video and text by Brian Willson

It’s pretty quiet in the woods and fields these days, as our seasonal residents get their youngsters ready for fall migration, so I thought I’d go back a few weeks and mention a curious peculiarity of summertime bird song.

Serious birders soon learn to identify a species by its spring song. This can be easy with Maine’s state bird (and others that sing their name), or those that holler for Old Sam Peabody-Peabody-Peabody! or urge you to Drink your teeeaaa! But an ID can be a trickier among the many little wood-warbler species that nest in our midst each year, often requiring an ear for the exact placement of a buzz or whistle.

Still, with a little practice, it shouldn’t take more than a couple-three seasons to be able to tell apart our commonest warbler species. That is, until the arrival of summer, when a lot of them change their tune. These birds’ primary (or Type I) songs—their most familiar—are intended to attract mates; but once that business is taken care of, their singing turns to territorial purposes, which require alternate (or Type II) songs.

Perhaps the easiest bird to recognize by both its songs is the black-throated green warbler: its early call is a long clear note with a buzzy hiccup at the end; its late call is a series of four notes—two buzzy ones, a clear one, a buzzy one. More difficult to learn is the the alternate song of the chestnut-sided warbler, a sort of mashup of garbled trills that sounds nothing like its familiar, clear pleased, pleased, pleased to meet you!

Back in July I was lucky enough to get a good look at a preening black-and-white warbler that was singing its alternate, territorial song. [Note: in spring, while singing their primary/mating songs, these birds never stop moving about trunks and branches and would not be caught dead posing like this.] It’s a multi-part composition, much unlike the bird’s monotonous love song of weesy-weesy-weesy-weesy

Incidentally, among the other audible bird voices you can hear in the background here, the loudest happens to be the confusing, Type II song of a chestnut-sided warbler. (Can you ID the three other species?)