Re: bcintbird-pics golden moment

Keeps the grey cells active Rick. Incidentally, I only skull as a last resort. 
I consider it a largely unnecessary mildly invasive technique which does not 
hold a lot of clout this side of the pond.

Barry
M B Lancaster,
Currently - Tenerife, Islas Canarias
  ----- Original Message ----- 
  From: Rick Howie 
  To: [EMAIL PROTECTED] 
  Sent: Saturday, February 04, 2012 4:45 PM
  Subject: RE: bcintbird-pics golden moment


  10-4 Barry. Now with this case firmly nailed shut, I think it is a good thing 
us bino toters don't have to routinely separate too great a complex of ages 
amongst passerines. Juvenile + adult can be enough. We can leave the rest to 
you in the "skullers and ringers" group. Then of course  there are the 
larophiles who get pretty caught up in feather trivia so perhaps the skullers 
and gullers share kindred spirits. Hmmm, but we can't forget about those who 
search for the elusive Hoary, so we have skullers, gullers and pollers 
focussing on plumage minutiae for sure. Oh,  and the shorebird crowd - we can't 
ignore  the mudders .

   

  I've long had an interest in obtaining a full suite of Bald eagle plumage 
photos along with the other raptors but have not pursued them recently. Lots of 
challenges as we go lensing around.

   

  Rick Howie  

   

   

  From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of M Lancaster
  Sent: February-04-12 7:56 AM
  To: [EMAIL PROTECTED]
  Subject: Re: bcintbird-pics golden moment

   

  Rick et al,

   

  From Forsman:

  Fourth plumage type (from fourth calendar year autumn)  - most birds have at 
least one juvenile secondary feather (central) and one outer juvenile feather. 
He also says that the tail is rather juvenile like, whitish with dark terminal 
band.  In flight from below, the birds still show large white wing patches, but 
the primary patch is now split from the secondary patch by three or four 
largely adult type primaries - yes, which may still have partly white bases. 
Tail is still rather juvenile like. Certainly the white patches are separated 
but they are not large, indeed the primary 'patch' is almost non-existent - 
'spikes' on 'our bird'.

   

  Fifth plumage type (from 5th calendar year autumn). The black and white 
rectrices frequently show bold dark bars just inside the dark terminal band; 
which I can see.  Underwings show less white than in previous plumages, now 
mainly as white spikes confined to the base of some inner primaries but with 
more white to the bases of the secondaries  - yes? It also seems to me that the 
greater underwing coverts are moulting? If so, this would show more white than 
otherwise.

   

  Sixth plumage type (from 6th calendar year autumn) Underwing still shows 
irregularly scattered white 'spikes' basally on some primaries and secondaries 
-'our' bird has a distinct white patch on the secondaries. However, he does 
state that the fifth and sixth plumage types are usually not possible to 
separate in the field - unless you have in the field one Alistair Fraser with 
camera??

   

  It seems to me that apart from the adult like secondary patch, there are also 
two ages of primaries with an inner patch being fresher. That indicates that 
these and the secondaries have been moulted at least twice, that would make it 
a minimum of three years old (i.e at least fourth plumage type). 

   

  Adult plumage( thus 7th plumage type - my words) is attained from the 7th 
calendar year autumn, therefore the bird will be 6 years old. 

   

  He does state that it is possible, even likely, that southern and non 
migratory populations may differ as regards moult sequences BUT, the birds seen 
in Canada are of course from migrating populations.

   

  Barry

   

  M B Lancaster,
  Currently - Tenerife, Islas Canarias

    ----- Original Message ----- 

    From: Rick Howie 

    To: [EMAIL PROTECTED] 

    Sent: Saturday, February 04, 2012 8:07 AM

    Subject: RE: bcintbird-pics golden moment

     

    So Barry: you are suggesting that this bird is at least 1 year older than 
my first assumption of it being a sub-adult lll bird and possibly a lV.  I must 
confess as to not knowing what to make of the white bases in the secondaries. 
It may be that moulting coverts are exposing the bases more. I agree that the 
remiges appear to have molted at least once and are adult -like.. The wings are 
developing more of a two-toned look and the tail seems close to adult type.  I 
don't see any retained juvenile secondaries which project beyond the trailing 
edge of the wing which Liguori says is typical of basic ll birds, so I am back 
to the older rather than younger category. In Liguori's book "Hawks from Every 
Angle," he indicates that Basic lll birds would have wide patches near the 
margins of the tail which this bird clearly does not. I should have read that 
book earlier. Clark supports the notion that the tail shows it to be at least a 
sub-adult or basic lV bird with no white in the fanned tail. This is a very 
fortunate shot as I think the rectrices are fanned enough that some white 
markings would show. These lateral patches are generally gone by the time Basic 
lV is reached, but some secondaries could retain some white at the base. So as 
a Basic lV it would be in its 5th year of life and just into the 6th calendar 
year,  so I can support your thoughts on hatch year.

