Date: 12/27/18 9:47 pm
From: Tom Crabtree <tc...>
Subject: [obol] Re: Fw: [BIRDWG01] Intermediate Egret - Lane County Oregon
I think the one field mark pointed out in Noah’s post that hasn’t gotten any discussion here is the much larger eye of Intermediate Egrets (to check this out go to the Macaulay Library and look at their photos of Intermediate Egret). It is a striking difference. The Washburn Lane bird seems to have a typical smaller eye of a Great Egret.

Tom Crabtree, Bend

From: <obol-bounce...> [mailto:<obol-bounce...>] On Behalf Of Leith McKenzie (Redacted sender "loinneilceol" for DMARC)
Sent: Thursday, December 27, 2018 9:35 PM
To: Obol
Subject: [obol] Fw: [BIRDWG01] Intermediate Egret - Lane County Oregon

Cross posting in case anyone has relevant photos.

At this point in the discussion, it seems to me that any and all "field marks" other than the size of the bird (and perhaps Mr Reid's ratio below) have been both expounded and called into question at length by experienced birders. (e.g. Intermediate does not have a kinked neck) . . .


----- Forwarded Message -----
From: Martin Reid <upupa...>
To: <BIRDWG01...>
Sent: Thursday, December 27, 2018 5:37 AM
Subject: Re: [BIRDWG01] White Egret - Lane County Oregon

Are there any photos that provide a clear look at the tarsus and foot? INEGs have big feet! Well, toes actually. With a good view this is often obvious - rather like the difference between the toes of Orange-breasted Falcon versus Bat Falcon.
Given that INEG has a proportionally shorter tarsus than GREG, a comparison of tarsus length to toe length might provide a useful difference.
I took the liberty of downloading the images at the following two web pages, and used them to create a ratio of tarsus length (from bend of knee to base of “exposed” toe) : toe length (base of “exposed” toe to tip of tail). The measurements were made with each element of the leg in the horizontal position.
The results: Great Egret 1.67 : 1 ; Intermediate Egret 1.25 : 1

Even allowing for imprecise measurement and that this is a sample of one, this suggests that there is a significant difference in leg and foot structure between the two taxa. <> <> <> <>


Martin Reid
San Antonio

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