The alarm calls of the Alder and Willow Flycatcher are very different, and a good way to identify an unknown bird if you are lucky enough to hear it call.
The most common Willow Flycatcher call is a whit. Alder does not have a similar call (June, NJ).
Compare with the common Alder Flycatcher call (July, ME).
Be aware that the Willow Flycatcher has a similar, but rarely heard call (see pip below).
Other Willow Flycatcher calls include whup, similar to whit but metallic-sounding (versus dry) (three examples, with a whit and trill, edited from trill recording below, July, PA).
A quite common call is zweeoo, which has a slight resemblance to the Alder Flycatcher song, and could lead to confusion. Alder also has a similar call (see below).
Another less often heard call, pip, used more as a contact call, is close in sound to the most common call of the Alder (July, PA).
Agitated pair near nest, with whit calls by one bird and a squeaky chatter by the other (June, PA).
reduced time scale
Another example of the chatter and other calls, between two males, including trills at 84 and 150s (June, PA).
Calls by two Willow Flycatchers in close vicinity (presumably males as both sang), with interaction calls and numerous trills (with Gray Catbird, July, PA).
The common alarm call of the Alder Flycatcher sounds like the first note of the Olive-sided Flycatcher song (July, ME).
As with some other flycatchers, the Alder Flycatcher has quite a varied vocabulary:
The double-peaked call is commonly given, but apparently not diagnostic as the Willow Flycatcher has a similar rarely heard call (July, ME).
Zweeo, apparently associated with nest defense. Willow Flycatcher has a similar call but with a break in it (July, ME).
Weeoo recalls Acadian. Again, Willow has a similar call but rarely given (July, ME).
This call monotonously repeated predawn by a presumed Alder Flycatcher appeared to be a song variant. It may be previously undescribed as it is not included in the exhaustive vocal repertoire described
here (from which the call nomenclature is derived) (4.30am, July, ME)
Call-like vocalizations may be strung together in what sound like song variants (July, ME).
call at 13s
These longer sequences have been termed complex calls (July, ME).
The Least Flycatcher call is a whit, similar to Willow Flycatcher, but softer (Sep, PA).
The Acadian Flycatcher has two commonly given calls, a descending pwer and a rising pweet.
In my experience, "pwer" is a call usually given by the female. This was a presumed female returning to nest with eggs (June, PA).
Another example of pwer with another call, a short trill (May, PA).
Two more examples, each a presumed female sitting on a nest, with different associated calls (June, DE)
(with a weet, weet, June, DE)
Pweet, note the subtle difference from pwer.
(sex unknown, May, PA)
Same call, by female building a nest. This call may be more of an alarm call.
(with Downy Woodpecker nestlings, June, DE)
Two birds calling (July, PA).
Yellow-bellied Flycatcher. This call is similar to the Acadian Flycatcher pwer, but a little squeakier, and is commonly heard on the wintering grounds. There is another call, heard more often on the breeding grounds, but also in migration, that sounds similar (but is shorter) to the pewee call of Eastern Wood-Pewee. See this
Xeno-Canto discussion for more on these calls. (migrant, Sep, PA).
The chip call of the Eastern Phoebe is commonly heard. It is similar to the chip of the Swamp Sparrow, but a little softer (Apr, PA).
Calls made by male while fluttering at potential nest-site under a bridge (Apr, PA).
time scale reduced
This call was repeated over a period of at least ten minutes by an overwintering bird (Feb, NC).
Recently paired male calling in the vicinity of the female, "tkeet" (Apr, PA).
Interaction calls between two phoebes in aggressive interaction (Feb, NC)
Note piteer call at 13s
The Eastern Wood-Pewee has a surprisingly large repertoire of calls.
The pewee call is probably the one most often heard (June, NJ).
call at 6s
Eastern Wood-Pewee calling at dawn. This vocalization may be repeated over and over after sunset as a twilight song (June, NJ).
A longer version of the call (July, PA).
Squeaky interaction calls between two pewees (May, NJ).
Frequently heard is a soft chip (June, NJ)
Bill snapping and other calls by two birds interacting (with Tufted Titmouse scolding, June, NJ)
short call at 11s
part of long call starting at 18s
The common call of the Olive-sided Flycatcher is a repeated pip-pip-pip (July, ME).
Eastern Kingbird tzee contact calls (July, NJ).
A common call sequence is the tzee-chatter (May, RI).
zeer and tzee-chatter
Female calling in foreground and twittering, male calling zeer in background, after female had flown from incomplete nest to adjacent tree (May, RI).
zeer and tzee by female
zeer and tzee-chatter
Eastern Kingbird alarm calls, pair chasing a Blue Jay from nest vicinity (May, RI).
Great Crested Flycatchers have vocalizations that can be termed as calls or song depending on the delivery (see Flycatcher songs).
They also have calls that are used in interactions. The following were made by pairs of birds in flight or just landed, with one bird being chased by the other.
Quiet calls by interacting Great Crested Flycatchers (Northern Flicker calling in between, June, NJ).
Quiet calls by a vagrant Ash-throated Flycatcher (another call, a brrt, is more diagnostic, Dec, NJ).