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Snowy Egret and Little Blue Heron - juvenile identification


Kaaren Perry
 

While a Little Blue Heron is definitely considered a rarity in SLOCounty there is always the possibility that one just might show up any time!  The last report was from Pismo Creek mouth in November 2019, one in June 2018 at Arroyo Grande Creek mouth and a very few earlier records that I found from 1988 and 2005 in May-August.

The adult plumaged of either species are fairly easy to recognize but the juveniles can be very difficult and often misidentified.  Just in case, some time in the future, you find yourself faced with this challenge I am forwarding a very well constructed summary of how to separate the two species when in juvenile plumage.  Thanks to Ryan Winkleman for posting this to the Orange County Birding for further discussion, reference and distribution. 

Let's go find one!!

Kaaren Perry
Morro Bay
http://www.flickr.com/photos/kaarenp/

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Subject: [OrangeCountyBirding] Orange County Birding: For Discussing and Sharing Local Bird Info - Digest #704
Date: July 29, 2020 at 6:13:31 AM PDT

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1.Snowy Egrets and Little Blue Herons (4)
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1a. 
Snowy Egrets and Little Blue Herons 
From: Ryan Winkleman
Date: Tue, 28 Jul 2020 08:29:20 PDT 

Like last year, there are suddenly a bunch of reports of juvenile Little Blue Herons in the county. This is a recurring issue. However, Doug Willick, Tom Wurster, Jeff Bray, and I have reviewed the photos that have been submitted online so far and we all feel that these birds are juvenile Snowy Egrets. Here are some field marks to keep in mind for immature (hatch year) individuals of these two species when they are young out of the nest. There is overlap between the two species. Bill color and lore color can show overlap, although on the more extreme ends they are distinctive and easily distinguishable. Leg and feet color can overlap. It is important to keep in mind that juvenile Snowy Egrets that are still young out of the nest will not fit the stereotypical image of a Snowy Egret that we all have, and that lack of typical adult Snowy Egret features does not mean a bird is a juvenile Little Blue Heron. Thanks to Doug and Tom for their feedback on this post.

 

Juvenile Snowy Egret

- Body plumage is all white.

- Bill color ranges from mostly pale with a black tip to mostly black with a pale lower mandible. Birds still in the nest tend to have predominantly black bills, and those that are very young out of the nest, like in July, tend to have very pale bill bases. 

- Bill shape is relatively slim and evenly tapers to a point, although this can be difficult to judge when not seen in juxtaposition.

- Lores are generally NOT bright yellow on young birds, instead often being a pale yellow or greenish-yellow. This can overlap with juvenile Little Blue Herons. Lores turn brighter yellow as the birds age.

- Legs are greenish-yellow and often have black on the front. Lack of black does not mean it is not a Snowy Egret, but presence of black does.

- Feet are dull yellow (turning brighter yellow as the bird ages). If the feet are the same greenish-yellow color as the legs, that does not mean it is not a Snowy Egret, but if the feet appear contrastingly brighter yellow than the legs, it does.

 

Here are some photos of juvenile Snowy Egrets:

 

Juvenile Little Blue Heron

- Body plumage is nearly all white. The tips of the outer primaries are dusky or blue-gray. This feature can sometimes be covered up by the long tertial feathers and requires careful viewing (or for the bird to spread its wings). Because of this, lack of dusky wingtips does not mean it's not a Little Blue Heron, but presence of them does.

- Bill base color is gray, green, or pink on both upper and lower mandibles with a black tip.

- Bill shape is relatively thick and the culmen more abruptly curves downward near the tip, although this is still subtle and again this can be difficult to tell when not seen in juxtaposition with a Snowy Egret.

- Lores are greenish, greenish-yellow, or blue-gray, but never bright yellow.

- Legs and feet are both the same shade of greenish-yellow, never black, and the feet are never brighter yellow than the legs.

 

Here are some photos of juvenile Little Blue Herons:

 

We are also on the early side for juvenile Little Blue Herons, with fall vagrants generally not expected until more like mid- to late August and adults expected in late spring/early summer, although late July for adults is not unprecedented. So please keep in mind that we are in a time of year when juvenile Snowy Egrets are newly emerging off their nests, they look very similar to juvenile Little Blue Herons, and that the burden of proof is on the observer to show--and explain--why any given bird is not a Snowy Egret, keeping in mind that identification of any juvenile Little Blue Heron without clear confirmation of the presence of dusky primary tips is likely to be incorrect, and that juveniles of both species have yellow legs. When diagnostic field marks are not visible, identifications should be made based on multiple features coming together to indicate the probability of one species over the other, and even then, there may be times when a species-specific ID is not possible (although of course one species is way more likely than the other in Orange County).


-- 
Ryan Winkleman
Rancho Santa Margarita

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1b. 
Re: Snowy Egrets and Little Blue Herons 
From: Joe Morlan
Date: Tue, 28 Jul 2020 08:39:44 PDT 

Hi Ryan,

Good summary. I'd like to add that some (up to 20%) juvenile Snowy Egrets
have a decidedly yellow bill with dark tip. See photos and notes here:

https://fog.ccsf.edu/~jmorlan/SnowyEgretP1100155.htm

On Tue, 28 Jul 2020 08:29:07 -0700, "Ryan Winkleman"
<rswinkleman@...> wrote:

Juvenile Snowy Egret

- Body plumage is all white.

- Bill color ranges from mostly pale with a black tip to mostly black with a pale lower mandible. Birds still in the nest tend to have predominantly black bills, and those that are very young out of the nest, like in July, tend to have very pale bill bases.
--
Joseph Morlan, Pacifica, CA

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