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 Willow Flycatcher call is a whit (June, NJ).
The common call of the Alder Flycatcher sounds like the first note of the Olive-sided Flycatcher song (July, ME).
Another Alder Flycatcher call (July, ME).
The Least Flycatcher call is a whit, similar to Willow Flycatcher, but softer and lower (Sep, NJ).
Yellow-bellied Flycatcher (Sep, PA).
The Acadian Flycatcher has two commonly given calls, a descending pwer and a rising pweet.
In my experience, "pwer" is a call given by the female. This was a female returning to nest with eggs (June, PA).
Another example of pwer with another call, a short trill (May, PA).
Pweet, note the subtle difference from pwer.
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).
Interaction calls between two phoebes high in trees (Mar, PA)
Interaction calls between four phoebes (Mar, PA)
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).
Chip call (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
Eastern Kingbird zeer 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
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).