Date: 3/15/17 5:48 am From: Ron Rovansek <rrovansek...> Subject: Re: Allegheny County - Chickadees
Is there a current map available that shows the chickadee hybrid zone? Where is the line in central PA?
From: Bird discussion list for Pennsylvania [mailto:<PABIRDS...>] On Behalf Of Geoff Malosh
Sent: Tuesday, March 14, 2017 3:35 PM
Subject: Re: [PABIRDS] Allegheny County - Chickadees
Thanks all for this excellent thread so far. The State of the Chickadees is something that I too have long tracked (informally) around here in Allegheny and surrounding counties. I certainly agree with those who have suggested that the only place left in Allegheny Co. for "good" Black-caps is in the far northeastern corner, where, at places like Harrison Hills Park, Black-caps are still the norm and the odd "messy" bird with a quick "dee-dee-dee-dee" call is still the very rare exception.
The opposite side of this question, though, is also worth thinking about. The location of the *southern* limit of the contact zone has always been just as interesting a question to me as the northern limit. Of course the true edge of the southern limit is impossible to define with any sort of precision without a DNA study, but that said, just as some birders in the county are sometimes too cavalier with Black-capped IDs away from the northeastern corner, it's my feeling that people can be just as excessively cavalier with reports of "good" Carolinas along the southern edge of the zone, with many birds being identified by song or call. A perfect case in point is Sewickley Park, which lies about 6-7 miles west-southwest of North Park, where this discussion started. When I first birded there years ago, Sewickley was dominated by Black-caps, whereas today it's quite deep in the contact zone and all traces of Black-capped heritage are fading fast. But even just this past fall, I was still finding messy chickadees among the hordes at Sewickley. Just about all the chickadees in that park sound pretty much spot on for Carolina, but there is an echo of bygone Black-capped days still discernable if you look closely enough for it. In my view, "Carolina Chickadee" is over-reported in the park even today because of this, and I personally still classify a lot of the birds there as Black-capped/Carolina, and will probably still keep doing so until such time that I can go a whole season without seeing any trace of Black-capped lineage there at all. Of course, even when that day comes, many (all?) of the chickadees there will still carry some Black-capped genes, but there is only so much a birder can do when looking for the southern edge of the hybrid zone...
Anyway, the same thing goes for a whole swath of Allegheny County along the hybrid line, even south of the rivers in some areas. Many chickadees even far south of the current northern edge of the contact zone are still better left as the "slash" if you take a really good look at them.
I've also over the years noticed little pockets of chickadees that aren't like the other birds in their immediate area, yet are all deep within the zone. For example after spending many bored, gull- and tern-less hours at Dashields Dam in the springtime and occupying myself with the chickadees instead, I realized there was a much higher percentage of "Carolinas" right along the river in that area than there were in my yard, which is less than 2 miles due south from the dam (i.e., my yard is *deeper* into the contact zone than the dam, but had proportionally fewer "Carolinas"). These observations were all from well after the hybrid zone had moved well north of either location. To this day I still sometimes have reason to use the slash for yard chickadees even all the way out here in Moon Twp. -- quite far from North Park! (12 miles) The point is not to take any of Pittsburgh's chickadees for granted pretty much anywhere within maybe 15 miles of the northern edge.
Anyway, it's a fascinating problem and I can't agree more with Aidan's advice to take a closer look at all the chickadees in Allegheny County and nearby. (The situation in Washington and Beaver counties is just as much of a mess.) But don't ignore the "southern problem" either -- and don't be afraid to make copious use of the slash if you're eBirding around here.
From: Bird discussion list for Pennsylvania [mailto:<PABIRDS...>] On Behalf Of Aidan Place
Sent: Monday, March 13, 2017 10:10 PM
Subject: Re: [PABIRDS] 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.
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
> <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
> 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
> 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
> 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