Tuesday, October 2, 2012

The Alder Flycatcher in Fall

 The Alder Flycatcher is a member of the tyrant flycatchers and is very difficult to distinguish from other flycatchers.  In fact, it is so similar to the Willow Flycatcher that they were once considered the same species, referred to as the Traills Flycatcher.  Research conducted by Stein in 1958 and 1963 determined the vocalizations of the Willow and the Alder were distinguishably different:  The Willow's song sounds like "Fitzbew" while the Alder's song sounds like "Feebeeo." Hence, these were two different species. Since ranges of these two species overlap and their habitat and behaviour is virtually the same, unless the vocalization is heard, there is no chance of me differentiating them. Even then, would I be able to tell the difference in the song, even if they were singing side-by-side?
 Probably not. That is why we are very lucky to have many knowledgeable birders in our midst to help us out. The first bird pictured here was photographed on the 29th on Blackhead Road near Cape Spear.  It is quite unusual to find a flycatcher still around this late in the year, but there it was. Not for long, however, as I only got three pictures and only one relatively clear one.
The second and third image were taken during the summer.  The color of the Summer is much fresher than the Fall bird.  The eye ring of the Fall bird also seems to be a little bigger than the summer bird. I looked and looked at these two bird images and stared hard at the images on the Internet. All for naught. Without having heard the song of the Fall bird, there is no distinguishing it as anything other than an Alder.  It's really an odds-on guess without all the information.

At this time of year, there is rarely any sound coming from the woods. I guess to overcome my inability to nail down the ID of this bird definitively, I will have to go looking for the visiting Great Crested Flycatcher that was found on Blackhead Road on Sunday. There will be no mistaking the ID of that one.

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