Wednesday, 6 September 2017

White-browed Scrubwren: reflections and infections

Recently on a visit to Honeymoon Bay on the north shore of Jervis Bay NSW, the various mirror surfaces of our vehicle were vigorously attacked by a White-browed Scrubwren in the picnic area while we enjoyed an afternoon cuppa. I have plenty of White-browed Scrubwren photos however, the bird was so persistent I eventually got the camera out and captured a few photos.

Please click on photos to enlarge.

The Scrubwren’s reflection in the side mirrors - just one of many mirror surfaces the bird attacked on the vehicle.
The windows were another location where the Scrubwren saw an “intruder” which was pecked with determination.

It probably seemed to the Scrubwren that everywhere it looked there was an intruder.


Even the side mirror surround was silver and reflective and though it took quite an effort to reach, the bird still attacked with serious intent to see the intruder off. 
The bird took a brief rest now and again to assert its ownership of the area from atop the vehicle’s snorkel. I am not sure if it was the cold or the need to assume size and importance that caused the bird to fluff up its feathers?

It was not until I was processing the photos on the laptop that I noticed the Scrubwren had some blister like growths on its legs. Take a close look at the bird’s legs in the next photo. There are several warty or blister like growths on both legs, though the left leg seems to have more.

I had no idea what afflicted this Scrubwren and had never seen anything like it before.

We rarely see sick and diseased wild birds in the bush. Dead beach washed sea birds are common enough and the remains of larger birds such as pelicans and swans for example are sometimes found. However, in the bush, apart perhaps from a small pile of feathers, the remains of a predator’s meal, we rarely see dead, injured or diseased and sick birds. I guess this is because life in the wild is a hard and unforgiving existence and any birds that are not fully healthy and fit will soon be taken by a predator. That said, the reality is that wild birds are subject to various diseases with some proving fatal or in some cases birds may be able to live with the disease or eventually recover from it.

In a quest to try and discover the cause of the blisters on this Scrubwren , and after a suggestion from a vet friend that it might be a type of pox and a Google search for “pox in wild birds”, I eventually arrived at a facts sheet on the Wildlife Health Australia (WHA) web site. This in turn led me to email a report and some photos to WHA. Here is the reply I received:

Dear John,

Thank you for your email and sending the excellent images of this White-browed Scubwren. It is always difficult to determine the exact nature of raised lumps like this on birds. A pox lesion is certainly high on the list of possibilities but there are likely several possibilities and it can be difficult to determine the exact cause based just on an image. Thank you for providing the exact location and date of your sighting as well as noting that you have not observed any other birds with similar lumps. This is very useful information and we can use this to determine if there is an unusual increase in this type of sighting. To date, WHA hasn’t received any reports of similar sightings in birds from this region. I will pass this report onto our key points of contact for wildlife health in NSW ( ) so they are aware of this report and link this to any other reports they may have received directly.

Hopefully this little bird’s lump resolves with time and returns to full beauty. If the lumps are caused by a poxvirus, these infections are generally self-limiting with uncomplicated lesions healing in three to four weeks. If the bird is observed to be unwell in future, then information about who to call in NSW can be found here:  licensed rehabilitation group or call OEH. [Note: Only people authorised under an OEH wildlife licence may take a native animal into care.]

All the very best and thank you so much for the report and image.

While I did not find a definite diagnosis for the Scrubwren’s lumps I did learn in the process that as birders we are in a unique position because we are often in the field making detailed observations of wild birds so we can play an important role in reporting any sick, infected, diseased or dead birds we find.

I encourage interested birders to look at the WHA web site and record it for future reference:

Please note each State or Territory has a WHA Coordinator who should be our first point of contact when reporting wildlife disease events.

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