Strange color (1 Viewer)

volker sthamer

Well-known member

• Apr 20, 2018

• #1

Hi,
I took this photo aprox 4 weeks ago at Castro Marim /Algarve, Portugal.
There was a group of 7 Cattle Egrets, all showing the same greenish coloration which I have never seen before.

Has this been observed somewhere else ? What could be the reason?

Thanks and best wishes
Volker

 

Attachments

• 
  DSC_0238a.JPG

  274.9 KB · Views: 134

Nutcracker

Stop Brexit!

• Apr 20, 2018

• #2

Staining of some sort?

 

F

fugl

Well-known member

• Apr 20, 2018

• #3

Agreed. Certainly not natural. . ..

 

Paul Longland

Well-known member

• Apr 20, 2018

• #4

some sort of blue/green algae in the water?

 

Andy Adcock

Worst person on Birdforum

• Apr 20, 2018

• #5

If this had been in Asia, I'd have no hesitation in saying that they had been deliberately dyed.



A

 

volker sthamer

Well-known member

• Apr 21, 2018

• #6

Thanks to all for the comments

 

Torchepot

Well-known member

• Apr 21, 2018

• #7

Here's a more extreme coloured bird I came across in S. Spain - honeym mentions copper sulphate as a possible cause of cattle egrets "getting the blues"

https://www.birdforum.net/showthread.php?t=301090

 

HLousa

Well-known member

• Apr 23, 2018

• #8

Torchepot said:

Here's a more extreme coloured bird I came across in S. Spain - honeym mentions copper sulphate as a possible cause of cattle egrets "getting the blues"

https://www.birdforum.net/showthread.php?t=301090

Click to expand...

I agree with the copper sulphate hypothesis. I've seen other birds with the same colouration, near Beja (a bit towards North from Castro Marim).
There are similar reports also around Beja. Cattle egret usually follow tractors and other farming machinery, inclusively when chemicals are being applied to the crops.

 

Barred Wobbler

Well-known member

• Apr 23, 2018

• #9

Maybe copper oxide? Are there any copper mines or copper deposits nearby?

I'm off to South-western Spain next week, near Algeciras and the cottage we rent has water supplied from a borehole. The rocks are high in copper and a side effect of this is that when a bath is run the water is perfectly clear (with maybe the slightest hint of straw colour). But then when soap is added the water instantly takes on a noticeable blue-green tint as copper oxide is precipitated out of the water by the action of the alkaline soap. The egret in the picture has a colouration very like the colour of copper oxide, so maybe something to do with that, if it's been knocking around settling ponds or something of the sort.

In connection with this I've often noticed that when flying into that part of Spain that a lot of the reservoirs have an eerily blue tint when seen from the air, which I've put down to the presence of naturally occurring copper salts in the bedrock.

 

HLousa

Well-known member

• Apr 23, 2018

• #10

Barred Wobbler said:

In connection with this I've often noticed that when flying into that part of Spain that a lot of the reservoirs have an eerily blue tint when seen from the air, which I've put down to the presence of naturally occurring copper salts in the bedrock.

Click to expand...

In Portugal in some pools near olive groves, and vineyards it's possible to observe a blue tint on the water, probably from leachate collected from these fields. Probably it is the same case in southern Spain?

 

Barred Wobbler

Well-known member

• Apr 23, 2018

• #11

It is a copper mining area. This mine is just 15km from Castro Verde itself.

http://www.lundinmining.com/s/Neves-Corvo.asp

 

HLousa

Well-known member

• Apr 23, 2018

• #12

Barred Wobbler said:

It is a copper mining area. This mine is just 15km from Castro Verde itself.

http://www.lundinmining.com/s/Neves-Corvo.asp

Click to expand...

I'm aware of it. But I'm more prone to believe the colouration derives from farming chemicals.