Re: [SBB] Pajaro River grosbeak

["Roy Churchwell" <[[email protected]]>]

Hey Guys,

I do know of at least one record of red-breasted grosbeak nesting in Marin 
County in the last five years.  I thought I would just throw that into your 
discussion.

Roy Churchwell
Landbird Program Director
San Francisco Bay Bird Observatory
524 Valley Way
Milpitas, CA 95035
(408) 946-6548 ext. 11
[[email protected]]

NOTICE NEW ADDRESS
----- Original Message ----- 
From: "michael mammoser" <[[email protected]]>
To: "south-bay-birds" <[[email protected]]>
Sent: Sunday, August 05, 2007 5:32 PM
Subject: [SBB] Pajaro River grosbeak


> All,
>
> There has been some discussion between myself, Mike
> Rogers, and Steve Rottenborn about the identity of the
> alleged Rose-breasted Grosbeak along the Pajaro River
> last month. Some questions have been raised and I
> thought it might be informative to the members of this
> list to see that discussion.
>
> Michael Mammoser
>
>
>> -----Original Message-----
>> From: Mike Rogers
>> Sent: Tuesday, July 24, 2007
>> To: Mike Mammoser; Steve Rottenborn
>> Subject: Re: [SBB] Pajaro River etc.
>>
>>
>> Based on the photos taken of the "Rose-breasted
>> Grosbeak", it appears to be an HY bird. I doubt RBGR
>> are breeding down there, which makes the ID
>> questionable in my mind, given the time of year. The
>> fact that the bird was not that different from Tom
>> Grey's first photographed bird suggests to me that
> it
>> may be a heavily streaked juvenile BHGR, which Steve
>> Rottenborn agreed with. Of course, I haven't seen
> the
>> bird - but it is not encouraging that nobody is
>> getting photos or good looks at the center of
>> the breast. Call notes would be helpful too...
>
>
>> -----Original Message-----
>> From: michael mammoser
>> Sent: Monday, July 23, 2007 9:28 PM
>> To: Mike Rogers; Steve Rottenborn
>> Subject: Re: [SBB] Pajaro River etc.
>>
>>
>> I was back and forth on that apparent RBGR, but I
>> couldn't find any literature reference that
> indicated
>> a Black-headed would have streaking that heavy on
> the
>> underparts. What, in Tom's photo, indicated that the
>> bird was a "bird-of-the-year"?
>
>
>> -----Original Message-----
>> From: Steve Rottenborn
>> Sent: Tuesday, July 24, 2007
>> To: Mike Rogers; Mike Mammoser
>> Subject: Re: [SBB] Pajaro River etc.
>>
>>
>> I've been surprised that there hasn't been more
>> discussion of the identity of the "RBGR" on SBB,
>> especially since so many people have now claimed to
>> have seen one.
>>
>> I'll be the first to admit that I haven't done any
>> detailed research (e.g., using Pyle) to establish
>> either the age or the identity of this bird using
>> finer points of plumage, so my "analysis" is
>> admittedly superficial.
>>
>> I think the bird in Tom Grey's photos is definitely
>> a juvenile. The wing feathers appear very fresh, not
>> worn at all. I think an adult female would be worn.
>> Also, I could swear that bird still has enlarged
>> pinkish rictal flanges. I can't find a photo of an
>> adult RBGR on the web with enlarge pink rictal
>> flanges. If it's a juvenile, the chances of it being
>> a RBGR, or a hybrid, are greater than zero but still
>> very, very low.
>>
>> MJM, in your post to SBB you mentioned that Rich
>> said that the center of the breast is streaked. It
>> is my understanding that female BHGR can have
>> streaking on the center of the breast, but it is
>> finer than on RBGR
>> (see http://fog.ccsf.cc.ca.us/~jmorlan/grbkid.htm).
>
>>
>> When I saw Peggy Don's photos, I thought that the
>> streaking on that bird looked broader (not as fine)
>> as I'd expect on a BHGR. However, if I had to guess,
>> I'd bet that the bird is just a heavily streaked
