1. Bird Migration 2. "Rosella"

To: "Dr Richard Nowotny" <>, "birding aus" <>
Subject: 1. Bird Migration 2. "Rosella"
From: "Philip A. Veerman" <>
Date: Mon, 25 Aug 2003 00:04:51 +1000
1. Day length is probably the main aspect. At high latitudes, winter day length is very short, not to mention the cold and low food supply, so it makes sense to follow the summer.
2. Yes that is the only explanation I have ever heard for it and it appears to be as good or better an explanation as anything else. Since then the word Rosella has been used for that group of broadtail parrots that really are all fairly similar and share certain plumage features (most obviously the cheek patch of different colour and scalloped backs).
-----Original Message-----
From: Dr Richard Nowotny <>
To: Messages Birding-aus <>
Date: Sunday, 24 August 2003 22:26
Subject: [BIRDING-AUS] 1. Bird Migration 2. "Rosella"

Two questions:

1. A semi-birding friend who went with us to see Travelling Birds asked me
why birds migrate such long, and dangerous, distances when they seem to
have quite suitable habitat for their needs (including nesting?) in their
wintering grounds.  I started proffering responses gathered from my reading
over the years, but found it more difficult than I expected justifying say
a Red-necked Stint flying from what seems to be relatively food-rich
mud-flats (and associated coastal habitat) in south-eastern Australia to
somewhere in northern Asia to breed, and then to endure the equally long
and hazardous return flight for the non-breeding season.
What are the scientific reasons/theories for these complex and frequently
very long migration patterns, ie what are the present (or past - assuming
that it is now genetically-acquired behaviour, which may not any longer
actually be necessary) survival advantages of making such a flight, over
the obvious disadvantages.  Does it date back to a previous age when the
advantages were more apparent, or are the present advantages of migration
still so great that the behaviour continues to be truly necessary?

2. A much more prosaic matter:  Is it correct that the name "rosellas" is a
corruption of "Rose Hillers" after the early Botany Bay locale, and
present-day Sydney suburb, of Rose Hill where they were commonly seen by
early naturalists and travellers between Sydney Cove and (?)
Parramatta?  If not, what is the correct origin of the name?

Richard Nowotny

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