The only good magpie is a...?

6 Dec 2011

Back in the late 1950s, when I was about 12-years-old, the local NFU office gave you a crispy 10 shillings note for a dead magpie. Now 10 shillings (equivalent to 50p) doesn’t sound a lot, but then you could take a bus into town, go to the cinema, have fish and chips and still get home with change. Or is that the opening line from a Monty Python sketch...?

I also remember waking up to deafening dawn choruses. According to statistics it was the halcyon days of farmland birds.

Can these two observations be just coincidental? Did a lack of predators, like magpies, enable farmland birds to flourish? Or, are there other factors involved in the decline in farmland bird numbers over the past forty years? 

I’m now old enough to know that nothing is that simple, but there is now a vigorous debate on the role of predators with regard to the decline of farmland birds. As a non-expert reading experimental results and listening to both sides of the debate, I think those who argue for predator control have the stronger case.

However, resolving this issue appears to be challenging for the RSPB. Sometimes it seems that it is totally against predator control, and sometimes the charity appears to say that if you want to control predators then go ahead; after all predator control is carried out on some of the RSPB’s reserves. The lack of a clear message might be due to differing internal views.  And, of course, predator control could be unpalatable for many of those who support the charity organisation.

But as I suggested earlier, the decline in farmland birds is bound to be much more complicated than just a single factor.

Pesticides seem to be the first port of call by the media when any environmental problem is reported. The 1950s and 1960s were also the halcyon days of organochlorine and organophosphate availability. And there’s proof that some of these insecticides may have had a direct impact on bird fertility, including reducing the thickness of egg shells. DDT was also used as a herbicide as late as the mid-1970s; in wheat DDT could control susceptible barley varieties.

The generally agreed position is that pesticides didn’t directly contribute to the decline in UK farmland bird numbers. However, one of the major factors in the decline has been land use change facilitated by pesticides.

I was reminded of the extensive availability of organochlorine and organophosphate insecticides in the late 1960s and early 1970s by reading the 1970 Approved Products for Farmers and Growers Guide. Someone lent me it as a result of my previous blog ‘What’s in a name?’ I hope say more about the contents of this publication at a later date.

By the way, as I walked back from the paper shop this morning there were five magpies standing on the road...