Crikey, Ian! On a quick first reading I took it that several bird species learned the technique FROM the CBN article. Anything is possible these days …
From: Baird, Ian [
Sent: Thursday, 17 November 2016 10:13 AM
To: Susan Robertson
Cc:
Subject: [canberrabirds] Birds hawking for insects (including Siver Gulls) [SEC=UNCLASSIFIED]
Hi Susan,
Henry Nix drew attention to birds hawking for insects generally in his Canberra Bird Notes (CBN) note: ‘Vertical hawking by both native and introduced birds in Canberra’ in CBN 4:5 p 24 in the January issue of
1979. He suggests, based on his observations, that several different birds species may have learned the technique in that article.
The note I referred to about Silver Gulls hawking was by myself and Henry in the following CBN issue 4:6 pp.9-12 published in April of the same year, see the direct link to that issue on COG website below:
http://canberrabirds.org.au/wp-content/uploads/2012/06/CBN/cbnvol4no6.pdf
I think I misdescribed the prey at least some gulls were catching in the 1979 article above. Upon reflection. I now think the beetle prey was probably of the Porrostoma genus I mentioned in my recent email.
In that beetle species the elytra (wing cases) themselves are coloured orange, not the body.
Ian Baird | Senior Policy Officer
Phone: +61 2 6207 2336
Nature Conservation Policy
| Environment, Planning and Sustainable Development Directorate |
ACT Government
Level 1 North, Dame Pattie Menzies House, 16 Challis Street DICKSON | GPO Box 158 CANBERRA ACT 2601 |
www.environment.act.gov.au
From: Susan Robertson
Sent: Thursday, 17 November 2016 7:15 AM
To:
Subject: [canberrabirds] More on gulls
Thinking about what the gulls were hawking for yesterday, I think that it could have been midges newly hatched from larvae at the bottom of Lake BG. They were TINY as I couldn’t see them with or without binoculars. The gulls were hawking
from nearly ground level up to 100 metres. As I saw several gulls flying with their beaks open, perhaps they were scooping the midges out of the air. That’s my best guess.
Susan Robertson
-----------------------------------------------------------------------
This email, and any attachments, may be confidential and also privileged. If you are not the intended recipient, please notify the sender and delete all copies of this transmission along with any attachments immediately. You should not copy or use it for any
purpose, nor disclose its contents to any other person.
-----------------------------------------------------------------------
