Monday, August 1, 2011

Two Snakes from Kazakhstan

I have recently returned from a trip to the Aqtau area of Western Kazakhstan, near the Caspian Sea shore. During this trip I encountered two snakes (well, a snake and a snake slough) that I fail to identify, and I would appreciate any suggestions.

First snake:
a possible Natrix tessellata lacking dark spots or a form of Natrix natrix?

A classic Natrix tessellata found at the same location

The mystery snake:

Second snake, snake slough:

The length was around 90 cm, and the snake appeared very slender, with a small head. It was found in semi-desert surroundings with very sparse vegetation, in a small ravine on clay soil.

According to general distribution, the following species might occur (not mentioning Natrix and Gloydius halys):

Hemorrhois (Coluber) ravergieri

Elaphe dione

Elaphe (quatrolineata) sauromates

I have observed several Elaphe sauromates in the area but none of the other two.

Monday, May 30, 2011

Strange Buzzard over my office

Today, I observed a strange buzzard over my office. What struck me - struck the living crap out of me to be honest - was looking at it with my bare eyes and, upon the bird's banking, noticing the pale whitish contrasting upside of the tail.
Now, the entire bird, in proportions and colouration / pattern doesn't exactly scream "Long-legged Buzzard" in your face, and in fact it looks just fine for an average plain ol' boring 2 cy Common Buzzard. But frankly, I really can't recall ever seeing such a pale upper tail, with whitish base slowly changin into cinnamon-reddish at the tips, combined with an entirely dark back (uppertail coverts, rump etc.). This is a contrast I usually associate with Long-legged Buzzard. I have seen plenty of very pale and cinnamon upper tails on Common Buzzards, but in these birds the rump and/or back were always very pale as well.

Any suggestions or opinions on the bird?
For the time being, this is nothing but an interesting Common Buzzard to me, but how much weight am I to put on the field mark of a contrast between pale upper tail and dark rump?

Monday, February 28, 2011

Common or Rough-legged Buzzard?

This shouldn't happen. But it does, over and over again.

Today I went up into the hills to check how the local breeding pair of Eurasian Eagle Owl was doing, when I saw three Buteos gliding over. I took many photos of the first one, then noticed the second one had passed so much overhead already that I only took one pic (bad angle), and then focussed on the third one to take better pictures.
And of course, it turns out that the second Buteo was indeed the most interesting one - and I have only one picture.


Okay, the other two were clearly Common Buzzards, Buteo buteo, but the picture of the second bird does seem to show a few hints that might point towards it being a Rough-legged Buzzard (or Rough-legged Hawk if you will).

I am not sure though, but should be as this species would be a local rarity. not extremely unlikely, but very nice nevertheless.

What do you think?
The first picture is not altered at all beyond cropping. The second picture is brightened up and with increased contrast.

Tuesday, February 22, 2011

Remarks on the identification of American and Eurasian Moorhens

In a recent blog post, David Sibley suggested the following four identification criteria for separating Eurasian from American Moorhen:

1) Bill tip pattern: American shows more red on lower mandible, with the yellow on the upper and lower mandible forming a wedge shape whereas Eurasian birds show a more or less straight line angled back across both mandibles. He cautions that Eurasian birds sometimes show the pattern of American birds.
I have investigated the bill tip pattern on the pictures I have of German birds (not many, maybe 5 or 6 birds in total) and on the galleries of the websites,,, and The sample size is thus around 60 birds. I have applied the qualitative character of the line on the lower mandible angling forward, as any quantitative character regarding extend of yellow on the lower mandible would be extremely difficult to assess in the field.
In doing so, I reached the following statistics:

Of all birds photographed in Europe, 70 % showed a pattern described by David Sibley as "Eurasian" while 30 % showed a pattern reminiscent of "American". As David Sibley points out himself, this character's significance as an identification criterion indeed appears to be rather small.

2) Shield size: American birds show a distinctly larger shield that is flat or even notched at the top.
I have not analysed this field character quantitatively as above. However, the shape of the frontal shield - as pointed out by Sibley - is very variable within Eurasian birds, reflecting age, sex and hormone levels of the respective birds.
While most Eurasian birds show a frontal shield that broadens only very little towards the top and forms an evenly rounded tip, some broaden significantly. Those broadening shields even tend to show a somewhat flattened top in that they develop slight rounded "corners". However, even in these broadest shields the highest point is always in the centre in the form of a little tip. A notched top of the frontal shield might indeed be a valid qualitative field character of the American form.

3) Eye colour: more or less bright red on Eurasian and much duller maroon or reddish-brown on American Moorhens. David Sibley states that the differences are small and eye colour is notoriously unreliable as a field character.
Most pictures of Eurasian Moorhen show birds with very dark eye colouration. The very few pictures I found of birds with rather bright irides were taken of breeding birds in June and July, suggesting seasonal variation (relating to hormone levels maybe?). As Eurasian vagrants are most likely to show up in North America outside the breeding season, this field character is of very little value - if of any value at all.

4) Leg colouration: both forms show differences in the amount of red on the upper part of the leg (sources differ on what form shows more).
Leg colouration is quite difficult to assess in the first place as the upper part of the leg, above the joint, is hidden in the bird's plumage most of the time. However, I concur with David Sibley that Eurasian birds seem to show less red than American birds, but that this is very variable and the stronger-patterned Eurasian birds might very well overlap widely with the weaker-patterned American birds.

I have included a few of my photographs of Common (Eurasian) Moorhen to illustrate my points below. All images were taken in Stralsund, NE Germany, in April 2009.

A "classic" Eurasian bird, with a small frontal shield (older immature or female?) that does not broaden towards the top, and an extensive yellow tip to the lower mandible. Notice however that this bird's eye is clearly very dark.

This image shows a bird with a broadening frontal shield and a hint of "rounded corners". Note however that the highest point is in the middle of the shield, in the form of a clearly defined tip. The pattern on the lower mandible is clearly "American" in that it angles forward, although a classic American would likely show more red/less yellow. This bird's eye colouration is on the bright side of the variation shown by Eurasian Moorhens, although the eyes can get a bit brighter on some birds.

The bill tip pattern on this bird approaches the "American" pattern, and the eye is dark, appearing almost black (an effect of it being in the shade, compared to the previous bird). The shield clearly broadens towards the top and has rather well-defined "corners", yet still is clearly pointed at the top.

This bird also shows the "American" pattern on the lower mandible and a dark eye. However, the frontal shield is relatively narrow and clearly rounded / pointed at the top.

Monday, February 21, 2011

Überfrorene Amsel - frozen-over Blackbird

Hier sind drei Bilder einer mit Raureif bedeckten Amsel aus Stralsund, vom Dezember 2009. Das erste Bild wurde recht früh am Morgen gegen 10:00 Uhr angefertigt, die anderen beiden Bilder eine dreiviertel Stunde später.
Bei flüchtiger Betrachtung, u. a. bei abfliegenden Vögeln, kann durch die helle Verfärbung der Eindruck einer Ringdrossel entstehen.

Here are three images of a Eurasian Blackbird (Turdus merula) covered in hoar frost. A very fleeting glimpse at such a bird flying off might remind the observer of a Ring Ouzel (Turdus torquatus) and seems like a possible explanation for out-of-season winter observations. [There was a discussion about a December Ring Ouzel from NE Germany on one of the listservs I am a member of, and this is the reason behind posting these images here and now.]