Scare & Sensitive

I have referred to a “cool/scarce and sensitive” species which I have been watching this winter. You may have already guessed that they were Long-eared Owls. I stumbled upon a roost in early January and was able to follow it for many weeks. There were 1-4 birds using the roost on a daily basis with normally 3 to be found and on only one occasion there were none (and I used this opportunity to go in and collect a pellet). I discovered the roost without needing my thermal imager although it was extremely useful in helping me to thoroughly check the area and in the evenings to follow the birds.  The roost had broken up by the end of February and I thought this was because they were paired up and thinking of breeding but evening visits failed to reveal any singing birds. Towards the end of Feb there had been an increasing number of records of clearly hungry Long-eared Owls turning up daytime or being found injured around the coast of Norway so I think the birds vanishing from the roost is most likely because they have moved on searching for food. It is clearly not a rodent year in southern Norway with very few records of singing owls of any species and they are probably just thinking about surviving rather than passing on their genes.

The roost was surprisingly close to a footpath and it is rather amazing that it wasn’t discovered by others especially as I know that the initial sighting in December attracted a lot of attention. It would have been nice to share the information and allow others to enjoy these charismatic birds but unfortunately the population of undisciplined toggers in Oslo is growing far too quickly and their behaviour with the Bearded Tits (tramping down the reedbed to get a slightly better picture) and Hawk Owl (surrounding it and throwing out dead mice on fishing line) this winter meant that there was absolutely no way they could be allowed to know about the roost.

The four birds were all different in plumage with one being especially dark and another especially pale. According to the literature females are darker than males and I am quite sure there were 2 males and 2 females. They were also different in how shy they were. The 2 presumed females seemed to be unaffected by people or dogs in their vicinity whereas both the males (paler birds) were far warier with one in particular often flying off deeper into scrub and being therefore the bird seen least often.

I find it fascinating to wonder how these communal roosts form  - how do the birds find each other? Is this a roost that has been used before? Why did they chose an area close to people when they had a vast choice of more secluded areas near by? Did the fact that I never saw them hunting in daylight and that they would wait until long after sunset to leave the roost mean that they were not having problems finding food?

I had 4 visits after dark two of which revealed no birds and 2 revealed birds hunting from either posts or trees. I had expected to see birds hunting in flight but maybe with the snow there were not rodents to be found in the open areas. I also stayed by the roost until after sunset on three occasions with the birds only becoming active about 30 minutes after sunset and after some preening they would silently fly off and only once did I then refind a bird which I watched and filmed hunting.

I of course took far too many photos and videos and here is a (too) quickly chosen selection shown in more or less chronological order although the videos are randomly inserted with the 4 best at the beginning

3 birds together

here are the two palest birds which must be males

the darkest bird and presumed female

the second dark(er) bird

I very rarely saw them in flight and this was the only picture I got

the darkest bird

a thermal imager picture of one of the birds hunting from posts near a house

the darkest bird and the one that often perched most in the open and closest to the path

2 birds in snow

the darkest bird again

the second dark bird

the darkest bird

and the two dark birds together (darkest is lowest)

the darkest bird now with one of the paler birds

a great comparison of male and female

darkest bird

two birds in this picture

easier to find them in the thermal imager

a pale bird

and this is I think the second darker bird. I have not spent a lot of time studying my pictures trying to individually identify the birds I saw on different days but some of the birds have been difficult to classify as dark or pale which makes me wonder whether more than 4 birds have actually used the roost

There was only one occasion when I had a bird active during the day. Here it is in the open and had been mobbed by a Magpie and adopted a very thin and upright stance