The Barn Owls of London only fly at night - any thoughts

[Deb London]

When I've seen Barn Owls flying, it has been in the afternoon or evening, in fairly well-lit conditions. I've only seen a few in my time. I was intrigued to learn that there are Barn Owls to be found near where I live. But they are only ever seen at night. No one knows where they breed. I know, it sounds like an urban legend. But I have it on good authority.

I was wondering it there might be a reason for them only showing at night. Proximity to the urban environment maybe.



Any thoughts greatly appreciated.

Thanks.

[Hobjob]

They don't usually hunt much in the day. Dawn, Dusk and night is 'their' time, even in the country.

They hunt by sound and sight, so in London I'd expect them to only hunt at night when things are a bit quieter.

[RoyW]

I have quite regularly seen Barn Owls during the day within a mile of the M25 (both sides), and am aware of occasional sightings during the day further south in the Lea Valley.

It does seem far easier to see Barn Owls in day time in some other areas, and this is probably linked to disturbance (including the potential problems with noise mentioned by Hobjob).

[Dogghound]

Originally Posted by Deb London

When I've seen Barn Owls flying, it has been in the afternoon or evening, in fairly well-lit conditions. I've only seen a few in my time. I was intrigued to learn that there are Barn Owls to be found near where I live. But they are only ever seen at night. No one knows where they breed. I know, it sounds like an urban legend. But I have it on good authority.

I was wondering it there might be a reason for them only showing at night. Proximity to the urban environment maybe.



Any thoughts greatly appreciated.

Thanks.

It is not quite as black and white as this Deb. Barn owls ecologically are influenced by a number of factors which influence feeding times, these can change throughout the year or from year to year. I will try and explain.

As mentioned disturbance can play a part in activity periods, areas frequented by people such as dog walkers, ramblers etc or areas with agricultural activities, industrial activities, shooting, lots of noise etc can make barn owls hunt nocturnally, or early morning/late evening when levels of human disturbance are low. Additionally on some sites i.e. near landfill sites, near urban parks which have high densities of gulls or corvids can make barn owls more nocturnal to avoid them being mobbed and attacked. As indeed can areas with lots of diurnal raptors such as kestrels which will rob barn owls of prey and mob them or areas with peregrine which will actually predate barn owls.

Disturbance is not the only factor though and barn owls can be found in areas such as the sides of busy roads and brown field sites which seem to have high levels of disturbance. Habitat quality plays a major role in barn owl behaviour, good habitats with large prey densities require less effort (time) hunting and they can get what they need within a night. Poor habitats with lower prey numbers may result in the barn owl having to hunt longer into the day and into unfavourable hunting times. This is also influenced by prey cycles and habitat succession/change(field voles) so one year a habitat may be good but the next poor, causing changes in hunting behaviour over a small time scale. In some cases it may be more gradual and the owl will slowly start to hunt longer during the day over progressive years. A poor intensive arable landscape with spread out field margins will take longer to hunt than a rich area of riparian grassland, influence huting into the day.

Time of year influences activity, for example when they are feeding young more prey needs to be captured resulting in hunting around the clock. This often leads to birds hunting earlier in the afternoon to supply food for nestlings, especially as they grow older and have a higher food intake. Winter may result in higher prey mortality which results in more hunting time being required, especially towards the end of winter when barn owls are often very diurnal.

Weather also plays a part, prolonged wet weather and wet nights prohibit hunting. So hunting often has to extend into the day to compensate for losing time during the night. Excessive snow cover make hunting harder which means more time is required and hunting again often extends into the day. The opposite can be said for dry warm nights when hunting is done at night without the need to risk daytime hunting.

There are one or two other factors, perhaps not as relevant such as condition of the bird etc.

[Deb London]

Thanks all very much.

There are lots of Kestrels and a murderous () number of Carrion Crows, Jays and Jackdaws in the area. It might well be that they do not want to get mobbed. Interesting. Furthermore, I have no details as to how long they may have been in the area, it may well be that they become (or are forced to become) bolder. The area is well watched though and the people who told me sensible enough to make me think that Barn Owls are never seen after sunrise, for however many years this has been.

[Hobjob]

The other thing not yet mentioned is prey availability.

Their chief diet, the field vole, goes through natural massive three yearly cycles of population explosion and collapse. Last year was a good year, but came after two harsh winters which is bad for the Barn Owls - especially if snow hampers feeding.

Perhaps the two harsh winters have caused the youngsters to move towards London? Adults establish territories and don't move much after that.