....Results just In

Well, that was a disappointing turnout given the apparent 'interest' in crossbills and the amount of crossbill sonagrams that are being posted on blogs etc. I don't think there is going to be a rush of contributions so well done to Dougie Preston and Stephen Menzie for being bold enough to have a go, and not a bad go at that, getting the species correct.

I guess people just don't want to appear "wrong" in public and perhaps this goes to demonstrate that identifying crossbills from sonagrams is just as difficult, possibly more so, than identifying them through a scope or images ? Or maybe my example was too difficult ? Well hey, it is a 'real life' snapshot of crossbill behaviour afterall !

Okay, there were two species, Common and Parrot Crossbill and of which there were 4 Common Crossbill individuals of the same 'type' (1A) and only one Parrot specimen. So a total of 5 Crossbills. Only the Parrot gave both a Fc and an Ec. Admittedly the actual numbers of birds was easier to ascertain from the recording which neither Stephen or Dougie had, though it can be seen on the sonagram.

So, here is my analysis ( all timings given are approx.):

1.0 secs = 2x Fc1 types. I call these "parroty" Fc1's as they are easily confused with Fc2. However, they much higher pitched than Fc2 Parrot and the descending element is much weaker ( thinner on the sonagram). Notice one individual is slightly lower pitched than the other, but still higher than Parrot.

1.3 secs = Bird "two"  of Fc1. Continues through sonogram faintly.

1.4 secs = EcA Variant, bird "three". Fundamental has an initial down turn or upturned 'horn' appearance. The harmonics are slightly different from typical EcA.

1.6 secs = Bird "one" of Fc1.

1.9 secs = EcA variant, bird "four".

2.0 secs = Fc1, bird "one".

2.2 secs = EcA bird "four".

2.6 secs = EcA bird "four".

2.8 secs = EcA bird "three".

3.3 secs = EcD Parrot Crossbill. There is no coinciding Fc here ( sorry Dougie) it is a feature of the excitement call structure (though may be related to a fc?). Notice how the Parrot EcD is lower piched and of a considerably shorter duration than the Common Crossbill EcA ( which they can be confused with aurally).

3.8 secs = EcA bird "three" and "four" together.

3.95 secs = Fc2 Parrot Crossbill - same individual as 3.3 secs. Compare with Fc's at start of sonagram, notice the Parrot calls are lower in frequency ( I call it pitch cos I hear it) and are a much stronger in amplitude. This gives a "choop" rather than "cheep".

4.1 secs = EcA bird "three".

4.2 secs = Fc2 Parrot ( same bird as 3.95 secs).

The appearance of a seemingly extra component on the Parrot Fc's at 3.95 and 4.2 secs can be misleading and may in the past have led to examples of this call being classified as Fc3 Scottish ( all will become clearer soon !). It is a harmonic of the main trace in my opinion. Only large billed birds I have handled have given this call on release.

So well done lads, other than the Scotbill reference, you got the right answer ( though the working out may not agree with my own analysis).

Just shows what information you can get from a sonagram. And there are people that say Crossbill calls are baloney ! Their loss.......

S'on-ly A Game !

Many interesting revelations to come in the crossbill world very soon so keep posted but meantime a bit of fun ! If Menzie can put up blurry, dodgy pics of his Spanny birds and ask "how many species" then so can I with Crossbills. To make it easier though rather than photos of crossers, which most people seem to get wrong or concede "they just don't know", I have this sonogram instead:

It was recorded on 16th April 2009 in upper Deeside, native Scots Pine habitat (using ME67 and Sony HiMD). So, how many crossbills and of what crossbill species, and more importantly how many call types ? I bet Menzie gets them all correct, he always does !

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Spread the crossbill love.

"Northern Exposure", Crossbills in Northern Isles....Again !

For the past few weeks (since approx. early/mid June) Common Crossbills have been trickling in through Orkney, Shetland and North Ronaldsay. Readers may recall that last year there was a biggish influx of type 4E Common Crossbills to mainland Scotland ( and presumably UK). I picked up  birds in decent numbers in lower Deeside by early July, where they had not been present previously that Winter/Spring.

Okay, guys and gals in Orkney and Shetland, what call types are you getting this year ? It would be very interesting to know. Colleagues in Grampian Ringing Group had a ringing recovery of a Common Crossbill in April near Dufftown. This bird was ringed in September 2009 in lower Deeside so had moved Northwards somewhat in the six months since ringing. Was this a bird returning 'back' to where it had come from ? My instinct is 'no', it was possibly part of a nomadic post breeding flock that was seeking a decent cone crop. But the possibility remains, especially given the accepted view is that birds move south and westwards.

