Wednesday, 14 September 2011

Common Crossbill Calls and Dragonflies, Summer 2011

Been a while but have been really, really busy with work and other commitments - apologies to regular LF readers who may have missed their fix of Crossbill nonsense.

In June I was lucky enough to spend a week over Glen Affric/Beinn Eighe way, primarily to look for Odonata but of course I was on the look out for Crossbills and had recording equipment with me. Turned out to be a really bad year for dragonflies - even seing a couple of Large Reds was a welcome sight some days. That said, in the end the only target species we missed that way was White-faced Darter, but we picked them up at a reliable site in Abernethy on the way home. Dragonfly highlight was Azure Hawkers at Loch Maree:

And even some blue form Azure Dragonfly females:

And a 'blue' form female and male together so you can see the difference (female on left):

There were actually several of these blue form females at this site and we did wonder if it was a result of the particularly cool Summer we had been having up till that point - to date it has been the worst Summer I can recall, winds and wet weather have made it very difficult to do any serious ringing on my days off which has been really frustrating. It is worth pointing out that at this site we had blanked Azures on two previous visits - the day we got them in good numbers was sunny and warm.

Quite a lot of these going around:

And another highlight, Northern Emerald:

I had flocks of Common Crossbills every day arounf the Beinn Eighe Visitor Centre and surrounding woods. Many juveniles were present and the birds were feeding on Scots Pine. Regular reader will already know of my concern at the interpretation of certain crossbill flight calls and here is a good example from Beinn Eighe:

There is a juvenile begging call in there ( "teet-ow") but look at the adult flight call and how it 'morphs'. At the far left it almost resembles classic published Scottish Flight Call (fc3) with its extra trialing component. Then the extra component disappears and the second call in is a typical Fc1 ( choopy or parroty variant as I call them) but the last 4 fcs all have that quite strong trailing component ala Scottish Crossbill, and which give the call a flutey quality when appraising them aurally. These birds were definitely Common Crossbills - I had a really good chance to examine their plumage, body proportions and bill structures.

The flock flying off (14 birds) and clear Fc1 (parroty variants):

On the way home we discovered a really big feeding flock of Common Crossbills at Dinnet in Deeside. These too were feeding on Scots Pine. And, another "morpher":

This bird is a Fc1 Common Crossbill. But, how many would classify it as a Parrot on the second, third and fourth calls ? How many would classify it as a Scottish on the last call ( a two syallable structure) ?

This sequence adds in a variant Crossbill call I have been recording since last year:

The third call in from the left ( and replicants at the end of the sequence) looks like a Fc1B (or parakeet)type on the sonagram, but aurally they sound very like Fc4 (or glip) type Fc's ( due to the higher frequenct trailing tail). The corresponding Ec does seem to be EcB so I am classifying them as 1B types but aurally they really are like Fc4's ! To me 1B "parakeets" sound really "cheepy" whilst these jobbies sound quite "clippy", a big difference. I don't think it is safe to assume these ones above are "parakeet" types, vocally.

A "real" glip to compare, from lower Deeside 31st July 2011:

And on the same day a Fc1 with extra component (ala Scotbill ???):

I am pretty sure that Crossbills add these 'artifacts' as a result of their double syrinx - they can produce more than one note at a time and thus can easily produce two different notes at two different times as above ( I think it may be a 'resonance' of the first note through the second chamber of the syrinx, exaggerated when calling particularly strongly - but this is just a hunch). I am prety sure that in the lexicon of published data this call might have been good for Scottish......

If anyone wants copies of the sonagrams then just ask - don't copy and fob off as your own please !

© Lindsay Cargill 2011

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