Author: Pat OMalley

More than 50k from WTP perhaps, but not far as the plover flies – over the past few weeks there has been a group of about 50+ DBPs at Sandy Point, roosting on the sand spit between Shallow Inlet and the surf beach. Cheers Pat _______________________________________________ Birding-Aus mailing list Birding-Aus@birding-aus.org To change settings or unsubscribe visit: http://birding-aus.org/mailman/listinfo/birding-aus_birding-aus.org

Can anyone enlighten me about possible nest parasitism for Welcome Swallows. A pair raising a brood seemed to be doing well (they raised five last year), when three nestlings appear to have been turfed out. The parents are still attending the nest and I am loath to get up a ladder and peer in to see what is there, In case of adverse reactions. Any insights or data appreciated, Cheers Pat — Pat O’Malley, Faculty of Law University of Sydney NSW 2006 Australia 0404273392 (Mobile) pat.omalley@sydney.edu.au Sent from my iPad =============================== To unsubscribe from this mailing list, send the message: unsubscribe (in the body of the message, with no Subject line) to: birding-aus-request@vicnet.net.au http://birding-aus.org ===============================

Dear all,

Excuse my ignorance on matters nocturnal. Last night about 11pm a series of 1 then 3 very loud ringing hoots – perhaps more like’ hyoo’ than the hoots of the Powerful Owl on the Morcombe soundtrack.

We live in the country (Fish Creek, Vic) amid lowland woodland mosaic with pasture – not what I think of as N. strenua territory even though they are of course in range.

I just didn’t sound like the Morcombe hoots (though much more like the female than the male).

I can’t think however what it would have been. Any ideas?

Best Pat

Pat O’Malley Professorial Research Fellow|Faculty of Law | University of Sydney | NSW 2006|Australia Voice: +61 (0)2 9351 0395|Mobile +61 (0)404 273392| Fax +61 (0)2 9351 0200 Email: pat.omalley@sydney.edu.au Visiting Professor, School of Law and Social Justice, University of Liverpool.

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At Fish Creek 3959 Thursday c1700hrs, 32 Needletails heading sw toward an approaching rain front. Spread out over 10 minutes in group of 2-5.

Pat O’Malley Professorial Research Fellow|Faculty of Law | University of Sydney | NSW 2006|Australia Voice: +61 (0)2 9351 0395|Mobile +61 (0)404 273392| Fax +61 (0)2 9351 0200 Email: pat.omalley@sydney.edu.au Visiting Professor, School of Law and Social Justice, University of Liverpool.

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Hi all

I will be spending a couple of weeks during October in Argentina – Buenos Aires, Santa Fe and Neuquén.

I guess the Zona Ecologica will occupy my time in BsAs, as I have birded there in winter and it was wonderful: spring should be wonderful especially for an inner city location.

I have birded a little at Santa Fe before, mainly floating down the Parana channels (in a leaky boat weighted down with mozzies) but any advice gratefully received.

Most important however is Neuquén. My ‘Where to find birds in SA’ has a huge blank area around this part of northern Patagonia. Does anyone know this area?

Of course will post a full report when I return.

Cheers and many thanks in advance

Pat

_____________________________________________ Pat O’Malley Professorial Research Fellow, Faculty of Law, F.10 Eastern Avenue, The University of Sydney, NSW, 2006, AUSTRALIA. Tel: +61 (0)2 9351 0395; Fax +61 (0)2 9351 0200; Mobile +61 (0)4 04273392 pat.omalley@sydney.edu.au

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In South Gippsland (Fish Creek) at the moment and over the past few days have seen what appears to be a lone White Throated Needletail on three occasions. Only feeble bins with me and its quite high, so ID not 100% Doesn’t appear to be a Hobby (Pizzey and Knight suggest this as a possibility). I can’t recall seeing a lone specimen before – any suggestions/comments (other than always take the good bins with me).?

Cheers Pat

Pat O’Malley Voice: +61 (0)2 9351 0395, Fax +61 (0)2 9351 0200 Mob +61 (0)4 0427 3392

________________________________________ From: birding-aus-bounces@lists.vicnet.net.au [birding-aus-bounces@lists.vicnet.net.au] on behalf of birding-aus-request@lists.vicnet.net.au [birding-aus-request@lists.vicnet.net.au] Sent: Tuesday, 24 January 2012 12:00 PM To: birding-aus@lists.vicnet.net.au Subject: birding-aus Digest, Vol 70, Issue 43

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Hi all,

I’ve been sent the following for comment. can anyone enlighten me (and thus my physicist friend)?

Best

Pat

It occurred to me while watching a flock of birds take off that they were doing it in a manner conducive to injury: they were all very close together, and three dimensionally so. Why would they do this? Here is the answer, I think.

There has been, of course a lot of study and modelling of flocking and schooling (fish) and so on, but in my brief perusal of the literature, viz., I googled , I saw no reference to the following:

Birds expend a lot of energy taking off. Some big birds have adopted take-off strategies like running to increase lift and so on. So, let’s first model a bird wing very badly, but sufficiently for our purposes, by an umbrella: on the up stroke the umbrella collapses, and although there will be drag, and a slight increase in pressure above the umbrella, compared to the down stroke, wherein the umbrella opens up, this will be a lot less. Hence the lift. Now, one bird taking off (vertically, for simplicity) will be flapping downwards against normal atmospheric pressure, and the pressure will locally increase during the downstroke. But because the air is free to move sideways, the increase in pressure will be limited. If, however, we have a hundred birds tightly arranged in a circular area, the pressure increase, particularly towards the center of the flock, will be greatly increased, since the air can only move sideways at the perimeter of the circle. This will result in increased lift for most of the birds (actually for all the birds, since the ones at the perimeter will still benefit from some pressure increase) for the same energy expenditure.

The above argument works a fortiori for a three dimensional flock.

Let me know what you think.

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