Generally I agree with Geoffrey, also in the point that being too
prescriptive may often not help. The original question asked about
dependent precocial young. I would suggest that most of the precocial
young are only to a limited extent dependent. For megapodes they are
completely independent. So then the word has limited value, even if we
still use it as a reporting category.
Philip
Geoffrey
Thank you.
regards
Con
On 25/08/2014 6:48 PM, Geoffrey Dabb wrote:
> Con - Such terms can indeed be confusing. It is best if serious
> writing
> uses a given set of definitions, either those (helpfully) given by the
> writer, or a standard set adopted by reference. Like most definitional
> issues there can be unproductive debate about which expression is most
> appropriate. My own comments are as follows.
>
> I would leave aside 'dependant' - that is a reporting category ('DY')
> and,
> locally, depends on the parameters specified by those who organise and
> direct the reporting process.
>
> 'Nestling' is a convenient term for a young bird in the nest, or that
> might
> have prematurely left the nest.
>
> 'Fledgling' refers to a bird in the process of leaving the nest and
> making
> its first flight(s).
>
> 'Juvenile' and 'immature' are sometimes used simply for obviously young
> birds. However, technically they are different plumage stages. It if
> you
> want to know more about this I suggest HANZAB vol 1 pp 28/29. This
> refers
> to variations in usage in the scientific literature. I do not think
> there
> is any point in trying to align chatline usage with the HANZAB
> conventions
> which are intended for detailed plumage descriptions. Technically some
> birds do not have an 'immature' stage but proceed directly from juvenile
> to
> 'adult'. On the other hand the male Satin Bowerbird has 5 separable
> plumages between juvenile and 'adult'.
>
> 'Adult' can mean a sexually mature bird or it can mean a plumage stage.
> If
> the latter is intended some species acquire it at the end of the
> juvenile
> plumage stage - or the SBB in year 7.
>
> I see little point in trying for a standard approach in chatline
> messages.
> That would mean that some expressions used informally would have to be
> regarded as 'WRONG'.
>
> We have been through all that.
>
>
> -----Original Message-----
> From: Con Boekel
> Sent: Monday, 25 August 2014 6:13 PM
> To: COG list
> Subject: [canberrabirds] Some technical questions about the definition
> of
> life stages in birds
>
> In the trajectory of a bird's life, some stages appear to be straight
> forward. For example: egg/not egg; egg/nestling; alive/dead.
>
> But beyond that, it gets tricky.
>
> We have had on the chat line, for example, much discussion about how to
> apply 'dependent' to the young of precocial species.
>
> When does a nestling turn into a fledgling?
> When does a fledgling turn into a juvenile?
> When does a juvenile turn into an immature?
> When does an immature turn into an adult?
>
> Does COG (or a reputable scientific body accredited for the purpose by
> COG) have a standard set of definitions for a bird's life stages?
>
> regards
>
> Con
>
>
> ****************************************************************************
> ***************************
> This is the email announcement and discussion list of the Canberra
> Ornithologists Group.
> Emails posted to the list that exceed 200 kB in size, including
> attachments,
> will be rejected.
> When subscribing or unsubscribing, please insert the word 'Subscribe' or
> 'Unsubscribe', as applicable, in the email's subject line.
> List-Post: <>
> List-Help: <>
> List-Unsubscribe:
> <>
> List-Subscribe: <>
> List archive:
> <http://bioacoustics.cse.unsw.edu.au/archives/html/canberrabirds>
> List manager: David McDonald, email
> <>
>
>
>
> *******************************************************************************************************
> This is the email announcement and discussion list of the Canberra
> Ornithologists Group.
> Emails posted to the list that exceed 200 kB in size, including
> attachments, will be rejected.
> When subscribing or unsubscribing, please insert the word 'Subscribe' or
> 'Unsubscribe', as applicable, in the email's subject line.
> List-Post: <>
> List-Help: <>
> List-Unsubscribe:
> <>
> List-Subscribe: <>
> List archive:
> <http://bioacoustics.cse.unsw.edu.au/archives/html/canberrabirds>
> List manager: David McDonald, email
> <>
>
>
*******************************************************************************************************
|
