Date: 3/13/17 7:10 pm From: Aidan Place <placea...> Subject: Re: Allegheny County - Chickadees
Very elucidating observations, thank you very much Alan Buriak! Based off what I saw this weekend (honestly likely the only time I've really paid much attention to chickadees in North Park), I would generally agree that the birds seemed like hybrids and I, personally, would not enter any as anything other than BCCH/CACH. That being said, we didn't bird the Upper Field and I'm very interested in returning now and checking out the chickadees there!
Speaking on Gibsonia, I have heard third hand (so can't really vouch for this myself) from I believe Bob Mulvihill that Gibsonia marks essentially the current north/south demarcation point between the two species with those north being black-capped and south being Carolina. Your observations of phenotypically black-capped chickadees in Gibsonia would fit this.
Even excluding North Park (where a number of recent black-capped reports exist away from the Upper Field), there remain a number of rather erroneous reports of black-capped chickadees from Allegheny County. Recent ebird records exist of black-capped chickadee from Frick Park, Schenley Park, the Homewood Cemetery, and even Boyce-Mayview Park among other areas well within the zone of Carolinas. While of course, it is within the range of possibility for a BCCH to occur in these areas (particularly during the winter), the number of these reports at the very least suggests these are simply misreported birds.
Essentially my point is that birders ought to be much more cautious about what chickadees they are reporting, especially in around Pittsburgh. The method by which birders are reporting chickadees currently seems to be creating a sizable dump of rather inaccurate eBird data which is exaggerating the number of black-capped chickadees in the county.
Good birding, Aidan Place Allegheny County
On Mon, Mar 13, 2017 at 7:31 PM, Dave Brooke <davbrooke...> wrote:
> I found your discussion about Black-capped vs Carolina quite interesting > and > it led me to wonder if I was reporting my Chickadee observations correctly. > Interestingly, I just had this discussion with Gabi Hughes from the WPAS. > She stated that they saw a mix at Beechwood but we probably only see > Black-capped at Harrison Hills Park (where we were having this discussion). > Using the map tools available on Google Maps, I measured from the edge of > the contact zone sited in the Sibley article to North Park (5mi), to > Beechwood Farms (5.5mi), and to Harrison Hills (23mi). If in fact, the > contact zone has shifted north since the original map was created, North > Park and Beechwood could easily be within the zone while Harrison Hills > would remain a reasonable distance away. > I birded Harrison Hills today and feel pretty confident that all of the > Chickadees I saw were Black-capped. I'm a fairly new birder so I lack the > skills and experience of most of you posting to this list. > Those Chickadees from Harrison Hills can be seen here > https://www.flickr.com/photos/ddbphoto/shares/88sZ9N > Or on the Ebird checklist http://ebird.org/ebird/view/checklist/S35163129 > > Dave Brooke > > -----Original Message----- > From: Bird discussion list for Pennsylvania > [mailto:<PABIRDS...>] On Behalf Of Alan Buriak > Sent: Monday, March 13, 2017 11:31 AM > To: <PABIRDS...> > Subject: Re: [PABIRDS] Allegheny County - Chickadees > > Sameer and PA Birders, > > > I have been one of the primary eBird contributors for the North Park area > for the last 1-2 years, so I can speak to this topic. > > > First, if you check the map of the hybrid zone in the following link by > David Sibley, it places North Park just north of the top edge of the zone, > suggesting that pure Black-capped should be found there. > > http://www.sibleyguides.com/bird-info/black-capped- > chickadee/black-capped-ca > rolina-chickadee/ > > <http://www.sibleyguides.com/bird-info/black-capped- > chickadee/black-capped-c > arolina-chickadee/>However that article was posted in 2010, and the data > used for the map was probably even older. > > > Pertaining to North Park, I have also absolutely observed that the > chickadee > situation there has become very muddled. I haven't paid that close of > attention to how others are submitting them, but you will notice that for a > couple years, I have been submitting all chickadees in North Park from > Latodami Nature Center south as Carolina/Black-capped Chickadee. I > observed > a gradual intrusion of Carolina physical traits and vocalizations that made > it clear to me that the hybrid zone had shifted north to engulf most of > North Park. I do, however, still observe birds in the upper field area, at > the northernmost part of North Park, that fit pure Black-capped Chickadee, > and I regularly still hear Black-capped songs around the field. I think it > is reasonable to say that the upper field is one of the last holdout areas > of pure Black-cappeds in North Park, both because it is at the northernmost > extreme part of the park, and also because it is at one of the higher > elevations