This bird had us tricked big time! We first heard it calling an atypical 'whit' and thought there was a Willow Flycatcher around. We found this bird and identified it as a Wood-Pewee but soon saw that it gave the call. We were convinced that we had a Willow Flycatcher and looked at it as such. Just before it left it actually sang and the confusion started. At home looking at this and the following picture (and others) I saw that the wing was too long for an Empidonax but fitted Wood-Pewee. While looking at it, it behaved like a Wood-Pewee but as it sounded like a Willow Flycatcher and not the typical 'pee-wee' call, we were fooled.
The bottom line is of course - you learn something every day!