>> BHGR. The photo of a female RBGR on the following
>> web page shows my impressions of a typical female
>> RBGR:
>>
>>
> http://www.wbu.com/chipperwoods/photos/rbgrosbeak.htm
>
>>
>> The female shown on the following web page shows a
>> bird with much, much less buff (and not nearly as
>> orange) as on the Pajaro River bird. Interestingly,
>> the streaking on this bird is even less extensive
>> than on the Pajaro River bird:
>>
>> http://www.pbase.com/lilwings/image/60639418
>>
>> I haven't seen the bird, nor have I done a detailed
>> analysis of age or species using Pyle, so I'm not
>> claiming that the bird is definitely a BHGR.
> However,
>> someone claiming a RBGR should do such an analysis
> to
>> age the bird and, if it is a juvenile, rule out
> BHGR.
>
>
>> -----Original Message-----
>> From: Mike Rogers
>> Sent: Tuesday, July 24, 2007
>> To: Mike Mammoser; Steve Rottenborn
>> Subject: Re: [SBB] Pajaro River etc.
>>
>>
>> The AHY (after hatch-year) female RBGR I saw along
>> Stevens Creek on 2 June looked very much like:
>>
>> http://www.pbase.com/lilwings/image/43569873
>>
>> http://www.pbase.com/lilwings/image/43669763
>>
>> Broad streaks with similarly broad streaking across
>> the mid-breast and some buff in the upper
>> breast/flanks, but none of the orange of the Pajaro
>> bird.
>>
>> I aged the Pajaro birds (Tom Grey's photos are of
> two
>> different birds) based on their very fresh,
> uniformly
>> aged plumage. As Steve pointed out, Tom Grey's
> photos
>> in particular show narrow yellow-green edges to all
>> flight feathers, something I don't think an adult
>> would ever show, especially this early in fall.
>>
>> It is my understanding that the pink bill (upper
>> mandible) is only a good field mark for RBGR in
> AHYs.
>>
>> I too still have to check Pyle on these birds, but
>> I suspect that juveniles may be more extensively
>> streaked than first-winters, which could explain the
>
>> heavier than expected streaking on the Pajaro bird.
>> It's yellow underwing coverts rule out a male RBGR I
>
>> think (I know these are pink in male RBGRs by Sep
>> anyway).
>
>
>> -----Original Message-----
>> From: michael mammoser
>> Sent: Tuesday, July 24, 2007 3:40 PM
>> To: Steve Rottenborn; Mike Rogers
>> Subject: RE: [SBB] Pajaro River etc.
>>
>>
>> I just looked at all the photos (I've dismissed Tom
>> Grey's first 3 photos - they're obviously of a
>> different bird) and these all seem to show virtually
>> the same bird. So, I think everyone is on the same
>> page in that regard.
>>
>> I don't think this bird is in "juvenal" plumage.
> That
>> plumage should show cinnamon wing bars and cinnamon
>> edging to upperpart feathers. At a minimum this bird
>> would be in 1st basic plumage, which, according to
>> Pyle, can be held into the second year.
>>
>> Steve's comment about the rictal flanges is very
>> interesting. I think these can be seen most easily
> in
>> Peggy Don's photo 47171_IMG5Q_RB_Grosbeak_Pajaro...
>> This would seem to be indicative of a
>> "bird-of-the-year", and unless your willing to
>> believe that Rose-breasted Grosbeaks breed in Santa
>> Clara County, or nearby...?
>>
>> After all, these aren't Swainson's Hawks :-)
>
>
>> -----Original Message-----
>> From: Steve Rottenborn
>> Sent: Tuesday, July 24, 2007
>> To: Mike Mammoser; Mike Rogers
>> Subject: RE: [SBB] Pajaro River etc.
>>
>>
>> It's obviously an interesting bird.  I'll try to
> take
>> a closer look at the photos later, but in the
>> meantime, it wouldn't hurt to send them to Joe
> Morlan
>> (and others? Kimball Garrett?) for an opinion.
>> We'll learn something one way or the other.
>
>
>
>
>
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