Tawny Owls scavenging dead rabbits

[RobSutton]

With snow now having been on the ground for nearly four weeks a lot of our wildlife here in the Dales is really suffering. The rabbits in particular are dropping like flies and other wildlife is really struggling. As a consequence we're starting to see some quite odd behaviour. On two occasions today I have watched Tawny Owls in broad daylight scavenging on dead rabbit carcasses.

The first I think was a recent stoat kill or at least the stoat was interested in the same carcass. At about 12:30 this afternoon we were watching one owl feeding on a dead rabbit which was also taking the interest of a stoat. The owl kept trying to fly off carrying the rabbit which was obviously far too heavy for it but it did succeed in moving it 10 - 15cm along the ground each time it tried and eventually dragged it maybe 4-5m into the cover of a yew tree. All the time the stoat which I suspect may have killed the rabbit was running towards the owl and then away, obviously a bit intimidated by the owl and not wanting to get too close.

At about 3:30pm I saw another Tawny Owl feeding on another dead rabbit on another part of the estate. Don't know if this was another stoat victim or just one of the many dead rabbits that we are now starting to see. There's obviously very little food for any of them at the moment and I suspect there will be a big knock on effect on the breeding populations of lots of species next year.

It's been quite difficult for the owls over the last two seasons anyway as our woodmouse and vole populations have been very low and as far as I know non of the four or five pairs we have resident here have reared any young for the last two seasons. This hard spell could really have a devastating effect on the owls around here and it doesn't bode well for this forthcoming season.

[aeshna5]

Interesting observations Rob. It really is a worrying time at the moment with so much suffering for wildlife. At least your Tawny Owls have managed a meal from the dead Rabbits.

I'm particularly worried about the fate of Dartford Warblers. The Surrey/East Sussex popualtions crashed by over 80% after last Feb's snow. This winter the snow has hit everywhere + wonder how many will remain? Yes they can probably bounce back again, but it takes time.

[RobSutton]

Originally Posted by aeshna5

Interesting observations Rob. It really is a worrying time at the moment with so much suffering for wildlife. At least your Tawny Owls have managed a meal from the dead Rabbits.

I'm particularly worried about the fate of Dartford Warblers. The Surrey/East Sussex popualtions crashed by over 80% after last Feb's snow. This winter the snow has hit everywhere + wonder how many will remain? Yes they can probably bounce back again, but it takes time.

That would be a real shame as they seem to have done very well over the last thirty years. If it carries on much longer I think we could be seeing something similar to the crashes we saw in the 1960's in populations of wren, goldcrest and lots of other insect feeders too.

I'm pretty sure that some of the other things that have only recently colonised the higher parts of the Dales (butterflies like Comma, Speckled Wood and Orange-tip were unknown here 20 years ago) will be badly affected also.

[Gaina]

Staying with Owls but shifting species for a moment, so forgive me but I just read something by the Barn Owl Trust with regard to supplementary feeding and it's been a real success so they've produced a PDF document advising people on the subject .

The link doesn't work so just go to the 'Barn Owl Trust' at it's easy enough to find the pdf from there.

Wonder if it would/could work for Tawny's?

[RobSutton]

Originally Posted by Gaina

Staying with Owls but shifting species for a moment, so forgive me but I just read something by the Barn Owl Trust with regard to supplementary feeding and it's been a real success so they've produced a PDF document advising people on the subject .

The link doesn't work so just go to the 'Barn Owl Trust' at it's easy enough to find the pdf from there.

Wonder if it would/could work for Tawny's?

If the population of mice and voles is very low then you'd be committing yourself to feeding for a long time and I suspect Tawny Owls are not scarce enough to justify people doing it.

I'm just hoping that as they are long lived birds a couple of poor seasons won't have too big an effect. The problem this year could be that if they succumb to the cold this winter then as it's such an isolated woodland c5 miles to nearest woodland then recolonisation could be difficult.

[Gaina]

Originally Posted by RobSutton

If the population of mice and voles is very low then you'd be committing yourself to feeding for a long time and I suspect Tawny Owls are not scarce enough to justify people doing it.

I'm just hoping that as they are long lived birds a couple of poor seasons won't have too big an effect. The problem this year could be that if they succumb to the cold this winter then as it's such an isolated woodland c5 miles to nearest woodland then recolonisation could be difficult.

Saying as it's staying cold at the moment so adult prey animals aren't coming out of hibernation early to possibly get caught out and die when it turns cold again like we've seen in recent years, do you think this may result in more for the owls to eat and feed their young when they start breeding?

...did I completely mangle that question or do you understand what I'm trying to say?

[RobSutton]

Originally Posted by Gaina

Saying as it's staying cold at the moment so adult prey animals aren't coming out of hibernation early to possibly get caught out and die when it turns cold again like we've seen in recent years, do you think this may result in more for the owls to eat and feed their young when they start breeding?

...did I completely mangle that question or do you understand what I'm trying to say?

It's fine the question makes good sense but the things that owls eat - woodmice, voles and shrews, don't hibernate so I think the hard weather will knock back numbers quite considerably. We survey the small mammals (using live mammal traps - Longworth Traps) fairly regularly and after last years hard spell we didn't catch any mice or voles until probably May. They must have still been there but the population was so low we weren't picking them up and this will be why the Tawnies didn't breed. By October the small mammal population had picked up quite well but this will hit them hard again I think.

[Dogghound]

Most of a tawny owls prey consists of woodmice, bank and field voles none of which hibernate (although can go into a torpid state). In most cases small mammal populations decline towards the end of the winter, resulting in more day active or odd acting owls. By the time chicks are born prey is starting to increase in number again. Clearly its hard to predict the population dynamics for an area we dont know (apart from Rob) but I would have thought that this behaviour is short term as a result of less above ground small mammal activity, being harder to hunt etc. I would think small mammal populations would get through short term sudden cold snaps fine. Alot is dependant on predation, disease, habitat quality, food availability in the summer to get a large base population for the winter to breed in the spring.

[RobSutton]

Originally Posted by Dogghound

Most of a tawny owls prey consists of woodmice, bank and field voles none of which hibernate (although can go into a torpid state). In most cases small mammal populations decline towards the end of the winter, resulting in more day active or odd acting owls. By the time chicks are born prey is starting to increase in number again. Clearly its hard to predict the population dynamics for an area we dont know (apart from Rob) but I would have thought that this behaviour is short term as a result of less above ground small mammal activity, being harder to hunt etc. I would think small mammal populations would get through short term sudden cold snaps fine. Alot is dependant on predation, disease, habitat quality, food availability in the summer to get a large base population for the winter to breed in the spring.

I'm sure you're right about why the owls are taking rabbit carcases. Having complete and such deep snow cover for such a long period (four weeks now) hasn't happened for a long long time and it will be interesting to monitor both owl and small mammal populations over the next six months.

Over the last couple of years the pick up in small mammal populations in spring seems to have been far too late and as far as we know the Tawny Owls haven't even tried to nest as shown by a distinct lack of territorial behaviour in the early spring. Presumably they are assessing the productivity of their prey before deciding whether to lay or not. I think the small mammal populations here have been at a low point in their population cycle for a couple of years and the cold winters are stopping them recovering properly.

[Gaina]

Thanks Dogghound and Rob. I find this very interesting . I just joined the Hawk and Owl trust so I'm sure I'll learn a lot more very soon.

Can people do anything in their own gardens to help out woodmice and field voles (assuming they live in an area suitable for those species)?