So if this years influx of Commons on the Northern Isles is giving 4E calls does this mean they are last year's birds going home ? Maybe and maybe not. Maybe, for the scant evidence cited above and 'not' because some 4E's may have remained in Fennoscandia where there was a localised food source and are only moving now after breeding ( there are juvs in the recent photos I have seen of birds on Shetland). This is this 'lag' effect I spoke of last year, and this would depend on how far from the East the birds were erupting. However, if the calls of this years irruption is different from 4E then at least it rules out the 2009 population returning or a new one of the same type irrupting. As I recall there were some 1A's and 1B's last year also, though in much smaller numbers than the 4E's.

4E Common Crossbill

The other intruiging possibility is that of small numbers of Crossbills trickling in during the winter months and early spring. I have had Common Crossbills at coastal sites in November and December and two flew over my garden this April ( there is no substancial viable food source near me and I am less than a mile from the coast). These may also have been birds moving Northward back up the coast. However, I would expect the legions of Vismiggers to have picked up such movements if they were happening with any regularity ?

If anyone wants to post comments please do - I have not completely disabled the comments but am unfortunately having to moderate them due to the chinese spamming that seems to be more and more prolific on blogger these days !

14th June 2010, Catch Me If You Can, Deeside

Today started off too windy to catch crossbills with mist nets, so it was frustrating to watch the little beggars come in and quench their thirst at drinking pools:

However, later in the afternoon the wind dropped and I managed to get the net up for an hour and caught an adult (4F) female Parrot Crossbill:

And she was in wing moult, in the process of replacing her first two primaries P1 and P2 ( and associated primary coverts already renewed):

This bird's bill structure is typical of so many on Birdguides and in publications that are labelled as "Scottish Crossbill". However, the bill depth on this specimen was 12.7mm which would make it more likey a Parrot Crossbill - it is the 'minimum' bill depth that is measured as this apparently provides the most consistent measurement within and between ringers. Some might argue it is a 'big' Scottish Crossbill. However, it also gave Fc2 on it's release, identified first aurally, then confirmed by sonogram analysis. So, what do we give prevalence to, the biometrics or the call structure ? Some ringers are happy to classify on biomterics alone and for many crossbills this is possibly safe, but there will always be those iffy ones in the overlap zone.

There has been some recent chitter chatter in the crossbill world that the calls are 'cultural' possibly implying that they are not a valid taxonomic tool or diagnostic criteria. Also, calls can be learned or change. So what ? For me, as a musician and a humanties graduate, this cultural aspect, if it exists, is all the more important and may provide some clues and insight within the overlap zone where biomteric analysis alone may struggle.

In the end 'local knowledge' formed my diagnosis that this was indeed what is currently classified as a Parrot Crossbill. At this site birds that have bill depths in the region of 11.5 plus or minus a bit give what I would classify as Scottish Crossbill calls. Birds in the region of 12.5 plus or minus some give Parrot Crossbill Calls. Thus there is a positive correlation of biometrics to call structure......for most birds ! There has been the odd 11.9 or 12.1 bill depth specimen that gives Parrot Calls where you might expect it to give Scottish Calls. This, I feel, reflects the limitation of minimum bill depth as a completely reliable measurement on its own. For example, it does not take into account the shape or structure of the bill, often a very large gonys bill mass which is so important for the Pine species in opening closed cones ( and why Parrots often have a pronounced gonys). Effectively, a crossbill can have quite a narrow minimum bill depth but still have a massive gonyal 'bulge', so this measurement may be biased, though as stated, for most it is accurate. Bill width is also important structurally, but a difficult measurement to make consistent between workers. Parrot Crossbills also have thick, chunky necks, the 'bull necked' appearance often referred to in field guide books and these neck and cheek muscles contribute to their feeding preferences.

Parrot Crossbills power their way into a closed Scots Pine cone, 'smash and grab' if you will - they use the downcurved culmen to cut into it, large bill width and depth ( the gonys increasing this) to lever 'open' and make the cone split (they do not "slice" it per se, though sometimes "peel" the scales), and the powerful neck a cheek/ jaw muscles to literally brutalize the cone, manupulating the cone the whole time with the powerful feet ( not legs as was suggested to me). A female Parrot Crossbill feeding on Scots Pine, October 2006 upper Deeside:

Notice that the tail is used for balance during the feeding process, often firmly angled or wedged on to the feeding perch. I have some more detailed stuff I am preparing as a short article on Parrot Crossbill feeding, how they work the cones etc, maybe on here or the new site.

31st May 2010, Scottish Crossbill

For those who think Scottish Crossbill harder to find than a decent English goalkeeper (he-he) I was fortunate to find several today with several adults and juveniles feeding on Larch ( the bird is perched in a Scot's Pine):

The chunky little streakies can be located by their high pitched whistle or "tee-t'ow" begging calls when the adults are close. Interesting that this group were feeding on Larch when there was so much pine available - it is usually later in the summer that scotica switches to Larch.