Nature Notes

As spring gets underway in April, are you one of the many New Englanders who make a point of noticing beginnings – of the growing season, birdsong, bird migration, and more? The hermit thrush is a not-so-noticeable “early arrival” that migrates to and through our region. This woodland bird with a haunting, flute-like song is a treat if you find one.

As you walk in the still-bare woods, watch and listen for the hermit thrush (Catharus guttatus). Brown with a spotted breast, it’s a shy and wary bird. That’s not surprising for a bird that both feeds and nests on or near the ground. Look for one hopping among the leaf litter, flipping over leaves with its beak, or perching on a fallen log or low branch. Like so many other birds at this time of year, hermit thrushes search for insects to fuel their migration and their reproduction.

You might hear the hermit thrush’s short, 2-second bursts of echoing song, with pauses between bursts. Hermit thrushes learn their songs early in life. Those in our region sing about 10 variations.

These thrushes create songs with their specialized voicebox, or “songbox” (syrinx). It has two branches, which the thrush controls independently with different nerves. As a result, hermit thrushes can sing different notes at the same time.

How did the hermit thrush get its name? It has long been known for living in deep woods, and this lifestyle is probably the reason for the name. The hermit thrush is the state bird of Vermont. The environment in Massachusetts became more suitable for hermit thrushes as forests grew back after the late 1800s, when 60-80 percent of our state had been cleared for agriculture and timber. In the 1920s, hermit thrushes appeared in central Massachusetts.

Mid-April is an ideal time to be on the lookout for hermit thrushes because many are passing through to breed in the forests of northern New England and Canada. Some hermit thrushes do stay in our region to breed. A few may even overwinter here, but they don’t like snow or temperatures below 25-30 degrees F. Most migrate to more southern states in October-November, searching out wild berries along the way. Migrating thrushes typically fly at night, when the air is more stable.

In mid-May, a similar-looking relative will arrive: the wood thrush (Hylocichla mustelina). It has similar habits. It also sings its own different, flute-like song with many variations.

What differences might help you tell these two thrushes apart?

Behavior can help you recognize a hermit thrush. These thrushes tend to flick their tail up and down when they’re perched. They also tend to flick their wings.

Timing can be a clue as to which thrush is which. Hermit thrushes are more common here in early spring (April) during their northward migration. Wood thrushes are more common locally from mid-May through summer, because many breed here.

Another clue is the type of woods where these two birds tend to hang out. You can find both in mixed woods (both evergreen and deciduous trees), but hermit thrushes are partial to evergreen woods, with local pines or hemlocks. Wood thrushes favor deciduous woods.

The two birds differ somewhat in appearance, but it’s often hard to get a good look. Hermit thrushes have a subtle, two-toned look, with a reddish-brown tail contrasting with a brown back. Wood thrushes are reddish cinnamon-brown on back and tail. Both birds have spotting on throat and breast, but the wood thrush’s spotting goes farther down the belly.

Their songs are also different, but not easy for everyone to tell apart. Listen for a longer, steady introductory note in the hermit thrush’s song. Notice an “ee-oh-lay” sound in the wood thrush’s song. But above all, enjoy whatever birdsong you’re hearing.

What other birds might you see or hear locally in April? A couple of favorite singers are also in the thrush family: American robins and eastern bluebirds. Local wild turkeys breed March-May (be careful during turkey hunting season, April 28-May 24).

Other birds arriving here or coming through in April include: eastern phoebes; wood ducks; tree swallows; pine warblers; palm warblers; yellow-bellied sapsuckers, and more.

Enjoy all the early arrivals you might find.