I agree strongly with John and Angus. The consequences for the eBird Hot 100 
are at most not very important and at least potentially amusing. I thought 
everybody knew they were supposed to keep track of their own lists, rather than 
to trust in the algorithms of strangers!

More specifically, regarding European Goldfinches in the New York City area 
now, the numbers of birds present and the area occupied are large enough to 
suggest establishment. Perhaps not everybody is aware that this species 
established breeding populations on western Long Island for decades. It is even 
conceivable that these were never completely extirpated, and that today's birds 
derive at least in part from those naturalized populations (but they are 
certainly at least partly derived from recent escapes, as proven by the 
presence of plastic leg bands on some). The best argument against the 
hypothesis of demographic continuity between the period of establishment and 
the current resurgence in reported abundance is that very few or none were 
reported for several decades. But this is at best a weak argument from negative 
data that are known to be systematically biased against reporting. 

Monk Parakeets provide a parallel example that is very instructive. This 
species established breeding populations in the New York City/Long Island 
region that were fairly large and widespread by the early 1970s. These were 
subjected to eradication programs during the mid-1970s, and perceptions shifted 
to the extent that NYSARC acted (overly boldly in my opinion) to remove the 
species from the official New York State Checklist in 1982. Reports almost 
ceased during this period, but we know in this case that the gap in documented 
occurrence was an error arising from two sources: because backyard birders who 
liked the parakeets concealed their presence to protect them from destruction; 
but also because the remaining birds were perceived as "not countable" by 
competitive birders. 

Today's thread illustrates that under-reporting of "not countable" species has 
persisted in birding culture, to the detriment of our ability to infer the 
actual statuses of non-native species.

Shai Mitra
Bay Shore
From: bounce-122144147-11143...@list.cornell.edu 
[bounce-122144147-11143...@list.cornell.edu] on behalf of John Laver 
Sent: Tuesday, December 19, 2017 2:20 PM
To: Angus Wilson
Cc: NYSBIRDS-L@cornell.edu
Subject: Re: [nysbirds-l] Governors Island: European Goldfinch Flock (18-Dec)

"Personally, I think tracking these potential colonizers is important and 
interesting. Simply invalidating them or discouraging reporting isn't a good 

Agreed, particularly as range flux is likely to accelerate in ways we'll need 
to observe and measure as climate changes take hold.  We need to think about 
the Big Picture.

John Laver

On Tue, Dec 19, 2017 at 1:50 PM, Angus Wilson 
<oceanwander...@gmail.com<mailto:oceanwander...@gmail.com>> wrote:
For European Goldfinch I suspect 'domesticated' isn't an option. Same for other 
known or presumed escapes or deliberate releases that occur with regularity in 
NYS (e.g. Chukar and various non-domesticated waterfowl). Personally, I think 
tracking these potential colonizers is important and interesting. Simply 
invalidating them or discouraging reporting isn't a good solution. Issues with 
list purity can be a separate conversation, decoupled from the scientific uses 
of this information.

Angus Wilson
New York City, NY

NYSbirds-L List Info:

1) http://www.mail-archive.com/nysbirds-l@cornell.edu/maillist.html
2) http://www.surfbirds.com/birdingmail/Group/NYSBirds-L
3) http://birding.aba.org/maillist/NY01

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