Dear Mike and all,

This is an interesting bird, and well worth careful discussion. The photos are, 
as is so often necessarily the case, not ideal for assessing wing pattern and 
structure, and several other features. To my eye, the combination of adult-like 
plumage, darkish bill, not so dark legs, and not very deeply gray underparts is 
consistent with an early season variation of adult hirundo Common Tern that we 
do see from time to time.

The jury is certainly still out on the status of longipennis Common Terns on 
the east coast, and in the past I have eBirded the ones I've seen under regular 
"Common Tern"--but with lots of notation and documentation. Based on the 
checklists you've linked from Jay and Michael, provisionally specifying this 
form, I agree it might be best to take this approach while we work things out. 
At least it would be easier to collect and access the evidence.

Anyway, two of the best (and earliest in NY) candidates for longipennis were 
birds at Cupsogue on 26 Jun 2011 and 24 Jun 2014. I've aggregated photos of 
these at the following link:

As you will see, these birds were not only different in soft parts colors and 
plumage from same-aged hirundo COTE, but also different in terms of structure 
and molt (as explained in part in the note to this listserv from 27 Jun 2011, 
copied at the end of this note).

I've seen a few more also, including these two I was able to find quickly just 

It seems odd that the best candidates have always been second-summer (TY) 
birds, but there are two points worth emphasizing on this front. First, 
subadult terns are definitely proven to be prone to wander; second, these 
longipennis candidates differ very strongly in multiple ways from the range of 
variation I've documented in same-aged hirundo COTE over the past 20 years. The 
links in my copied email are long defunct, but I can direct those who are 
interested to long series of images of TY hirundo COTE from our area.

Shai Mitra
Bay Shore

[] on behalf of Long Island Birding 
Sent: Thursday, June 7, 2018 8:08 PM
To: birds
Subject: [nysbirds-l] Nickerson Beach - Possible Common Tern (longipennis) 
Species - Comments and thoughts welcome

Hello all,
On 5/22 at Nickerson Beach I observed a Common Tern that stood out from the 
rest.  It was the same size/shape as the other common terns, but the bill and 
legs were much darker.
I showed the bird to a friend who is an eBird reviewer and he suggested that it 
was a Common Tern (longipennis).  He also mentioned that this particular 
subspecies has been previously reported on Long Island.
Looking up those reports, I found there were two entries with photos by Jay 
McGowan and Michael McBrien on eBird, described by both as exceedingly rare.  
Here are the checklists:

After seeing this I was surprised, because I have seen birds that looked like 
this before (even one yesterday).  In the past I have heard them referred to as 
portlandica type birds, but it is my understanding that portlandica refers to 
first summer tern plumage, which this bird clearly was not (I would say it was 
also clearly not second summer tern plumage either.....).  My report was not 
accepted to eBird as of yet, so it is not in eBird output, but here is the bird 
I saw (Pictures in the linked eBird checklist and short video in youtube):

Anyway I would like to hear any thoughts or comments. Thanks,
Mike Z.

[] on behalf of Shaibal Mitra 
Sent: Monday, June 27, 2011 11:43 AM
Subject: [nysbirds-l] Possible Siberian Common Tern (S. h. longipennis) on Long 

A second-summer type Common Tern present at Cupsogue, just east of Moriches 
Inlet, last weekend (25-26 June) resembled the Siberian subspecies of Common 
Tern (Sterna hirundo longipennis):

Bill black, with a slight red tinge
Legs dark reddish-black
Ventral body deeply gray, especially for a second-summer type individual
Wings appeared relatively long both at rest and in flight

Its wingtip pattern also differed from the typical summer pattern of local 
Common Terns in that all the primaries (except perhaps p10) appeared uniformly 
fresh and pale, but it is not very unusual for non-adults to vary in this 

In my experience, however, it is extremely rare to see such dark legs on any 
early summer Common Tern (even first summer birds), and it is also extremely 
rare to see an all-dark bill in combination with deeply gray underparts, at 
least prior to very late summer.

Photos of this bird can be seen at:

Some representative photos of second-summer type Common Terns can be seen at:

I've never seen longipennis in its core range and am unfamiliar with how to 
assess other published characters, such as its whiter inner rectrices and 
subtly different tertials, but the photos might help here (even its 
second-to-outermost rectrices appeared less extensively dark in the field than 
in many local Common Terns).

Longipennis is said to have a shorter bill than hirundo, but this bird's bill 
looked pretty similar in size to those of local birds.

I'm calling this bird a second-summer type because its forehead and its gray 
underbody were mottled to varying degrees with white. I first noticed it on 
Saturday but I was not able to get good photos. It was present again on Sunday 
and studied by at least 19 observers.

Shai Mitra
Bay Shore


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