What's killing the crows?

colmwexford

Hi, I'm after finding the remains of a number of dead crows around the farm in the last month, maybe 5 or 6. By the time I see them it's just normally the wings left and a pile of feathers, no carcass as such, but today I came across a dead magpie. It was half eaten and it looked like the predator had been disturbed and abandoned the kill. It was surrounded by feathers and looked like it had been plucked rather than chewed (I think). We have a pair of buzzards that regularly fly over the farm and there is also a sparrowhawk around. Could be these be the culprits?

There is also a fox den on the farm and I found a evidence for additional dead crows around the entrance (wings and feathers). Would foxes be able to hunt crows? or are they just taking other animals kills?

fryup

sparrowhawk maybe

Tiercel Dave

There are lots of young, inexperienced 'crows'/magpies around at this time of year and they fall prey to hawks etc.. I would guess the principle suspect is a female sparrowhawk and the remains are being cleaned up by foxes! Dave

Sam Kade

I've seen sparrow hawks chasing crows over the last few weeks.

Fr Dougal

I was always of the opinion that birds die during harvest season. The grain trailers drop grain along the roads, birds eat it. The grain then swells in their stomach and causes them to die or makes them easier prey to be killed. Not sure how true this is

ytpe2r5bxkn0c1

Not an overload of grain. It is the Sparrowhawk and Buzzards. Crows are a regular prey for Buzzards at this time of year.

colmwexford

Thanks for all the replies folks, much appreciated. It looks like the birds of prey are the culprits

Zoo4m8

Fr Dougal wrote: »

I was always of the opinion that birds die during harvest season. The grain trailers drop grain along the roads, birds eat it. The grain then swells in their stomach and causes them to die or makes them easier prey to be killed. Not sure how true this is

Not true...there have been hundreds of crows on my patch recently feeding on the lodged ( flattened by heavy rain) barley..we have buzzards and a resident sparrowhawk and I have not seen a single dead crow anywhere..
Maybe there is something else going on , for instance do you have a neighbour with crops that would be damaged like here and would someone be controlling crows with Alphacloralose, puts them to sleep and they die of hypothermia, not legal any more of course. Just a thought but I would be very suspicious if I found that many dead birds.

ytpe2r5bxkn0c1

The description of the corvid remains is very clearly predation by birds of prey. Crows are a large part of the diet of Buzzards. I see it in action every day.

OpenYourEyes

colmwexford wrote: »

.......a number of dead crows ...... normally the wings left and a pile of feathers, no carcass as such...............half eaten and it looked like the predator had been disturbed and abandoned the kill.........surrounded by feathers and looked like it had been plucked rather than chewed (I think).......We have a pair of buzzards that regularly fly over the farm and there is also a sparrowhawk around. .................................
There is also a fox den on the farm and I found a evidence for additional dead crows around the entrance (wings and feathers).

All characteristic signs of predation, and raptors will be having a good time of it at the moment between juvenile crows having left the nest, and there being so many crows feeding on spilt grain, fields were grass has been cut/harvested etc.

Zoo4m8 wrote: »

Maybe there is something else going on , for instance do you have a neighbour with crops that would be damaged like here and would someone be controlling crows with Alphacloralose, puts them to sleep and they die of hypothermia, not legal any more of course. Just a thought but I would be very suspicious if I found that many dead birds.

Not a conclusion we should jump to without any evidence - and there's no evidence here. The poster isn't finding full dead bodies of crows - they're finding wings without the carcass, so these birds have been eaten - predation is definitely the cause. To add to that, if Alphacloralose was being used and several crows both had access to it and were dying from it you'd likely have dead raptors and foxes etc too. If it was just grain that was poisoned you'd have dead pigeons and songbirds too.


It's predation - I envy the OP having regular visits of Buzzards and Sparrowhawks on their farm!

Sloan Panicky Satin wrote: »

Crows are a large part of the diet of Buzzards. I see it in action every day.

Just to add to that, I was visiting a Buzzards nest with an NPWS Ranger before during the breeding season - the nest was almost completely lined with black feathers from crows that had been predated by the pair - with a few rats tails and the odd rabbit scattered around the nest too. Another bird of prey thats great to have on a farm!

