Bird of prey ID

[FalconBirder]

Originally Posted by Picidae

Hi FB

Just to clarify and apologies for any confusion but I didn't actually say it was 'a few months old' rather it was a late autumn juvenile. However, this is just based on date of photo and not on plumage ie. late September so an early May fledging will be around 5-6 months old - Since Peregrines don't moult their body feathers until late winter, early the following Spring, it can only be aged as a 1cy/2cy juvenile until this first moult anyway, so regardless of how many months old it is, until Dec/February at least it's still in juvenile plumage. (Moult of primaries doesn't start until the 2cy Spring since raptors don't moult their flight feathers in their 1cy Autumn). The relatively unpatterned underwing will be attributed to wear rather than moult.

Thanks again Picidae,

Not quite sure about your maths here though. Early May to late September is surely only 4-5 months?

And in South-West England at least, the average fledging date is actually early/mid June - very few young Peregrines leave their eyries in May and those that do take their first flights in the last week. So if the photo was taken in late September, then the bird is most likely to be only 3-4 months old, which surely equates neatly to my earlier assessment of a 'few months old'.

You suggest that it's not possible to age juvenile birds more accurately than 1cy/2cy but if you read all my postings in this thread you see that's exactly what I did!

Thanks again to Colin for posting the shots that inspired this interesting debate.

FalconBirder

[Picidae]

[quote=FalconBirder;437670]Thanks again Picidae,

Not quite sure about your maths here though. Early May to late September is surely only 4-5 months?

[quote]

Yes, i should have said 4 months (still older than a few months though from which I assumed you meant two!). Point I was making however, is that once the down disappears, the plumage remains the same, apart from wear, right through until late winter/early spring. So whether the bird is four months old or 8 months old, can only be determined in this photo by the date seen/photo'd rather than plumage.

And in South-West England at least, the average fledging date is actually early/mid June.

This is variable and subject to weather and location. However, just one example of an early May bird in the SW, is from a Devon webcam at an undisclosed natural site where the first chick was hatched on 5th May followed by two more on 6th. First flight was observed 17th June. When I said an 'early May' fledgling, I meant a bird born in early May, apologies again for being unclear. Last year, a webcam from Germany showed Peregrine chicks hatching on 1st April which would make them 6 months old in the following September.

You suggest that it's not possible to age juvenile birds more accurately than 1cy/2cy but if you read all my postings in this thread you see that's exactly what I did!

FalconBirder

I'm not sure what you are basing that on other than me telling you it was from a photo taken in late September. Obviously a juvenile in September can only be a 1cy! In January, it becomes a 2cy. The only reference on the thread I can find where you age either bird is in post #19 where you say the Kestrel is ''probably an immature'' male. And in post #22 where you say you ''believe the peregrine is younger than the Kestrel''. By what? A month? Two months? How would you know unless I'd told you the date of the photo?! I'm sure I can find you a few links of January/Feb 2cy Peregrines that also show juvenile plumage and looking much the same as they did back in September of their 1cy!

Up until then that's the only ''accurate'' aging you stated until I told you in post #23 it was a 1cy bird ie. taken in autumn of it's juvenile year, so an obviously juvenile plumaged bird couldn't have been a 2cy based on this date! If the photo had been taken in January, it would have been aged as a 2cy bird but the plumage differences would have been minimal and any attributed to wear rather than moult. On a picture this quality, that would not have been possible to judge accurately without been given the date of the photo. Age is in this case assessed based on date of photo rather than plumage until first moult. Thus aging a juvenile Peregrine as 1cy/2cy depends on when photo was taken, up until the first juvenile moult in late winter/early Spring 2cy. Aging raptors down to how many months old they are rather than what calendar year they are in, is dependent on date of photo or first hand observation from date of hatching/ringing. Calendar year aging can be done by moult strategy but even then, after the 2cy Autumn moult, when plumage is described as 2cy to 3cy Spring, it becomes very difficult at times to separate first adult plumage from adult plumage but this can be done on many individuals from very clear pictures showing some retained juvenile flight feathers and/or judged largely on shape and wear of those feathers /or in the hand examination of moult limit/vis a vis fresh growth.

