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Evening Grosbeak Call Types

posted by Ryan O'Donnell at
on Wednesday, May 11, 2011 



Like Red Crossbills and Pine Grosbeaks, Evening Grosbeaks (Coccothraustes vespertinus) have been described as having distinct call types that vary geographically (Sewall et al. 2004). These distinct call types also correspond approximately with subspecies that have been described based on morphology. Because of these distinct call types which correlate to geography and morphology, it has been suggested that Evening Grosbeaks may be in need of further taxonomic work, that is, that they may be candidates for future splitting. In that Sewall et al. paper, they leave northern Utah as a question mark in their map, an unsampled area between the ranges of (morphologically-defined) subspecies C. v. brooksi and C. v. warreni, where no birds were examined and no calls recorded.

Yesterday I recorded a small flock of 4-6 Evening Grosbeaks calling in the treetops above my yard in Logan, Utah. Evening Grosbeak call types are distinct enough that they can be told apart by ear, but I don't have any practice at this so I imported recordings into the software RavenLite to examine the sonograms.

Most of the calls were of Type 1. This is the call type that is given by C. v. brooksi, the subspecies which ranges from Oregon, Idaho, and Wyoming north to northern British Columbia. Here is a sonogram of a Type 1 call I recorded yesterday:

And here is a recording of Type 1 calls from Washington you can listen to:


In my recording yesterday, I was also able to pick out a few examples of Type 4 calls in my recordings, which is typical of C. v. warreni and mapped by Sewell et al. as occurring from about the Uintah Mountains, through Colorado, to northern Arizona and northern New Mexico. Here is a sonogram of one of the Type 4 calls from my yard:


And here are some Type 4 calls from Colorado you can listen to:


Sewall et al. documented both call types 1 and 4 from northwestern Wyoming and southern Colorado. It appears that both call types also occur in northern Utah. More work will have to be done to tell whether this is the result of movement of individuals, intergradation between subspecies, or overlap between reproductively isolated cryptic species.

Sewall, K., R. Kelsey, and T. P. Hahn. 2004. Discrete variants of Evening Grosbeak flight calls. Condor 106:161-165.

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3 Comments:
Anonymous Jerry Liguori said...

Cool post Ryan

I have seen/heard an unusually large number of Evening Grosbeaks for Utah this past fall/winter/spring. All giving the "whistled" flight note or "crackly trill"

Jerry

May 12, 2011 at 8:20 AM  
Anonymous Anonymous said...

Thank you for that information.
I am terrible at sounds but most of mine seem
to sound like that Washington call with the distinctive
extension to the note. With 50 of them calling at once who knows
what is in the mix!

Are there any physical distinctions?

Watching them since February: in the past month
the green gloss on the bill has become quite obvious.

Kimberly Roush

May 12, 2011 at 10:15 AM  
Blogger Ryan O'Donnell said...

I'm told someone asked about morphological differences between the two types. There are some differences, at least on average, but they are very subtle and probably not noticeable in the field. According to the Identification Guide to North American Birds, by Peter Pyle, warreni "may average paler and with narrower bills [than brooksi] but differences, if present, are slight and obscured by individual variation." For this reason, some authors don't even consider warreni and brooksi to be separate subspecies, but lump them together as brooksi.

May 18, 2011 at 12:26 PM  

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