Kestrels & Sparrowhawk questions

[FUDGEY]

I have been having a discussion about these birds numbers and was wondering your thoughts on it. Kestrels have declined at an alarming rate around my area and I believe across the UK too and I cant think of a good reason why. I also think Sprawks have increased over the last few years, but I do have a theory on this one. I think its because the prey items are surviving Winter better these days because of the number of people feeding these birds through hard times. I would be interested to know an estimate of the tonnage sold say 20 years ago, 10 years ago and last year to see how much it has increased. Id bet it is a huge amount. What are your thoughts on this folks?

[Lemars]

Makes perfect sense to me - I buy at least one of those tons annually !!

C

[FUDGEY]

Double that for me

[mpiekp]

Think your right on the sprawk.
With kestrels, latest thoughts are the recent trend for long grass road verges has impacted, as they need shorter grass to hunt in.

[FUDGEY]

Very interesting that, Im sure it wont just be one factor but a combination of several. That is one that could have a bearing on numbers for sure. Thanks

[King Edward]

I'm not aware that the populations of either species have changed that much in the last 15-20 years, going by BTO data up to 2007 here: Kestrel, Sparrowhawk. Maybe there are more up-to-date figures elsewhere but I'd be wary of reading too much into short trends which could be unduly influenced by the weather.

I suppose that bird feeding might benefit Sparrowhawks, especially in urban/suburban areas, by increasing prey numbers and providing easy hunting locations, but that's got to be set against population declines in many species in the general countryside. So perhaps Sparrowhawks could become more visible as a result of hunting in gardens (especially the gardens of keen birders who put out lots of food), while not being more abundant overall.

[aeshna5]

The data does show a 25-50 % decline for Kestrel over the last c30 years which is why it has been Amber listed, though the trough does appear to have flattened out a bit.

Recent BTO data has also shown a small decline for Sparrowhawk.

[aeshna5]

Originally Posted by mpiekp

Think your right on the sprawk.
With kestrels, latest thoughts are the recent trend for long grass road verges has impacted, as they need shorter grass to hunt in.

But surely the long grass is where voles + other rodents will be found. You won't get many on the road equivalent of a lawn.

[Dogghound]

Originally Posted by FUDGEY

Kestrels have declined at an alarming rate around my area and I believe across the UK too and I cant think of a good reason why.

Kestrel have declined largely through agricultural intensification and loss of suitable hunting and breeding habitat.

Originally Posted by FUDGEY

I also think Sprawks have increased over the last few years, but I do have a theory on this one. I think its because the prey items are surviving Winter better these days because of the number of people feeding these birds through hard times.

The increase is probably just numbers returning to a normal levels after recent history (DDT, Persecution etc) suppressing the population. The recent small decline may be due to the population tailing off. Im not sure song birds are at an all time high considering the declines in farmland and more recently woodland species. Although some species are increasing/stable at high levels like blue tits, blackbirds etc.

[Dogghound]

Originally Posted by aeshna5

But surely the long grass is where voles + other rodents will be found. You won't get many on the road equivalent of a lawn.

I agree.

Long grass over 2 years old is optimum for field voles, they need at least one years growth prior to establishing themselves. This grass litter is where they live and is important to their biology. It is important that longer grass 2-5 years is maintained before it starts to turn ito scrub which is less often used for foraging. Cropped grassland has far fewer small mammals.