Tuesday, September 18, 2012

Another owl visits the water

Raccoon and Great Blue Heron tracks
(Seneca Falls, NY 9/12)
In a previous post I wrote about capturing an image and video of an Eastern Screech-owl at our pond. This week, it was a different owl leaving different evidence of its passing. When checking cameras  on Sunday, my wife and I came upon some nice tracking mud at our wetland. First, we have raccoons and a Great Blue Heron. Notice that there are heron tracks going in each direction. I wonder if this was the same heron photographed a few weeks ago at the pond. The long hallux or hind toe helps distinguish this track from other large birds like turkeys and geese.

But it was the owl tracks that really got my blood pumping. I cannot recall ever noticing owl tracks before. These are large tracks, so that rules out the little screechie. And after 17 years of ownership, I can only recall hearing one or two Barred Owls. But we routinely hear Great Horned Owls and I suspect that these are from that species. Let's have a closer look and pick out some details....

Great Horned Owl tracks
(Seneca Falls, NY 9/12)
 MOST birds have four toes (but not all... there is an aptly named Three-toed Woodpecker for example and ostriches have only two toes...). And MOST of those birds have three toes that point foreword and one that points back. Refer to the photo above for a classic bird track. So these owl tracks have the typical four toes but they are not arranged in the typical manner. There are two toes that point foreword and two toes that point (somewhat) rearward on each track. These two prints are paired so that the track on the right is from the right foot of the bird as the left track is from the left foot. You can see the advantage of this arrangement to a predator: If an owl pounced on a prey animal the eight total toes form a cage with restraining claws in every direction. The name for this arrangement of toes is zygodactyl. Aside from the aforementioned owls, woodpeckers are also zygodactyl (to help them cling to the side of a tree while hammering). Anyone with a pet parrot or parakeet may have wondered about the odd arrangement of toes before as they are also zygodactyl. For you track nerds out there, the number one toe is pointing straight down (my fingers point to each number one toe in the photo to the left). The number two toe points straight forward in the photo followed by the three and four on the side...


Great Horned Owl tracks
(Seneca Falls, NY 9/12)
 I found a second spot of owl tracks which is likely to be the same bird. In this case, the bird landed on the harder mud at the edge and then moved forward into the shallowest of water where the mud is softer. Now you are looking for four distinct tracks in the photo, all from the same bird but each pair is an entirely different shape. The initial tracks present the toes in a more traditional arrangement with three toes pointing forward and one back. In the photo, you are looking at the track that I have framed by my hand and its fainter mate a little lower and to the right. It isn't until the bird moves forward into the softer mud that the zygodactyl arrangement is obvious. Toe number four is flexible and can point towards the rear or the front as the need arises. I do not catch owls when I band birds but I have handled many woodpeckers and students are always impressed with the flexibility of that toe. Note the clear circular talon marks in the harder mud and how different the track looks in the softer mud. Below, a closer view of the same tracks.

I woke up this morning to the sound of steady rain outside. I knew that meant these tracks were erased forever. I had wanted to visit them one more time. Instead, I am daydreaming of what will be the next story written on the newly cleaned slate....
Great Horned Owl tracks
(Seneca Falls, NY 9/12)


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