Otterly fascinating

Yes, that cheesy pun in the title was completely necessary.

Today started off well in that I spotted a Golden Plover Pluvialis apricaria in the field behind my house whilst I was having a half-hearted attempt at finding a white-winger amongst the Herring Gulls Larus argentatus and Lesser Black-backs Larus fuscus that had gathered to feed. When I first panned past it I was completely stumped as to what it was and even considered Jay for a second. Beautiful bird and a brilliant patch tick for my inland Edinburgh patch!

I went out later on from about 16:30 until 18:00. My main aim in this time was tracking of mammals. I’ve become engrossed in mammals recently. Not sure exactly why, but I’ve been liking all sorts of IUCN Specialist Group pages on Facebook, scrolling through numerous trip reports from all over the place, and looking at buying myself a trail camera.

Before I get into the mammal stuff, I was on top of Agassiz Rock on patch where I picked up that Tawny Owl Strix aluco pellet that I showed you in my last blog post. I was hoping for another one so I could look at more dentition of whatever small mammals the owl had caught, but there were no new pellets visible. I did find a small crack in the rock where pellets had clearly accumulated though, with bones and the general matrix of the pellets sitting there, making some nice new substrate for colonisation by plants!

P1190956
Owl pellet creating new substrate

Here’s a selection of other tracks and signs found while wading up the Braid Burn…

Now, on to the main attraction. As you will have guessed from the title, this means Otters, Lutra lutra. I have known for a while that Otters are present on my patch. I’ve seen one in the dark from my bedroom window and fairly frequently find signs of their presence. Plus they occasionally get press coverage and the rangers like people knowing that an animal as enigmatic and exciting as an Otter is living on this reserve in a city as busy as Edinburgh.

I decided to focus today on Otter tracking for that last reason I mentioned, they are enigmatic and exciting. However they are also a species that I don’t see a lot of and would like to learn more about. I also chose to focus on Otters today as I recently found some very fresh spraint on the Braid Burn, and funnily enough it appeared to have been placed quite purposefully on a bag of dog s**t that someone had carefully and clearly very thoughtfully placed on a rock. Either that or it’s just coincidence that the Otter has decided to place it on the bag. I’ve found a possible sign of Otters marking territory against Red Fox Vulpes vulpes in Findhorn Bay so perhaps this is a somewhat similar case?

Anyway, I passed that spraint today and actually collected it and will be taking apart later to try and see what the local Otters are eating.

I continued wading upstream from this piece of spraint to see if there were any more bits for me to see and possibly collect. Here’s a map showing where I found each of the 5 spraint sites.

spraintmap

I had thought that I’d be able to find information on the usual intervals along a watercourse that Otters spraint at, but found nothing. I’m thinking that maybe it depends on the watercourse. The close togetherness of the spraint on the Braid Burn may be due to the likelihood of other Otters discovering the area, or because it’s easier to cover the area in markers since it’s not such a big area, or because of how busy the area is (people/dog-wise)… I dunno. On the other hand, perhaps I’ve not looked hard enough for this information! I did find a couple of good sources of information on Otters; one is a little more information heavy than the other.

Anyway, from that map you can quite clearly see they are pretty evenly spaced apart (except the last two) and the pictures below give you an idea of where the spraints are being placed…

To put it simply, on rocks. I have a feeling this is actually because most of the large logs have been washed downstream by all the rain we had towards the start of the year, but I might see if there’s a running theme of my patch Otters only placing spraints on rocks.

You’ll maybe notice I have only shown 4 photos above, despite saying there were 5 spraint sites. The fifth one is actually in a spot that I’m not going to disclose because I suspect the Otters may sometimes use it as a place to lie up during the day, called a holt or a couch. I’ll maybe place my trail camera there when I get it!

Now for some dissecting of stuff that actually smells pretty surprisingly nice! I mean, it’s not the best smell but it’s not unpleasant. I’ve heard it described as smelling like jasmine tea!


 

Right, well that took a wee while to take it apart and get the bigger bits out, but I’ve managed, with perhaps slightly less signs of diet as I’d hoped. But there are still things to learn! (also, if you’re exposed to a concentrated enough amount of spraint, it begins to smell not so nice, more fishy)

For starters, here’s the spraint being broken up in some hot, disinfectant-filled water…

P1190965
Otter spraint water

Well, what did I find?

P1190968

One thing I was slightly expecting was for there to be a lot of frog bones in the fresh spraint, considering the recent spawnathon that has been under way in ponds across the country. This was the case (I think)!

P1190982
Suspected frog bone fragments

Above, from left to right:

  1. No idea
  2. Maybe the ball joints at the top of the femur?
  3. 4. 5. Think these are parts of the tibiofibula

This wee exercise taught me that frogs have tibiofibulas as opposed to a tibia and a fibula. This makes sense as it gives frogs a far better anatomy for jumping. Toads have it as well. I wonder if newts do… It would appear not.

Next up, the usual food of Lutra lutra, fish!

P1190983
Bits from Otter spraint

From top left to bottom right:

  1. Fish rib, this is the only part here that I’m pretty certain is from a fish.
  2. I think this and number 3 might be scales, but they feel very bony and hard, as opposed to slightly flexible and thin…
  3. See number 2…
  4. 5.6.7. I really have no idea what these bits are. Maybe 4 and 7 are parts of scales, after having a look with the hand lens. The hand lens has revealed that 5 and 6 are actually a bit more interesting though…

If you look at the pic below you’ll see that there are small circular things coming from this piece of bone (or cartilage or something else?). It almost looks like peas bursting from a pod.

P1190989
Anyone know?

Could this be part of a jaw? The only fish I’m aware of living in my general area are Brown Trout Salmo trutta, Stone Loach Barbatula barbatula and maybe Minnow Phoxinus phoxinus. Not sure whether that helps with ID but now you know how little I know about fish!

I have no idea what this is, so if anyone thinks they know, do tell!

The other bits and pieces are really just fragments of bone and things that I have no chance of identifying.

Anyway, I hope that wasn’t too boring. Hopefully, when I have my trail camera, I’ll be able to supplement all of this with pictures of the Otter(s?) Lutra lutra that live on my patch! And there’s always the possibility of getting Pine Marten Martes martes when I’m up in Aberdeen…

PINEMARTEN3
Pine Marten caught on trail camera on my campus
Advertisements
Otterly fascinating

2 thoughts on “Otterly fascinating

  1. julietwilson says:

    This is fascinating, I have smelt otter spraint (definitely jasmine tea!) but never dissected it. Food to know that golden plovers are still sometimes seen in Edinburgh, i used to see them regularly and in number on the fields at Silverknowes, not for many years now though

    Juliet
    http://craftygreenpoet.blogspot.com

    Like

    1. Thanks Juliet. Glad you share my interest in such things! And it’s interesting to know that you’ve noticed a lack of Golden Plovers near you. I read a sort of site description focusing on birds for my local patch and it mentioned a lot of species that definitely don’t breed in the area any more: Wood Warbler, Spotted Flycatcher, Whinchat, Stonechat, Redstart, Grey Partridge, and quite a few others. Wonder what has caused this decline in birds…

      Like

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s