Thanks for that. This is probably a trivial response and may be wrong. If
the beak capacity of the Australian Pelican, at around 13 litres,
is the largest for any species in the world that does not necessarily mean that they use full capacity each time. I recall seeing them at the Murray River locks many years
ago, catching fish as they spewed over the locks. So the only water included was a small amount of splash water and these were big fish, I guess carp.
Philip
From: Con Boekel [
Sent: Friday, 2 February, 2018 8:20 PM
To:
Subject: Re: FW: [canberrabirds] Pelican feeding on Gambusia holbrooki
Hi Geoffrey
Gambusia do fascinate me. The species difference between water that has Gambusia and water that does not can be quite large. I am pleased that the JWNR crew have created shallow ephemeral scrapes. Even if they are colonized by Gambusia during floods, the
Gambusia die when the scrapes dry up. At other times, in the absence of Gambusia, the temporary water often seems to teem with aquatic life. I believe that this is particularly important for the smaller species of frogs. Well done, those managers!
It is interesting watch the various species of avian fish hunters pursuing Gambusia at Kelly's. The Pelican seems to be almost absurd in the size discrepancy between predator and prey. Apparently the beak capacity of the Australian Pelican, at around 13
litres, is the largest for any species in the world. The Pelicans lunge forward and grab 13 litres of water. They then strain the water out of their beaks before swallowing whatever fish was in the 13 litres of water. The straining process requires a fair
bit of energy and they only seem to do it when they know they have a fish - even if only a tiny Gambusia. If there is no fish, they do not strain the water, but simply open their beaks to let all the water out, ready for another lunge.
On another matter, your short Morseby fish and bird lists seem to reinforce the biogeographical connectedness between Aus and PNG.
regards
Con
