birding-aus
Philip A Veerman wrote:
>
> birding-aus
>
> Is it not true that the African Harrier Hawk (Gymnogenys typicus) is a
> specialist hunter of things in cavities? I'm sure you have thought of that
> one yet you say "there appear to be few natural enemies while the chicks are
> still in the cavity". What about snakes but that defence would not work as
> (as far as I know) snakes are deaf.
> -----Original Message-----
> From: Peter Thompson <>
> To: <>
> Date: Tuesday, 16 February 1999 23:56
> Subject: birding-aus (Fwd) Defence calls in cavity nesting birds
>
> birding-aus
>
> ------- Forwarded Message Follows -------
> Date sent: Tue, 16 Feb 1999 13:52:02 +0200
> From: "Craig Symes" <>
> To:
> Subject: Defence calls in cavity nesting birds
>
> Information Wanted: Cavity Nesting Birds and Defense Vocalisation
> Calls.
>
> While attending the I.O.C. in July 1998 I in Durban, I had the chance
> to discuss and share various ideas concerning my own and other
> researchers studies worldwide
>
> The Cape Parrot is a secondary cavity nester in the Afromontane
> forests of south-eastern South Africa. Juveniles and adults make a
> characteristic growling sound if threatened in their nest cavity, yet
> there appear to be few natural enemies while the chicks are still in
> the cavity. The cavity is usually quite deep and inaccessible from the
> ground in an upright forest canopy or canopy emergent tree.
>
> This form of vocalisation made by any bird species in the nest would
> nonethelesss serve as an effective defensive mechanism for a cavity
> nesting species. A mammal like growling sound emanating from a dark
> cavity would surely raise suspicions to the actual occupant of the
> hole to any intruder/predator. My question is, does it occur in other
> cavity nesters or species constructing an enclosed nest? The
> threatening defensive vocalisations of this species has driven my
> interest in investigating the phenomenon in birds worldwide and
> investigating and reviewing where such defensive mechanisms may be
> utilised. I did post a similar request a while back on SABirdnet and
> had a few responses. Thank you to those who did respond.
>
> I am unaware of any publications directly confronting this issue and
> would appreciate views and input on various species that different
> subscribers may have studied or encountered.
>
> Please bear in mind the following points when replying:
> 1. Species (Specific as possible)
> 2. Distribution of species (e.g. Cape Parrot Poicephalus robustus
> robustus - Afromontane forests of south-eastern South Africa)
> 3. Type of defensive call of adult and/or nestling and form of threat
> (e.g. mammal like growl when cavity hole approached, snake like hiss,
> bee like buzz/hum etc.)
> 4. Potential/known nestling predators
> 5. Co-operative breeder/Polygynous/Polyandrous/Monogamous/Other
> 6. Type of nester: Primary cavity nester (constructs own cavity),
> Secondary cavity nester (uses natural cavity or old cavity of primary
> cavity nester, or, Constructs enclosed nest (e.g. Ploceus spp.)
> 7. Does the species in question supply nest material to the cavity and
> what type of material.
> 8. Obligate/facultative cavity nester?
> 9. Further remarks.
>
> I hope to accumulate data from various sources in investigating this
> issue. Any input will be duly acknowledged should any publications
> result.
>
> If there is anyone on SABirdnet who is connected to any other
> "chatgroups", or has any contacts who may be able to help, please
> forward this message to them.
>
> I look forward to a flood of responses.
>
> Yours sincerely
> Craig Symes
>
> *************************************************
> Craig Symes
> Research Centre for African Parrot Conservation
> Dept. of Zoology and Entomology
> University of Natal
> P/Bag X01
> Scottsville 3209
> South Africa
>
> Phone: (0331) 260-5104/03/27
> Fax: (0331) 260-5105
> e-mail:
> *************************************************
>
> ---------------------------------------------
> | To unsubscribe from sabirdnet, send email to
> |
> | with a single line
> | unsubscribe sabirdnet
>
> To unsubscribe from this list, please send a message to
>
> Include "unsubscribe birding-aus" in the message body (without the quotes)
>
> To unsubscribe from this list, please send a message to
>
> Include "unsubscribe birding-aus" in the message body (without the quotes)
In Australia at least, goanna's (varanids) would also be another cavity
predator, who are not deaf like the snakes. A low growling would mean
much more to them, I am proposing.
John Harris
To unsubscribe from this list, please send a message to
Include "unsubscribe birding-aus" in the message body (without the quotes)
|
