Friday, 7 November 2014

Frogmouths ride the Rock Island Line

There have been many versions of the song "Rock Island Line" which seems to have started as a song by a bunch of prisoners.  The version I have in mind is one by the Weavers.  The particular lines occur about 1:00 into the linked performance:
"The 7:45 was always late
But arrived today at a quarter to 8.
The engineer said, as they cheered his name,
We're right on time, but this is yesterday's train."
I had expected the chicks to fledge yesterday (6 November) based on the average length of the period after hatching occurred.  Possibly they did, as the nest was empty when I took Tammy out for a comfort break at 21:15.  However that is the first year I have checked the nest in the evening and my standard metric is the first date in which the nest is empty in the morning.  Which is today, 7 November.  So they are a day late.

The length of various stages in the process is summarised in this chart:

Note: they shifted nest site in 2011 which I didn't realise until the eggs were laid so there is no length for nest building.

The nest buildng period for 2014 was atypical, as they started approximately 3 weeks early but a cold snap in August caused construction to pause for a tad over 2 weeks.  The incubation and nestling periods were both longer, by 2 and 1 days respectively, than in the preceding years.  Possibly the few periods of rain have reduced frog and/or moth numbers so the chicks have taken longer to develop?

The first flight appears to have been very brief, as they are all heaped up on another branch of the nest tree about 7m from the nest: I don't think the chicks crawled there.
It was still quite cool 5.8oC when this photo was taken but I think I can see part of both chicks in that image.  Let us see what happens when the day warms up!  (I can't see any splatted chicks on the ground so they're both around somewhere, and I suspect the parents would keep them together.)

About 40 minutes later when we set out on our dog walk it appeared that the two chicks were heaped on top of each other.  On returning from our perambulation this was the story:
Definitely two chicks, but Mum has done a runner or (more correctly, I suspect) a flier.  She is proving most difficult to track down.  My memory is that last year Dad and the one chick set up a roost in about this position while Mum was somewhere else.  On that occasion she returned when a Currawong got bolshie.  I shall explore the more far-flung roosts shortly.

Despite several searches during the day I didn't find the female again.  The other three spent the day in the spot I first found them.  I always enjoy watching the young ones reaction to people walking past: they open their eyes wide and watch with great intensity.
I think in that case a Currawong must have been around - something was distracting them.

After dark I went for a prowl and found the chicks sitting on a couple of small branches in a Yellow Box on the opposite side of the lawn to the nest tree.  I have never known the adults to roost in this tree, but it is a popular hunting perch, especially for Swift Moths off the windows.  I didn't like to use the flash (and my headlamp seems to need new batteries) so have no photo of this.

By 6am on 8 November the 4 birds were all together on the derepid Acacia branch often used as a roost at this stage of the breeding cycle.

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