Tuesday, November 27, 2012

Jacky Winter display 19th November 2012

Whilst at Gluepot I watched a pair of Jacky Winter, Microeca fascinans assimilis, perform a bonding, or bonding/territorial display. I was standing on top of a treed sand dune on Track 8 (33º 44’ 46.22”S  140º 12’ 37.43”E) at 0545 when a Jacky Winter took off from a branch in front of me and flew high into the sky. I did not hear the bird call but about 30 seconds later I saw it come back down and land on a horizontal dead branch.

A second bird then flew in and joined it and the pair began a display. They sat close together on the branch and went into a hunched back, rump up, wings slightly extend and tails fanned posture and reached their bills toward each other while wagging their tales from side to side. This behaviour lasted for about 3 seconds and then both birds took off and flew high as would a pair of Eurasian Skylark, Alauda arvensis. They hung for a few seconds at the top of the ascent before dropping back to a different but nearby horizontal branch. After this joint flight and a second display session both birds did one more joint flight/display session and then flew off together into the low Mallee cover on the sand dune.

Before I arrived or noticed its presence the first bird may have done more than one the one solo "skylark-like" display flight that I saw.
Second bird arriving after first solo flight by bird at top
Start of display

Both birds waging tails

Both birds in display position with continued tail waging

Second bird (left) starts to move away. At this point both birds took off to do a joint "skylark-type" display flight

The Handbook of Australian, New Zealand and Antarctic Birds [2002] volume 6 page 582 (HANZAB) has the following information under the heading “Sexual behaviour” sub-heading “Song-flights”:      “Individuals, usually assumed to be males, sometimes soar into the air while singing, reaching heights of up to 120 – 150 m and flying about apparently aimlessly, in manner reminiscent of Common Skylark Alauda arvensis (Boem 1956). Song-flights noted from mid-winter to spring, and thought to function as advertisement of ownership of territory (Marchant1985; North).”

It is possible that the first solo flight I observed was a presumed male doing a territorial ownership flight but the subsequent paired flights and displays could have been part of a display of morning re-bonding or flight and territorial ownership flight. At the apex of the three observed flights the bird/s did not “fly about apparently aimlessly” as stated in HANZAB but returned together directly to a perch and carried out a display. It is possible that both birds were carrying out a joint territorial ownership flight as mentioned in HANZAB but the bonding display following each flight would suggest a more complex reason for these particular flights.

On 15th November, 4 days earlier, I had seen a single Jacky Winter do the same “skylark flight” at 1644 near Froggy Dam at the junction of Gluepot Tracks 5,6 and 7. I did not see a second bird on this occasion or hear any call from the bird in flight. Perhaps a single bird in soaring flight is an “advertisement of ownership of territory” behaviour while a soaring flight at daybreak done by a pair of birds is a combination of dawn re-bonding and advertisement of ownership of territory?

On each morning of my stay Jacky Winters sang strongly from about 0500 until 0800 as part of the dawn chorus but after this they were more or less silent, as were most birds. Morning temperature were about 9º C and rose during the day to about 26ºC. Young Jacky Winters seen during the stay were well advanced in age and I did not see any sign of Jacky Winters flying to or from, or at, nests.
Young Jacky Winter with heavy breast marking

Young Jacky Winter with breast markings fading out

Young and adult Jacky Winter showing heavy spotting on back of young bird

Adult bird with hard-cased prey

All images © Jenny Spry

1 comment:

  1. they are lovely little birds. I havent seen any for ages...