At this time of year, based purely on an unclear photo, the only indication you would have that a juvenile plumaged Peregrine is a 2cy bird and not a 1cy bird is the time of year the photo was taken, which I gave you in post 23!

Apologies again for the long post ... and for any further confusion based on my muddled approach to explaining this ... my excuse is it's now gone one o'clock in the morning!

[Picidae]

Apologies if anyone's feeling left behind with the terminology and moult stuff!

Aging done as follows: 'cy' is Calendar Year which runs from each January to the following December - Aging category starts as the 1cy being the calendar year in which the bird is born and from the first January of that same 12 month period, it's in it's 2cy until the following December.

1cy = from date of birth until the end of the first December/1st winter when Peregrine in first Juvenile plumage = that plumage being first plumage after chick down has moulted in the scrape/box

1cy Autumn - juvenile raptors do not have a primary moult in their first calendar year.

2cy January - the first January/1st winter juvenile reaches after it's birth
Juvenile plumage all retained until late 1st winter/early spring.

2cy late January/February/March - first partial moult of some body feathers rump, mantle, and scapulars continuing to Spring. (note these are only visible on clear views of upperparts!). Individual timing of moult and it's extent depends on fitness and location etc

2cy late March - First annual moult begins in flight feathers with renewal of some body feathers and lasts through until Autumn.

NOTE Birds in 2cy are similar to juveniles until completion of their first annual moult in the Autumn of their 2cy with upperparts however showing signs of adult grey in some mantle and rump feathers up until then. After that moult, birds are described as being in 2cy/3cy plumage until Spring 3cy.

[Nightranger]

Originally Posted by FalconBirder

Nightranger - it may well be the case that most people are poor at estimating the size of objects in the field. My point is simply that this is a skill that can be improved significantly by training, experience and practice.

I agree. I think the hardest thing to do is to make your eyes take a step back (figuratively speaking). As I said, BoPs tend to fill one's field of view even if the bird is being viewed at a distance if only because they command attention so well. Strangely enough, the wheatear is another bird that is constantly over-estimated and most people think they are the size of a thrush (including me up to just a few years ago despite seeing the birds relatively close up at Elton Reservoir).

[nigel_b]

So what was it?

[Picidae]

It's a Kestrel, Nigel.

[willing to learn]

Originally Posted by Picidae

Hi FB

Just to clarify and apologies for any confusion but I didn't actually say it was 'a few months old' rather it was a late autumn juvenile. However, this is just based on date of photo and not on plumage ie. late September so an early May fledging will be around 5-6 months old - Since Peregrines don't moult their body feathers until late winter, early the following Spring, it can only be aged as a 1cy/2cy juvenile until this first moult anyway, so regardless of how many months old it is, until Dec/February at least it's still in juvenile plumage. (Moult of primaries doesn't start until the 2cy Spring since raptors don't moult their flight feathers in their 1cy Autumn). The relatively unpatterned underwing will be attributed to wear rather than moult.

Sorry to disagree but Peregrines no not moult any body feathers during the late winter. An eyass starts to moult late spring the following year after its hatch by late august/september the moult is complete if natures been kind and they have full adult plumage.
Regards
Colin

[Picidae]

Nice photo of one of the Derby juveniles WTL.



''Juvenile first moult'' Central Europe F.Peregrinus

''Start to moult body plumage as early as late winter beginning with rump, mantle and scapulars. Moult of remiges starts earlier by March, than in adult and is completed by early autumn''

(The Raptors of Europe and the Middle East, Dick Forsman, Helm 2007)

from then on, it's in adult/2cy plumage.

Depending on ssp and range, Peregrines have varying moult strategy: The scandinavian caldis (seen on passage late Sept-Oct to Africa also wintering in France/Spain) suspend moult which is completed on their wintering grounds in February-April.

(my earlier point to FB being it would be very difficult indeed to age a juvenile peregrine down to how many months old it is before the first moult unless you knew the date of the photo. Even harder to assign a ssp from an unclear pic unless you knew the location the photo was taken!)

However, we seem to have gone way off thread here to the point it's caused some confusion with the original ID .... So apologies all!