Mystery Corvid (1 Viewer)

Jane Turner · Nov 11, 2003

This bird has had me foxed for about 15 years. Lets see if anyone out there can help.

One hot late May morning, I was birding with a few friends at Red Rocks when I picked up a Corvid about a mile away coming in from Wales. Without a seconds hesitation I excitedly shouted Chough...since that is just what it looked like. Small, barely bigger than a Jackdaw, with long wings and huge fingers...and a longish narrow tail...and flying just like a Chough. As it came closer things started to go wrong... it had white wing flashes and where was its bill? It landed on the lawn of the point garden and was clearly not a chough.

There were odd patches of grey showing on the bird and I started to worry what Daurian Jackdaw might look like, having heard the name but never seen a description. It was hellishy shy and hard to photograph, but I got a few. At rest the bird was black though the understory of feathers was whitish grey. It had white bases (about 1/3) to inner and outer webs of its secondaries and primaries. The bill was quite stout and had a dull grey "wrinkly" oval on the base of the upper mandible.

I looked for possible escape species, but never got close. The most likely explaination I ever came up with was partial albino Jackdaw x Rook, but I'd love to hear other theories!

Jane Turner · Nov 11, 2003

I reckon I could get photo 3 accepted as a Chough

Michael Frankis · Nov 11, 2003

There's a lot of Carrion Crows around here with the albinism you mention, white bases to the secondaries & primaries. It seems to be a fairly common congenital disorder, particularly in urban populations (probably because survival rates are better in urban areas).

Lacking the normal protective feather pigments, they are subject to extremely heavy feather wear (by early/mid summer just before the moult, they can barely fly), which does make them look small, particularly in flight, but not so much smaller as to be Jackdaw size. Even so, one of these is my best guess.

Interestingly, the same disorder also occurs in American Crow, commonly enough for Sibley to have a pic of it (N American Bird Guide: 360)

Michael

Andrew Rowlands · Nov 11, 2003

Hi Jane,

The flight feather pattern on the flight shot reminds me of the Carrion Crows I sometimes see in urban areas - 'cellophanus' subspecies.

Jackdaw/Rook sounds unlikely - high populations of both wouldn't make them likely to interbreed, would it?

I have seen 'odd' plumaged Jackdaws, but all were good for structure.

Could the 'fingers' be a result of abnormal feather shape, due to ?mites? or similar?

Strange bird!

Andy.

Jane Turner · Nov 11, 2003

This really was barely larger than a Jackdaw..... and look at the structure...small head, long legs wings and tail....

I assumed the white was albinism..

Jane Turner · Nov 11, 2003

The grey bare base to the upper mandible looked very Rook too.

Joern Lehmhus · Nov 11, 2003

Sounds highly unlikely, but have you considered House Crow (Corvus splendens)? I know the bare rooklike patch at the base of the bill doesn´t fit and the colour of the flight feathers also does only fit to some carrion crow with malnutrition,

but overall shape and description of the build of the bird could fit, especially seing the first pic.
House crow can be very variable in colour, is about jackdaw sized and has a fairly strong bill.

Furthermore they often travel with ships and can therefore reach areas quite far from their natural distribution (eg. the populations in Southern Cape and Durban in SA, and I think there were also some in Rotterdam some time ago)

Joern

An afterthought- a long ship journey could also account for malnutrition and therefore for partially lack of feathers and partially light flight feathers-but I admit the bird would have to be in such a situation for quite some time...

Andrew Rowlands · Nov 11, 2003

A few years since I've seen any, but it doesn't remind me of House Crow. They are not known to be shy birds.

House Crow hybrid!?!?

Andy.

Jane Turner · Nov 11, 2003

I thought it might be a House Crow at the time... that was my best guess as I left the bird and I since have seen a fair few. They can look small but they usually look heavy headed to me....this was a small headed bird, like a chough. As I say it completely stumped me and everyone else who saw it!

Runt partial albino Rook is another possibility.

steve_nova · Nov 11, 2003

Well, being a lover of all things corvine i must say that it looks like a Carrion Crow. The proportions are just not right for the House Crow which is a much sleeker bird (regardless of which subspecies). There was a record of one living in Holland for a few years.
Jane, again the proportions and lack of red/orange bill and legs exclude this possibility. Anyway, the cone shaped black bill is about the right length and thickness for C. Crow.
Michael has already made reference to the feather pigment possibility and this looks from your flight picture to be almost certainly what it is.
Incidently, as an addition to the Crow species already mentioned, the Australian species C. orru (Torresian Crow or occasionally called the Australian Crow) has been recorded as having this disorder.

For your records Jane, here are some excellent pictures of the Daurian Jackdaw. Note that in some of the images, the juveniles look more like the western species. http://knusun.kangnung.ac.kr/~subbio/report/03-02/page13.htm

steve_nova · Nov 11, 2003

Of interest also are the Rook images, as they are of the eastern race that has more feathering on the face than the western form.

Jasonbirder · Nov 11, 2003

Not two words you usually see associated are they? Mystery and Corvid?

I did think about House Crow for about 2 secs before dismissing it...but as to what it was I`m stumped...my gut feel from the photo`s alone would be Carrion Crow but you`ve already said that in real life the size and proportions where all wrong so where that leaves me I`ve no idea!

Incidently I have some notes on a Carrion Crow I saw last year at New Fancy View - with a similar pattern - a striking broad white bar across the Secondaries and a White band across the tail feathers - but a bog standard CC in every other way. I`m not ashamed to admit when I first saw it I thought what the bl**dy hell is that!

Jane Turner · Nov 11, 2003

Steve... you will have to believe me when I say than middle pic didn't look anything like the proportions on the bird......that pic does indeed look like a CC. It was no larger (ok a wee bit longer) but lighter than a feral pigeon it was seen alongside.

I wonder what Corvids with feathering on the bill wouild look like if for some reason they lost it all.

Jane Turner · Nov 11, 2003

Been back to the original notes...took me a while to find them.

We recorded the bill as CC like in shape , but with rook-like bare patch on the upper mandible only. The eye was pale too, like a jackdaw. It was no larger than Feral pigeon, admittedly a fat FP.

Here are some more pics. I know that wall its in front of well, (I blimp into the garden most mornings) and its so small it could pass as a Blackbird!

Extreme runt CC was my other choice...but then I have to worry aboutt he Rook-like upper mandible and jackdaw-like eye.

Jane Turner · Nov 11, 2003

Two more

Don't the primaries look like Magpie.....

Michael Frankis · Nov 11, 2003

Is that stone wall still there? Might be worth going back to measure some of the more distinctively shaped rocks in it, to get a better judgement of the size.

I still think it looks most like a Carrion Crow with this feather disorder, and even Carrion Crows can look small when you're in a habitat with nothing familiar to judge size by (and particularly so when they've got this disorder, too)

Michael

Jane Turner · Nov 11, 2003

The wall is still there...might be hard to get in there..the new owners are not so birder friendly! I could rest my elbows on it though.

HH75 · Nov 11, 2003

Hi Jane,
What about Carrion Crow x Jackdaw?Unlikely,but would explain a few features!Structure looks wrong for an aberrant Jackdaw(have often seen birds with 1-2 primaries or secondaries completely white)
Harry H

Edward woodwood · Nov 11, 2003

can't argue with a Carrion Crow with albinism

anyone ever seen a CC X Jackdaw hybrid?

seb_seb · Nov 11, 2003

Not sure its even possible?

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