Wanaka Sun column by retired zoologist John Darby
I have been fretting of late perplexed at the slow pace of grebe activity. You may recall that for much of the winter and early spring last year there was a great deal of fisticuffs between grebes competing for nest space. It was strange behaviour in that there were ample rafts to cater for their needs and fights only appeared to happen on rafts where birds had decided to nest.
Thus far, there have been two pairs of birds attempting to breed. The birds attending raft (No 3) delivered their first egg on August 31 and the last to make a clutch of three on September 3.
The birds on nest (1) followed suit with their first egg on September 15. Those lay dates are more in keeping with the recorded breeding season for grebes being September to February.
But Wanaka grebes are non-conformists. Last breeding season the first egg was not laid until the first week of October, but in the 2014-15-16 breeding seasons, the first eggs were laid in June and breeding continued through to March.
One of our first jobs this season has been to repair and renumber all of the rafts so that hopefully they make more sense.
When we first started in 2013 I had only two platforms, logically numbered 1 and 2. But then another pair of birds arrived so I added another platform No 3, and this was where a pair of birds started to build a nest on the transom of a boat.
Trouble was that that boat was between nest 1 and 2, thus the numbering ran 1,3,2, and then 5, 4 and so on up to nest 14, all muddled up. So we are starting all over and trust that the grebes will co-operate.
I have my gang of “grebies” to help me again, but in addition, I have some big muscle and lots of it by way of Paddle Wanaka who have joined forces with me to assist with all aspects of the grebe project.
The Law of Diminishing Returns does apply to physical attributes as one ages and given that saturated rafts with nests can weigh as much as 40kg every bit of muscle counts. Welcome aboard!
- John Darby
Pictured: Grebes on Lake Wanaka. Photo: Supplied
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