RE: No honeyeater migration yet

Subject: RE: No honeyeater migration yet
Date: Fri, 1 Apr 2005 09:44:18 +1000

Alastair wrote "My understanding is that while you have mentioned Noisy Friarbirds on the move in the context of honeyeater migration, friarbirds are not migrants in the true sense of the word (i.e. moving from cooler to warmer), rather they move between areas of flowering eucalypts, which may take them in any direction."

First things first.  There are many, and varied, definitions of migration.  Most people picture migration as the classic Point A to Point B, back to Point A.  This may fit many northern hemisphere migrants but is not a terribly good fit for many Australian species.  A number of texts on migration (that I Unfortuneately don't have in front of me at the moment) deal with migration simply as a series of movements that may, or may not, be regular or take the animal back to it's starting point.  One author went to the extreme suggesting that migration is any movement that takes the animal outside it's immediate area of familiarity (there's better word!) - ie over the hill, across the river.

This was a concept I was dealing with when researching Cattle Egret migration.  We had birds that would migrate from their natal colony in northern NSW to Victoria (1000 km) each year, some birds wintering in the same paddock each year while others switched wintering areas.  Most of these would return to the natal colony to breed while others bred at other sites.  Then there were the birds (from the same colony) that would move 500 km, 100 km or even just 10 km away for the winter.  All of these birds were deemed to have migrated.  In short, migration can be a complicated concept.

Back to friarbirds and honeyeaters.  Honeyeater migration is generally not well understood.  There are the strongly migratory species - Yellow-faced and White-naped, for example but even these species may have more resident components within populations.  I personally regard Noisy Friarbirds to be among the more migratory of the honeyeaters - up there with the Yellow-faced and White-naped.  Yes, they do move between flowering areas but, then again, so do the smaller migratory honeyeaters.  The very nature of the Australian bush dictates that they must.  Only a few areas (eg some heathlands) have what could be deemed to be a reliable nectar flow.  The temperate woodlands of south-eastern Australia may have Mugga Ironbark flowering one winter, White Box in another or nothing at all.  Where there is flowering you will often find large numbers of migrating honeyeaters.  No blossom (or more strictly n! o nectar) = no honeyeaters.  This is obviously an oversimplification but you get the general message.  

This scenario is something I'm trying to come to grips with in regards Regent Honeyeater movements.  I personally think Regent Honeyeaters have a movement pattern that is largely programmed.  This however, can be, and often is, easily over-ridden by environmental factors. (such as a rich nectar flow).  In some years Regents move far greater distances than in others.  I don't think these movements are random (the species was previously thought to be "nomadic" - a state some authors encompass as just another form of migration).  I think they move through a series of resource-rich patches (by which process - eg a "collective memory" - I don't know) testing each and moving on if they fall short until they reach an area where resources are sufficient for their needs.  As I say, I think the process is complicated, often masked by environmental factors.  Mind you, here is a chance I'm complete! ly wrong and that I know absolutely nothing about Regent Honeyeater movements.

Now, there's some food for thought.


David Geering
Regent Honeyeater Recovery Coordinator
Department of Environment & Conservation
P.O. Box 2111
Dubbo  NSW  2830
Ph: 02 6883 5335 or Freecall 1800 621 056
Fax: 02 6884 9382

This message is intended for the addressee named and may contain
confidential information.

If you are not the intended recipient, please notify the sender and then delete the message. Views expressed in this message may be those of the individual sender, and are not necessarily the views of the NSW Department of Environment and Conservation.
<Prev in Thread] Current Thread [Next in Thread>

The University of NSW School of Computer and Engineering takes no responsibility for the contents of this archive. It is purely a compilation of material sent by many people to the birding-aus mailing list. It has not been checked for accuracy nor its content verified in any way. If you wish to get material removed from the archive or have other queries about the archive e-mail Andrew Taylor at this address: andrewt@cse.unsw.EDU.AU