Nikon D300, 300/2.8 AF-S Nikkor plus TC20E III (2x), Gitzo tripod with gimbal head, ISO 800, 1/125th second at f/8, spot meter
The Empidonax flycatchers present a real challenge to birders trying to identify birds in the wild. They are a group of closely related birds that look very similar and require skill, experience, and good looks at the bird in question. All the field guides I own have variations on the same cautionary tale: these birds are best separated by call and breeding territory, two clues that are useless for almost all migrant birds who don’t call.
I learned most of what I know about birds and their identification when I lived in NJ and was an active birder for over 20 years. I knew the calls of each breeding species and through the excellent network of active birders I learned where most could be observed in breeding season. I tried to learn the subtle visual differences but even with years of practice I mostly passed on trying to id migrant birds, calling them simply “empids.”
When I came to AZ in 1994 I was confronted by a different mix of empid species that are seen primarily as silent migrants and I’ve never felt confident in any of my identifications of these birds.
Nikon D300, 300/2.8 AF-S Nikkor plus TC20E III (2x), Gitzo tripod with gimbal head, ISO 800, 1/80th second at f/8, spot meter
The subject of this post is an empid that I photographed at Boyce Thompson Arboretum on Tuesday, September 18, 2012 around 9:00 am in the Demonstration Garden.
Identification begins with classifying the bird as a flycatcher from general size, posture, activity, and overall color. The predominant greenish-yellow tones eliminate pewee and phoebe and put this bird in the difficult category of empid. The wing bars are good for empid, as is the two tone bill. Most empids have prominent distinctive eye rings; this bird has a very minimal eye ring. That, plus the buffy yellow color of tghe wing bars as seen in the top image, lead me to label this bird as a Willow Flycatcher (Empidonax traillii).
Nikon D300, 300/2.8 AF-S Nikkor plus TC20E III (2x), Gitzo tripod with gimbal head, ISO 800, 1/60th second at f/8, spot meter
But I’m still not 100% sure and I’d love to have comments from anyone explaining why they think it is or is not a Willow Flycatcher.