Not too long ago, it was commonplace for birders to make casual references to THE call or THE song of a bird species, as though every bird had only two modes of communication.  Now we know better.

These days, I’m more likely to hear casual references to THE flight call and THE alarm call.  After all, when we notice that, for example, many species of warblers and sparrows give similar high “seets” on the wing in migration and sharp “chips” in alarm when perched, it makes sense to group those calls into categories and name them after similarities in their form or function.

But there’s an odd, insidious trick of psychology at work in all of us.  If a sound doesn’t match our expectations — if it doesn’t fit one of our pre-existing mental categories — we’re much less likely to hear it.  If we do hear it, we’re likely to dismiss it as a quirk of the individual, a bird doing “something weird.”  Or else we’ll just cram it into a category we recognize: “must be the flight call, I guess.”

Something like this happened to me as I researched the “call notes” of various warblers.  I regularly ran into sounds that didn’t fit my mental categories, and after a brief period of confusion, I tended to dismiss them as atypical versions of the normal call.  Beware that word “atypical” — it strongly suggests that what you’re hearing is best ignored, that it’s an outlier at risk of messing up your dataset.

A few months ago, an online chat with my co-blogger Andrew Spencer started unraveling some of my preconceptions:

Andrew: are you going to cover alarm calls in warblers?

me: What kinds of alarm calls?

Andrew: those high pitched tink calls that many warblers give

like http://www.xeno-canto.org/13861

I think every warbler just about does tink calls when alarmed

I heard Connecticut Warbler give one

and I’ve heard it from a number of other species

but I don’t know how many recordings there are

me: Just higher-pitched versions of the normal call? Or something distinct?

Andrew: the one I linked of the Orange-crowned Warbler is distinct I think

all the ones I’ve heard sound damn near the same

me: I remember when I was researching Louisiana Waterthrush calls I came upon a recording in the Macaulay collection of a bird giving calls much higher than all the other recordings — more like your tinks. I just figured it was a crazy variation on the normal call.

Andrew: I have calls like that from Black-throated Blue Warbler as well: http://www.xeno-canto.org/30783

me: And I have a recording of an agitated Kentucky Warbler switching back and forth from a chip-like to a tink-like note.

Andrew: and I got a few from Golden-winged Warbler this past trip

me: These “tink” notes appear to be poorly described in field guides and the literature.

Andrew: doesn’t surprise me

me: This calls for a blog post.

Andrew: haha I was about to say the same thing

As soon as I started digging, I realized that these “tink” calls hadn’t gone unnoticed by everyone.  Paul Driver featured them on his blog back in 2009, under the name “high chip calls”:

A number of warblers (perhaps most?) have high chip alarm calls different to the typical chip call, sounding more like titmice or Golden-crowned Kinglet. They seem to be heard most often on breeding grounds and are often given by birds that are highly agitated; in this way they seem analogous to the high chip call of the Song Sparrow.

Funny he should mention Song Sparrow.  Recordings show that a great many species of sparrow give a “tink” note that sounds much like the “tinks” of warblers, and is given in similar situations of high alarm.  (This warbler-sparrow similarity is no coincidence – but that’s a subject for another day.)

These “tink” notes seem worth of their own category, separate from the “call” and the “flight call.”  They tend to indicate a higher level of alarm than “typical” calls, but not as high as the buzzes and shrieks that these birds give when they’re really upset (e.g., when a predator is attacking a nest, or when the bird is caught in a mist net).  Sometimes one hears calls intermediate between the high “tinks” and the lower “chips,” especially from sparrows.

“Tinks” can raise some interesting questions.  In some species, like Cape May Warbler, the “typical” call sounds much like a tink, and there may be little distinction — or is it perhaps that the tink is just more frequently given, so that we think of it as typical?  At the very least, if you happen to be in the habit of identifying Cape May Warblers by call alone, the existence of similar sounds in all these other species should give you pause.

An online catalog of “tink” recordings

Not every warbler and sparrow has a “tink,” apparently. For example, I haven’t been able to find any convincing examples from the genus Spizella (except for American Tree Sparrow, which many researchers agree is misplaced in Spizella and overdue for a move to its own genus).

I’ve attempted to assemble a collection of “tink” recordings that are available online, in order to document their existence in as many species as possible.  No doubt there are other “tinking” species not currently represented below.

• Ovenbird (maybe these are tinks)
• Worm-eating Warbler (also on Paul Driver’s site)
• Louisiana Waterthrush (mostly chip notes with a few tinks thrown in)
• Blue-winged Warbler
• Golden-winged Warbler
• Lucy’s Warbler
• Orange-crowned Warbler
• Kentucky Warbler (on Paul Driver’s site)
• Common Yellowthroat (on Paul Driver’s site)
• Yellow Warbler (on Paul Driver’s site)
• Black-throated Blue Warbler
• Cape May Warbler (this species may not give lower-pitched calls)
• Blackburnian Warbler (also on Paul Driver’s site)
• “Audubon’s” Yellow-rumped Warbler
• Pine Warbler (on Paul Driver’s site)
• Black-throated Gray Warbler
• Golden-cheeked Warbler
• Black-throated Green Warbler
• Bay-breasted Warbler
• Canada Warbler (maybe these are tinks)
• Painted Redstart
• Spotted Towhee
• Eastern Towhee
• Green-tailed Towhee
• Song Sparrow (on Paul Driver’s site)
• Swamp Sparrow
• Vesper Sparrow
• Fox Sparrow (Slate-colored)
• White-throated Sparrow
• White-crowned Sparrow 
• American Tree Sparrow
• Savannah Sparrow
• Le Conte’s Sparrow

If you can add to the list above, or have other useful observations of “tink”-like notes, let me know!