Thursday, 29 August 2019

Musk Duck displaying

Anyone fortunate enough to have observed a male Musk Duck at close quarters, particularly while displaying, will most likely agree this is one very strange duck. In the Pizzey & Knight Birds of Australia guide Pizzey starts his notes on the Musk Duck with “Male larger. A very strange duck.”

The Musk Duck is a diving duck and spends most of its time on and under the water – it even sleeps on water. It is supremely adapted to a life on the water, catches its prey by diving and per Michael Morcombe’s guide, “occasionally emerges onto land, where it waddles clumsily”.

Recently we encountered a lone male Musk Duck on Lake Vancouver near Albany in WA. The small lake was a deep fresh water marsh, well vegetated around the margins, a habitat preferred by Musk Duck, though they can be found in a diverse range of habitats including salt water - estuaries, lakes and even in the sea off sea-beaches.

There were no other water birds on Lake Vancouver – from my initial scan of the lake I thought there were no birds until the Musk Duck emerged from a dive.

At first the bird was very busy diving for food when it spent long periods submerged and only briefly appeared on the surface. We observed the bird from a metal clad timber hide built out over the water and fringing vegetation. I was hoping the bird might come closer for photos and had reached the point where I thought this was unlikely. Then a lone Pacific Black Duck flew in and landed across the lake from us. The Musk Duck immediately made its way to the Black Duck which departed with what seemed indignant calls as the aggressive Musk Duck saw it off with a very impressive and loud splash of water.

We decided to wait and observe a little longer. The Musk Duck then swam along the far shore and disappeared into a small embayment in the dense fringing reeds. After several minutes, we thought that was it for our session observing the duck, however he then emerged again and swam back towards the hide, and for us most interestingly the bird’s behaviour had changed from foraging to displaying. 

The male in display fans its stiff pin-like tail feathers forwards over its back and expands the undertail-coverts like a powderpuff and with the bill raised and bill-flap expanded the bird throws loud foot-splashes while making a k-plonk like call that is far carrying. In the hide we at first thought the k-plonk call was coming from a frog under the hide. There were two species of frog calling. However, watching the Musk Duck closely, it was clear he was making the k-plonk sound which was like a very loud drop of water in a deep well. The sound was perfectly the same each time making us think the bird must be making the sound with its throat and not by splashing with its feet which you would think would result in a variable sound. It was hard to believe the sound was coming from the duck some 80 metres or so away and not from right under the hide, it was so loud and clear (1).

In addition to the k-plonk sound and dramatic foot splashes the Musk Duck male in display also utters grunts and a shrill far-carrying whistle.

As the Musk Duck displayed it moved across the lake past the hide to a position where we were looking directly into the late afternoon sun. It then returned as it continued displaying to the small embayment again. A selection of photos shows some of the display.

Please click on photos to enlarge.

The male Musk Duck emerged from the reedy embayment.
He begins to display with tail spread and raised forward over his back and head raised while calling.
He swims forward between displays.

Another display. 
After alternately swimming forward and displaying he reaches a point where we are looking directly into the sun.
While a silhouette, this photo shows the fanned pin tail feathers well. 
This cropped version of the photo above shows there are 22 pin feathers – P&K field guide states there are 28? Perhaps there are some smaller pin feathers not visible in this photo?

When in stationary display the males slowly rotate as they call and foot-splash.
The tail is pressed forward onto the back in this photo.

I was hoping to capture the foot-splash however this is a very rapid action and hard to snap.

In display the male seems to raise his throat and neck feathers to form a ruff like collar.

In this photo the feet are visible however I still missed the splash.

Finally as the bird reached the embayment where he would disappear I managed to capture a somewhat fuzzy shot that clearly shows the feet well splayed during a foot-splash.

As we walked away from the lake the Musk Duck was still in the reeds where he disappeared and still making the k-plonk call though not the foot-splashes. We speculated as we walked back to the car that a female was on a nest in the reeds of the small embayment. The breeding conditions (recent good rains) and time of year were right and the male’s behaviour suggested there was a female present – why show aggression to the Black Duck and invest time and energy in an elaborate display if there was no female present?

On our arrival, the lake looked to be empty of birds - how lucky were we to have ended up with a great experience observing a male Musk Duck displaying?

(1)  If you have the P&K and Morcombe smart phone Apps then both are worth checking for the recorded male Musk Duck display calls and foot splash however the k-plonk call is only on the Morcombe App. I have used the k-plonk term in this post to describe the call we heard because this is the term and spelling used in field guides. It is a challenge to adequately describe bird calls in words!

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