     

    Clark recognizes 6 plumages - juvenal, Basic 1-4 , adult. He suggests adult 
plumage is reached as a 5 year old in 6th year of life. The BNA account 
recognizes 5 plumages - juvenal, basic 1-3, adult -  with the adult plumage 
being reached at age 4 in 5th year of life. So take your pick in terms of how 
many plumage classes  - range 5-7. 

     

    My conclusion is that Alistair's bird is 1 year older than it was this time 
last year. And that conclusion is golden.

     

    Rick Howie

     

    From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of M Lancaster
    Sent: February-03-12 10:48 PM
    To: [EMAIL PROTECTED]
    Subject: Re: bcintbird-pics golden moment

     

    Hi Rick et al,

    Forsman (1999) The Raptors of Europe and the Middle East, distinguishes 7 
plumage types which includes adult. Juvenile (first CALENDAR year autumn/2cy 
spring) to adult which is attained in the 7cy autumn and later.

     

    This bird shows no signs of retained juvenile secondaries or primaries (to 
my eyes) which would make it a 5cy/6cyspring and therefore hatched in 2007. 
This assumes that Nearctic Golden Eagles follow the same timescale as Western 
Palearctic and according to Liguori, (thanks Rick) this bird would be classed 
as a sub-adult which he says is 4-5years old.

     

    At least, that is how I assess the photo and the information.

     

    Year of life is of course 1 yr less than calendar year AFTER first calendar 
year. One cannot be one year of age until you achieve 12mths which of course 
takes place in the second calendar year. 

     

     

    Barry

    M B Lancaster,
    Currently - Tenerife, Islas Canarias

      ----- Original Message ----- 

      From: Rick Howie 

      To: [EMAIL PROTECTED] 

      Sent: Friday, February 03, 2012 5:19 PM

      Subject: RE: bcintbird-pics golden moment

       

      HI Alistair: it is always nice to see pictures of Golden Eagles and I 
note your perception at separating it from the various plumages of Bald Eagles 
which often confuse people. The additional pictures on your website were very 
nice and present some additional insight into this bird and its age.  Which 
brings me to the subject of jargon.

       

      I noted there that you referred to it as a juvenile. The normal use of 
the term "juvenile" is for a raptor in its first year of life after being born. 
 Based on the lack of white in the primaries (your bird has white at the base 
of the secondaries) and in the base of tail in your bird plus the mottled body 
visible in one of your web pictures, I would suggest that it is well on its way 
towards adult plumage.  Typically, the term used would be "sub-adult" with a 
numeral assigned (where possible) to suggest an age.  In this bird, I think it 
could be a sub-adult lll . This would be age 3  so the bird would be in its 4th 
 year of life. I don't think it has reached class lV.   Full adult plumage is 
normally attained at age 5 when the bird is in its 6th year of life. 

       

      I must confess that I don't have enough experience to sort out the 
variations that can occur in the different age classes so I can't be totally 
sure of placement in class lll or lV.   I think sub-adult l or ll birds would 
have more white tail feathers retained after the partial molt out of the 
juvenile plumage.

       

      Categorization of Bald Eagles is done in the same way. Juvenile is used 
for the bird in its first year of life and then the various sub-adult terms are 
used to refer to the remaining plumages before the birds reach adult plumage at 
age 5 or older.

       

      If anyone has any further opinions on this bird, it would be great to 
hear them. 

      Cheers

       

      Rick Howie  

      Kamloops

       

      From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Alistair B 
Fraser
      Sent: February-03-12 8:01 AM
      To: BCs Interesting Bird Pictures
      Subject: bcintbird-pics golden moment

       

      It is not that this is a superb picture, but as few shots of this locally 
uncommon bird have been posted to the list, folks may allow it to sneak 
through. 

       

      Also discussed at,

       

      http://blog.kootenay-lake.ca/?p=4089

       

      Alistair

       

      Alistair Fraser

      Kootenay Lake

       



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