Zoo4m8

I envy you both (Srameen and Open Your Eyes) your experiences and certainty and how easily you dismiss sixty plus years living and working in the countryside, forty of them in this spot.
I can only relate my experiences, we have had Buzzards regularly for c.twenty years and breeding in my neighbours woodland for the last seven. I have never seen or known them to take anything other than worms and rodents. Of course they take corvids etc but I have no evidence of it here.
Regarding Alphacloralose , I put forward a suggestion , was not jumping to a conclusion ... I'm not going to get into how it can be administered to target mostly corvids..
Open You Eyes, I'm very glad you saw fit to remove the paragraph you did, I had my reply all prepared...
My final comment on this.. If I found the number of dead birds on my farm that the op has mentioned, and don't forget he said there were addional birds at the foxes den, no matter how they looked I would KNOW that something was wrong. In fact I have been meaning for a while to start a thread on how very few dead birds we come across in the countryside.
Oh yes, last Feb I found a buzzard carcase in the bottom of a ditch close to the wood they nest in , breast eaten and legs gone and I have very little idea what happened but I can make one or two educated guess's...
On a more cheerful note , four Curlews have just flown over the house, the first this year..:)

OpenYourEyes

Zoo4m8 wrote: »

I envy you both (Srameen and Open Your Eyes) your experiences and certainty and how easily you dismiss sixty plus years living and working in the countryside, forty of them in this spot.
I can only relate my experiences, we have had Buzzards regularly for c.twenty years and breeding in my neighbours woodland for the last seven. I have never seen or known them to take anything other than worms and rodents. Of course they take corvids etc but I have no evidence of it here.
Regarding Alphacloralose , I put forward a suggestion , was not jumping to a conclusion ... I'm not going to get into how it can be administered to target mostly corvids..
Open You Eyes, I'm very glad you saw fit to remove the paragraph you did, I had my reply all prepared...

My final comment on this.. If I found the number of dead birds on my farm that the op has mentioned, and don't forget he said there were addional birds at the foxes den, no matter how they looked I would KNOW that something was wrong. In fact I have been meaning for a while to start a thread on how very few dead birds we come across in the countryside.
Oh yes, last Feb I found a buzzard carcase in the bottom of a ditch close to the wood they nest in , breast eaten and legs gone and I have very little idea what happened but I can make one or two educated guess's...
On a more cheerful note , four Curlews have just flown over the house, the first this year..:)

Not dismissing your comment or experience - to the contrary I addressed it in great detail and presented the evidence that it was unlikely to be anything except natural predation.

I fully believe that your Buzzards either rarely, or at least aren't seen to take many crows - plenty of individual pairs of raptors live on more specialised diets than their conspecifics. But more generally they often do take crows, particularly at this time of year.

I removed a line from my comment having re-read your previous comment - I had taken something up the wrong way a bit. Sorry that you didn't get a chance to use your reply!

Like you said there, we don't come across many dead birds in the countryside because they are often taken by scavengers, or weak birds/mammals predated before they die of other causes. That being said, when we do come across a dead bird or animal it doesn't immediately mean foul play - particularly when they exhibit all of the classic signs of natural predation as the OP's finds did.

A dead Buzzard on your land is a completely different scenario to the one presented by the OP here. I presume/hope that if you have the slightest suspicion of foul play that you reported it to the appropriate authorities immediately.

ytpe2r5bxkn0c1

Buzzards have bred 80 yards from my front door for decades - one of the first 6 breeding sites in the republic since the 1950s - I studied birds of prey, and buzzards in particular, professionally for decades and the remains of crows as described by the OP are typical of Buzzards. Of course foul play occurs and I had the misfortune to find a poisoned Buzzard in the fields adjacent to my home 3 years ago. A buzzard I hand reared many years ago was also found poisoned 6 months after it's release in the 90s. Both were reported, investigated and action taken (no crimal charges unfortunately). However 99% of bird mortality is not deliberate nor malicious. We don't find many dead birds, mammals etc because nature tidies up after itself.

Zoo4m8

I absolutely agree, thankfully 99% of birds die naturally ( despite what some would have us believe) and indeed nature tidies up after itself which is why I find the op's discoveries a little puzzling.. Anyway this could lead off at a tangent into all sorts of tangles so I'll leave well enough alone..