
layers. This kind of habitat, these large tracts of mature forests are getting harder to come by, as
the large trees are logged out, or even worse, these remaining forest tracts are continually
fragmented into smaller parcels, which are less suitable for this big diversity of forest-nesting
birds.
Blum: Now, Dan, I’ve seen the bird books. These birds are extremely colorful. Any tips on the
best chance of actually seeing them?
Best: Well, bring your binoculars into the forest with you. And don’t charge up to every song
that you hear. Just slow down, take it nice and easy. Look where you hear a song. Watch for that
little movement of leaves. Spot that movement. Raise your binoculars and you’ll eventually see
them. You’ll get to see these different kinds of birds.
Blum: That’s naturalist Dan Best. Some of us live in one story houses and some in high-rise
buildings. It’s a good idea when bird-watching to remember that birds also have their own
preferred level. For the Great Lakes Radio Consortium, I’m Jim Blum.