Very int'g info - thanks for sharing your analysis with us.
Joe
-----Original Message-----
From: va-bird-bounce@xxxxxxxxxxxxx [mailto:va-bird-bounce@xxxxxxxxxxxxx] On
Behalf Of Redacted sender "kurtcapt87" for DMARC
Sent: Friday, September 11, 2020 8:56 PM
To: va-bird@xxxxxxxxxxxxx
Subject: [va-bird] What are the Late Breeders in Virginia?
VA BIRDers,
Sunday, Sept 6, David Ledwith and I were birding Leesylvania SP (Pr Wm Co).
We heard and glimpsed a Summer Tanager on the hillside with the house ruins.
And Ana Argules and Jeff Wneck saw the bird as well as another Summer
Tanager - the view that David and I had was obstructed. One of Ana's birds
begged by fluttering its wings and the second (in female plumage) came over
and fed it. This indicates a late breeding confirmation: I entered it into
the Breeding Bird Atlas as a proxy for Ana and Jeff (who are not Ebird
connected). But this event got me wondering: what other species have been
confirmed as late breeders?
Of course, all the information is contained in the VA BB Atlas portal (the
importance of this Ebird data is probably not fully appreciated!). One
could spend lots of time digging out late breeding data from the various
state-wide species maps. Fortunately, there is a solution provided by Steve
Johnson. You can download the Ebird data and then search through with your
favorite software (of course, one must be careful handling spreadsheets with
a million or more lines!). Fortunately, Steve had a recent download of
Virginia data thru June 30 which he obtained to learn more about bird
species distribution in Virginia. He sent it my way and with the help of my
resident database expert, i.e., Cheryl Gaskill, we did a quick analysis.
Since this is Ebird data, an acknowledgement must made and this is what
Ebird provided: eBird Basic Dataset. Version: EBD_relJun-2020. Cornell Lab
of Ornithology, Ithaca, New York. Jun 2020.
Also, the data set used should be treated as preliminary. Although it has
gone through a first pass editing process, it may still require a more
in-depth examination. This means what we extracted should be considered
preliminary. Moreover, we only looked at the first 4 years of Atlas data
for late breeders.
The first question we had: how many species were confirmed in the last half
of August over the prior 4 years of Atlas data? The results were quite
significant: 99 species are listed as confirmed. Using the number of
instances of confirmation (which may contain duplications for the same Atlas
blocks) I list the top 10 species:
No. Cardinal - 91
Chipping Sparrow - 75
American Goldfinch - 73
E. Bluebird - 65
No. Mockingbird - 41
Blue Grosbeak - 34
Carolina Wren - 30
Indigo Bunting - 29
House Finch - 25
American Robin & Song Sparrow - 22
Given this late date, I note that these confirmations are not representative
for all blocks but are indications of the more unusual late breeding
confirmations. For example, remember there are over 4000 blocks in Virginia
- sure, not all are being visited in late August, but a large number have
lists (I could figure this number out later). Also, I found that Red-eyed
Vireo, a very common species in Virginia, was close to the top but just a
few places below the top 10.
For the month of September, the number of confirmed species drops - only 51
were recorded. The top 10 are:
American Goldfinch - 83 (September is the top month for AMGO confirmations)
Northern Cardinal - 63
Chipping Sparrow - 26
E. Bluebird - 24
Northern Mockingbird - 17
Carolina Wren - 16
American Robin - 16
Wild Turkey, Cedar Waxwing and House Finch - 12
For the month of October only 24 species were confirmed. Looking at the
results there were some species that were claimed to be confirmed which
seemed suspicious to me due to the date (I have not looked into details, but
these species were: Killdeer, Osprey, Northern Harrier, and Bald Eagle) and
I do not include into the below listing:
American Goldfinch - 9
Northern Cardinal - 7
House Sparrow - 3
Eastern Wood Pewee, E. Starling, E. Bluebird, and Cedar Waxing - 2
The other species had just one confirmation (Mourning Dove, Yellow-billed
Cuckoo, Great Horned Owl, Barn Owl, Blue-headed Vireo, American Crow, Tufted
Titmouse, Carolina Wren, House Finch, Chipping Sparrow, Savannah Sparrow,
and Song Sparrow)
Circling back to my comments in the beginning, Summer Tanager has not been
listed as confirmed from the latter half of August through December, which
may mean that Ana and Jeff's confirmation is the latest date of
confirmation.
This has been an interesting exploration!
Kurt Gaskill
You are subscribed to VA-BIRD. To post to this mailing list, simply send
email to va- bird@xxxxxxxxxxxxx. To unsubscribe, send email to
va-bird-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field. You
can also unsubscribe, change your mail delivery settings to digest mode, or
temporarily disable emails with vacation mode by going to
https://www.freelists.org/list/va-bird, entering your email and selecting
the desired option from the drop down.
You are subscribed to VA-BIRD. To post to this mailing list, simply send email
to va-
bird@xxxxxxxxxxxxx. To unsubscribe, send email to
va-bird-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field. You can
also
unsubscribe, change your mail delivery settings to digest mode, or temporarily
disable
emails with vacation mode by going to https://www.freelists.org/list/va-bird, ;
entering
your email and selecting the desired option from the drop down.