vs most of the park. Doing a quick check of the Latodami Nature > Center hot spot, most of the recent checklists by people other than myself > also report the chickadees as Carolina/Black-capped Chickadee, although > there are a few that are listed as pure Black-capped. If you are seeing > that most reports are pure Black-capped, that might be including older > data. > I actually made a comment in my January 13th checklist from Latodami Nature > Center that speaks directly to this topic: > > http://ebird.org/ebird/view/checklist/S33645124 > > I live in Gibsonia, to the east and a little north of North Park's > latitude. > I still have predominantly pure Black-capped Chickadees here, both in > physical appearance, song, and call. I have never heard a Carolina song > here yet, and can't see any obvious intrusion of Carolina physical traits. > I have, however, noticed an ever so slightly quickened call pace of a > couple > single birds in the past few months, which makes we wary of the possibility > of hybrid intrusion. With all my observations on the issue locally coming > from my house and North Park, I personally would place the new top edge of > the hybrid zone somewhere east of North Park and just west of the Gibsonia > area. If you are wanting to go somewhere in Allegheny County where you > should have no problem seeing pure Black-capped Chickadees, Harrison Hills > County Park in Natrona Heights would be the place, as it is physically > located at the far northeast corner of the county, the farthest point from > the hybrid zone. > > As for the birds you were seeing at North Park yesterday, I'd say that even > though they are singing Carolina and have Carolina physical traits, they > are > likely hybrids. It seems certain that the hybrid zone has shifted north, > but not far enough north to place pure Carolinas regularly in North Park, > and as you alluded to, there is no reason to think that pure Carolinas > would > be irrupting northward at this time of year. Admittedly, I often do not > attempt to discern individual birds within the hybrid zone, and often just > submit them as Carolina/Black-capped Chickadee. Catching pure birds of > either type irrupting northward or southward is dicey because the hybrids > themselves are so variable. The fact that you heard so many Carolina songs > is notable however, as I personally have still heard a lot of Black-capped > songs even in the main part of the park. This may be a very recent > development. You have certainly brought up a topic that I intend to keep a > closer eye on. If anything I have said here is incorrect or > misrepresented, > somebody out there please call me out on it, but hopefully I have > contributed something useful! > > Good birding, > Alan Buriak > Gibsonia, Allegheny County > > > ________________________________ > From: Bird discussion list for Pennsylvania <PABIRDS...> on > behalf of Sameer Apte <sameerapte1...> > Sent: Monday, March 13, 2017 1:20 AM > To: <PABIRDS...> > Subject: [PABIRDS] Allegheny County - Chickadees > > This afternoon, Aidan Place, Jack Chaillet, and I birded North Park, where > we searched for Black-capped Chickadee (which Jack and I needed for our > county year lists). Despite the many reports of exclusively BCCH at this > location, every chickadee we found either resembled a pure Carolina or > predominantly resembled Carolina in phenotype. One chickadee at lake > elevation (970') had extensive white on the tertials and on the cheek > patch, > and several chickadees at the Latodami Nature Center (1110') were clear > phenotypic hybrids between Black-capped and Carolina. Although we heard > many > Carolina songs, we did not hear a single Black-capped song, and many of the > hybrids certainly appeared to be possible backcrosses with Carolina > Chickadees. > > With BCCH reaching their furthest range southward around this time of year, > it begs the question as to why almost every chickadee seen in North Park is > identified as BCCH on eBird. Are most of these reports are from a higher > elevation, where pure Black-cappeds are certainly plausible? Are Carolinas > (which are expanding northward) being dismissed as the traditional species > of Black-capped at this particular location and in other places north of > the > Allegheny River (which I believe has been the demarcation line for the last > fifteen years or so)? Or was our sighting just highly unlikely and > exceptional? > > I'd love to hear thoughts and experiences from people in the Pittsburgh > metro area about this paradox -- it seems like chickadee identification is > a > thing that comes up once in a while, but maybe not as much as it should in > an area smack dab in the middle (or maybe not anymore) of the hybridization > zone. Perhaps it would be constructive to conduct a sort of informal census > of areas north of the Allegheny River to determine the current demarcation > line and hybrid zone of this species in the area. > > And if anyone has any clue what exactly those mutt chickadees in North Park > really are, please let me know. > > Thanks and good birding, > Sameer Apte >