Recently Shorty reported Australasian Shoveler diving at Kellys Swamp. There are some previous reports of this species diving but they are rare. HANZAB reported only one source which was NZ data from 1959 - mean length of dives 8.5 s (7-10;
7 dives) in 1-2 m water.
I have loaded a couple of videos taken from Cygnus Hide (links below) showing this behaviour, one with several birds diving near vortexing Pink-eared Duck. I have also seen shovelers diving in front of Snipe Hide. It is not a response to
predators. Some of my video shows the bird eating when it returned to the surface. Both male and female birds have been seen to dive on my video, although many more dives by males were observed (5 female, 41 male). My videos show at least 5 birds diving (3
male and 2 female) and that they are capable of diving 5 times in a minute with between 3.9 and 8.9 seconds under water each dive and as little as 2.9 seconds between dives (analysis of 44 dives). As well, 2 outliers were recorded with dives of 11.2 and 11.9
seconds, both by females. The dives analysed were those where the bird could be clearly identified diving and surfacing. Many more incomplete dives were recorded. The high number of dives recorded recently does raise the question of why this rare behaviour
has become common at Kellys.
BTW, Con commented on the use of the term ‘vortexing’. I believe it was first applied to the circling behaviour of Pink-eared Duck in HANZAB.
Steve
http://ibc.lynxeds.com/node/345389
http://ibc.lynxeds.com/node/345390
