Richard
You are right about northern NSW and southern Qld being colonised first -
from the mid 1950's. The stock probably originated from the Top End, or
directly from Asia. The origins of the north Qld birds is more likely from
the same original source.
We tagged about 2000 Cattle Egrets a year over 5 years from 1990 (the period
I was working full time on them at Shortland Wetlands Centre) and about 500
to 800 a year from 1983 to 1990 (when I was doing it on my own time). We
did have some birds move north but generally no more than a few hundred
kilometres compared with the 1000 to 1500 km southward covered by most other
birds (it is far more complex than this but I don't have time to go into it
now). Birds generally returned to their natal colony or, a smaller, number
to a nearby colony. We did, however, have a fair number of birds breed at
distant colonies although these were generally colonies to the south of
their place of birth. We had two birds breed in colonies 500 km to the
north of their natal colony. On this basis I would suggest that even the
Bundaberg Cattle Egrets were unlikely to travel north. Bear in mind that
the country changes at that point, to the south is almost continuous prime
Cattle Egret country. This is not to say they don't, it is just unlikely.
Supporting this is the number of tagged Intermediate Egrets we have had
reported from central and north Qld. If there were tagged Cattle Egrets
moving north I would expect them to be also reported.
I really enjoyed my work on Cattle Egrets, glad to be keeping my feet dry
now though.
Cheers
David
> -----Original Message-----
> From: [SMTP:
> Sent: Wednesday, 29 March 2000 17:18
> To: David Geering
> Cc: Birding-Aus Mail
> Subject: cattle egrets
>
> Hi David
>
> There has been very little work done on egrets in northern
> Australia so it
> is uncertain what movement there might be from there into
> southern
> Australia. Obviously some Cattle Egrets must have come south
> in order to
> have colonised NSW in the first place. Just how regular this
> is and what
> number of birds might be involved is beyond us at this stage.
>
> I read your email on the source of Cattle egrets in Vic with some
> interest. It's generally assumed that Australia was colonised by the
> Cattle Egret from the north southwards, but I reckon it's possible that
> the reverse may have applied in northern Qld. In no way do I claim to be
> an expert on these birds but base my thoughts on evidence collected in the
> field over a longish period.
> As I understand it, Cattle Egrets have been in southern Qld for a long
> time now. I believe the first record of Cattle Egret at Townsville came
> in the mid-1960's. They remained a very scarce vagrant for a long time. In
> the mid-80's a group of us were banding ibis and egrets in a rookery on
> Ross river, T'ville and found that there were a few nesting Cattle Egrets
> ( about 3 nests from memory). At that time, Cattle Egrets were still
> virtually unknown - I certainly never saw them despite many, many hours in
> the local wetlands. Since then numbers around T'ville have increased to
> the point that they are relatively common. I left the city after 20 years
> residence in 1990 so am not in touch as much as I would like, but I see
> the birds on every visit I have made since. Having watched flocks flying
> up the river at dusk, I suspect that there may be a colony on Ross River
> Dam somewhere. Over the last 3-4 years I have also encountered birds
> flying over the Bruce Highway south of Sarina. It appears that a colony
> exists in that area somewhere. [As an aside, the last time I drove through
> that area I had the pleasure of seeing a young Peregrine Falcon astride
> its freshly-killed prey - a Cattle Egret - on the highway! As I approached
> I saw several cars swerve to avoid the unconcerned falcon, so I pulled up
> and relocated the egret to a bare patch off the road. The falcon circled
> around, calling - very reluctant to part with the prize - and with a bit
> of luck it got to eat breakfast without being skittled].
> If I'm right about Cattle Egrets being originally scarce in NQ while they
> were common in northern NSW and southern Qld, but having since undergone a
> boom in numbers, it could be that southern birds have dispersed northward
> into NQ (NB your banding controls) and eventually colonised in suitable
> habitat. Is there any firm evidence to confirm or refute this idea?
>
> Richard
> --
> +----------------------------------------+
> Richard Johnson
> Roma District
> Tel: (07) 4622 4266 Fax: (07) 46 22 4151
> E-mail:
>
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