Idaho Bird Records Committee Rarities Report Form

 

Species: MacGillivray’s Warbler

 

Reporter: Heidi Ware

Email: HeidiTheBirdNerd@yahoo.com

Cell: (208) 860-5935

2120 Mortimer Drive Boise, ID 83712

 

Other Observers: Jay Carlisle

 

Date Report Prepared: December 7, 2009

 

Date Sighting Occurred:  December 5, 2009

 

Locality of Observation: Veterans Memorial Park Greenbelt (Boise River)—Boise, ID

 

Habitat: Bushes and tree on riverbank

 

Conditions: Bird was observed for less than 5 minutes total, including the brief glimpses and hearing the call notes. (stayed hidden and silent for quite a while). The sun was still rising so it was somewhat dark, but definitely light enough to see color and markings clearly. I observed the bird from approx. 10-15’ away with Vortex 10X42 binoculars. Very cold day. Low of 18 high 35. Clear sky and slight breeze

 

Did you take notes? No. but discussed ID points with other observer during and after sighting

 

Did you consult a field guide or other reference work? Not for the MGWA ID. (I did check the Sibley Guide to Birds to remember details about CONW and MOWA for this report)

 

Description: an Adult Male MacGillivray’s Warbler. Bird was initially heard while walking on the greenbelt path. Chip note was clearly the “marble-click” MGWA sound. Heard this call >5 times, and caught fleeting glimpses of the bird through grass and branches. I finally got a clear view, and was able to confirm the long tail, greenish and yellow body coloration, full gray hood, dark black on the lores and border of the hood/chest, and very clear broken white eye ring.

 

Behavior: The bird called multiple times but was very elusive (which definitely fits the species!). It hopped through the low bushes and a tree along the edge of the river and continued to “pop out” of the bushes for a few seconds before disappearing again.

 

How and when did you positively identify the bird, and what clinched the identification for you? For both observers, the first thought at hearing the call note was “warbler”….then we were confused because it was not the expected Yellow-rump or maybe orange-crowned call note. Once our brains were out of “winter bird mode” it was easy to tell that it was a MacGillivray’s Warbler call. For a while I only got views of its tail (I could see it was long-ish and that it was the “right” green color for a Mac), but before seeing the full bird, we both joked about the possibility of a Mourning Warbler or something else rare. So when I finally got good looks at the bird I was ready to make sure it really had a broken eye ring! The identification was made easier because it was an adult male MGWA with the dark lores plus the eye ring…which is pretty unmistakable!

 

How did you eliminate similar species, and what were they?

I eliminated other Oporornis warblers based mostly on the broken eye ring. I knew that a Mourning Warbler would not have an obvious eye ring. Also, a Connecticut Warbler would have a full eye ring and would not have the dark lores.

 

Experience with this species (and similar species): Both observers band 100’s of MacGillivray’s Warblers each season at the Idaho Bird Observatory; both also have experience detecting MGWA’s using sight and sound during official point counts. I am confident with MGWA chip notes and the other observer, Jay Carlisle, is very familiar with these and other warbler calls. Jay has seen both MOWA and CONW’s. I have not seen either of those species, but know enough about them from field guides to always be “on the lookout” for them.

 

General birding experience: I have been seriously birding for a little over a year. I now feel confident on my visual and auditory ID skills of many common Idaho bird species. I

spent the summer of 09 conducting bird point count surveys using both sight and sound for ID. I also have in-hand experience with many Idaho species.

 

 

Were photo(s), video, and/or audio obtained by you? no