Saturday 7 April 2007

The Mysteries of Owling

My problem with owls is actually not as much my problem as it is theirs: for some reason, they seem to avoid me at all costs. Sure, this is sometimes a well of frustration for me but the effort owls must put into avoiding me must surely work hard on their nerves as well.

This is plainly revealed by taking a look at how quickly owls had to adapt to my presence here. Normally they are quite reliably found by scanning the forest floor for white-wash, which is birder slang for an accumulation of big white splashes of owl poop underneath their favourite perch. Any bird's droppings are easy to spot due to their white colouration caused by uric acid (their way to rid themselves of nitric waste as opposed to our rather clear urea). Here however, owls were forced to switch from uric acid to urea excretion within days of my arrival, as can be seen below:

A forest floor underneath a tree full of ... invisible-wash!
Well, a skeptic might say now that I cannot be sure there are any owl droppings at all on this picture, after all an invisible-wash looks just like no wash at all.
Yes, that's true and I asked myself the very same question but was finally convinced by the structure of the tree above the invisible-wash site.

It's just far too good to not be used by owls as a perch during their night time hunt, so there you have it: evolution revolution!

They are really making it hard for me.

I have spent many months now working through all the dense bushes and trees throughout the Arb and have as yet - today, 3:39 pm - located no Eastern Screech Owl at all. As a matter of fact, I haven't found any owl myself yet, but as I only deliberately searched for Eastern Screech Owls this lapse is most apparent.

It was mentioned to me by local birders that there should be a pair of Eastern Screech Owls hanging around the Arb. The place to go and have a good look around was supposed to be Rhododendron Glen in the heart of the Arb. Well, apparently there used to be a pair, which is not a pair anymore, but possibly there is at least one left.
The picture below shows the southern end of Rhododendron Glen.

It's not that big really and there are not too many nice old trees with cavities around or shrubbery attached to trees that might be suitable to hide a Screech Owl.

To any other birder or at any other location, this hollow tree below would surely be used by an Eastern Screech Owl as a daytime roost.

I don't see an owl there. I never see an owl anywhere. Unless shown by others.

And to anyone but me, a family of Eastern Screech Owls would surely dance a little ballet along that nice horizontal branch whereas all I get to see is a nice horizontal branch.

And I am sure after posting this, a reader will comment that there always used to be an Eastern Screech Owl roosting in the tree seen below, right until they started the construction of the board walk, and that this was bad luck but the board walk would surely be nice in May for watching warblers.
Yes, surely, I agree. Very nice.

Quite as nice as the comment this following picture is going to generate about how beautiful it was to watch the Eastern Screech Owls nesting in this particularly nice tree cavity for many years until they suddenly and inexplicably stopped doing so, even using it as a day time perch, some time in late October 2006.

Oh, wait, I can see now that you doubt my birding abilities. No, no, it is not as if I wasn't spotting stuff, I am. I just can't seem to get my bearings on the right taxonomic group of the targeted species.

Close, but no Cigar

A few weeks back I had a short but intriguing sound detection from this little stand of evergreens, seen below. They are right next to Rhododendron Glen, just across the central grassland, and were thus predestined to be incorporated into my core search area.

A search of the forest floors beneath these trees revealed an exciting piece of evidence, a smallish Owl Pellet. The picture is admittedly pretty bad but I must be said that the pellet was pretty old anyway and if it wasn't for the freezing and conserving effect of winter, I doubt it would have been recognizable as anything more than organic matter by the time I found it.

Could this pellet have been produced by an Eastern Screech Owl?
It was sadly too old to have it DNA-tested, so I can't be sure it wasn't of a vagrant Western Screech Owl, a wintering Boreal Owl or maybe a Burrowing Owl. But at least I was intrigued.
Well, it is possibly most likely it was formed in the crop of an Eastern Screech Owl but even if I'd have had a means to find out, it might have been just the very same individual that - according to the feathers I found - ended up forming a vital part of a Great Horned Owl pellet. So yet again: tantalizing hints and detections but nothing definite, no indisputable evidence.

mind you, I have read about these things before, somewhere.

But of course, I did not spend a total of 2 years tracking mammals in Southern Africa for nothing: I looked up and considered inspecting the branches above the pellet:

Hmmmm, there could have well been interesting scratch marks and small injuries on the branches that might have been caused by the claws of an Eastern Screech Owl. Of course, one would not be able to be completely certain but it could potentially be intriguingly similar to known Screech Owl scratches but what would they prove? Not much, for sure because how do we differentiate between Eastern and Western Screech Owl scratches or rule out an aberrant Boreal Owl with claw deformations leading to Screech-owl-like scratches?
Thank goodness therefore I didn't bother looking for any scratches because even I thought that was a dumb idea.

I have now come to the conclusion that I probably won't find Eastern blinking invisible Screech Owls at the Arb myself. But with so many other birdwatchers, dog-walkers and joggers around, it would be foolish to not make an effort at trying to incorporate them into the search. So what I did is I installed two Call Boxes at the Arb, which are small telephone units powered by solar energy that directly connect any potential finder of an Eastern Screech Owl to my cell phone.

I think this is rather smart and I don't see why this shouldn't work as well along the White River or the Choctawhatchee. Maybe because no-one would use them there either?
Good point...

Frankly I suppose they have just decided it was too crowded at the Arb. It was probably quite bad already with all those joggers and dog-walkers around, but when even Bell Tower Birders started to walk the park, the Owls just had enough and decided it was time to move out, to ride across the river, deep and wide, ride across the river to the other side.

The tree cavities always look better on the other side of the fence, don't you think?

Or maybe, just maybe, my failure at finding Eastern Screech Owls might be explained by other things...

Now that I mention it, and come to think of it, there might be something about them worth another post some time later, don't you think?


Anonymous said...

Perhaps you could leave a note by the phone asking the owls themselves to call?

Jochen said...

Oh, I listened to their call on the Stokes's CD. That's not quite the sound you want to hear on your phone at night and when it's dark outside!

Anonymous said...

Great post Jochen. Still missing my E. Screech for the year too. I even have a Saw-whet Owl this year but no screech. Even the owl box we put up at my folks' house remains empty. Maybe they're on strike?

Jochen said...

Thanks, Corey, but a post along the lines of "Here we can see the pair of Screech Owls I recently found preening each other, the following picture is a portrait of ..." would have been appreciated a bit more, at least by me!
I do suppose they really are on strike!

lisa said...

I have non-digital pictures of a screech owl in my uncle's livingroom, fetching a small toy...not exactly natural habitat, I'm afraid. Guess I could computer-gen in some trees...

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Or maybe, just maybe, my failure at finding Eastern Screech Owls might be explained by other things...
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