Friday, May 24, 2013

Banded Stilt Courtship Plumage at WTP 23rd May 2013

There are large numbers of Banded Stilts at the WTP and based on the strong colour of their breast bands they are moulting into breeding plumage. This would seem to be expected at this time of year as most breeding events listed in HANZAB have occurred between May and September.
What I have noticed though is that not only are the breast bands gaining colour but that the birds have grown elongated feathers on their backs that can be raised in display. When raised the elongated back feathers give the birds a distinct ridge of erect feathers between the folded wings and, when lowered, they form a mantle that spreads out over the folded wings.

It appears also that the chestnut breast band can be raised from the body when the bird moves into a display position. This gives the impression that the bird has a “chest plate” that is held out from the body.

I photographed one bird that seemed to be doing a brief display but as I can find no written documentation of Banded Stilts using body feathers as part of their courtship display I cannot be 100% sure. The whole “display” event took about 4 seconds so the bird may have just been stretching, however, the way the feathers were positioned during the event showed that both breast and back feathers could be raised as part of a courtship display.

I would expect that most of the courtship rituals and display would be carried out on the breeding grounds so I am not sure that full courtship displays will be seen at the WTP and similar locations but it would be worth watching Banded Stilt flocks to see if the birds use both raised breast and back feathers for courtship display.
Rear view showing raised feathers
Rear view showing lowered feathers spread over wing feathers
1) Rear bird walks past with lowered feathers. Front bird has drawn its head up at start of "display" (stretching?) movement
2) Back feathers starting to rise
3) Back feathers raised further and neck feathers fluffing up. Breast feathers beginning to rise
4) Back feathers raised further. Head pulled back and neck feathers puffing out above chest band
5) Head moved forward with neck feathers well puffed out. Chest band raised clear from body.  Back and rump feathers fluffed out
6) Neck coming back but body feathers still fluffed out
7) Front bird has lowered its feathers and both are feeding again
Bird preening showing back feathers raised from body
Birds at roost slept with back feathers spread out over wing feathers

All text and photos © Jenny Spry

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