Status of Greater Scaup in eBird in Louisiana

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Subject: [LABIRD-L] Status of Greater Scaup in eBird in Louisiana
Date: Wed, 17 Jan 2018 15:21:36 +0000
From: James V Remsen
Reply-To: James V Remsen
To: LABIRD-L@LISTSERV.LSU.EDU

LABIRD: I suspect that Greater Scaup is one of the most over-identified species in Louisiana. The eBid filter for all inland parishes
has always been set to zero, and so the current records have all been vetted to one degree or another. Although there are (or were,
until I purged them) hundreds of undocumented records from coastal parishes in eBird, the vast majority are from inexperienced birders,
especially from out of state.

Consider this: Steve Cardiff, who has been birding in Louisiana since the early 1980s, has only 5 records of 8 individuals in eBird. I
predict those totals would be higher if he had birded more in SE LA, where reports from other reliable observers seem to peak, but
nonetheless, this should be a wake-up call.

Scaup ID is very difficult. If only I’d kept track of all the times when I tried to make scaup into Greater but walked away uncertain.
Photos are often tricky unless there are multiple shots, including resting birds.

Two points everyone needs to know are:

(1) head color is useless — Lessers typically show green heads in the right light
(2) head shape is basically useless in feeding birds, because Lessers that are diving and feeding, when their head plumage is compressed and
head looks rounded.

The new Nat Geo guide does a good job with the two species. The best treatment I know of is a paper by Tony Leukering that can be
downloaded from Colorado Birds: https://cobirds.org/CFO/ColoradoBirds/InTheScope/21.pdf

Borderline platitude but nonetheless apt: experience matters. Scaup can be humbling, and the more one is humbled, the more careful one’s
identifications become.

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Dr. J. V. Remsen
Prof. of Natural Science and Curator of Birds
Museum of Natural Science/Dept. Biological Sciences
LSU, Baton Rouge, LA 70803
najames (at) LSU.edu

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-------- Forwarded Message --------
Subject: Re: [LABIRD-L] Status of Greater Scaup in eBird in Louisiana
Date: Wed, 17 Jan 2018 10:15:20 -0600
From: Steven W. Cardiff
Reply-To: Steven W. Cardiff
To: LABIRD-L@LISTSERV.LSU.EDU

All- I would add:

1. There’s no shame in entering Greater/Lesser (scaup sp.) if you aren’t absolutely certain about ID.

2. At least a small percentage of reported Greaters are “typos” where the observer meant to report Lesser but marked the wrong box.
Review your lists after entering/submitting!

Steve Cardiff

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-------- Forwarded Message --------
Subject: Re: [LABIRD-L] Status of Greater Scaup in eBird in Louisiana
Date: Wed, 17 Jan 2018 13:56:21 -0600
From: Steven W. Cardiff
Reply-To: Steven W. Cardiff
To: LABIRD-L@LISTSERV.LSU.EDU

Labird-
Just to clarify.... in general, close inspection of large
concentrations of scaup has shown that it’s ok to assume that 99% of big
flocks (e.g., on Lake Pontchartrain, the inshore waters of the Gulf of
Mexico, and on most inland bodies of water) can be listed as Lessers
without skewing the eBird data-base. Use of "scaup sp.” should indicate
reasonable doubt that some strong % of birds could be either, which would
be misleading in the case of mega-flocks in Louisiana.

Steve Cardiff